EPIDEMIOLOGY OF TUBERCULOSIS

1. EPIDEMIOLOGY OF
TUBERCULOSIS
DR MAHESWARI JAIKUMAR
maheswarijaikumar2103@gmail.com

2. TUBERCULOSIS
• Tuberculosis is a specific
respiratory disease caused by m.
tuberculosis.
• The disease primarily affects
lungs and causes pulmonary
tuberculosis.

3. • It can also affect intestine,
meninges, bones and joints,
lymph glands, skin and other
tissues of the body.
• The disease is usually chronic
with varying clinical
manifestations.

4. • The disease also affects animals
like cattle (bovine tuberculosis)
which may be sometimes
communicated to man.
• Pulmonary TB is the most
important form of TB which
affects man.

5. DISEASE BURDEN

6. NATURAL HISTORY
OF TUBERCULOSIS

7. AGENT
Mycobacterium tuberculosis

8. • M. tuberculosis is a facultative
intracellular parasite.(readily
ingested by phagocytes and is
resistant to intracellular killing).
• It is an acid fast, gram positive,
rod shaped bacilli.

9. SOURCE OF INFECTION
• There are two sources of
infection-human and bovine.

10. • HUMAN SOURCE : The most
common source of infection is
the human case whose sputum is
positive for tubercle bacilli, who
has not received treatment or
not treated fully.

11. COMMUNICABILITY
• Patients are infective as long as
they remain untreated.
• Effective antimicrobial treatment
reduces infectivity by 90% within
48 hours.

12. HOST FACTORS

13. AGE & GENDER
• Tuberculosis affects all ages.
• TB is more prevalent in males
than in females.

14. HEREDITY
• Tuberculosis is not a hereditary
disease.

15. NUTRITION
• Malnutrition (under nutrition)
is widely believed to
predispose TB.

16. IMMUNITY
• Man has no inherited immunity
against TB.
• It is acquired as a result of
natural infection or BCG
vaccination.

17. SOCIAL FACTORS
• TB is social disease with medical
aspects.
It is considered to be a
barometer of social welfare.

18. • The social factors include factors
such as poor quality of life, poor
housing, overcrowding,
population explosion, under
nutrition, lack of education,
large families, lack of awareness
of cause of illness.

19. • All the afore said factors are
interrelated and contribute to
the occurrence of TB.

20. MODE OF TRANSMISSION
• TB is transmitted through
droplet infection and droplet
nuclei generated by sputum
positive patients with pulmonary
TB.

21. • To transmit infection, the
particles must be fresh enough
to carry viable organism.
• Coughing generates the largest
number of droplets of all sizes.

22. • The frequency and vigour of
cough and the ventilation of the
environment influence
transmission of infection.
• TB is not transmitted by fomites.

23. INCUBATION PERIOD
• Ranges from 3 to 6 weeks, and
thereafter the disease depends
upon the closeness of contact,
extent of the disease and
sputum positivity of the source
case (dose of infection) and host
parasite relationship.

24. • Thus the incubation period in
the real sense may extend to
weeks, months or years.

29. CLINICAL MANIFESTATION

30. CONTROL OF TB

31. • The control measures consists of :
1. CURATIVE COMPONENT.
2. PREVENTIVE COMPONENT.

32. • The most powerful tool in
containing the disease is CASE
FINDING AND TREATMENT.

33. CASE FINDING
• The first step in a tuberculosis
control programme is early
detection of sputum positive cases.
• This must be done as an intensified
ongoing programme.

34. CASE DEFINITION
• WHO defines a case as “a patient
whose sputum is positive for
tubercle bacilli, and such cases
are the target of case finding.

35. SUSPECTS
• All other possible sufferers from
tuberculosis whose sputum is
negative but show suggestive
shadows in chest x-rays are
reckoned as “suspects”.

36. CASE FINDING TOOLS
1. SPUTUM EXAMINATION.
2. RADIOGRAPHY.
3. SPUTUM CULTURE.

37. SPUTUM EXAMINATION
• Sputum smear examination is
considered as the method of
choice.
• The tool is reliable and cheap.

38. • It enables to discover
epidemiologically most
importance cases of pulmonary
TB.
• This group contributes most of
the new cases to the “pool of
infection” every year.

39. COLLECTION OF SPUTUM
SAMPLES
• Secretions build up in the airways
overnight.
• So an early morning sputum
sample is more likely to contain TB
bacilli.

40. In practice an out patient usually
provides sputum sample as follows.
DAY 1 SAMPLE 1 PROVIDES AN “ON THE SPOT”
SAMPLE UNDER SUPERVISION
WHEN PRESENTING TO THE
HEALTH FACILITY.
GIVE THE PATIENT A SPUTUM
CONTAINER TO TAKE HOME
FOR AN EARLY MORNING
SAMPLE FO THE FOLLOWING
MORNING.

41. DAY 2 SAMPLE 2 PATIENT BRINGS AN EARLY
MORNING SAMPLE.

42. ZIEHL-NEELSON ACID FAST STAIN
• ZN Stain detects the acid fast
bacilli.
• The ZN staining procedure is as
follows.

43. • Fix the smear on the side by
passing the slide with the smear
up about three times slowly
through a flame.
• It can also be done by covering
the smear with alcohol and
letting this evaporate.

44. • Cover with Carbolfuchsin, steam
gently for 5 minutes over the
direct flame( or for 20 min over a
water bath).
• Wash with deionized water.

45. • Decolourize in 3 percent acid-
alcohol (95% ethanol and 3%
Hcl) until only a faint pink colour
remains.
• Wash with water.

46. • Counter stain for 1 min with
Loeffler’s methylene blue.
• Wash with deionized water and
let it dry.

47. SLIDE REPORTIING
• The number of bacilli seen in a
smear reflects disease severity and
patient infectivity.
• Therefore it is important to record
the number of bacilli seen on each
smear.

48. NUMBER OF BACILLI RESULT
REPORTED
NO AFB per 100 oil
immersions fields
0
1-9 AFB per 100 oil
immersions fields
Scanty (or
number AFB
seen)

49. NUMBER OF BACILLI RESULT
REPORTED
10-99 AFB per 100 oil
immersions fields
+ (1+)
1-10 AFB per 100 oil
immersions fields
++ (2+)

50. NUMBER OF BACILLI RESULT
REPORTED
> 10 AFB per oil
immersion field
+++ (3+)

51. • Sputum smear microscopy for
tubercle bacilli is positive when
there are at least 10,000
organisms present per ml of
sputum.

52. • One positive specimen out of the
two is enough to declare a patient
smear positive.
• Patients in whom both specimens
are smear negative should be
prescribed symptomatic
treatment and broad spectrum
antibiotic for 10-14 days.

53. • In such cases antibiotics such as
FLUOROQUINOLONES
(ciprofloxacin, ofloxacin),
rifampicin or streptomycin,
which are active against TB
should not be used.

54. FALSE POSITIVE RESULTS
• A false positive result means
that the sputum smear result is
positive even though the patient
does not really have sputum
smear positive PTB.

55. FALSE NEGATIVE RESULT
• A false negative result means
that the sputum smear result is
negative even though the
patient does have sputum smear
positive PTB.

56. FLUORESCENCE MICROSCOPY
• Is mainly used in industrialized
countries. It is performed with
auramine stain.
• This is a speedy examination and
the field view of view is 5-10 times
bigger.

57. LEDs
• LIGHT EMITTING DIODE
FLUORESCENCE MICROSCOPY
provide a much less expensive
light source for fluorescence
microscopy.

58. RADIOGRAPHY
• Chest X rays are useful for the
diagnosis of smear negative PTB
and TB in children.
• It is essential in the diagnosis of
miliary TB.

59. SPUTUM CULTURE
• Culture examination of sputum is
only second importance in case
finding programme.
• It takes 6 to 8 weeks for sputum
culture.

60. DRUG SUSCEPTIBITY
TESTING(DST)
• DST provides a definitive
diagnosis of drug-resistant TB.

61. • Phenotypic methods involves
culturing M.tubercolosis in the
presence of anti TB drugs to
detect the growth (indicating
drug resistance) or inhibition of
growth (indicating drug
susceptabity)

62. • Genotypic method targets
specific molecular mutations
associated with resistance
against individual drugs.

63. TUBERCULIN TEST
• Tuberculin test was discovered by
Von Pirquet in 1907.
• A positive reaction to the test is
generally accepted as evidence or
past or present infection by
M.tubercolosis.

64. • Tuberculin test is the only means
of estimating the prevalence of
infection in the population.
• There are three main tests
currently in use.

65. • They are:
1. MANTOUX TEST.
2. INTRADERMAL TEST.
3. HEAF & The TINE MULTIPLE
PUNCTURE TEST.

66. TUBERCULIN
• The test material or antigen used
for the test is called tuberculin.
• There are two major antigens-
the old tuberculin (OT) and the
Purified Protein Derivative(PPD).

67. DOSAGE
The dosages of PPD in vogue are:
1. First Strength or 1 TU.
2. Intermediate Strength or 250
TU.

68. MANTOUX TEST
• The Mantoux test is carried out by
injecting intradermally on the flex
or surface of the forearm 1 TU of
PPD in 0.1ml.
• The result is read after 72 hours (on
the 3 day).

69. • Tuberculin reaction consists of
erythema and induration.
• Since erythema is difficult to
measure induration alone is
measured using a transparent
plastic ruler or callipers).

70. • Reaction exceeding 10mm are
considered “positive”.
• Those less than 6 mm are
considered negative.
• Those between 6 and 9 mm are
considered “doubtful”

71. TREATMENT

72. CHEMOTHERAPHY
• THE
FOLLOWING
DRUGS ARE
USED IN THE
MANAGEME
NT PTB.

73. BACTERICIDAL DRUGS BACTERIOSTATIC
DRUGS
1.Rifampicin (RMP). 1. Ethambutol.
2. INH. 2. Thiacetazone.
3. Strptomycin.
4. Pyrazinamide.

74. THE SECOND LINE DRUGS
• Fluoroquinalones.
• Ethionamide.
• Capreomycin.
• Kanamycin and Amikacin.
• Cycloserine.
• Macrolides.

75. DOSAGE FOR ADULTS
WHO RECOMMENDED TREATMENT REGIMEN -
TUBERCULOSIS
CATEGORY OF TREATMENT TYPE OF PATIENT REGIMEN
Category I New sputum
smear positive
2(HRZE)3, 4(HR)3
Seriously ill
sputum smear
negative
Seriously ill
extra-
pulmonary

76. CATEGORY OF
TREATMENT
TYPE OF
PATIENT
REGIMEN
Category II Sputum smear-
positive
relapse
Sputum smear-
positive failure
Sputum smear-
positive
treatment
after default
2(HRZES)3
1(HRZE)3
5(HRE)3

77. CATEGORY OF
TREATMENT
TYPE OF
PATIENT
REGIMEN
Category III New sputum
smear-negative,
not seriously ill
New extra-
pulmonary, not
seriously ill
2(HRZ)3
4(HR)3

78. NOTE
• H - Isoniaid (600mg)
• R - Rifampicin (450mg)
• Z - Pyrazinamide(1500mg)
• E - Ethambutol(1200mg)
• S - Streptomycin(750mg)

79. • Patient who weight more than
60kg receive additional
rifampicin 150mg.
• patient more than 50years old
receive Streptomycin 500mg.

80. DOSAGE FOR CHILDREN
DRUG THERAPHY per
DOSE (THRICE A
WEEK)
ISONIAZID 10-15 mg/kg
RIFAMPICIN 10 mg/kg

81. DRUG THERAPHY per DOSE
(THRICE A WEEK)
PYRAZINAMIDE 35 mg/kg
STREPTOMYCIN 15 mg/kg
ETHAMBUTOL 30 mg/kg

82. • ETHAMBUTOL should not be
given to children below 6
years of age.

83. DRUGS & SIDE EFFECTS
REACTION DRUG
RESPONSIBLE
SEVERE RASH,
AGRANULOCYTISIS
THIOACETAZONE
HEARING LOSS OR
DISTURBED
BALANCE
STREPTOMYCIN

84. DRUGS & SIDE EFFECTSREACTION DRUG
RESPONSIBLE
VISUAL
DISTURBANCE
(poor vision and
colour perception)
ETHAMBUTOL
RENAL FAILURE,
SHOCK OR
THROMBOCYPENIA
RIFAMPICIN

85. DRUGS & SIDE EFFECTS
REACTION DRUG
RESPONSIBLE
RENAL FAILURE,
SHOCK OR
THROMBOCYPENIA
RIFAMPICIN
HEPATITIS PYRAZINAMIDE

86. • A patient who develops one of
the afore said reactions must
never receive that drug again.

87. TB CONTROL PROGRAMME
• The National TB Control
Programme was mounted in India
as early as 1962.

88. • Since then it has been edified
and the treatment strategies has
been upgraded as per the
programme objectives. One such
strategy is DOTS.

89. DOTS

91. PREVENTION

92. BCG VACCINATION
• BCG vaccination which was first
developed was known as bacille
Calmette Guerin.
• The initial vaccine was avirulent
for man while retaining its
capacity to induce an immune
response.

93. AIM
• The aim of BCG vaccination is to
induce a benign, artificial
primary infection which will
stimulate an acquired resistance
to possible subsequent
infections with virulent tubercle
bacilli and thus reduce the
morbidity & mortality due to TB

94. VACCINE
• BCG is the only live bacterial
vaccine.
• It consists of living bacteria
derives from an attenuated
bovine strain of tubercle bacilli.

95. TYPES OF VACCINE
• There are two types of BCG
vaccine : the liquid (fresh)
vaccine and freeze dried vaccine.
• Freeze dried vaccine is a more
stable preparation.

96. • Present day vaccines are
supplied in freezed dried form.

97. • BCG vaccine is stable for several
weeks at ambient temperature in a
tropical climate and for up to one
year if kept away from direct light
and stored in cool environment,
preferably refrigerated at a
temperature below 10 degree C.

98. • The vaccine must be protected
from exposure to light during
storage (wrapped up in a double
layer of red or black cloth) and in
the field.

99. • Normal saline is recommended
as a diluent for reconstituting
the vaccine, as distilled water
may cause irritation.

100. • The reconstituted vaccine may
be used up within 3 hours, and
left-over vaccine should be
discarded.

101. DOSAGE
• For vaccination, the usual
strength is 0.1 mg in 0.1 ml
volume.
• The dose to newborn aged
below 4 weeks is 0.05 ml.

102. • This is because the skin of the
newborn is rather thin and an
intradermal injection with full
dose (0.1ml) in some of them
might penetrate into deeper
tissue and give rise to local
abcess formation and enlarged
regional (axillary) lymph nodes.

103. ADMINISTRATION
• The standard procedure
recommended by WHO is to
inject the vaccine intradermally
using a “Tubercullin”
syringe.(Omega microstat
syringe fitted with a 1 cm steel
26 gauge intradermal needle).

104. • The syringe and needle
technique remains the most
precise way of administering the
desired dose.

105. SITE OF INJECTION
• The site of injection should be just
above the insertion of the deltoid
muscle.
• If it is injected too high, too
forward or backward, the
adjacent lymph nodes may
become involved and tender.

106. • A satisfactory injection should
produce a wheal of 5mm in
diameter.
• The vaccine must not be
contaminated with an antiseptic
or detergent.

107. • If alcohol is used to swab the
skin, it must be allowed to
evaporate before the vaccine is
given.

108. AGE
• The national vaccine policy
differs from country to country.
• In India BCG is administered at
birth.

109. PHENOMENON AFTER
VACCINATION
• Two or three weeks after a
correct ID injection of a potent
vaccine, a papule develops at the
site of vaccination.

110. • It increases slowly in size and
reaches a diameter of about 4 to
8mm in about 5 weeks.
• It then subsides or breaks into a
shallow ulcer, rarely open, but
usually covered with a crust.

111. • Healing occurs spontaneously
within 6 to 12 weeks leaving a
permanent tiny, round scar,
typically 4 to 8 mm in diameter.
• This is a normal reaction.

112. • However, with over dosage, the
local lesion and later the scar
may be considered larger and of
irregular size.

113. • Normally the individual becomes
Mantoux -positive after a period
of 8 weeks has elapsed, but
sometimes about 14 weeks are
needed.

114. COMPLICATIONS
• BCG has been associated with
adverse reactions which include:
prolonged severe ulceration at
the site of vaccination,
suppurative lymphadenitis,
osteomyelitis, disseminated BCG
infection and death.

115. PROTECTIVE VALUE
• The duration of protection is
from 15 to 20 years.

116. CONTRAINDICATIONS
• BCG should not be given to
patients suffering from eczema,
infective dermatosis,
hypogammaglobunemia.

119. THANK YOU