All in one

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Epidemiology of Risk Factors
and Communicable Disease – 1
48 Hours
Upendra Raj Dhakal
urdhakal@gmail.com
Lecturer: Valley College of Technical Sciences
Draft version 2.1
Concept of Epidemiology
• In Greek Word,
• Epi – on or upon/among
• Demos – People
• Logos – Study
• Word meaning says, Epidemiology is a study done upon people.
• Epidemiology is the basic science of Public Health.
Draft Version 2.1 (Feedback Welcomed) 2

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What is Epidemiology
• Epidemiology is the study of the distribution and determinants of
health related states or events in specified populations, and the
application of this study to the control of health problems (Last,
1988)
• The branch of medical science which treats epidemics (Oxford English
Dictionary)
• Epidemiology is the study of Epidemics and their prevention (Kuller
LH: American J of Epidemiology 1991; 134:1051)
• The study of occurrence of Illness (Anderson G. In: Rothman KJ:
Modern Epidemiology)
Historical Development of Epidemiology
• Hippocrates (460 – 377 BC): Malaria associated with swampy environment.
• John Graunt (1662): “Nature and Political Observations Made Upon the Bills of Mortality” – First
to employ quantative methods in describing population vital statistics.
• Edward Jenner in late 18th century: Cow pox protects from small pox; first vaccination.
• John Snow (1850): Formulated natural epidemiological experiment to test the hypothesis that
cholera was transmitted by contaminated water.
• Ignaz Semmelweis in 19th century: Childbed fever (puerperal sepsis)
• Florence Nightangale: Epidemic typhus during war of Crimean in mid 19th century.
• Doll & Hill (1950): Used a case control design to describe and test the association between
smoking and lung cancer.
• Frances et. al (1950): Huge formal field trial of the Poliomyelitis vaccine in school children.
• Dawber et. al (1955): Used the cohort design to study risk factors for cardiovascular disease in the
Framingham Heart Study.

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John Snow and Cholera
• Cholera epidemics in London 1846 – 1849
• Snow analyzed the death records and interviewed
survivors
• Created map
• Most individuals who died of cholera used water
from Broad street pump
• Survivors did not drink water but beer instead or
used another pump
• Identified the Broad street water pump as likely
source
• After closing this pump number of cholera cases
dropped significantly
Florence Nightingale and Epidemic Typhus
• Recorded statistics on epidemic typhus in
English civilian and military populations
• Published a 1000 page report in 1858:
oStatistically linked disease and death
with poor food and unsanitary
conditions
oNovel graph: coxcomb chart or polar
area diagram chart
➢Fixed angle and variable radii
• Resulted in reforms in the British Army
• Nightingale became the first female
member of the StatisticalSociety

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Scope of Epidemiology
• Disease definition: Characteristics or Combination of character that best
discriminate disease from non disease
• Disease occurrence: The rate of development of new case in population. The
proportion of current disease within population
• Disease causation: The risk factors for disease development and their relative
strength with respect to an individual and population
• Disease outcome: The outcome following disease onset and of the risk factors
• Disease management: The relative effectiveness of proposed therapeutic
interventions
• Disease prevention: The relative effectiveness of proposed preventive strategies
including screening
These Scope can be classified into Classical Epidemiology, Clinical Epidemiology
and Research which are eventually are applied
Purpose of Epidemiology
• To investigate nature/extent of health – related phenomena in the
community.
• To study natural history and prognosis of health – related problem.
• To identify causes and risk factors.
• To recommend/assist in application of/evaluatebest interventions
(preventive and therapeutic measures)
• To provide foundation for public policy.

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Use of Epidemiology
• To find the causation of the disease.
• To describe natural history of disease.
• Description of health status of population.
• Evaluation of intervention.
• Community diagnosis
• Planning and evaluation
• Investigate epidemics of unknown etiology
• Elucidate mechanism of disease transmission
Aims of epidemiology
• To describe the health status of a population
• To access the pubic heath importance of disease
• To describe the natural history of disease
• To explain the etiology of disease
• To predict the disease occurrence
• To evaluate the prevention and control of disease
• To control the disease distribution
Descriptive epidemiology
Draft Version 2.1 (Feedback Welcomed)
Analytical epidemiology
Applied/Experimental/Int
erventional epidemiology
Descriptive epidemiology
10

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Types of Epidemiological Studies (Design)
Study
Observational
Analytical
Cross sectional
study
Longitudinal
Study
Case Control Study
Cohort Study (Retrospective and
prospective)
Descriptive
Case Study
Case Series Study
Cross – sectional Study
Ecological/Correlational
Study
Experimental
Randomized Control Trial (RCT)
Quasi Experimental
Community Trial
Field Trial
Populations
(Correlational studies),
and Individual
Study of
occurrence
and
distribution of
disease
Further studies
to determine the
validity of a
hypothesis
concerning the
occurrence of
disease
Deliberate
manipulation of the
cause is predictably
followed by an
alternation in the effect
not due to chance
It is applied or
interventional
type of study
Endemic, Epidemic/Outbreak and Pandemic
• Pandemic: A worldwide epidemic affecting an exceptionally high
proportion of the global population.
• Endemic: The habitual presence (or usual
occurrence) of a disease within a given
geographic area.
• Epidemic: An increase in incidence above the
expected in a defined geographic area within a
defined time period. It is the occurrence of an
infectious disease clearly in excess of normal
expectancy, and generated from a common or
propagated source.

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Spectrum of Health and Disease
• It is a graphical representation of variation of disease manifestation,
which is similar to the spectrum of light. It is called spectrum, because
there is no clear cut demarcation between the health and disease
status and we cannot determine where one ends, and another
begins.
Optimum health
Better health
Normal health
Health & Disease Disease with undiagnosed
Disease with diagnosed
Severe disease
Death
Few terminologies used in this subject
• Clinical Features (Signs and Symptoms)
• ….
• Pathogenesis and Pathophysiology
• …..
• Vaccination and Immunization
• …..

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Unit 1: Introduction to communicable disease and
risk factors
Unit 1 (8 hours) Draft version 2.1
Upendra Raj Dhakal, Lecturer VCTS
urdhakal@gmail.com
15
Definition of Communicable disease
• A communicable disease is a disease that spreads from one person
or animal to another. Pathogens such as viruses, bacteria, fungi,
protozoa, multicellular parasites, and aberrant proteins known as
prions cause these diseases.
• AKA infectious disease or transmissible disease
• There should always be an agent factor for the occurrence of
(communicable) disease
• Even if the host is infected, it may not have disease

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Contd …
• An illness due to a specific infectious agent or its toxic products that
arises through transmission of that agent or its products from an
infected person, animal or inanimate reservoir to a susceptible host;
either directly or indirectly through an intermediate plant or animal
host, vector or the inanimate environment.
• A communicable disease is one that is spread from one person to
another through a variety of way that include: contact with blood and
bodily fluids, breathing in an airborne virus, bite of an insect
• Communicable disease is caused by bacteria, viruses, parasites or
fungi.
• Communicable disease can be transmitted directly (human – human),
or indirectly.
• Organisms that cause communicable disease are known as pathogens
Natural History of Disease
It signifies the way in which disease evolves
over time from the earliest stage of its pre-
pathogenesis phase to its termination, as
recovery, disability or death, in the absence
of treatment or prevention

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Natural History of Disease
Stage of
susceptibility
Stage of
sub – clinical disease
Stage of
clinical disease
Stage of recovery,
disability or death
Exposure
Pathologic
Changes
Onset of
symptoms
Usual time of Diagnosis
(Early Dx) (Late Dx)
Primary prevention aims to
reduce occurrence
Secondary prevention aims to
reduce severity
Tertiary prevention aims
to reduce disability and
mortality
Health
Promotion
Specific
protection
Early detection
and treatment
Disability limitation Rehabilitation
Positive
health
Levels of prevention
19
Stages/Phases of Natural history of disease
• Pre – pathogenesis phase
• Pathogenesis phase
• Post – Pathogenic Phase

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Pre Pathogenic Phase - Natural History of Disease
• Disease agent has not entered
the host, but factors favoring
disease exist in the environment
• In order to enter into the
pathogenic phase, there must be
appropriate interaction between
agent, host and environment.
• Situation also referred as “Host
exposed to the risk of disease”
Epidemiological Triad
Pathogenic Phase - Natural History of Disease
Reversable Phase
1. Incubation Period: Infection occurs but no symptoms
2. Prodromal Stage: Onset of symptoms and appearance of characterstics. Eg
between coryza and rash appearance in measles.
3. Stage of Overt Disease: The sign and symptoms are at peak. It is also known
as period of illness
4. Stage of deffervescence: The sign and symptoms start decreasing. It is also
known as period of decline
Non Reversable Condition leads to recovery, death, chroinc disease, disability or
coma

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Post – Pathogenic Phase – Natural HD
• Stage of Convalescence:
• Recovery
• Disability/chronic disease/Coma
• Death
Pathogenic Micro organisms
• Organisms can be classified into micro and macro according to their
size
• Micro organisms are only visible under microscope
• If the organisms cause disease, they are called pathogenic organisms
• Pathogenicity is the potential disease causing capacity of the
organism
• Virulence is the tendency of a pathogens to reduce the fitness of
host, many times used interchangeably with pathogenicity
• If the organism are microscopic and cause disease, it is than called as
pathogenic microorganisms

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Types
• Prokaryotic:
• Bacteria
• Archaea
• Few Eukaryote (most protists, some fungi and even parasites)
• Virions and Virus : Generally not regarded as microorganism, as they are
regarded non living, so they are neither prokaryotic nor eukaryotic.
Regardless of above classification,as pathogenic micro organisms, we deal
with Bacteria, Fungi and Viruses, and ignore macro organisms, protozoa and
worms
Koch’s Postulates
• The suspected pathogen must be found in every case of disease and
not be found in healthy individuals.
• The suspected pathogen can be isolated and grown in pure culture.
• A healthy test subject infected with the suspected pathogen must
develop the same signs and symptoms of disease as seen in postulate
1.
• The pathogen must be re-isolated from the new host and must be
identical to the pathogen from postulate 2

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How pathogens cause disease
• The ability of a microbial agent to cause disease is called pathogenicity, and the
degree to which an organism is pathogenic is called virulence
• Pathogens enter the body through portals of entry and leave through portal of
exit. The stage of pathogenesis include exposure, adhesion, invasion, infection
and transmission.
• Pathogens generally create pathological changes, structural deformities, related to
the disease.
• Infection might occur when the pathogens change their site (within the body or
transmitted from others.)
• Pathological changes brought by toxic substances produced by microorganism
generally when reaches the saturation level, incubation/windows period begins.
• Secondary infection can sometimes occur after the host’s defense or normal
microbiota are compromised by a primary infection or antibiotic treatment.
• Infection can be local, focal or systemic
Contd …
• Infection does not necessarily lead to disease.
• Infection occurs when viruses, bacteria, or other microbes enter your
body and begin to multiply.
• Disease, which typically happens in a small proportion of infected
people, occurs when the cells in your body are damaged as a result of
infection, and signs and symptoms of an illness appear.
• In response to infection, your immune system springs into action.
• White blood cells, antibodies, and other mechanisms go to work to rid
your body of the foreign invader.
• Indeed, many of the symptoms that make a person suffer during an
infection—fever, malaise, headache, rash—result from the activities of
the immune system trying to eliminate the infection from the body.

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Contd …
• Pathogenic microbes challenge the immune system in many ways.
• Viruses make us sick by killing cells or disrupting cell function.
• Our bodies often respond with fever (heat inactivates many viruses), the secretion of a
chemical called interferon (which blocks viruses from reproducing), or by marshaling the
immune system’s antibodies and other cells to target the invader.
• Many bacteria make us sick the same way, but they also have other strategies at their
disposal.
• Sometimes bacteria multiply so rapidly they crowd out host tissues and disrupt normal
function. Sometimes they kill cells and tissues outright.
• Sometimes they make toxins that can paralyze, destroy cells’ metabolic machinery, or
precipitate a massive immune reaction that is itself toxic.
• Some fungus transmits histoplasmosis, grows in soil contaminated with bird or bat
droppings. Spores of the fungus emerge from disturbed soil and, once inhaled into the lungs,
germinate and transform into budding yeast cells. In its acute phase, the disease causes
coughing and flu-like symptoms. Sometimes histoplasmosis affects multiple organ systems
and can be fatal unless treated.
Microbiology in disease prevention and control
• Public Health Microbiology laboratories play a central role in
detection, monitoring, outbreak response, and providing scientific
evidence to prevent and control infectious disease
• Early detection and diagnosis
• Surveillance, screening and alerting
• Outbreak detection and management
• Antimicrobial stewardship (support/response)
• Infection control committee participation
• Education
• Controlling Microbial Agents, vaccination
• Waste management

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Pathogenesis – according to unit 2 and 3
Will be done separately in unit 2 and unit 3
Pre Pathogenic and Pathogenic
Done in Natural History of Disease

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Determinants of communicable disease
• Imbalance in epidemiological triage
• Social determinants: poverty, illiteracy, gender inequality and rapid
urbanization, climate change
• Cultural determinants: feeding habit, habitat, alcohol consumption, etc
• Behavioral factor: Working condition and exposure
• Biochemical change within the body
• Transportation of agents from one part of the body to another
• Emergence of new disease and viral mutations
• Privatization of health (unequal access)
• …..
Classification of Communicable Ds acc to micro organisms
• Bacterial infection: Survive on appropriate media, stain gram positive
(retain color of crystal violet dye) or negative (does not retain). Eg.
Leprosy, TB, etc
• Viruses: Obligate intracellular parasite which only replicate
intracellularly (DNA and RNA). Eg. COVID, chickenpox, flu, etc
• Fungi: Non – motile filamentous, branching strands of connected
cells. Infectious fungal infection are of two types: Yeast (unicellular)
and molds (multicellular). Eg. Athletes foot, ringworm, etc
• Protozoal infection: Single celled, microscopic organisms.
• Prions disease: Prions are abnormal, transmissible agents that are able to induce abnormal folding of normal
cellular prion proteins in the brain, leading to brain damage and the characterstics SS of disease. Prion
disease are usually rapidly progressive and always fatal.

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Modes of Transmission
Direct Transmission Indirect transmission
Direct contact (Skin – Skin, Mucosa –
Mucosa, Mucosa – Skin)
Vehicle Borne (Water, Blood or organ
transplantation)
Droplet infection (Tears, salivary
droppings,…)
Vector borne (Mechanical/Biological)
– Arthropods or any living carriers
Contact with soil (hookworm,
tetanus)
Air Borne (Droplet nuclei/dust)
Inoculation into skin or mucosa (dog
bite, injections)
Fomite borne (soiled clothes, linen,
cups, spoon, pencils, etc)
Transplacental (vertical) (varicella,
syphilis, HIV)
Unclean hands and fingers
Environmental:eg. hospital based – nosocomial or intragenic infections
MoT: Fecal – Oral route of transmission (5F)

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Risk Factors
• Risk Factor are determinants or variable associated with an increased
risk of disease or infection. It can be anything like age, gender, habit
and habitat,etc.
• Common risk Factors
• Modifiable risk factors: Overcrowding, Malnutrition, physical activity, etc
• Unmodifiable risk factors: Age, gender, family history, etc
• Risk factors can also be classified as:
• Category 1: Factors for which interventions have been proven to lower risk
• Category 2: Factors for which interventions are likely to lower risk
• Category 3: Factors for which modifications may lower the risk
• Category 4: Factors for which modification is not possible
Risk factor prevention and control of disease
• Eliminating the risk factors if possible
• If not possible to eliminate the risk factors, mitigating it
• It can be done within 5 levels of prevention
• Primordial: Preventing the risk through behavior change mitigation. Education,
legislation.
• Primary: Preventing disease before the onset. vaccination
• Secondary: By reducing the impact of a disease or injury in community. Screening.
• Tertiary: Soften the ongoing illness and help community to function and maintain the
quality of life. Eg. Vocational rehabilitations,
• Quaternary: Preventing unnecessary tests and experiments

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General Principle of prevention and control of disease and their
risk factors
(Difference between prevention and control)
Prevention Outbreak Control
Risk Factors
Primordial : People with harmful lifestyles
Primary : Anti Immunization, laggards or not seeking treatment.
Secondary : Unpreparedness for Early diagnosis and prompt treatment.
Tertiary : compromise with disability and mortality, rehabilitation as a course of treatment
Quaternary : Dr. swapping behavior
41
General principle of prevention of disease
• Primordial: Health promotion and prevent disease which has not appeared
yet. Eg. Encourage good habits and discourage harmful
lifestyles
• Primary: Primary prevention aims to reduce occurrence. Eg. Immunization,
chemoprophylaxis. It is carried with two strategies
(Population/mass strategy and High risk stratigy)
• Secondary: Secondary prevention aims to reduce severity. Early diagnosis
and prompt treatment.
• Tertiary: Tertiary prevention aims to reduce disability and mortality,
rehabilitation
• Quaternary: Prevent with the burden of unnecessary trials and burden.
(support/palliativecare)

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For communicable disease
Agent
Reservoir
Portal of
exit
MoT
Portal of
Entry
Susceptible
host
Breaking the chain
of
infection/interveni
ng in Natural
history of disease
43
Breaking the chain of Infection

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Contd …
Balancing the Epidemiological triage
45
General Principles for the control of disease
• To lower the incidence, prevalence, duration, infectivity, morbidity, mortality,
other effects and financial burden of the disease to a level that no longer is
problem to the country
• When disease is under control, the control measures normally have to be
continued indefinitely, since the incidence may start to rise again if they are
stopped
• Ideally, we would like to eradicate all communicable disease, but in practice this is
only occasionally possible, like smallpox
• The methods used to turn the ecological “balance” against the agent by
attempting to break the transmission cycle operate at one of the three points by:
• Attacking the source
• Interrupting the route of transmission
• Protecting the susceptible host

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Contd ….eg
Attacking the source Interrupting the transmission Protecting the susceptible host
Treatment of cases and carriers Environmental hygiene Immunization
Isolation Personal hygiene Chemoprophylaxis
Surveillance of suspects Vector control Personal protection
Reservoir control Disinfection and sterilization Better nutrition
Notification Population movements
It should be defined on the bass of different levels of prevention
Primordial prevention: ………..
Primary prevention: ………..
Secondary prevention: …………
Tertiary prevention: …………
Quaternary prevention: ……….. 47
Attacking the source
Treatment of cases
• If sufficient clinical cases can be treated with chemotherapeutic drugs
that are effective against the organism, than these organisms cannot
spread to new hosts. Eg. TB, Leprosy
• This is called mass treatment and its effectiveness depends on the
coverage that can be obtained over all the infective cases in the
community
• Good to note down
• Clinical Infection
• Subclinical infection

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Contd ….
Subclinicalcases and carriers
• The same applies to subclinical cases and carriers as to the treatment of clinical
cases. But with these patients special efforts have been made to find them first,
as they do not usually present with any apparent illness. Eg. Subclinical infectious
hepatitis, or ancylostomiasis
• The most important method for finding subclinical case is through contact
tracing. This means going to each clinical case, getting from the case the names of
all the contacts, finding those people and doing something about their exposure
testing surveillance, prophylaxis, etc)
• In addition to contact tracing, screening method and surveys/surveillance may
have to be used
CONTACT TRACING IS AN IMPORTANT PART OF SECONDARY LEVEL OF PREVENTION
Contd …. (To break MoT)
Isolation of cases
• Isolation means that the patient is not allowed to come into contact with other
people, so that the organisms cannot spread. Isolation is very difficult to enforce
but was very successfully used during the eradication of smallpox. If isolation is
done at home than it is considered as home isolation.
Surveillance of contacts
• If a susceptible host has been exposed to a case or sources of infection it may be
necessary to keep him under close watch and out of contact with other people
for the time of the maximum incubation period. This particularly applies to a
contagious disease like plague. This form of control used is called quarantine.
Quarantine can be absolute (complete) or modified quarantine.
CASES ARE USUALLY THE MAIN SOURCE OF INFECTION

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Contd …
Reservoir control
• In those diseases that have their main reservoir in animals, mass
treatment, chemoprophylaxis, or immunization can be used. Eg.
Trypanosomiasis and brucellosis. Other ways include separating man from
animals or killing the animals and so destroying the reservoir. Eg. Plague
and rabies.
Notification and reports
• Although these do not directly affect the source, notifications are an
essential means of keeping a watch (surveillance) on the number of new
cases and thereby monitoring the effectivenessof the control program.
• Notifiable disease and epidemics should be reported to the Ministry of
Health via the local health facility. A good notification system provides
early warning of epidemics before they become serious.
Interrupting transmission
Environmental hygiene
• Many organisms are able to spread through contaminated food and water,
particularly those that are dependent on the fecal-oral route.
• Other diseases are spread through refuse and dirty living conditions. The airborne
diseases are more likely to spread when housing is inadequate and people live
and sleep in crowded rooms
Personal hygiene
• Many personal habits make some diseases more likely, particularly the contact
and venereal diseases and those that may spread due to fecal contamination of
hands, food, and water.
• This is why it is so important to teach children to wash their hands after using the
latrine and before meals, until this becomes an automatic habit.
Disinfection and sterilization
• These measures aim at destroying the organism when it is in the environment,
e.g. sterilization of surgical instruments to prevent clostridial and other infections,
the chlorinating of water supplies to prevent typhoid and cholera.

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Contd …
Population movements
• Communicable diseases can be spread by people who are incubating the illness,
by carriers or by actual cases travelling around.
• During an epidemic it may be necessary to stop people moving around or going
on safari, and even to forbid gatherings like markets or festivals whilst the
epidemic lasts. Migration of people and refugees can spread diseases from one
area to another.
Vector control
• Any organism that requires a vector, like a mosquito or snail, for its transmission
cycle may be controlled if the vectors can be killed off or reduced.
• Methods of vector control can be through altering the environment so that it is
unfavourable to the vector (e.g. draining swamps), by using toxic substances
(e.g. larvicides or molluscicides), or by using other living organisms that attack
the vector (biological methods).
Protecting the host
Immunization
• By giving vaccines (made of toxoids, or living or dead organisms) the level
of active immunity can be raised eg, DPT, BCG, polio, and measles. All
these offer personal protection. If immunization is to be effective in
community control, the population coverage of susceptible has to be high.
• The protective effect that is obtained when a high proportion of the
population have been immunized is called herd immunity.
• Passive immunity produced by immune globulins may give personal
protection, e.g. in rabies, but it is not helpful in mass control.
IMMUNIZATION GIVES PRIMARY PROTECTION, and leads to HERD
immunity.

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Contd ….
Chemoprophylaxis
• Drugs that protect the host may be used for suppressing malaria, and for preventing
infection with such diseases as plaque and cerebrospinal meningitis
Personal protection
• This means some barriers. eg. shoes against ankylostomiasis, nets and insect repellants
against mosquitoes. Better nutrition
• When famine is present then epidemics are more likely to occur
• Malnourished children also appear more prone to infections and may suffer from
complications such as measles, and malnutrition. Therefore, the prevention of malnutrition
can help in control of communicable diseases
Proper Nutrition
Elimination of disease and infections (reducing to zero)
Eradication
Extinction
Principle of non existence of risk factors of
communicable disease
• Removing all risk factors that can promote the disease causation
• Modifiable risk factors can be removed
• We do not have control over non modifiable risk factors. Removing
non modifiable risk factors simple means killing the host.
• Since there are multiple risk factors (Multifactorial cause – not a
single factor), eliminating one risk factor does not assure that we are
preventing the disease.
• Though some risk factors are not modifiable, we can adjust with
them. Eg. Changing the location where there is disease.

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Principle of total removal of infectious agent,
reservoir, vector
• Total removal should not be done (extinguish), either it is Agent or host
(reservoir or carrier/vector)
• Sterilization can remove agent totally from specific tools (Non living)
• Eradication preserves sample only in laboratory, so that if necessary it can
be replicated in future
• Extinction means, the sample is not even preserved in laboratories.
Permanent end of the existence of species. E.g. Disappeared dinosorous.
• Extinction is a natural process (1 species per million years extinct), now a
days induced by humans.
• After extinction, the imbalance of eco system can bring inevitable induced
disasters.
Principle of reducing infection and chances of
exposure
• Reducing infection means reducing the incidence case in the
community
• When incidence rate is reduced, prevalence is gradually reduced and
so the exposure.
• Five levels of prevention is an useful concept to reduce infection
(discussed previously)
• We should never forget nosocomial and iatrogenic infection
• Preventing infection (IP)
• Hygiene and sanitation
• Waste management

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Public Health Interventions for prevention and
control of risk factors of disease
• Educational:……..
• Empowerment:……
• Hygiene and sanitation…………..
• Infection Prevention (IP) and waste management:………..
• Policy and Legal measures:…….
• Community organizations:……..
• Infrastructure development:…………
• Managerial intervention:……
• Research:……….
ASSIGNMENTS BASED ON SCIENTIFIC ARTICLES
Public Health Measures
Prevention/Immunization
Early detection
Community interventions

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Epidemiology of Risk Factors of disease
following respiratory infections
Merge prevention and control early detection, public health interventions in single slide
Unit 2 (20 hours) Draft 2.1
Upendra Raj Dhakal, Lecturer VCTS
urdhakal@gmail.com
Version 2.1 (Feedback Welcomed) 61
For Exam, if epidemiology is asked – Plz write
• Agent factor
• Host Factor
• Environment factor
• MoT
• Incbation Period
• CF (SS): Remember typical only – less priority
• Prevention and Control: Describe on the basis of levels of prevention
• Mass management (less priority to individual treatment)
• Mortality and morbidity History, major incidents
• Vaccine development history
• Present and contextual disease scenario (Not policy)

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Chickenpox

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Epidemiology
• Pox means curse, or wishing bad luck.
• Primary chickenpox is globally distributed.
• In 1990 – 8900 death occurred which dropped in 2015 to 6,400
deaths globally
• There were 7,000 deaths in 2013
• In temperate countries, chickenpox is primarily a disease of
children, with most cases occurring during the winter and spring,
most likely due to school contact.
• It is one of the classic diseases of childhood, with most cases
occurring in children up to age 15
Epidemiology
• Like rubella, it is uncommon in preschool children.
• Chicken Pox is highly communicable, with an infection rate of
90% in close contacts.
• In temperate countries, most people become infected before
adulthood, and 10% of young adults remain susceptible.
• In the tropics, chickenpox often occurs in older people and
may cause more serious disease
• In adults, the pox marks are darker and the scars more
prominent than in children.
• Transmitted through direct contact and droplets

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Contd …
• First outbreak in Nepal was recorded in 2015 in Baidauli VDC of
nawalparasi where 55 cases from 27 households were affected
• This outbreak continued for 45 days
• The number of cases rapidly rise after the detection of primary case
• In 2018, 4 patients visited every day in April in Sukrraj Tropical and
Infectious Disease Hosspital
• No specific data publiched
Contd …
• High risk population
• Pregnant
• Lesser than 1 year or older than 12 years
• Weakened immune system (Chronic skin ds, Lung ds, HIV/AIDS or Cancer)
• Health care needed if
• Fever lasts for > 4 days or above 102 F
• Pus/blood discharge, secondary infections (Children)
• Stiffness in body, difficult walking
• Severe cough and vomiting, difficult breathing
• Severe abdominal pain
• Pneumonia (esp adults)

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Ds - Chicken Pox
• Causative agent: Varicella – zoster virus (VZV), (More generally aka
herpesvirus (actually not a poxviridae) / aka Human (alpha) herpes virus.
• Host Factors: All population, specially Children and adolescents
• Environmental factor: Winter/Spring
• MoT: Directly through droplets and direct contact, and indirectly through
clothing
• Incubation Period: 14 - 16days.
• Other risk factors: Newborn and infants whose mothers are not vaccinated,
Adolescents and adults Pregnant. It is usually not serious in between 1 to
15 years, but can be severe below 1 and above 15 years (Biological
situation …, Disease condition…, Physical situation…, Sociocultural situation
…..)
Pathogenesis
Inhalation of respiratory
droplets
Virus infects URTI
Viral proliferation in regional
lymph nodes of the URTI (2 –
4 days after initial infection)
Stage of primary viremia
Viral replication in other
organs (liver and spleen)
Stage of secondary viremia
Diffuse viral invasion of
capillary endothelial cells and
the epidermis
VZV infection of cells of the
malphigian layer produces
both intercellular oedema
and intracellular oedeama,
resulting in the characterstic
vesicle

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Signs and symptoms
• Flu – like symptoms such as fever, fatigue, loss of appetite body aches and
headache.
• These symptoms typically start a day or two before a rash appears.
• Illness usually lasts for 4 - 7 days leaving the scabs.
• Red spots appear on the trunk, back, shoulder, face, inside the mouth, eyelids, or
genital area, eventually spreading over the entire body
• Mild Fever (101 – 102)
• Tiredness
• Loss of appetite
• Headache
• Malaise
• Coryza (fever, cough, runny nose, sneezing, red eye, lacrimation,)
• Often Koplik spot (though it is considered specific for measles)
General Treatment
• No specific treatment
• Personal hygiene
• Calamine lotion and a cool bath with added baking soda, or colloidal
oatmeal.
• Antihistamine to reduce itching
• Antiviral drugs (acyclovir) within 24 hours of rash appearance
20mg/kg QID for 5 days
• Acetiminophn (Paracetamol)
• Do not use aspirin or aspirin based products (Ma led to Reye’s
disease)

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Protective measures/Immunization
• Vaccination (live and attenuated): 1st dose 12 – 18 moths, 2nd dose 4 –
6 years.
• Older children and adults should take two dose within 4 – 8 weeks.
• Varicella zoster immune globulin (1.25 – 5 ml IM) for those who
cannot receive vaccine ASAP (within 10 days) after exposure to VZV.
Early detection
• Contact with the chickenpox positive cases.
• Rashes and itchy blisters (filled) after some days of development of
fever

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Preventive and control measures
• Vaccination
• Isolation of the chickenpox positive cases for a week after the rash
appears
• Contagious before 3 days of the onset of symptoms
• No specific control mechanism developed, as the disease is
considered mild
• Temporarily shutdown of schools if necessary
Public Health Intervention
• Awareness
• Vaccination
• Early detection
• Isolation if necessary
• Vital registration
• Preventing complications (secondary bacterial infection of skin and
mucosa, Neurological complications – Barre Syndrome (Encephalitis),
Pneumonia

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Government Program
• No specific chickenpox related program in Nepal.
All vaccination programs are under National Immunization Program,
that will be discussed in last
Measles
(Rubeola)
(Morbilli)

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Epidemiology
• Measles is a highly contagious and serious disease caused by measles virus from
paramyxovirus family
• Measles means continuously present in the community.
• It is transmitted directly through air and droplets
• It infects the respiratory tract and spreads throughout the body
• Measles is of zoonotic origin having evolved from rinderpest that infects cattle.
• It was first detected in 4th century BC.
• Major epidemics used to occur every 2 – 3 years and it caused an estimated death of 2.6
millions/year
• 158,000 death occurred in 2011 and 630,000in 1990
• More than 140,000 people died from measles in 2018, mostly under 5 though there was
the availability of vaccine
Contd …
• In 1529, measles outbreak killed 2/3rd population in Cuba and in 1531, half of the
population were killed in Honduras
• Between 1855 – 2005, 200 million people were killed
• 20% of Hawaii population were killed in 1850, and in 1875 more than 40000 Fijians
were killed.
• In between 2018 – 2020, approximately 23.2 million death is prevented, which is a
decrease of 73% since 2018.
• More than 95% of the community need to be immunized to attain herd immunity
• Mortality is 10% in malnourished population.
• German anti – vaccination campaigner Stefan Lanka claimed that there is no virus
that causes measles (measles does not exist), and the case was filed to court but
he was not penaltized because there were no sufficient evidences against him.

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Contd …
• In Nepal measles outbreak was reported in 2001 AD with 1070 cases and 74
death with CFR of 6.9% but cases were reported from 1994
• In between 1994 – 2002, approximately 90000 cases were reported each year,
though routine vaccination had already started in 3 districts in Terai in 1979
• Piloting rotine vaccination from 3 districts were scaled up nationally in 1989
• In 2003, more epidemic was seen in Terai
• In 2004 6050 children were affected and 138 measles outbreak was confirmed by
lab and was sharply reduced to 12 in 2005 as a result of measles campaign
• Nepal reduced 97% of the case reduction by 2017
• For eliminating, more than 95% vaccine coverage is targeted in measles
• Government of Nepal is doing MR campaign in high risk districts since 2020
Ds - Measles
• Agent : RNA Paramyxovirus
• Host Factor : Human is only reservoir, common in pre
school children
• Environmentalfactor: Overcrowding environment, winter/spring
• MoT : Droplets, usually 4 days prior and 5 days after
appearance of rashes
• Incubation period: 8 – 12 days
• Risk factors : Malnutrition, immunodeficiency, pregnancy,
Vitamin A deficiency, low vaccine coverage,
population displacement, overcrowding, etc

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Pathogenesis
Inoculation of
respiratory tract
Local replication
in respiratory
tract
Lymphatic
spread
Viremia
Wide
dissemination
Conjunctivitis,
Respiratory tract, urinary
tract, Small blood
vessels, Lymphatic
system, CNS
Virus infected
endothelial cells
plus immune T
cells
Rash
Recovery
(Life long
immunity)
Postinfectious
encephalitis
(immunopathologic
etiology)
Subacute sclerosing
panencephalitis
defective measles virus
infection of CNS
No resolution of acute
infection caused by
defective CMI (frequently
fatal outcome)
Rare outcome
Classification according to IMCI
• Severe Complicated Measles:
• Any general danger sign or clouding of corners or deep or extensive mouth
ulcers.
• Measles with eye or mouth complications:
• Pus from eye or mouth ulcers
• Measles:
• Now or within the last 3 months

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Signs and symptoms
• Prodromal Phase (coryza symptoms)
• Fever
• Cough
• Running nose
• Sneezing
• Redness of eyes
• Lacrimation
• Koplik spot (Greyish/Bluish white lesion on inner side of cheek, opposite to
second molar), appears in 2nd or 3rd day of illness and disappears at the
second day of the rash
Contd…
• Eruptive phase
• Maculopapular rash
• Appears in 4th day of fever (Behind ears → Forehead→ Face→ Neck → Trunk →
Extremities → Palm and sole)
• Starts disappearing after 4 – 5 days in same order
• Fever rises as rash appears

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General Treatment
• Bed rest
• Maintain hygiene: Give bath to child, Mouthwash, tooth brushing
• Adequate oral fluid
• Good Nutrition
• Fever: Paracetamol, Hydrotherapy
• VA: 2 lakhs IU orally to children > 1 years repeated in 2nd day, &
1 lakh IU orally to children 6 – < 12 months repeated in 2nd day.
• Antibiotics if bacterial infection seen in eye/lungs
• Cotrimoxazole (orally)
• Penicillin + Gentamycin for severe pneumonia (IV)
• Isolation: Isolate until 5 days after rash appears
• Treatment of complications according IMCI guidelines
• Vaccination : 9 – 12 months
• Revaccination at 15 – 18 months as a part of MR

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Early detection
• Contact with the measles positive cases.
• Location for the eruption of rashes
• Vaccination
• Isolation of the measles positive cases for a week
• Temporarily shutdown of schools if necessary

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• Awareness
• Vaccination
• Early detection
Government Program
• Measles vaccination program – in 9 months (under National
Immunization Program)
• Presently combined with Rubella, as MR vaccination program given at
9 and 15 months

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Mumps
Epidemiology
• Mumps is a viral disease caused by mumps virus, that effects parotoid glands
• Mumps is a pleural form of Mump meaning “To whine or mutter like a begger” and
was named after facial expression.
• Symptoms occur 16 – 18 days after exposure, and resolve within 2 weeks
• 1/3rd of the infections are asymptomatic
• It is globally distributed
• There were 100 – 1000 cases per 10000 people each year before vaccination
• Every 2 – 5 years, it reached a peak specially in the children of age 5 – 9 years
• It contributed to 10% of the meningitis cases and about a third of encephalitis cases,
before vaccination was initiated

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Contd …
• In children, it was the most common cause of deafness in one ear if inner ear is
damaged.
• Infection rate is same in both gender but male appear to experience symptoms
and complications, including neurological involvement, at a higher rate than
females.
• It was first recorded in 640 BC in China and Hippocrates documented outbreak in
Thasos in 410 BC
• Robert Hmilton described it in 1970
• It was the most debilitating disease in first world war
• Etiology was identified by Claude D. Johnson and Ernest William Goodpasture in
1934.
• In 1945 mumps virus was isolated for the first time and in 1948 inactivated
vaccine using killed virus was invented.
Contd …
• It only provided short term immunity, which was discontinued after the
invention of live weakened virus in 1970.
• Hamilton combined Mumps with Measles and Rubella as a combined
vaccine in 1971
• Hamilton combined Mumps with Measles and Rubella as a combined
vaccine in 1971
• 2 doses were approved by different countries in 1980
• In 2013, outbreak occurred in China infecting 300000 cases, and
• 56000 cases in England in 2004/05
• Generally, it does not reoccur.

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Contd …
• In 2019, measles cases for Nepal was 430.
• Though Nepal measles cases fluctuated substantially in recent
years, it tended to decrease through 2000 - 2019 period ending at
430 in 2019.
• In 2009, there were 27880 cases, 2010, there were 29022 cases, in
2011 there were 39023 cases, in 2012 there were 35874 cases, in
2017 it reached to 61228 cases, in 2018 there were 29624 cases
and in 2019 there were 0 cases of measles reported in Nepal
Ds - Mumps
• Agent Factor : RNA Myxovirus
• Host Factor : 5 – 15 years children
• EnvironmentalFactor: Winter and Spring
• MoT : Through infected saliva or droplets
• Incubation Period: 2 – 4 weeks (18 days)
• Risk factors : Same as measles

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Pathogenesis
Virus spreads throughout body to testes, ovary, pancreas, thyroid, salivary glands
DISEASE
18 days and after)
Viremia
Approx. 15 days
Virus spreads to spleen and distant lymphoid tissue 7 – 10 days)
Virus grows in salivary glands and local lymphoid tissue
Virus enters respiratory tract
Signs and symptoms
• Malaise
• Muscle ache
• Fever/Headache
• Nausea/Vomiting
• Painful parotoid swelling

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General Treatment
• Acetaminophen (Paracetamol) for pain and fever
• Warm saline mouth wash
• Isolation
• Vaccination at 15 – 18 months
• Mumps vaccination is not under national Immunization Schedule of
GoN.

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Early detection
• It can be confirmed by detecting mumps IgM antibody in serum
samples .
• Contact with the mumps positive cases.
• Vaccination
• Prevent droplets contamination
• Sanitization and hygiene

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• Awareness
• Vaccination
• Early detection
• Regular hand washing
• Prevent complications (Orchitis, Pancreatitis, Oophoritis, Nephritis)
Government Program
• No specific Mumps related program
• Vaccine can be combined with Measles and Rubella, as MMR
vaccination program given at 9 and 15 months

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Rubella (German Measles)
Not RUBEOLA (RUBEOLA means measles)
Epidemiology
• It s a contagious viral infection best known by its distinctive red rash
• It is also called as German Measles, as it was first descried by German
scientist George de Maton and was was similar to measles in 1814.
• Later in 1886, when it was epidemic in India – it was than renamed as
Rubella
• It is characterized by lymphadenopathy and maculopapular rash.
• It is distributed globally
• Before vaccination began in 1969, pandemic occurred sporadically.
• Since it is sporadic in nature, vaccination need to be continued for years
until we gain herd immunity

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Contd …
• In 1940, there was an outbreak in Australia and 78 congenital cataracts were
found in infants and 68 were born from mothers infected with rubella
• Girls if infected were in high risk of getting it again when they are pregnant
• In between 1962 – 1965, rubella infection during pregnancy caused 30000
stillbirth and 20000 were born with disability (congenital rubella syndrome –
deaf, blind, intellectually disabled) in US with total cases of 12.5 million.
• In between 1964 – 65; 11000 were spontaneous abortions and 20000 were
induced abortion that occurred dur to Rubella
• In 1967, molecular structure of rubella was observed under electronic
microscope using antigen – antibody complexes.
Contd …
• In 1969, attenuated vaccine was introduced and in 1970 triple vaccine of
MMR was initiated.
• By 2006, confirmed cases dropped below 3000 per year but outbreak again
occurred in Argentina, Brazil and Chile causing 13000 cases that year
• Still, outbreak occurs in developing countries where vaccine is not available
• It is most common in Africa and south east Asia at the rate of 121 per
100,000 live births compared to 2 per 100,000 live birth in US and Europe
• In between 2012 - 2014, 150000 cases were reported in Japan in men of
age 31 – 51 and young adults of age 24 – 34 years

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Contd …
• In 2018, Nepal was certified as having achieved control of rubella and
congenitalrubella syndrome which was 2 years ahead of the regional
targated year 2020 and nationaltargated year 2019.
• Control of rubella is achieved if there is 95% or more reduction in
number of rubella cases from 2008 levels and Nepal achieved 97%
reduction in 2017
• The decrease in different respiratory infections including rubella in
COVID 19 pandemics is due to lock down
Ds - Rubella
• Agent factor : Rubella Virus (RNA Virus)
• Host Factor : Pre school children, Congenital rubella in
neonates
• Environmental : Winter and Spring
• MoT : Droplets spread from nose and throat
secretions
• Incubation Period 14 – 21 days
• Risk factors : Same as rubeola

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Pathogenesis
Rubella
virus
Transmitte
d through
respiratory
droplets
Infects cells
in the URT
Virus
multiplies
Extends in the
regional
lymph node
Virus
replicates in
the
nasopharynx
Infection is
established in
the skin and
other tissues
including the
respiratory
tract
Forchheimer
’s spot may
develop
Rashes
develops,
cough etc
Virus can be
found in the
skin, blood
and
respiratory
tract
Diagnosis:
Doctor
suspects
whether
patient has
measles
Virus
culture/Blood
test
Recent infection
With German
Measles vaccine
Vaccination and
proper intervention
German measles left
untreated, it may cause
complications; Rubelal
Arthritis, Encephalitis,
Purpura bronchitis,
abscesses in the ears and
pneumonia
Signs and symptoms
• Mild coryza
• Diarrhea
• Fever
• Malaise
• Lymphadenopathy
• Sore throat
• Rash Maculopapular(1st on face, begin to disappear on 2nd day)

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General Treatment
• Isolation from pregnant women
• Vaccination at 15 – 18 months as a part of MR

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Early detection
• Contact with the rubella positive cases.
• Location for the eruption of rashes
• Duration of rashes
• Vaccination
• Isolation of the rubella positive cases for a week

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• Awareness
• Vaccination
• Early detection
Government Program
• Presently combined with Measles, as MR vaccination program given
at 9 and 15 months

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Influenza (Flu)
Epidemiology
• Influenza commonly known as “the flu” is an infectious disease caused by an
influenza virus.
• There are 4 types of influenza virus that effects humans: Type A, Type B, Type
C and type D. Type D is has not been known to infect humans, but is believed
to infect humans
• It spreads in world as an yearly outbreak, resulting about 5 million cases of
severe illness and 290000 to 650000 death with an average of 389000 .
• In developed world, age above 65 have highest mortality rate among
different population
• About 20% unvaccinated children and 10% unvaccinated adults are infected
each year
• It reaches peak prevalence in winter

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Contd …
• Since northern and southern hemispheres have winter at different times, there are two
differentflu seasons each year
• There are differentvaccines used in Northern and southern hemisphere
• Approx., 36000 death and more than 200000 hospitilizatios are directly associated with
influenza in US
• There is no specific cause identified for it being active in winters only, but not throughout
the year and only possible reason is due to the more time spend indoors during winter.
• First influenza pandemic occurred in 6000 BC in China
• Symptoms of human Influenza were defined by Hypocrates roughly 2400 years ago
• In 1493, indigenous people of Antilles were killed after the arrival of Christopher
Columbus
• First conviencing record was done in 1510 in east asia where 1% of the population were
killed
Contd …
• In 1918 flu pandemic (Spanish flu – Influenza type A ,H1N1 strain) killed 17
million to 100 million people
• In 1957 Asian Flu (Type A H2N2) and in 1968 Hong Kong Flu (Type A H3N2
strain) and in 1977 Russian Flu (Type A, H1N1 strain) had outbreak,, but
were found weaker than Spanish flu. Its because antibiotics were already
developed to prevent secondary infections.
• Lower humidity and dry air in winter where it is transmitted fast
• Seasonal changes impairs our immune system, and as an opportunity flu
outbreaks during this time
• Nearly 3 times per century, this pandemic occurs due to major antigenic
changes
• New influenza virus are constantly evolving by mutation or reassortment.

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Contd …
• Flu epidemic spread rapidly and are very difficult to control
• Most influenza virus strains are not very infectious and each infected
individual will only go on tho infect one or two other individuals
(general morbidity is 1.4)
• It means, Influenza have short generation time and thus, epidemic
peak only for 2 months and burn out after 3 months.
• People are infectious before symptoms develop, thus there is no
meaning of keeping them in quarentinee
Contd …
• In FY 2074/75, a total of 12 outbreaks of ILI was reported with more
than 4000 cases throughout the country including 10 death
• A total 2 outbreak of ILI was reported in FY 2075/76 with 3386 cases
throughout the country including 13 death
• In 2021, there was an outbreak in Tarkeshoror Muncipality in
Kathmandu and the detail human data is not available yet, though it is
said that 2300 fowls were killed in that area after confirming bird flu.
Total 1865 ducks, 32 chickens, 25 turkeys, 542 eggs and 75 kg poultry
feed were destroyed
• Similarly in February 13, 2020 there was an outbreak in Himali Rural
Muncipality in Bajura for about 3 weeks. 1170 population with ILI
were treated in Bajura

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Influenza Virus A
Influenza type are classified based on Hemagglutinin (H) and N
(Neuraminidase). i.e. (H1N1 to H18N11)
• H1N1, which caused Spanish flu in 1918, Russian flu in 1977, and Swine Flu in 2009
• H2N2, which caused Asian Flu in 1957
• H3N2, which caused Hong Kong Flu in 1968
• H5N1, which caused Bird Flu in 2004
• H5N8, Bird flu in Nepal in 2021
• H7N7, which has unusual zoonotic potential
• H1N2, endemic in humans, pigs and birds
• H7N9, rated in 2018 as having the greatest pandemic potential among the Type A
subtypes
• H6N1, which only infected one person, who recovered
(Novel CORONA VIRUS …yet to be studied …and presently not kept under influenza ….)
• ……
Influenza virus B
• Less common than A
• Other animals who get infected with Influenza virus B are seals and
ferrets
• This type mutates at a rate of 2 - 3 times slower than type A
• It does not cross species (antigenic shift) and thus pandemics does
not occur

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Influenza virus C
• This genus has one species, influenza C virus, which infects
humans, dogs and pigs, sometimes causing both severe illness
and outbreak.
• However, influenza C is less common than the other types and
usually only causes mild disease in children
Influenza virus D
• This genus has only one species, influenza D virus, which
infects pigs and cattle.
• The virus has the potential to infect humans, although no such
cases have been observed

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Type A and Type B cause most human illness, whereas Type C and Type D are
less common
• (Duck example): avian influenza A(H1N1), A/duck/Alberta/35/76
• (Human example): seasonal influenza A(H3N2), A/Perth/16/2019

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Ds - Influenza
• Agent factor : Influenza virus (RNA)
• Host Factor : All population
• Environmental : All seasons, esp during Winter and during
seasonal change
• MoT : Droplets and directly
• Incubation Period 1 – 3 days
• Risk factors : Crowds, High risk populationincludes
senior citizen, crowded environment, crowds,
native , American, Aspirin user under 19,
pregnancy, obesity
Pathogenesis

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Signs and symptoms
• Sudden onset of chills and fever
• Headache, sore throat
• Myalgia (tenderness of muscles) – Health consultation needed
• Arthralgia (joint pain) – Health consultation needed
• Dry, persistent cough,
• Runny and stuffy nose
• Shortness of Breathe (SoB) - Health consultation needed/May be Er
• Eye pain
• D/V most common in children
• Seizures – Health consultation needed/May be Er
• Cyanosis - Medical Emergency
General Treatment
• Bed rest until fever subsides
• Paracetamol as analgesics and antipyretics
• Codeine to suppress dry cough
• Antibiotics for secondary infection control
• Enough fluid
• Antiviral drugs

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• Prophylaxis can be done as influenza vaccination, which is not in
practice in Nepal
• Though vaccination is not practiced in Nepal, Vaccination with HiB at
6, 10, 14 weeks is for Hemophilus Influenza – Bacterial Infection are
found beneficial.
• Vaccination by Pneumococcal Conjugate vaccine at 10 weeks gives
relief to a level.
Early detection
• RDT and Polymerase chain reaction (PCR)
• Contact with the influenza positive cases.

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• Vaccination for prophylaxis
• Isolation of the influenza positive cases until fever subsides
• Avoid overcrowding
• Use mask
• RIDT (Rapid Influenza DT)
• Awareness
• Vaccination
• Early detection

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Government Program
• No specific Government program, but is seen by EDCD
Diphtheria
भयागुते रोग

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Epidemiology
• Diphtheria is a serious infection caused by strains of bacteria
called Corynebacterium diphtheriae that make toxin (poison).
• Previously known as Boulogne sore throat
• It can lead to difficulty breathing, heart failure, paralysis, and even death.
• Vaccination is necessary for infants, children, teens, and adults to prevent
diphtheria.
• Clinical features may vary from mild to severe
• It is fatal in 5 – 10% of cases
• In children below 5 years and adults above 40 years, fatality rate is above 20%
• Epidemic in Spain occurred in 1613
• Epidemic in New England occurred in 1735
Contd …
• In 1826, it began from France
• In 1878 Queen Victoria’s daughter Princes Alice and her family became
infected with diphtheria
• In 1883, Edwin Klebs identified the bacteria causing diphtheria
• In 1884, Friedrich Loeffler cultivated Diphtheria using Koch's Postulates
• In 1895, diphtheria antitoxin was tested in US and in 1897, it was than
standardized
• In 1990 – 8000 deaths and in 2013 – 3300 deaths occurred globally
• Number of cases has significantly decreased over 2 decades
• Outbreaks are rare, though is present everywhere in the world
• In Nazi population in German, it was the major cause of death that
increased in 20th century Version 2.1 (Feedback Welcomed) 145

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Contd …
• In 1991, after the breakdown of USSR, vaccination dropped which expanded
diphtheria and 2000 cases occurred only in USSR territories
• In between 1991 – 1998, 200000 cases were reported in commonwealth of
independent states with 5000 deaths
• In 1901, 10 out of 11 inoculated St. Louis children died from tetanus
contaminated diphtheria antitoxin which lead to tetanus outbreak.
• In 1904, daughter of the president of France did at the age of 12 due to
diphtheria
• In 1919, in Dallas, Texas, 10 children were killed and 60 others were seriously ill
by toxic antitoxin ad they were paid charges.
• In 1920 annually estimate of 100000 to 200000 diphtheria cases were reported
and 13000 – 15000 death occurred only in US
• In 1926, Alexander Thomas Glenny increased the effectiveness of diphtheria
toxoid by treating it with aluminum salts.
• In 1949, 68 out of 606 children died after diphtheria immunization.
Contd …
• In 1975, WHO incorporated Diphtheria vaccine in EPI
• In 1975 outbreak occurred in Washington
• In 1994 39703 cases were diagnosed in Russia where only 1211 cases were
reported in 1990
• In 2010, 15 years old male patient died in HAITI earthquake time
• In 2103, 3 children died in Haiderabad and in 2015 1 was diagnosed in
Barcelona, Spain. In 2016 3 years child died in Belgium, in 2016 3 children
died in Malaysia
• In 2017, 300 cases were recorded in Venezuela and outbreak occurred in
Indonesia with more than 600 cases with 38 fatalities
• In 2019, 2 cases were reported in Scotland and 8 years boy died in Athens

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Contd …
• In 1983, the incidence of diptheria was 14.5 per 100000 populations
• There were 82 cases in 1980 7 cases in 1990, 726 cases in 1997, 511
cases in 1998 268 cases in 2000 and 390 cases in 2001
• Annual incidence rate per 100000 population was 20 in 1994 10 in
1995 6 in 1996, 5 in 1997, 3 in 1998, 1.6 in 1999, 1.5 in 2001 and 1 in
2002
• In 1996 April, a six years child , showed symptom and in December, 9
year child showed symptoms in eastern part of Nepal. Later it was
identified that they had not taken total immunization
• Accurate data from Nepal is still not available
Ds - Diphtheria
• Agent factor Corynebacterium diphtheriae (gram positive)
• Host factor Pre school children
• Environmentalfactor Autumn and spring
• MoT Direct contact and droplets
• Incubation period 2 – 5 days
• Risk factors Lack of immunization, history of contact,
chronic illness and immunocompromised,
overcrowding, travel to diptheria endemic
area, absent or incomplete immunization

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Pathogenesis
• Entry : the bacilli multiply locally in throat and elaborate a powerful exotoxin which is lethal to the
adjacent host cells
• It first destroys a layer of superficial epithelium, usually in patches, and goes to the system.
• It produces local and systemic symptoms
Local lesions:
• Exotoxin causes necrosis of the epithelial cells and liberates serious and fibrinous material which
forms a grayish white pseudomembranous
• The membrane bleeds on being dislodged
• Surrounding tissue is inflamed and edematous
Systemic lesions:
• Exotoxin affects the heart, kidney and CNS
• Heart Myocardialfibersare degenerated/fatty degeneration and the heart is dilated, Conduction disturbance)
• CNS (Polyneuritis, degenerative changes in peripheral nerves chiefly motor fibers)
• Kidney (Renal tubular necrosis, reversable nephritis)
Signs and symptoms
• Fever
• Headache
• Malaise
• Lymphadenopathy
• Redness and swelling of throat
• Greeyish/White pseudomembrane

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General Treatment
• Isolation of suspected cases for at least 14 days
• Diphtheria antitoxin – IM, IV
• Antibiotics – Penicillin or erythromycin
• Supportive therapy – Bed rest, High calorie diet, treatment of fever
• Vaccination : 6, 10, 14 weeks as a combo DPT-HepB-HiB
Td Vaccine
• Tetanus – diptheri (Td) vaccine is planned to replace TT (5 dose)
vaccine in adults in low dose as an school based program to pregnant
women. Begin from high risk districts and gradually winging.
• Presently TT is given at grade 1, but Td is planned for grade 1 and 8
and extend the program to other districts.
• Td is planned to eliminate neonataltetanus

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Early detection
• Clinical features does not give rapidity of the infection
• Contact with the diphtheria positive cases.
• Vaccination
• Isolation of the diphtheria positive cases

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• Awareness
• Vaccination, extension of Td vaccination program
• Early detection
Government Program
• Diphtheria vaccination program – in 6, 10 and 14 weeks as a combo
vaccine (under National Immunization Program)
• Presently combined with DPT-HB-HiB vaccination program
• Dt vaccination in schools

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Whooping cough
Epidemiology
• Whooping cough is caused by highly contagious acute infectious bacteria in respiratory tract
• After the cough, high pitch whoop sound is heard.
• It is also known as 100 day cough as the cough lasts for around 10 and more weeks.
• Person cough so hard and vomit that even ribs can break, and person becomes tired of
coughing
• Children below 1 year may not cough, instead have periods where they do not breathe.
• Globally, around 16 million people are infected yearly
• It was identified in 1932 by Jules Bordet and Octave Gengou who also developed vaccine
• In 1920, Louis W Sauer developed a weak vaccine and in in 1925, Thorvald Madsen tested
whole cell vaccine
• Madsen used vaccine to control outbreak in Faroe Island in North Sea
• There is also an estimation that yearly 195000 children die annually

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Contd …
• About 90% of the cases occur in developing countries.
• Peak of whooping cough reach every 2 – 5 years
• Vaccination began in 1940 which dramatically decreased the incidence of whooping cough
• There 1000 cases in 1970 and was in increase of cases in 1980, which again decreased to 17 cases
in 2001 in US
• In 1990 – 138000 death occurred whereas in 2013 – 61000 death occurred because of whooping
cough
• In Canada, cases vary from 2000 to 10000 each year
• In 2009, Australia reported an average of 10000 cases per year
• In 2017, India had reported 23766 reported pertussis cases as the highest reported case of the
year
• Similarly, in 2017 Germany reported 16183, Australia and china reported 12114 and 1030 cases
Contd …
• In 2010, 10 infants in California (US) died and epidemic was declared
encompassing 9120 cases, and doctors had failed to diagnosis in infants
• During that time, parents had not given consent to vaccinate their child showing
non medical cause and personal belief, which lead to outbreak.
• Other reasons for US outbreak was reduced duration of immunity, and lack of
booster dose.
• In April and may 2012, epidemic was declared in Washington with 3308 cases
• In December 2012, Vermont declared epidemic with 522 cases
• In 1980 there were 1055 cases, in 1990 there were 18 cases, in 1997 there were
12443 cases, in 1998 there were 14339 cases, in 2000 there were 134 cases and
in 2001 there were 327 cases
• Annual incidence rate per 100000 population was 50 in 1994, 90 in 1995, 60 in
1996, 64 in 1997, 38 in 1998, 28 in 1999, 25 in 2000, 20 in 2001 and 18 in 2002

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Ds – Whooping cough
• Agent factor Bordetella pertussis (para pertussis)
• Host factor Child below 4 years, occasionally adults
• Environmentalfactor Winter and early spring
• MoT Droplet infections
• Incubation period 7 – 14 days
• Risk factors Non vaccinated children, obese adults,
asthmatic adult, prolonged cough >=5 days in
infants household contact, pregnancy
Pathogenesis
Pertussis Disease
Local epithelium damage & symptom appear
Inflammatory response to mucosa & secretion appear
Pathological changes in the respiratory tract (Nasopharynx to bronchioles)
Liberates numbers of antigen & toxins
Causative Agent (Bordetella Pertussis)

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Signs and symptoms
• Typical proximal cough
• Explosive type of cough
• Unable to breath
• Bouts of cough terminates with whoop, whoop is produced by
forceful inspiration of air
• Cough occurs every hours and terminates with vomiting
General Treatment
• Infants under 6 months – hospitalization
• Antibiotics (Erythromycin – orally for 14 days)
• Salbutamol Nebulization

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• Vaccination with diphtheria vaccine in combo DPT-HepB-HiB
• Dt
Early detection
• Contact with the Whooping cough positive cases.
• Cough plate technique: Individual is given a plate and while coughing,
it is kept at 6 inches distance and is exposed for 10 -15 seconds, so
that no mucus reaches the plate. Then the sample is further
investigated in laboratory

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• Vaccination, but it does not give life long immunity. Only for 3 – 6
years, some studies claim 7 – 20 years.
• Insufficient evidence to determine the effectiveness of antibiotics in
those who have been exposed, but are with symptoms
• Preventive antibiotics for high risk group (infants) if are exposed
• Awareness
• Vaccination
• Early detection

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Government Program
• Pertussis vaccination program – in 6, 10 and 14 weeks (under
National Immunization Program)
• Presently combined with DPT-HepB-HiB
• Dt
Acute Respiratory Infection (ARI)
Influenza like Illness (ILI)
Severe Acute Respiratory Infection (SARI)

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Epidemiology
• ARI is a condition with flu like symptoms and with/out fever >38 C, cough, SoB
and exposure history within 7 days prior to the onset of symptoms
• It indicates an infection of any part of respiratory tract of less than 30 days and
otitis media of less than 14 days duration
• ARI is an infection that may interfere with normal breathing
• It can effect upper respiratory system (sinus to vocal cords) or lower respiratory
system (below vocal cords)
• It is particularly dangerous for children, older adults, and people with immune
system disorders.
• Highest death rate are seen in Africa, esp. sub Saharan countries, followed by
Asia (excluding China) and than by Latin America and Chin, and with much
lower rate in America and Europe
Contd …
• ARI comprises 25 – 30 % of hospital consultations and 25% of total
hospital admissions. However, the incidence of ARI is similar in
industrialized and developing countries
• Respiratory infections often have strong seasonal patterns,
with temperate climates more affected during the winter.
• Several factors explain winter peaks in respiratory infections,
including environmental conditions and changes in human behaviors.
• Viruses that cause respiratory infections are affected by environmental
conditions like relative humidity and temperature.

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Contd …
• Temperate climate winters have lower relative humidity, which is known to
increase the transmission of influenza.
• Of the viruses that cause respiratory infections in humans, most have
seasonal variation in prevalence. Influenza, Human
orthopneumovirus (RSV), and human coronaviruses are more prevalent in
the winter. Human bocavirus and Human metapneumovirus occur year-
round, rhinoviruses (which cause the common cold) occur mostly in the
spring and fall, and human parainfluenza viruses have variable peaks
depending on the specific strain. Enteroviruses, with the exception of
rhinoviruses, tend to peak in the summer.
• In GoN Infectious Disease Guideline, ARI does not include SARS, NiV,
MERS CoV, Legionellosis, Influenza, Crimean Congo Hemorrhagic Fever
and Chikungunya fever, but is separately included as Respiratory illness
Contd …
• In Nepal, ARI is the leading cause of morbidity and mortality that kills
more children than any other illness more than AIDS, malaria and
measles combined together
• In 2071/72, there were total 208221 ARI cases reported
• The total new cases of ARI were 783/1000 among which 155/1000
deaths were reported
• Among 155 death, 58.84 was from pneumonia, 13.2 was from URTI
and 5.96 was from bronchitis and bronchiolitis

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Global distribution of ARI (including Pneumonia
and influenza)
Ds - ARI
• Normal RR
• At birth 30/60 min
• Up to 2 months 40/60 min
• 2 – 12 months 40/45 min
• 1 – 5 years 20/30 min
• > 5 years 18/30
• Episode of ARI per child per year is 5 – 8 times
• 20 – 25% of death from ARI occurs in infants < 2 months
• 50 – 60% of death from ARI in 2m – 1 year of age occurs
• Generally caused by:
• Viruses: Enterovirus, Influenza A, B and C, measles, parainfluenza 1, 2 and 3,
RSV, Rhinovirus, Coronavirus, Bacteria: Bordetella pertussis, Corynebacterium
diphtheriae, Hemophilus influenzae, Strep. Pneumoniae, Strep. Pyogenes

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Pathogenesis (Done separately, pneumonia only included here)
Sputum discharge
Increased production of sputum
Tissue necrosis
Promotion of abscess (secondary if viral)
Cavity extend to bronchus
Inflammatory response
Aspiration – bacteria (Virus) entry into lungs
Different types of ARI/ILI/SARI (AURTI/ALRTI) and etiology
AURTI ALRTI
Disease Caused by/Etiology Disease Caused by
Otitis media Streptococcus pneumoniae,
Haemophiles influenzae,
allergens, resp viruses
Tracheitis Staphylococcus aureus
Often viral
Sinusitis Viral, sometimes
Streptococcus and rarely
fungal, allergens, etc
Bronchitis Mycoplasma pneumoniae,
Streptococcal. H. Influenzae, acute
bronchitis generally viral, allergens
Tonsilitis Viral, sometimes
Streptococcal
Pneumonia Described separately
Laryngitis S. Peneumoniae
H. influenzae, Viral
Bronchiolitis Generally viral (Respiratory
Syncytial Virus), allergens
Pharyngitis Streptococcus pyogenes (A)
Measles, pertussis, common cold, Diphtheria - Already done

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Etiology for Pneumonia
Disease Etiology
Viral RSV (Respiratory Syncytial Virus), Influenza virus, Parainfluenza virus, Adenovirus
Bacterial S. aureus, Pneumococcus, Staphylococcus pyogenes, Klebsiella and Haemophiles Influenzae
Atypical Mycoplasma, Chlamydia
Fungal Histoplasma
Others Aspiration, Kerosine poisoning, Ascaris
Treatment for Pneumonia
Follow IMCI for Children
Prevention: The pneumococcal polysaccharide vaccine (PPV)
Pneumococcal conjugative vaccine (PCV) for chest infection
Contd …
The pneumococcal pneumonia is an acute febrile
infection with cough, dyspnea and often pleural pain.
Pneumonia is usually lobar or segmental but a
bronchopneumonial involvement is common in
childhood and old age. The causative agent is
streptococcus pneumoniae

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General Cause of ARI
• Adenoviruses
Adenoviruses are a class of microorganisms that can cause acute
respiratory infection. Adenoviruses consist of more than 50 different
types of viruses known to cause the common cold, bronchitis, and
pneumonia.
• Pneumococcus
Pneumococcus is a type of bacterium that causes meningitis.
However, it can also trigger certain respiratory illnesses like
pneumonia.
• Rhinoviruses
Rhinoviruses are the source of the common cold, which in most cases
is uncomplicated. However, in the very young, elderly, and people
with a weak immune system, a cold can advance to acute respiratory
infection.
Risk factors
Described individually in each disease

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Clinical features
Signs and symptoms for ARI
• Congestion, either in nasal sinuses or
lungs
• Runny nose
• Cough
• Sore throat
• Body ache
• Fatigue
• Fever (103 F call for medical
assistance)
• Breathlessness (call for medical
assistance)
• Dizziness (call for medical assistance)
• Loss of consciousness (call for
medical assistance)
• Lethargy
• Convulsions (call for medical
assistant)
• Not feeding well
• Chest indrawing in case of
pneumonia
• Cyanosis (call for medical assistant)
• Wheezing call for medical assistant
• Complication may be respiratory
arrest (apnea) / respiratory failure /
congestive heart failure.

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General Treatment for ARI
• For viral ARI, there is no specific treatment. Provide symptomatic treatment
• If ARI is caused by bacterial infections, antibiotics according as URTI or LRTI.
Antibiotics are needed to treat secondary infections, and also for
prophylaxis.
• Bronchodilators if necessary
• If bronchodilators does not work, oxygen therapy
• Analgesics (Acetaminophen and NSAIDs to reduce fever and body ache) if
necessary
• Antihistamines and cough syrups if necessary
• Different vaccines are available for different types of ARI, like:
….remember previous slides ….
• In …. Months according to National Immunization Schedule of GoN:
Will be described at last

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Early detection
• Contact with infected person.
• Clinical nature of disease onset.
• Most of the ARI are viral and cant be treated
• MMR and pertussis vaccine has been found reducing the risk of ARI
• Influenza vaccine and pneumovax has also been found reducing the
risk of ARI

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• Awareness
• Vaccination
• Early detection
• Avoid smoking
• Adequate vitamins in diet
• Vitamin C and Vitamin D (WHY- assumed to improve immune system)
• Close sneezing
• Avoid touching face, esp. eyes and mouth area
• Usage of masks.
Government Program
• No specific, but is seen by EDCD
• IMCI (CB IMCI and IMCI) later updated to NCP to IMNCI for children
• ARI (ARI/ILI/SARI)
• Emergency Response Plan for Epidemics
• Immunization

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Tuberculosis (TB)
(Koch’s disease)
Epidemiology
• TB is an infectious disease usually caused by Mycobacterium tuberculosis (MTB)
bacteria.
• It generally effects lungs, and than other organs of the body.
• It does not occur in Heart, Thyroid, pancreas and Skeletal Muscles - but the concept is
presently challenged as some cases has been seen where involvement of those organs
has been seen
• It is said that TB can present any complications
• If TB does not show symptoms, it is known as latent TB, and about 10% latent
infections progress to active TB if left untreated or if we are immunosuppressed.
• People with latent TB does not spread TB.
• It is a disease, where we use multiple antibiotics and is one of the disease where we
use longest duration of antibiotics.

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Contd …
• Active infection occurs more often with HIV/AIDS patients.
• Antibiotic resistance is a growing problem with increased rate of Multiple
Drug Resistance (MDR) TB and Extensively Drug Resistance (XDR) TB
• In 2018, it was assumed that one quarter of the worlds population have
latent TB
• Incidence of TB occurs in 1% of the population each year
• In 2018, there were 10 millions of active TB cases, where 1.5 million death
occurred globally making it number 1 cause of death from an infectious
disease
• About 80% cases in many Asian and African countries test positive while 5
– 10 % people in US test TB positive.
• TB was present since ancient times
Contd …
• About 90% of those infected with M. tuberculosis have asymptomatic,
latent TB Infection (LTBI)
• TB infection begins when the agent reach alveolar air sacs of the lungs
• It is uncommon in Canada, Western Europe and US
• WHO declared “Global Health Emergency” in 1993, and in 2006, the Stop
TB partnership developed a “Global Plan to Stop TB” that aimed to save 14
million lives within 2015
• Roughly one quarter of the worlds population has been infected with M.
tuberculosis, with new infection occurring in about 1% of the population
each year, however most infections does not lead to disease.

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Contd …
• 90 - 95% infections remain asymptomatic
• In 2012, an estimated 8.6 million chronic cases were active.
• In 2010, 8.8 million new cases of TB were diagnosed, and 1.20 - 1.45
million death occurred and among these death, 0.35 million occurred
in HIV infected.
• In 2018, tuberculosis was the leading cause of death worldwide from
a single infectious agent.
• The total number of TB cases has been decreasing since 2005, while
new cases have decreased since 2002
Contd …
• Tuberculosis is closely linked to both overcrowding and malnutrition
• It is also known as disease of poverty.
• In Africa, primary affects adolescents and young adults
• Though it is globally distributed, it is not uniform
• 80% of the population occur in (developing) Africa, Caribbean, South
Asian and East European countries, and only 5 – 10% in US
(developed)
• In Europe, death from TB fell from 500 out of 100000 in 1850 to 50
out of 100000 by 1950.

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Contd …
• Public health improvements significantly reduced TB even before the
arrival of antibiotics.
• In 2010, rates per 100000 people in different areas of the world were:
globally 178, Africa 332, the Americas 36, Eastern Mediterranean 173,
Europe 63, Southeast Asia 278, and Western Pacific 139.
• TB has been found existed 17000 years ago
• Skeleton in prehistoric humans (4000BC) had TB in Egyptian
mummies
• Research suggest presence of TB in America from 100 AD
• Until 1982, TB was not identified as a single disease.
Contd …
• Between 1838 1845, Dr. John Croghan, the owner of Mammoth Cave in
Kentucky from 1839 onwards, brought a number of TB positive people into
the cave in the hope of curing the disease with the constant temperature
and purity of the cave air, each died within a year
• In 1865, Jean Antonie Villemin demonstrated that tuberculosis could be
transmitted by inoculation from humans to animals
• Robert Koch identified and described the bacillus casing TB on 24th march,
1882 and got Novel prize in Physiology or Medicine in 1905
• In mid 1990, after milk were pasteurized, cases of TB dramatically
decreased (it lead to identify bovine type of TB)
• In 1906, Aldbert Calmette and Camille Guerin developed BCG and was used
for first time in France in 1921

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Contd …
• In 2075/76, the total of 32,043 cases of TB were notified and registered in NTP
• Among these, 98% were incident (new cases and relapse) and 2% were old cases
• 71% among all TB cases reported were pulmonary TB
• Province 3 holds the highest proportion of TB as 24%
• Kathmandu alone holds 41% in province 3 which is 10% in total
• 50% of TB cases in Terai are in reproductive age group population
• Case Notification rate (CNR) of all forms of TB is 109/100000 whereas incident cases (new and
relapse) was 107/100000 population
• 91% of TB cases in 2075/76 were successfully treated
• It is estimated that there are about 1500 MDR TB annually, where lesser than 500 are notified
annually
• In 2096/77, 635 MDR TB were notified
• There are 4382 treatment centers, 604 microscopic diagnostic centers, 56 GeneXpert centers.
• Drug Resistant TB service are provided through 20 treatment centers and 86 treatment sub centers
Ds - TB
• Agent Factor: Mycobacterium tuberculosis (Shows both Gram + ve and –ve
characterstics, and thus stained differently with Ziehl – Neelsen stain or Acid Fast
staining.
• Host Factor : All population
• Environment factors : Spring/Summer
• MoT : Droplets
• Incubation period : Weeks, Months or Years
• Types : Pulmonary and Extra pulmonary TB
• High-risk group includes: drug abusers, gathering habit, prisoners, homeless
shelters, medically underprivileged and resource poor communities high risk
ethnic minorities, children in close contact with high risk categories health care
providers treating TB, personal behavior like smoking, chronic illness,
malnutrition, Social contact, household workers, sorkplace environment, etc …

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Pathogenesis
Signs and symptoms
Pulmonary TB Extrapulmonary TB
25% people may be asymptomatic Depends on the type of tissue infected
Chest pain Confusion
Prolonged and productive cough Coma
Occasionally cough in blood Neurologic defect
Sometimes massive bleeding if pulmonary artery is
involved
Chorioretinitis (eye inflammation)
Upper lobes are more effected - cause unknown Lymphadenopathy
Mild fever at evening Cutaneous lesion

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General Treatment (SPRITE) and DOTS
• DOTS : Directly Observed Treatment, Short-course
• S = Streptomycin,
• P = Z (Pyrazinamide),
• R = Rifampicin,
• I = H (Isoniazid),
• T = Thiacetazone,
• E = Ethambutol
• Oral antibiotic regime added (levofloxacin – Quinolone group)
Treatment classification
Category of Treatment Patient
Category 1 New sputum smear positive
Seriously ill, sputum smear negative
Seriously ill, extrapulmonary
Category 2 Sputum smear positive, relapse
Sputum smear positive, failure
Sputum smear positive treatment after default
Category 3 Sputum smear negative, not seriously ill
Extrapulmonary, not seriously ill
Category 4 Multidrug resistance TB

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Alternative treatment regime
TB treatment TB patients
Alternative treatment TB regimes
Initial phase Continuation phase
Category 1 New smear positive PTB, smear
negative PTB and extrapulmonary
TB
2HRZE or 2 HRES 6HE or 4HR
Category 2 Sputum smear positive relapse,
treatment failure, and return after
default
2SHRZE/1HRZE
2SHRZE/1HRZE
2SHRZE/1HRZE
5HRE
Category 3 New smear negative PTB (other
than cat 1), new and less severe
form of Extra PTB
2HRZ 6HR or 4 HR
Category 4 Chronic case (still sputum positive
after supervised re treatment)
N/A
Second line drug need to be used in specil
centres as recommended by WHO
However, NTP Nepal is providing fixed dose combination drug treatment regime as recommended by WHO and
international experts which includes Levofloxacin added.
• Vaccination : at birth or ASAP by BCG vaccine
• DOTS

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Early detection
• Contact with the TB positive cases.
• Identifying TB endemic areas
• Vaccination
• Isolation of the TB positive cases until the treatment begins

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• Awareness
• Vaccination
• Early detection and treatment
• Isolation if necessary until the treatment begins
• Vital registration and
• TB Notification rate (TB detection rate)
Government Program
• BCG vaccination program – at birth or ASAP (under National
Immunization Program: More specific to Extrapulmonary Tuberculosis
(Tuberculosis meningitis and other extrapulmonary TB, bit not specific
to pulmonary TB)
• TB Control Program – DOTS
• Practical approach to lung health

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Meningococcal Meningitis
(Neisseria meningitidis)
Epidemiology
• Meningococcal meningitis is a form of meningitis caused by a specific bacterium
known as Neisseria meningitis, a serious infection of the thin lining that surrounds the
brain and spinal cord. (Though Meningitis can be caused by bacteria, viruses or fungi)
• There are twelve types of N. meningitis called as serogroups, out of which six types as :
A, B, C, W-135, X and Y can cause epidemics.
• It is life threatening CNS infectious disease affecting meninges.
• There is no animal reservoir, but is transmitted from person to person
• Upto 50% fatal if untreated and high frequency (more than 10%) of severe sequalae.
Early antibiotic treatment is the most important measure to save lives and reduce
complications

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Contd …
• Globally distributed, but high burden in belt of sub – Saharan Africa
• About 30,000 cases are still reported each year from sub Saharian Africa
• It can affect anyone of any age, but more prominent in preschool children and young
people
• Mostly transmitted through throat and sometimes overwhelms the body’s defense s
allowing to spread through the blood stream to brain
• It is believed that 1% to 10% of the population carry the disease in their throat and in
epidemic situation it can reach upto 25%
• In case of septicaemia, 8 – 15% patients die within 24 – 48 hours after onset of
symptoms even if treatment is initiated .
• Some reports suggest mortality can reach upto 50% within few hours.
• Even if treatment is successful,it may result in brain damage, hearing loss or disability in
10 – 20% survivors
• It is non pathogenic in nasopharynx
Contd …
• In December 2010, a new meningococcal A conjugate vaccine was introduced in Africa
through mass campaigns targeting persons 1 to 29 years of age. As of November 2017,
more than 280 million persons have been vaccinated in 21 African belt countries.
• About 10% of the adults are carriers of the bacteria to their nasopharynx
• About 10% of the cases develop impairment and death
• It is more prone in industrialized countries because of pollution.
• About 2500 to 3500 people get infected in US, with frequency of 1 in 100000 children
under 5 years
• In 1884, Ettore marchiafava and Angelo Celli first observed bacterium inside cells in CSF.
• In 1887, Anton Weichselbaum isolated the bacterium from CSF of patients with bacterial
meningitis and named as diplococcus intracellular meningitidis

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Contd ….
• Since 2008, European incidence rate has decreased form 0.95/100,000 to
0.68/100,000; higher rates have been registered in Lituania and UK (1.77
and 1.36, respectively).
• Newborns, 1-4year-old children and adolescents (15-25 years of age) are the
most affected subjects in all countries, irrespective of ongoing or not
immunization programs against MenC.
• In 2017, there were about 350 total cases of meningococcal disease reported
• The global incidence of meningococcal disease greatly changes in relation
to considered geographical areas; worldwide, 500,000-1,200,000 invasive
meningococcal diseases occur each year, with 50,000-135,000 deaths
Contd …
• The epidemiology of meningococcal infections has significantly changed over the
years in many regions of the world.
• Serogroup A has been the principal agent of invasive meningococcal disease in
Europe before and during I and II World Wars
• Serogroup B has been prevalent since 1970 in Europe and since 1980 in South
America; epidemic outbreaks due to W-135 and Y serogroups have emerged more
recently during the 21st century.
• Disease caused by serogroup A in Africa has an annual incidence equal to 10-20
cases per 100,000 inhabitants; epidemic outbreaks, occurring during dry season,
imply an attack rate greater than 1,000 cases per 100,000.
• Data from Latin America and Asia are limited. In Latin America, incidence ranges
between 0.1/100,000 in Mexico to 2 cases/100,000 in Brasil, with a predominance
of serogroups B and C
• In Asia, the epidemiological burden of meningococcal disease is not well defined.

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Contd …
• In 1982, outbreak occurred in Kathmandu
• In 1984 February, vaccination campaign was initiated in high risk
target population of age 1 – 24 years where 329000 doses of bivalent
meningococcal vaccines were given, achieving the overage of
approximate64%
• A dramatic decline occurred after vaccination
• The disease accounted 3.2% of all admissions and CFR was 8%

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