Epidemiology and public health aspects of TB in india

TB in India:

Epidemiology and

Public Health Aspects

DR Shyam Ashtekar

Asst Professor, Community Medicine

SMBT Medical college, Nashik

shyamashtekar@yahoo.com

20 Nov 2015

Historical

• TB is a companion for humanity from times of hominid ancestors

• 1882, 24 March-Robert Koch found Mycobacteria TB

• Hence 24th March-World’s Stop TB Day

• 1890-Tuberculin Protein-diagnostic tool for TB infection

• 1895-X-ray invention made diagnostics easy

In 20th Century

• 1921-BCG vaccine

• 1944-Streptomycin

• 1960-National Tuberculosis Institute of India

• 1962- National Tuberculosis Control Program

(NTCP)

• 1992-NTCP review went negative

• 1993-WHO made a Global Emergency call for

STOP TB

• 1997-Revised NTCP (RNTCP)

• 2005 RNTCP-Part of NRHM/now NHM

EPIDEMIOLOGY OF TUBERCULOSIS

Distribution of TBWhere, when, whom

Analytical aspects

Why, How, What is to be done for control

The Global Burden• About 2 billion (200 crores) infected by TB

–world pop 7 billion (nearly 1/3rd pop

infected asymptomatically)

• 65 million people with disease

• About 8-10 million new cases

annually(about 14 per thousand pop)

• 1.3 million deaths annually

• Multi-Drug Resistance (MDR & XDR) and

HIV infection make a dangerous

complication

Global Map of TB

The global scene

• A global problem of poverty, poor living

conditions

• Dramatic control with improvement of living

conditions

• Control also helped by BCG and streptomycin

& INH

• But now a Reemergence-

• HIV & TB a dangerous combination.

• Resistance to ATT

Drastic reduction of TB in developed

nations, but India ….

• Even before advent of TB

drugs, TB vanished as a public

health problem from Europe

and US.. With better life and

nutrition, workplace

improvements.

• In India, TB still is a big public

health problem despite best

anti TB drugs and diagnostic

tools.

No significant decline in TB in India- See more at: http://www.tbfacts.org/tb-statistics-india/#sthash.B6wFATk6.dpuf

Burden of TB in India (2013 Park)

• All forms of TB, old and new: 2.1/1000 pop ( about 26

lakhs in India)

• Incidence of all TB cases annual: 1.7 cases/1000 pop

(about 21 lakhs in India)

• Prevalence of Infection (30% pop)

• Annual incidence of TB infection is 1.5% (ARTI)

• Incidence of new smear positive cases per anum is 0.75

per thousand pop (75 per lakh pop)

• Deaths due to TB-all India-2.4 lakh

• Total HIV cases with TB -8.87 lakh

• Case detection-all forms 58%

• BUT MOST OF THESE ARE UNDERESTIMATES

India-worries and concernsTB &

HIV link

dangerous

2% new cases are MDR (N=20000),

Old & new MDR is 1.37 lakh accumulated cases

High Economic loss (annual 15000cr)-

Afflicts and kills working age people-5 lakhs annually

Silent chronic, often asymptomatic,

Highly infective. One open case is a risk to 15 new people annually

Epidemiology Triad

Agent

Host Environment

Reservoir and Transmission

• Main reservoir is Human cases, perhaps some role of cattle

• Infective material is TB sputum/coughed out droplets. Case remains infective for long.

• Becomes non-infective in 2 to 15 days after Short course chemotherapy starts.

• Infection mainly through respiratory route (or GIT)

• Main spread is indoor-to close contacts, esp children

• Public spitting-dust particles inhaled-less important

Host (Person) factors

Poverty-undernutrition, crowded living

Smoking, silicosis

Diabetes, HIV

BCG gives selective partial immunity

Men>women

Main age groups-Childhood, Young Adult, old age

Possibly cattle handling exposes to some risk

Immunity –not all infections become disease (only10% become TB disease)

Close contact with open case

Age And TB prevalence

0

5

10

15

20

25

0-14 15-24 25-34 35-44 45-5455-64 65+

2

2123

20

16

11

7

Pe

rce

nta

ge

Age-wise TB cases -India 2006

% of TB cases

Agent factors

• Main type -Mycobacterium TB-Hominis

• Mycobacterium TB-Bovis- vet TB

• Atypical Mycobacteria-

• TB bacteria may be fast or slow growers-decides future course

of disease

• May be intra or extra cellular

• Take Zeihl Neelson stain (are basically Gram+ve)

• Hardy-against weather, chemicals. But killed in sunlight.

• Tend to stay dormant in human body.

• Indian TB is milder than European TB.

MDR(multi Drug Resistant) &

XDR (Extensively Drug Resistant)• Drug resistant TB is a

new problem

• MDR is INH & Rifampicin

resistance

• XDR is Extensively Drug

Resistant TB--Resistant

to INH+R and also

second-line drugs.

• Diagnosis is by

sputum

microscopy that

continues to be

positive even

after 4 months of

SCC.

• DOTS+ Regimen

Global picture of MDR

Environmental factors

• Crowded habitations

• Poor localities, with poor

sanitation

• Indoor transmission to

contacts is most

important

• Public spitting is a lesser

threat

Larger Socio-Economic

Determinants (Risk Factors)

• Poverty, poor housing

• Urbanization, population

density

• Malnutrition

• Low-education

Disease forms

Pulmonary (PTB)

• Primary lung disease with regional

lymph nodes-(most children used to

get before BCG)-called PRIMAY

COMPLEX

• POST-PRIMARY PULMONARY TB-

Most common, usually a flare up of

primary complex or new infection in

adult life

• One third cases of PTB are infective

(lesion is open to bronchi)

Extra pulmonary

• Uncommon after

BCG coverage

• All organs were

affected-

meninges, Ovary,

uterus, spine,

bones, kidneys,

intestines, lymph

nodes, skin, joints

Clinical picture of PTB

Common/main features

• Cough for >2 weeks

• Fever-low grade

• Pain in Chest

• Hemoptysis (blood in

spit)

Other features

• Loss of appetite

• Loss of weight-otherwise

unexplained

• Breathlessness

• Weakness

• Malaise

Childhood TB

• About 10-20% total TB is childhood TB

• Age 1-4 years

• Often due to close contacts with TB patients

• Usually Pulmonary now, less of other organs

• But no sputum, hence difficult to diagnose

• Hence also does not transmit TB like adults

• Failure to thrive, Malnutrition-both underlying

cause and effect of TB

• Childhood PTB may spread to other organs

• Tuberculin test usually clueless because of prior

BCG vaccine, But a Mantoux test >10 mm is

assumed as diagnostic

TB & HIV-Lethal partnership• HIV depletes immunity, hence-

• People with HIV & TB INFECTION have 30% chance of developing opportunistic TB DISEASE.

• HIV invites TB infection and flares up old TB -10% of them in first year.

• (Otherwise for PTB a lifetime chance of 10% relapse)

• Reinfection is common

• HIV-PTB is often sputum negative-hence difficult to diagnose, TT, Xray Chest often fails. Sputum culture called for.

• Spread of TB is faster in community.

• TB disease high in HIV prevalence areas, hence should get HIV test.

Diabetes and TB

• Diabetes patients account for

15-20% of PTB cases, because

immunity weakening

• All TB patients should get

screening for TB-sputum test

TB CONTROL PROGRAM-RNTCP

Public Health measures

What is Public Health..

It is the art and science of ..preventing disease, promoting health

and Prolonging life, through organized efforts of

community/society

Five levels of Prevention

5 Rehabilitation

4 Disability Limitation

3 EDPT( Early Diagnosis & Prompt Treatment)

2 Specific Protection

1 Health Promotion

Strategy in TB control

5 Rehabilitation

4 Disability Limitation (mainly by timely and complete treatment)

3 EDPT (mainly sputum microscopy for

symptomatic persons)

2 Specific Protection-mainly BCG (partial success)

1 Health Promotion-through socio-economics, nutrition-RNTCP can not do much effort here

WHO’s Stop TB strategy

• Pursue high quality DOTS expansion & enhancement

• Address HIV related TB, MDR, high risk groups

• Health system strengthening

• Engage all health care providers

• Empower people with TB, and communities

• Enable and promote research

RNTCP (Revised NTCP)

Objectives

• 70% of cases should be

detected (4per 1000) by

RNTCP with sputum

microscopy

• 85% of detected cases

must be cured.

Strategies

• BCG at birth

• Passive detection with

sputum microscopy

• DOTS therapy

• IEC-(Information,

education

communication )

BCG vaccination

• High protection level for TB health workers with BCG vaccination is proven

• Protects for 15-20 years, or even longer

• 0-80% of vaccinated community protected, esp against childhood TB, but not so much for adult PTB

• BCG offers only partial protection

• Can not be given in HIV cases

Clinical Detection is unreliable-PTB

Diagnostics in RNTCP

Clinically suspected

• Chronic cough>2

weeks in adults

• Blood spit-

hemoptysis

Investigations

• Sputum microscopy-Usually Direct-detects 80% cases in first test, 93% in second test, 100% by third test

• (Unusually concentrated sputum needs to be tested)

• If necessary Culture (for HIV cases or Drug sensitivity)

• Xray Chest (has only additional value)

• TT-Tuberculin Test, for child<2Y, or any person with >20mm induration

Short Course

Chemotherapy (SCC)Evidence

• Domiciliary treatment is equally or more effective than hospital based treatment (Chennai study)

• Isolation (to protect the family) is not required with SCC, and is fruitless by the time of detection

• Peru and China have demonstrated success with DOTS approach

What defines ‘Control’ of TB

Infection Prevalence Rate

• When prevalence of

INFECTION in children

below 14Y is brought

under 1 (now 40)

To do this..

• Reduce human reservoir

(cattle reservoir?)

• Cut transmission by

improvement of living,

control spitting

• Protect susceptible with

BCG, (also better

nutrition)

The Indian Challenge of TB

• TB is a barometer of Socio-economic situation -malnutrition, poor living conditions

• High burden of chronic cases, high infection rate, deaths, loss of work and wages

• Targets of reducing TB burden not achieved

• MDR, XDR, HIV are additional challenges

• Childhood TB needs attention.

The Global challenges for

elimination of TB by 2050

• Supply of funds for TB control at global/national levels (nearly 60% shortfall)

• Need for revolutionary technology for new medicines, vaccines, diagnostic tests (espfor latent infection),

• Genome research on TB may provide new tools.

• Long way to go for elimination

ThanksDr Shyam Ashtekar

SMBT Medical College, Dt Nashik

shyamashtekar@yahoo.com

20 Nov 2015

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health-aspects-of-tb-in-india