epidemiology of communicable disease, Respiratory diseases.

2. DEFINITION
 Epidemiology is the study of the distribution and determinants of
health-related states or events (including disease), and the application
of this study to the control of diseases and other health problems.
-WHO
 The study of frequency ,distribution and determinants of disease and
health related states and events and application of knowledge in
prevention ,control and mitigation of these problem

3. EPIDEMIOLOGICAL TRIAD

4. EPIDEMIOLOGICAL TRIAD -
EXAMPLE

5. TYPES OF DISEASES

6. COMMUNICABLE DISEASES
 Small pox
 Varicella (Chickenpox)
 Cholera
 Typhoid
 Diphtheria
 Pertussis ( Whooping cough)
 Dengue
 Haemophilus influenzae
 Hepatitis A

7. Cont..
 Plague
 Poliovirus
 Rabies
 Measles (Rubeola)
 ​Meningococcal Infections
 ​Rubella, (German Measles)
 ​Tetanus
 ​Tetanus
 ​​Mumps
 Yellow Fever
 ChikungunyaMalaria

8. SMALL POX
1798 Edward Jenner Discovered
Eradicated in india
AGENT:
 Variola Virus ,a member of orthopox virus
HOST:
 All ages and both the sexes
ENVIRONMENT:
 overcrowding

9. MODE OF TRANSMISSION:
 Inhalation
 Direct contact with scabs or pustules material from skin
lesions
 Air borne route via droplet
INCUBATION PERIOD:
 12 days but ranges between 7 – 17 days

10. PRE-ERUPTIVE SIGNS AND
SYMPTOMS
 Fever
 Head ache
 Chills
 Back ache
 Pharyngitis
 Vomiting
 Delirium
 Diarrhoea
 Abdominal pain
 convulsion

11. PROGRESSION OF
SMALL POX
 Various stages of blisters like Macules, Papules, Vesicles, Pustules
and Scab.
 Macules appear 1st in tongue and palate
 Then on face and forehead
 Then proximal part of extremities
 Then distal part of extremities
 Then from day 3 -4 all lesions evolve quickly to papules, vesicles ,
pustules and finally fluid absorbed and lesions become flatter
and feel like hard peas in skin ( scab)

12. MACULE

13. PAPULE

15. PUSTULE

17. SMALL POX ERADICATED
FROM WORLD
 Last case reported in somalia in 1977
 1980 WHO declared Small pox eradicated
 In april 1977 India is declared as “ small pox free country”

18. CHICKEN POX

19. DEFINITION
Chicken pox is a viral infectious disease
characterised by different stages of rashes that may be
accompanied by fever, malaise and vesicular skin
lesions.

20. EPIDEMIOLOGICAL TRIAD
Causative Agent:
 Varicella zoster virus
 Found in oropharyngeal secretions and lesions of skin
Host:
 12 years of age
 All person develop life long immunity after chicken
pox
 Infection during pregnancy is risk for fetus and
neonate
Environment:
 Overcrowding and season ( 1 – 6 months)

21. MODE OF TRANSMISSION
 Person to person by air borne through droplets
 By direct contact with vesicle fluid
 Through infected articles
INCUBATION PERIOD:
14 – 16 days

22. CLINICAL FEATURES
2 STAGES
PRE ERUPTIVE
i. Sudden onset of
mild or moderate
fever
ii. Back ache and
malaise
ERUPTIVE
i. Eruption of rashes
ii. This stage is characterised
by
a. centripetal
distribution
b. Rapid advancement:
advances quickly
macules,papules,
vesicles and scabs.
a. Fever

23. CONTROL MEASURES
 Isolation
 Disinfection of articles
 Contact should be kept under the observation for 21 days

24. MANAGEMENT
 Symptomatic treatment
 Plenty of water
 Cotton gloves
 Varicella zoster immunoglobulin 1.25 to 5 ml IM – 72 hrs
after exposure
 Immunosuppressed and pregnant women
to avoid contact with affected person
 Sick children not to school

25. RUBELLA
Also called as german measles
Discovered in 18th century
Rubella infection in pregnancy may lead to fetal death or
congenital defects or congenital rubella syndrome
Exanthema begin initially on face and neck and spreads
centrifugally to trunk and extremities within 24 hours

27. EPIDEMIOLOGICAL TRIAD
1. AGENT:
a. RNA virus of the Toga virus family
b. Found in Naso pharynx,throat, blood, CSF and
urine of an infected person.
c. Clinical and sub clinical cases are source of infection
(person is infectious from a week before symptoms to
about a week after the appearance of rashes)
d. Infant born with rubella shed infection for many months

28. HOST:
Human are known host
Children 3 – 10 years
ENVIRONMNENT:
Seasonal pattern (later winter and spring)

29. MODE OF TRANSMISSION:
 Air borne droplet
 Placental Barrier

30. INCUBATION PERIOD:
 2 TO 3 weeks
SIGNS AND SYMPTOMS:
 Rash
 Low fever
 Sore throat
 Cough
 Nausea and mild conjunctivitis
 Rash starts in face and neck and progress down the body
 Lymph nodes swollen
 Arthritis and painful joints

31. COMPLICATIONS:
 Pregnant women show 90% chance of transmitting virus
to fetus leads miscarriage, still birth and severe birth
defects

32. CONGENITAL RUBELLA
SYNDROME

33. PREVENTION
 Monovalent and combined vaccines (MMR)

35. DEFINITION:
Mumps is a viral infection of humans that primarily
affects the salivary glands

36. AGENT:
 Myxo virus
 Virus found in saliva, blood, human milk and urine,
occasionally in CSF
HOST:
 Children 5 – 15 years
 Single attack gives lifelong immunity
ENVIRONMENT:
 Overcrowding

37. MODE OF TRANSMISSION:
 Human
 Direct contact and air borne droplets
INCUBATION PERIOD
 2 – 3 weeks
CLINICAL FEATURES:
Fever, headache
Pain and swelling in either one or both parotid gland

38. Cont..
 Ear ache in the affected side
 Pain and stiffness while opening the mouth
 It may also affects Pancreas,Testis,ovaries,Prostate and
CNS

40. PREVENTION
 Mono valent live attenuated 0.5ml IM or SC
 Combined vaccine MMR

41. ACUTE RESPIRATORY INFECTION

42. ARI
UPPER RESPIRATORY TRACT LOWER RESPIRATORY
INFECTION TRACT INFECTION
 (Nostril to Vocal cord) ( Trachea, Bronchi,Bronchioles
and alveoli)
 Common cold, Pharyngitis Epiglottitis, Laryngitis,
Otitis media. bronchitis, Bronchiolitis and
pneumonia

43. AGENT:
Bacteria:
Corynebacterium diphtheria
Haemophilus influenza
Klebsilla pneumoniae
Staphylococcus
Pyogens
Bordetella pertussis
Viral:
Influenza A,B,C
Adenovirus
Enterovirus
Corona virus
Measles

44. HOST:
 Small chidren
 Adult women
ENVIRONMENT:
 Climate conditions
 Poor housing
 Industralisation
 Urbanisation
 Overcrowding
 Poor nutrition
 LBW
 Smoke pollution

45. MODE OF TRANSMISSION:
 Air borne route
 Face to face contact
CLINICAL SYMPTOMS:
Fever
Cough
General malaise
Sore throat
Irregular breathing
Rhinitis
Inability to drink

46. ILLNESS OF YOUNG INFANT(LESS THAN 2
MONTHS OF AGE):
Young infants can become sick and die very quickly from
bacterial infections
Non specific signs – poor feeding,fever.
DANGER SIGNS OF VERY SERIOUS DISEASE IN
YOUNG INFANTS ( < 2 MONTHS OF AGE):
Unusually sleepy or hard to wake
Stridor when calm
Not feeding well
Wheezing
Fever or sub normal body temperature

47. PREVENTION:
 Facilitate good living conditions
 Advise to put on appropriate seasonal clothing
 Provide better nutrition
 Avoid long pouring baths in open air
 Try to avoid or reduce in door smoke pollution
 Advise parents to follow immunization schedule.
 Assess the knowledge of mother related o cause, spread,
prevention and management of ARI
 Health educate families to recognize pneumonia
 Conduct health promotional activities in vulnerable area

48. TUBERCULOSIS

49. INTRODUCTION
 About one third of the world’s population has dormant
TB.
 Tuberculosis takes its place in the top 5 causes of death
among women of 15 to 44 tears group
 The estimated number of TB is showing the downward
trend but in a slow phase
 Tuberculosis is a leding cause of all HIV – related deaths.

50. CAUSATIVE AGENT:
The causative organisms of tuberculosis is Mycobacterium
tuberculosis is a facultative intracellular parasite.
There are two strains – human strain responsible for vast
majority of cases occurring among human beings and
bovine strain is responsible for infecting cattle and other
animals
The source of infection is human cases whose sputum is
positive for tubercle bacilli and milk from infected animal.
Patients are infective as long as they remain untreated.

51. HOST FACTORS:
 TB affects all ages and more prevalent in males than in
females
 Though it is not a hereditory disease, twin studies indicate
that inherited susceptibility is an important risk factor.
 Malnutrition pre disposes tuberculosis due to poor
resistance
 BCG vaccination
 With initiation of chemotherapy host factors are
considered less relevant in the epidemiology of TB

52. ENVIRONMENTAL FACTORS:
 Poor quality of life
 Poor housing conditions
 Overcrowding
 Population explosion
 Malnutrition
 Lack of education
 Lack of awareness
 Large families
 Early marriages

53. MODE OF TRANSMISSION:
TB is transmitted mainly by droplet infection and droplet
nuclei generated by sputum of positive patients with
pulmonary TB. droplets are generated by coughing
TB is transmitted by fomites, such as dishes and other
articles used by the patients.
INCUBATION PERIOD:
 3 – 6 WEEKS

54. CLINICAL MANIFESTION
 Persistent cough
 Weight loss
 Fever
 Night sweats
 Hemoptysis
 Chest pain
 fatigue

55. LAB INVESTIGATION
MANTOUX TEST:
The TB screening test is conducted by injecting tuberculin
purified protein derivative of 0.1 ml into the inner surface
of the forearm.
The tuberculin syringe is used to administer this
intradermal injection.
This injection will produce a pale elevation of the skin as
a wheal 6 to 10 mm in diameter

56. Cont:
 The reaction of the skin test should be read within 48 – 72
hours administration.
 In case if the patient does not visit the clinic within 72
hours he has to be called for another skin test.
 The reaction is measured in millimeters of the induration
(palpable, raised, hardened area or swelling)
 If the induration is more than 10 mm the test is said to be
positive.

58. MANTOUX TEST
INTERPRETATION
INDURATION INTERPRETATION
Induration > 10 mm Positive
Induration > 6 mm Negative
Induration between 6 and 9mm Doubtful
Induration 5 and > 5mm is considered
positive in
HIV infected persons
A recent contact of a aperson with TB
disease
Person who are immuno suppressed for
other reasons

59. SPUTUM EXAMINATION
 Sputum examination is the cheapest and most suited tool
for finding the cases
 Sputum smear collected from suspected persons should be
collected early in the morning on three successive days
 The presence of atleast 10,000 oraganisms per ml of
sputum is considered “ TB positive”
 As per RNTCP priority for sputum smear examination
should be given to patients who come on their own to
hospital or health centre with the following symptoms

60. Cont…
 persistent cough 3 – 4 weeks duration
 Continuous fever
 Chest pain
 Hemoptysis
SPUTUM CULTURE:
It Is A Long Process Needs Trained People To Perform
It is delivered only as centralized service in hospitals
Advised for the patients whose sputum smear is negative but
has chest symptoms.

61. MASS MINIATURE RADIOGRAPHY:
This is abandoned as a case finding measure because of its
poor yields with high cost.
CHEST X – RAY:
 Additional method to diagnose pulmonary TB when only
one smear is positive.

62. TREATMENT

64. CHEMOTHERAPY
TREATMENT
GROUPS
TYPE OF PATIENT REGIMEN
INTENSIVE
PHASE (IP)
CONTINUATION
PHASE (CP)
New (Cat I) •New sputum smear
positive
•New sputum smear
negative
•New
extra‐pulmonary
•New others
2 H3R3Z3E3 4 H3R3
Previously treated
(Cat II)
•Smear positive
relapse
•Smear positive
failure
•Smear positive
treatment after default
•Others
2 H3R3Z3E3 S3/
1 H3R3Z3E3
5 H3R3E3

65. DIPHTHERIA

66. INTRODUCTION
 Diphtheria is an endemic disease.
 WHO estimates the global burden of the disease in terms of
healthy life cost attributable to diphtheria.
 It is about 185000 DALYs and about 5000 persons died due to
diphtheria.
 An acute toxic infection caused by Corynebacterium
diphtheriae and rarely toxigenic strains of Corynebacterium
ulcerans.

67. EPIDEMIOLOGY
Agent:
 Cornybacterium diphtheriae
 The source of infection are cases and carriers
 The causative organism is present in nasopharyngeal secretions,
discharge of skin lesions, contaminated fomites and infected dust.
Host :
 Children 1 – 5 years of age
 Both the sexes

68. EPIDEMIOLOGY
Environmental factors :
 Common in winter although it occurs in all seasons.
 Overcrowding, poor sanitation and hygiene, illiteracy, urban
migration and close contacts can lead to outbreak

69. MODE OF TRANSMISSION:
 Droplet nuclei
 Infected cutaneous lesion
 Infected object or dust, contaminated with nasopharyngeal
secretions.
PORTAL OF ENTRY:
 Respiratory route
 Skin cuts, wounds etc..
INCUBATION PERIOD:
 2 – 6 days.

70. CLINICAL MANIFESTATIONS
 The disease begins insidiously with a sore throat.
 Despite modest fever there is usually marked tachycardia.
 The diagnostic feature is the 'wash-leather' elevated
greyish-green membrane on the tonsils. It has a well-
defined edge, is firm and adherent, and is surrounded by a
zone of inflammation.
 There may be swelling of the neck ('bull-neck') and tender
enlargement of the lymph nodes.

71. Classification (location):
Pharyngeal tonsillar diphtheria
Nasal diphtheria
laryngeal or laryngotracheal diphtheria
 cutaneous diphtheria

72. CLINICAL MANIFESTATIONS
i. Nasal diphtheria:
 Infection of the anterior nares- more common among
infants, causes serosanguineous, purulent, erosive
rhinitis with membrane formation
 Shallow ulceration of the external nares and upper lip

73. Tonsillar and pharyngeal diphtheria:
sore throat is the universal early symptom
 Only half of patients have fever and fewer have dysphagia,
hoarseness, malaise, or headache
 unilateral or bilateral tonsillar membrane formation extend to the
uvula, soft palate, posterior oropharynx, hypopharynx, or glottic
areas
 Underlying soft tissue edema and enlarged lymph nodes: bull-neck
appearance

75.  Laryngeal diphtheria: At significant risk for suffocation
because of local soft tissue edema and airway obstruction by
the diphtheritic membrane
 Classic cutaneous diphtheria is an indolent, nonprogressive
infection characterized by a superficial, ecthymic, nonhealing
ulcer with a gray-brown membrane

78. TREATMENT
1. Antitoxin:
 Mainstay of therapy
 Neutralizes only free toxin, efficacy diminishes with elapsed time
 Antitoxin is administered as a single empirical dose of 20,000-120,000 U based on
the degree of toxicity, site and size of the membrane, and duration of illness
2. Antimicrobial therapy
 Halt toxin production, treat localized infection and prevent transmission of the
organism to contacts
 erythromycin (40-50 mg/kg/day 6 hrly [PO] or [IV]), aqueous crystalline
penicillin G (100,000-150,000 U/kg/day 6 hrly IV or [IM]), or procaine penicillin
(25,000-50,000 U/kg/day 12 hrly IM) for 14 days

79. PREVENTION
Asymptomatic Case Contacts:
 Antimicrobial prophylaxis -erythromycin (40-50 mg/kg/day divided qid
PO for 10 days) or a single injection of benzathine penicillin G
(600,000U IM for patients <30 kg, 1,200,000U IM for patients ≥30 kg)
Asymptomatic Carriers:
 Repeat cultures are performed about 2 wk after completion of therapy. if
results are positive, an additional 10-day course of oral erythromycin
should be given and follow-up cultures performed

81. VACCINE:
i. Combined vaccine: DPT vaccine
ii. Single vaccine: FT, PTAP, APT, PTAH
iii. Antisera: diphtheria anti toxins
 Prophylactic: 500 – 2000 units
 Therapeutic: 10,000 to 30000 units or
40000 to 100000 units ( 2 divided doses with an
interval of ½ to 2 hours)

82. Whooping cough: whooping sound made when
gasping for air after a fit of coughing
Cough of 100 days
PERTUSSIS (WHOOPING COUGH)

83. INTRODUCTION
 A highly contagious acute bacterial infection caused by the bacilli
Bordetella pertussis
 Currently worldwide prevalence is diminished due to active
immunization
 However it remains a public health problem among older children and
adults
 It continues to be an important respiratory disease afflicting
unvaccinated infants and previously vaccinated children and adults
(waning immunity)

88. SIGNS AND SYMPTOMS
Stage I (catarrhal stage; 1-2 weeks): insidious onset of coryza,
sneezing, low grade fever and occasional cough
Stage II (paroxysmal cough stage; 1-6 weeks):
 due to difficulty in expelling the thick mucous from the
tracheobronchial tree,At the end of paroxysm long inspiratory
effort is followed by a whoop
 In between episodes child look well. During episode of cough
the child may become cyanosed, followed by vomiting,
exhaustion and seizures

89. Signs and symptoms
 Cough increase for next 2-3 weeks and decreases over next 10
weeks
 Absence of whoop
 Stage III (convalescence stage): period of gradual recovery
even up to 6 months

90. TREATMENT
1. Avoidance of irritants, smoke, noise and other cough
promoting factors
2. Antibiotics: effective only if started early in the course of
illness. Erythromycin (40-50 mg/kg/day 6 hrly orally for 2
weeks or Azithromycin 10 mg/kg for 5 days in children<6
months and for children>6 months 10 mg/kg on day 1,
followed by 5mg/kg from day2-5 or Clarithromycin 15
mg/kg 12 hrly for 7 days
3. Supplemental oxygen, hydration, cough mixtures and
bronchodilators (in individual cases)

91. PREVENTION
 Early diagnosis
 Isolation
 All household contacts should be given erythromycin for 2 weeks
 Children <7 years of age not completed the four primary dose should
complete the same at the earliest
 Children <7 years of age completed primary vaccination but not received
the booster in the last 3 years have to be given a single booster dose
 VACCINE – DPT vaccine 3 doses given at the interval of 1 month.
 It is given at 1 ½ months,2 ½ and 3 ½ months.
 And booster dose is given at the age of 18 – 24 months.

92. MEASLES

93. DEFINITION
 Measles is an acute highly contagious viral disease
caused by the paramyxovirus. It is characterized by
fever,koplik’s spots and maculopapules.
 Measles is characterized by small red dots appearing on
the surface of the skin, irritation of the eyes (especially
on exposure to light), coughing, and a runny nose.
About 12 days after first exposure, the fever, sneezing,
and runny nose appear
 Also known as Morbilivirus or Rubeola

94. Agent
• Agent- RNA virus ( Paramyxo virus)
• Source of infection-cases of measles,but not carriers.
• No animal reservoir
• Infective material- Nasal secretion ,Respiratory tract
&Throat
• Communicability- Highly infectious during prodromal
period and at the time of eruption.
• Secondary attack rate- > 80%

95. Host factors
 Age- 6 months to 3 years even up to 10 years
 Incidence equal in both sexes
 Immunity – life long immunity
 Malnourished children are susceptible

96. Environmental factor
•Winter season, over crowding
•Transmission – Droplet infection
• 4 days before and 4 days after rash
•Incubation period- 7 days

97. Clinical features
 Prodromal stage
 Eruptive stage
 Post-measles stage

98. COMMON SYMPTOMS
• 3 Cs (Cough, Coryza & Conjunctivitis)
• Four days fever (400c)
• A high temperature, sore eyes, and a runny nose
usually occur first.
• Koplik spots - Small white spots usually develop inside
the mouth a day or so later. This can persist for several
days.
• Generalized, maculopapular,erythematous rash - A red
blotchy rash normally develops about three to four
days after the first symptoms. It usually start on the
head and neck ,and spreads down the body. It takes 2-3
days to cover most of the body. The rash often turns .a
brownish colour and gradually fades over a few day 8

100. KOPLIK SPOT

101. Complication
 Diarrhea,
 Pneumonia
 Otitis media
 Convulsions,
 SSPE (sub acute sclerosing panencephalitis)

103. Prevention
 Isolation precautions - especially in hospitals and
other institutions, should be maintained from the 7th
day after exposure until 5 days after the rash has
appeared.
 Immunization

104. Age Vaccines Note
9 months Measles
Deep subcutaneous injection
into the upper arm.
12-15
months MMR -1
Deep subcutaneous injection
into the upper arm.
5 years MMR -2
Deep subcutaneous injection
into the upper arm.