This document provides an overview of key concepts in epidemiology. It defines epidemiology and its components of study, distribution, determinants and health-related states or events. It describes epidemiological terminology including infection, contamination, infestation and different types of disease occurrence. It also outlines the epidemiological triad of agent, host and environment factors, modes of disease transmission, measurement tools and levels of disease prevention.
As per John M. Last (1988) 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.
Epidemiology is the study and analysis of the patterns, causes, and effects of health, disease & production conditions in defined populations, in terms of space and temporality.
As per John M. Last (1988) 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.
Epidemiology is the study and analysis of the patterns, causes, and effects of health, disease & production conditions in defined populations, in terms of space and temporality.
Introduction to Epidemiology
History of Epidemiology.
Definition of Epidemiology and its components.
Epidemiological Basic concepts.
Aims of Epidemiology.
Ten Uses of Epidemiology.
Scope or The Areas of Application .
Types of Epidemiological Studies.
This presentation will help to get an insight into Epidemiological methods and describes details of Descriptive epidemiology. It will be useful to medical researcher as an initial input.
Observingthedistributionofdiseaseorhealth related events in human population.
• Identify the characteristics with which the disease is associated.
• Basically 3 questions are asked who, when and where.
• Who means the person affected, where means the place and when is the time distribution.
The Presentation explains basic models of disease causation, to understand the etiology or causes of disease & altered production and helps to understand the applicability of causal criteria applied to epidemiological studies.
Introduction to Epidemiology
History of Epidemiology.
Definition of Epidemiology and its components.
Epidemiological Basic concepts.
Aims of Epidemiology.
Ten Uses of Epidemiology.
Scope or The Areas of Application .
Types of Epidemiological Studies.
This presentation will help to get an insight into Epidemiological methods and describes details of Descriptive epidemiology. It will be useful to medical researcher as an initial input.
Observingthedistributionofdiseaseorhealth related events in human population.
• Identify the characteristics with which the disease is associated.
• Basically 3 questions are asked who, when and where.
• Who means the person affected, where means the place and when is the time distribution.
The Presentation explains basic models of disease causation, to understand the etiology or causes of disease & altered production and helps to understand the applicability of causal criteria applied to epidemiological studies.
2nd year BSc Nursing - Unit- 3 BSc CHN_-Epidemiology.pptxthiru murugan
2nd Year B.Sc Nursing Community Health Nursing – IEPIDEMIOLOGY
By,
M. Thiru Murugan
UNIT-III: EPIDEMIOLOGY:
Definition, concept, aims, scope, uses and terminology used in epidemiology
Dynamics of disease transmission : epidemiological triad
Morbidity and mortality : measurements
Levels of prevention
Methods of epidemiology:
Descriptive
Analytical: Epidemic investigation
Experimental
Epidemiology
INTRODUCTION: Epidemiology is derived from Greek word “epidemic”
EPI – up on, DEMOS – people; LOGOS – study. Epidemiology means the study of disease in human population.
DEFINITION: “epidemiology is defined as the study of the distribution and determinants of health related states or events in specified populations and the application of this study to control the health problems”.
Concepts Basic to Epidemiology:
Host, Agent, and Environment Model:
Host: The host is a susceptible human or animal who harbors and nourishes a disease causing agent. Many physical, psychological, and lifestyle factors influence the host's susceptibility and response to an agent.
Concepts Basic to Epidemiology:
Agent: An agent is a factor that causes to a health problem or condition.
Causative agents can be Biological, Physical, Psychological, Economical, Nutritional, Environmental etc..
Concepts Basic to Epidemiology:
Environment: The environment refers to all the external factors surrounding the host that might influence vulnerability or resistance.
The physical environment
The psychosocial environment
AIMS OF EPIDEMIOLOGY
Aims:
to describe the distribution and size of disease problems in human population.
to identify the etiological factors.
to provide the data essential to the planning, implementation and evaluation.
SCOPE OF EPIDEMIOLOGY
I. According To Disease Group:
Infectious Disease Epidemiology
Cardio Vascular Epidemiology
Cancer Epidemiology
II. According To Group Of Factors
Nutritive Epidemiology
Reproductive Epidemiology
Environmental Epidemiology
Clinical Epidemiology
Molecular Epidemiology
Genetic Epidemiology
Computational Epidemiology
USES OF EPIDEMIOLOGY
Identify the causes of diseases.
Helps to describe the health status of the population.
Control the disease transmission.
Planning, implementing and evaluating health programmes on evidence basis.
TERMINOLOGIES USED IN EPIDEMIOLOGY
INFECTION: The entry and development or multiplication of an infectious agent in the body of man or animal.
ENDEMIC: The constant presence of a disease or infectious agent within a given geographical area or population group, without importation from outside.
EPIDEMIC: an out break of disease in a community in excess of normal expectation and derived from a common or propagated source.
SPORADIC: The cases occurs irregularly, haphazardly from time to time and generally infrequently.
TERMINOLOGIES USED IN EPIDEMIOLOGY
PANDEMIC: An epidemic which spreads from country to country or over the whole world.
ZOONOSES: Diseases or infections which are natu
A communicable disease is an illness due to a specific infectious (biological)agent or it's toxic products capable of being directly or indirectly transmitted from man to man,from animal to man,from animal to animal,from the environment (through air,water,food etc)to man.
infectious-diseases -lec 1.pptGangrene is a clinical condition of ischemic an...RabeaDia
Gangrene is a clinical condition of ischemic and necrotic tissue, often circumferential around a digit or extremity. It is identified by discolored or black tissue and associated sloughing of natural tissue planes. The three main types of gangrene are wet gangrene, dry gangrene, and gas gangrene.Aug 7, 2023
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Anti ulcer drugs and their Advance pharmacology ||
Anti-ulcer drugs are medications used to prevent and treat ulcers in the stomach and upper part of the small intestine (duodenal ulcers). These ulcers are often caused by an imbalance between stomach acid and the mucosal lining, which protects the stomach lining.
||Scope: Overview of various classes of anti-ulcer drugs, their mechanisms of action, indications, side effects, and clinical considerations.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
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Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
2. Content
• Definition
• Terminology
• Case Definition
• Mode of transmission
• Epidemiological Triad
• Natural History of Disease
• Iceberg Phenomenon of Disease
• Level Of Prevention
• Control of Disease
• Measurement in Epidemiology
• Epidemiological Studies
• Investigation Of Outbreaks
• Surveillance
3. Definition
• 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.
- John M. Last in 1988
Components
• Study - data driven, which relies on a systematic and unbiased
methods to the collection, analysis, and interpretation of
data.
• Distribution - deals with the frequency and pattern of
disease in specified population.
4. • Determinant -any factor, whether event, characteristic, or
other definable entity, that brings about a change in a health
condition or other defined characteristics.
• Health-related states or events - Anythings that affects the
well being of human being. It Includes communicable disease,
non-communicable disease chronic diseases, injuries, birth
defects, maternal-child health, occupational health,
environmental health and human behaviour like amount of
exercise and seat belt use.
5. Distribution of Disease
• It is concerned with the frequency and pattern of health
events in a population.
• Frequency- measurement of frequency of disease, disability
or death. The basic measure of disease frequency is a rate or
ratio.
• Pattern- refers to occurrence of health-related events by
time, place, and person. These are activites of descriptive
epidemiology.
• An important outcome of this study is formulation of
aetiological hypothesis
6. Determinant of Disease
• Determinants are the causes and other factors that influence
the occurrence of disease and other health-related events.
• Uses analytic epidemiological studies to provide the “Why”
and “How” of such events.
• Test aetiological hypotheses and findings provide sufficient
evidence to direct prompt and effective public health control
and prevention measures
7. TERMINOLOGY
INFECTION:The entry and development or multiplication of an
infectious agent in the body of man or animals.
Several levels of infection : colonization (e.g., S. aureus in skin
and normal nasopharynx); subclinical or inapparent infection
(e.g., polio); latent infection (e.g., virus of herpes simplex);
and manifest or clinical infection.
CONTAMINATION: The presence of an infectious agent on a
body surface; also on or in other inanimate articles or
substances including water, milk and food.
INFESTATION: the lodgement, development and reproduction
of arthropods on the surface of the body or in the clothing,
e.g., lice, itch mite.
8. • EPIDEMICS: The unusual occurrence of disease, specific
health-related behaviour or other health related events in a
community or region clearly in excess of "expected
occurrence".
• ENDEMIC :It refers to the constant presence of a disease or
infectious agent within a given geographic area or population
group, without importation from outside; may also refer to
the "usual" or expected frequency of the disease within such
area or population group. e.g. tuberculosis
9. • SPORADIC are those cases that occur irregularly, haphazardly
from time to time, and generally infrequently. e.g., polio,
tetanus. A sporadic disease may be the starting point of an
epidemic when conditions are favourable for its spread.
• PANDEMIC: An epidemic usually affecting a large proportion
of the population, occurring over a wide geographic area
such as a section of a nation, the entire nation, a continent
or the world. eg COVID-19 pandemic.
10. • SOURCE: Is a person, animal, object or substance from which
an infectious agent passes or is disseminated to the host .
Source refers to immediate source of infection & may or may
not be part of reservoir.
• RESERVOIR: Is any person, animal, arthropod,plant, soil or
substance in which an infectious agent lives & multiplies, on
which it primarily depends for survival, & where it
reproduces itself in such a manner that it can be transmitted
to a susceptible host.
HUMAN RESERVOIR: – Cases and Carriers
ANIMAL RESERVOIR: E.g. Rabies, Influenza, Yellow Fever,
Histoplasmosis
RESERVOIR IN NON-LIVING THINGS: E.g. Soil harbour agents
for Tetanus, Anthrax, Coccidiomycosis, Mycetoma
12. Case
• Cases: Persons having particular disease, health disorder or
condition under investigation. It can be clinical cases,
subclinical cases or Latent Infection.
Cases in Epidemiology
• Primary case: First case of communicable disease introduced
into the population unit being studied
• Secondary cases: Cases that develop from contact with the
primary case
• Index case: First case that comes to the notice of the
investigator (first case reported to the health system).
13. Case Definition
• A case definition is clinical criteria usually with confirmatory
laboratory tests, if available, or combinations of symptoms
(subjective complaints), signs (objective physical findings),
and other findings.
• Case definition may have several sets of criteria, depending
on how certain the diagnosis is. For example, during an
investigation of outbreak of COVID-19, a person with a fever
and cough might be classified as having a suspected,
probable, or confirmed case, depending on what evidence is
present.
14.
15.
16. Carriers
• Carriers: Infected person or animal that harbours a specific
agent in the absence of discernible clinical disease, & serves
as a potential source of infection for others
• Carriers are less infectious than cases but are more
dangerous epidemiologically.
• The "Typhoid Mary" is a classic example of a carrier.
17. MODE OF TRANSMISSION
DIRECT TRANSMISSION
1. Direct contact - contact from skin to skin, mucosa to mucosa,
or mucosa to skin of the same or another person. eg: STD
and AIDS, leprosy, leptospirosis, skin and eye infections
2. Droplet infection - direct projection of a spray of droplets of
saliva and nasopharyngeal secretions during coughing,
sneezing e.g. common cold, diphtheria, whooping cough,
tuberculosis, meningococcal meningitis,
3. Contact with soil – eg hookworm, tetanus, mycosis.
4. Inoculation into skin or mucosa e.g rabies, hepatitis B
5. Transplacental (vertical) :TORCH agents (Toxoplasma gondii,
rubella virus, cytomegalovirus and herpes virus), varicella
virus, syphilis, hepatitis B, Coxsackie B and AIDS.
18. INDIRECT TRANSMISSION mechanisms including the traditional
5 F's - "flies, fingers, fomites, food and fluid”
1. Vehicle-borne – through water, food and blood products, ,
acute diarrhoeas, typhoid fever, cholera, polio, hepatitis A,
food poisoning .
2. Vector-borne
a. Mechanical -infectious agent is mechanically transported
by a crawling or flying arthropod through soiling of its feet or
proboscis
b. Biological -infectious agent undergoing replication or
development or both in vector and requires an incubation
period before vector can transmit. three types
19. (i) Propagative : The agent merely multiplies in vector, but no
change in form, e.g., plague bacilli in rat fleas.
(ii) Cyclo-propagative : The agent changes in form and
number, e.g., malaria parasites in mosquito.
(iii) Cyclo-deve/opmental : The disease agent undergoes only
development but no multiplicatione.g.microfilaria in
mosquito
3. Air-borne
a. Droplet nuclei- tuberculosis, influenza, chickenpox
b. Dust - streptococcal and staphylococcal infection,
pneumonia, tuberculosis, Q fever and psittacosis
4. Fomite-borne e.g diphtheria, typhoid fever, bacillary
dysentery, hepatitis A, eye and skin infections
5. Unclean hands and fingers eg staphylococcal and
streptococcal infections, typhoid fever, dysentery, hepatitis A
and intestinal parasites
21. Incubation Period: It is the time interval between invasion by an
infectious agent and appearance of the first sign or symptom
of the disease in question .
Median incubation period: It is the time required for 50% of
cases to occur.
Generation time: It is the time taken for a person from receipt of
infection to develop maximum infectivity.
Latent period: It is the period from disease initiation to disease
detection, used in noninfectious diseases as equivalent of
incubation period.
Serial interval: It is the gap in onset between primary case (first
case in the community) and secondary case (case developing
through infection from the primary case)
22. Epidemiological Triad
The causative factors of disease may be classified as
1. AGENT,
2. HOST and
3. ENVIRONMENT.
• These three factors are referred to as epidemiological triad.
• The mere presence of agent, host and favourable
environmental factors in the prepathogenesis period is not
sufficient to start the disease in man.
• Interaction of these three factors is required to initiate the
disease process in man.
23. Agent Factor
• Agent factor is defined as a substance, living or non-living, or
a force, tangible or intangible, the excessive presence or
relative lack of which may initiate or perpetuate a disease
process.
Biological agent -viruses, rickettsiae, fungi, bacteria, protozoa
and metazoa
Nutrient agent- excess or deficiency of carbohydrate, protein,
vitamin and minerals
Physical agent- cold, heat, pressure, radiation
Chemical agent- Endogenous: urea, bilirubin
Exogenous:allergens, metals, fumes, dust
Mechanical agent - Exposure to chronic friction and other
mechanical forces may result in crushing, tearing.
24. Host factor
The host factors may be classified as:
(i) Demographic characteristics such as age, sex, ethnicity;
(ii) Biological characteristics such as genetic factors;
biochemical levels of the blood (e.g., cholesterol);
(iii) Social and economic characteristics such as
socioeconomic status, education, occupation, stress
(iv) Lifestyle factors such as personality traits, living habits,
nutrition.
25. Environmental factor
• The environment is defined as "all that which is external to
the individual human host, living and non-living, and with
which he is in constant interaction“.
• three components - physical, biological and psychosocial
26.
27. INFECTIVITY: this is the ability of an infectious agent to invade
and multiply in a host. Equals to Number infected/ Number
exposed .
PATHOGENICITY: this is the ability to induce clinically apparent
illness. Equals to Number of diseased/ Number infected .
VIRULENCE: this is defined as the proportion of clinical cases
resulting in severe clinical manifestations (including sequelae).
It is Number of serious condition & mortality/ Number
diseased .The case fatality rate is one way of measuring
virulence.
29. ICEBERG PHENOMENON OF DISEASE
• Disease in a community may be
compared to an iceberg
• Floating tip: What physician sees in
community (Clinical cases)
• Vast submerged portion: Hidden mass
of disease
• Line of demarcation (water surface):
Is between apparent and inapparent
infections.
• Not shown by rabies, tetanus,
measles and rubella
31. PRIMODIAL PREVENTION
• It is the prevention of the emergence or development of risk
factors in countries or population groups in which they have
not yet appeared .
• Modes of Intervention:
1. Individual Education
2. Mass Education
• Primordial Level is Best level of prevention for Non-
communicable diseases.
32. Primary Prevention
It is the action taken prior to onset of disease, which removes
the possibility that a disease will ever occur Modes of
Intervention:
1. Health Promotion: e.g. Health Education, Environmental
modifications, Nutritional interventions, Lifestyle and
behavioural changes.
2. Specific Protection: immunization (b) use of specific
nutrients (c) chemoprophylaxis (d) protection against
occupational hazards (e) protection against accidents
Primary level of prevention is applied when ‘risk factors are
present but disease has not yet taken place.
33. Secondary Prevention
• It halts the progress of disease at its incipient stage and
prevents complications.
• Modes of Intervention:
1. Early Diagnosis: Detection of disturbances while
biochemical, functional and morphological changes are still
reversible or prior to occurrence of manifest signs and
symptoms
2. Treatment: Shortens period of communicability, reduces
mortality and prevents occurrence of further cases (secondary
cases) or any long term disability –
• Secondary level of prevention is applied when disease has
possibly set in.
34. Tertiary Prevention
• Is applied when disease has advanced beyond early stages.
• It aims to reduce or limit impairments and disabilities,
minimize suffering caused by existing departures from good
health –
• Modes of Intervention:
1. Disability Limitation: It prevents the transition of disease
from impairment to handicap
2. Rehabilitation: Training and retraining of an individual to
the highest possible level of functional ability; It can be
medical, vocational, social or psychological.
35. EXAMPLES
• A patient with fever and cough >3 weeks comes to DOTS Clinic
for ‘Sputum for AFB’: Early diagnosis mode of intervention,
Secondary Level of Prevention (as disease has possibly set in
and sputum for AFB is used to confirm it as a case of
tuberculosis)
• A person sleeps inside a bednet: Specific Protection mode of
intervention, Primary Level of prevention (risk factors, i.e,
mosquitoes are already present, disease has not yet taken place)
• A child coming to Immunisation clinic for OPV Vaccine: Specific
Protection mode of intervention, Primary Level of prevention
(risk factors, i.e, polio infection already present, disease has not
yet taken place) .
• A Urine strip for sugar detection was employed to screen
diabetics in a community: Early diagnosis mode of intervention,
Secondary Level of prevention (screening is meant for early
diagnosis of a disease)
36. STEPS IN DISEASE CONTROL
• Disease control: Is reducing the transmission of disease agent
to such a low level that it ceases to be a public health
problem. Control program in Nepal: TB, Leprosy, Dengue
• Disease elimination: Is complete interruption of transmission
of disease in a defined geographical area, but the causative
organism may be persisting in environment. Elimination
program in Nepal: Poilo, malaria and Kalazar.
• Disease eradication: Is complete ‘extermination’ of organism–
Is ‘tearing out by roots’ of a disease e.g small pox.
37. Measurement in Epidemology
• Mortality – Crude death rate, Specific death rate, Case fatality
rate, Propotional mortality rate, survival rate
• Morbidity – Incidence and Prevalance, Notification rates,
Admission, re-admission and discharge rates , duration of stay
in hospital.
• Disability – DALY,
• Measurement of medical needs, health care facilities,
utilization of health services, other health-related events and
demographic events.
38. Measurement Tool
Rate: Numerator is a part of denominator and multiplier is 1000
or 10,000 or 100,000 or so on
Ratio: Numerator is not a part of denominator and both
numerator and denominator are unrelated .
Proportion: Numerator is a part of denominator and multiplier is
100.Proportion is always expressed in percentage.
40. INCIDENCE AND PREVALANCE
• Both are morbidity measurement
• Incidence is defined as the ‘no. of new cases’ occurring in a
defined population during a specified period of time .
• Incidence = No. of new cases of a disease in a year/ Total
population at risk X 1000
• It is Rate.
• Special types of incidence rates:
• Attack rate : Incidence rate used when population is exposed
for a small interval of time, e.g. epidemic
• Secondary Attack Rate (SAR): Is no. of exposed persons
developing the disease within range of incubation period,
following exposure to the primary case.
• Incidence can be determined from: Cohort study
41. • Prevalence: Is total current (Old + New) cases in a given population
over a point or period of time .
• Types of prevalence:
Point Prevalence - point of time
Period Prevalence - period of time
• Prevalance = No. of total (new + old) cases of a disease in a year /
total population X 100
• It is a proportion.
• It can be determined from: Cross Sectional Study
• Relationship between Incidence and Prevalence: Given the
assumption that population is stable AND incidence & duration are
unchanging, Prevalence = Incidence × Mean duration of the
disease
• Example incidence of hepatitis A virus (HAV) infections over a
period of 1 year is always greater than its prevalence at a given
point because the disease has a very short duration. In contrast, the
prevalence of HIV or M. tuberculosis infections is always greater
than its incidence because the infection is chronic, and infected
44. DESCRIPTIVE STUDIES
Steps
1.Defining the population to be studied
2. Defining the disease under study
3. Describing the disease by time, place and person
4. Measurement of disease
5. Comparing with known indices
6. Formulation of an aetiological hypothesis
45. ANALYTICAL STUDIES
Case control studies : often called retrospective studies.
Steps in Case control studies
• Statement of the hypothesis
• Selection of cases and control
• Matching between cases and controls
• Measurement of exposure
• Analysis and interpretation.
Odds ratio : is a measure of estimation of disease risk associated
with exposures in case control studies. Also called cross
product ratio. OR = ad/bc for 2x2 contigency table.
46.
47. Cohort is defined as a group of people who share a
common characteristic or experience within a defined
time period (e.g., age, occupation, exposure to a drug or
vaccine, pregnancy, insured persons, etc). Cohort studies
are prospective studies.
Steps in Cohort studies
• Selection of study subject
• Selection of comparison group
• Obtaining information on exposure
• Follow-up
• Analysis and interpretation.
48.
49. • Relative risk (RR) = Incidence among exposed/ Incidence
among non-exposed
• Attributable risk (AR) = (Incidence among exposed –
Incidence among nonexposed)/ Incidence among exposed ×
100
50.
51. • Bias: Is any ‘systematic error’ in an epidemiological study,
occurring during data collection, compilation, analysis and
interpretation.
• Confounding: Any factor associated with both exposure and
outcome, and has an independent effect in causation of
outcome is a confounder. Example In the study of the role of
alcohol in the aetiology of oesophageal cancer, smoking is a
confounding factor because it is associated with the
consumption of alcohol and it is an independent risk factor
for oesophageal cancer.
• Matching: Process of selecting controls in a such a way that
they are similar to cases.Matching eliminates confounding.
52.
53. Preclinical and clinical trials
• These are experimental studies, research activities that
involve the administration of a treatment or prevention
regimen to humans to evaluate its safety and efficacy.
54. Investigation of Outbreak
• Verification of diagnosis:
Is the first step in investigation of an epidemic.It is not
necessary to examine all cases, take sample Do not wait for
laboratory results for epidemiological investigations
• Confirmation of existence of an epidemic:
Compare with disease frequencies during same period in
previous years
• Defining the population at risk:
Obtaining the map of the area. Calculation of appropriate
denominator of population at risk.
• Rapid search for all cases and their characteristics:
Medical survey
Epidemiological case sheet
55. Searching for more cases :this period is usually taken as twice
the incubation period of the disease since the occurrence of
last case
• Data analysis:
Time: Construction of an epidemic curve
Place: Preparation of a spot map
Person: Analysis by age, sex, occupation and other risk factors
• Formulation of hypothesis
• Testing of hypothesis
• Evaluation of ecological factors
• Further investigation of population at risk
• Writing report
58. SURVEILLANCE
• Surveillance: Is the ongoing systematic collection and
analysis of data and the provision of information which
leads to action being taken to prevent and control a
disease, usually one of an infectious nature.
Types
• Passive Surveillance: Data is itself reported to the health
system - Example: A patient with fever coming on his own
to the PHC
• Active Surveillance: Health system seeks out ‘actively’ the
collection of data, i.e., goes out to community to collect
data
• Sentinel Surveillance: ‘identifying missing cases’ and
‘supplementing notified cases. s done in National AIDS
Control Program wherein STD Clinics.
60. SURVEILLANCE OF COMMUNICABLE
DISEASE IN NEPAL
A. Early Warning And Reporting System (EWARS)
• hospital based sentinel sentinel surveillance system
• Present in 118 hospitals covering all 75 districts of Nepal
• complement the country’s Health Management Information
System (HMIS) by providing timely reporting.
• weekly reporting of detailed line list of cases and deaths
(including "zero" reports)
• six priority diseases/syndromes—Malaria, Kala-azar, Dengue,
Acute Gastroenteritis (AGE), Cholera and Severe Acute
Respiratory Infection (SARI), and other epidemic potential
diseases/syndromes (like enteric fever, Leptospirosis,
Hydrophobia, Chickungunya etc.).
61. • Focuses on immediate reporting (to be reported as soon as
possible within 24 hours of diagnosis) of one confirmed case
of Cholera, Kala-azar, severe and complicated Malaria and one
suspect/clinical case of Dengue as well as 5 or more cases of
AGE and SARI from the same geographical locality in one
week period.
B. Active Surviellience
Active surveillance of infectious disease is done if an outbreak
occurred or is suspected to keep close track to the number of
cases.
C. Water Quality Monitoring and Surveillance
• Regular monitoring of drinking water quality from various
sources and distribution sites
• Regular surveillance of water borne diseases and coordinate
with different stakeholders for quality surveillance.
62. REFERANCES
• Park Textbook of Preventive and Social
Medicine 23rd edition
• Mandell, Douglas, and Bennett’s Principles
and Practice of INFECTIOUS DISEASES
• Mahajan and Gupta Textbook of Preventive
and Social Medicine, 4th edition
• Principles of Epidemiology in Public Health
Practice by CDC
• National Annual Report 75/76