Epidemiology & prevention of tuberculosis

India is the highest TB burden country in the world & accounts for nearly 1/5th (20 per cent) of global burden of tuberculosis, 2/3rd of cases in SEAR. Every year approximately 1.8 million persons develop tuberculosis, of which about 0.8 million are new smear positive highly'- infectious cases.Annual risk of becoming infected with TB is 1.5 % and once infected there is 10 % life-time risk of developing TB disease

1. EPIDEMIOLOGY AND PREVENTION OF TUBERCULOSIS PRESENTEDBY – Dr SOWNDARYA GUIDED BY - PROF HEMANT KUMAR

2. CONTENTS Introduction History Burden Epidemiological determinants Types pathogenesis Childhood TB HIV & TB Prevention Summary References 2 12/09/2015

3. INTRODUCTION Tuberculosis (TB ) - I nfectious bacterial disease caused by Mycobacterium tuberculosis - most commonly affects the lungs . T ransmitted from person to person via droplets from the throat & lungs of people with the active respiratory disease. 3 12/09/2015

4. HISTORY Consumption , phthisis, scrofula, Pott's disease , and the White Plague are all terms used to refer to tuberculosis throughout history . It is generally accepted that the microorganism originated from other, more primitive organisms of the same genus Mycobacterium Researchers theorize that humans first acquired it in Africa about 5,000 years ago 12/09/2015 4

5. HISTORY Hippocrates , in Book 1 of his Of the Epidemics, describes the characteristics of the disease: fever, colorless urine, cough resulting in a thick sputa, and loss of thirst and appetite He notes that most of the sufferers became delirious before they succumbed to the disease Hippocrates and many other at the time believed phthisis to be hereditary in nature Aristotle disagreed, believing the disease was contagious. 5 12/09/2015

6. CONT. 1865- Jean-Antoine Villemin proved TB is contagious 1882- Robert Koch discovers M.tuberculosis 1884- First TB sanatorium established in U.S 1943- Streptomycin- a drug to treat TB was discovered 1943-1952- Two more drugs discovered to treat TB – INH & PAS Mid 1970s- most TB sanatoriums in U.S closed 6 12/09/2015

7. FATHER OF MODERN TB EPIDEMIOLOGY Karel Styblo , MD, (1921 – 13 March 1998) was born in Czechoslovakia. Internationally renowned for his work with tuberculosis (TB ) - medical advisor to the Royal Netherlands Tuberculosis Association - director of the International Union Against Tuberculosis and Lung Disease (IUATLD) in Paris from 1979 Known as the “Father of modern TB epidemiology " and the "father of modern TB control " 7 12/09/2015

8. BURDEN GLOBALLY In 2013, mortality of TB including HIV was 16 per lakh cases Mortality of TB excluding HIV was 5 per lakh cases Prevalence of TB was 159 per lakh Incidence of TB was 80 per lakh 8 12/09/2015

9. INDIA India is the highest TB burden country in the world & accounts for nearly 1/5th (20 per cent) of global burden of tuberculosis , 2/3rd of cases in SEAR. Every year approximately 1.8 million persons develop tuberculosis, of which about 0.8 million are new smear positive highly'- infectious cases . Annual risk of becoming infected with TB is 1.5 % and once infected there is 10 % life-time risk of developing TB disease 12/09/2015 9

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13. EPIDEMIOLOGICAL DETERMINANTS 13 12/09/2015

14. AGENT FACTORS 12/09/2015 14 Agent Mycobacterium tuberculosis - facultative intracellular parasite, ingested by phagocytes & resistant to intracellular killing Source of infection Human - human case positive for tubercle bacilli & who has either received no treatment or has not been fully treated B ovine - infected milk Communicability Patients are infective as long as they remain untreated

15. HOST FACTORS Age, Affects all ages I n India, 0-14 age group – 2% 15-24 age group - 20% Sex, More prevalent in males Nutrition, Malnutrition – predisposes to TB Immunity, Man has no inherited immunity against TB 15 12/09/2015

16. Social factors TB is a social disease with medical aspects, also known as barometer of social welfare Social factors include poor quality of life, poor housing, overcrowding, population explosion, undernutrition , lack of education, large families, & lack of awareness of causes of illness All these factors are interrelated & contribute to the occurrence & spread of TB 12/09/2015 16

17. MODE OF TRANSMISSION 12/09/2015 17 Transmitted mainly by droplet infection and droplet nuclei – by sputum-positive patients with pulmonary TB Coughing generates the largest number of droplets of all sizes Frequency & vigour of cough & the ventilation of the enviroment influence transmission of infection

18. Incubation period Time from receipt of infection to the development of a positive tuberculin test ranges from 3 to 6 weeks Development of disease depends upon the closeness of contact, extent of disease & sputum positivity of the source Incubation period may be weeks, months or years 12/09/2015 18

19. TYPES OF TB 19 Pulmonary, In active cases – most commonly involves the lungs (90% cases) Symptoms – Chest pain & a prolonged cough producing sputum About 25% of people - asymptomatic Extra pulmonary, In 15–20% of active cases, the infection spreads outside the lungs, causing other kinds of TB More commonly in immunosuppressed persons and young children 12/09/2015

20. CONT. Extrapulmonary tuberculosis, C ommon sites are Meninges Lymph nodes Bones & joints Intestine Genitourinary tract 20 12/09/2015

21. CONT. A potentially more serious, widespread form of TB - " disseminated" TB - commonly known as Miliary Tuberculosis . Miliary TB -10% of extrapulmonary cases 21 12/09/2015

22. PATHOGENESIS 12/09/2015 22

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26. CLINICAL FEATURES 26 12/09/2015

27. CHILDHOOD TUBERCULOSIS WHO estimates(2013) – Upto 80,000 children die from TB each year & children account for over half a million new cases annually. E stimated deaths only include – HIV-negative children Actual burden of TB in children is likely higher, especially given the challenge in diagnosing childhood TB 27 12/09/2015

28. CONT . Children with TB, Poor families L ack of knowledge about the disease L ive in communities with limited access to health services 28 12/09/2015

29. HIV & TB People living with HIV – 26 to 31 times more likely to develop TB than persons without HIV TB - Most common presenting illness A mong people living with HIV A mong those taking antiretroviral treatment I t is the major cause of HIV-related death. Sub-Saharan Africa – dual epidemic, accounting for approximately 78% of the estimated burden in 2013 29 12/09/2015

30. To address HIV-related TB, WHO recommends a 12 point package of collaborative TB/HIV activities. Objectives, R educing burden of TB among people living with HIV R educing burden of HIV among TB patients . Implementation of these activities from 2005 to 2011 – Saved 1.3 million lives Universal access to these life-saving measures must be achieved & eliminate HIV-associated TB deaths 30 12/09/2015

31. MDR-TB Multi-drug-resistant tuberculosis ( MDR-TB ) is defined as – tuberculosis that is resistant to at least isoniazid (INH) and rifampicin (RMP ) ,the two most powerful first-line treatment anti-TB drugs When the course of antibiotics is interrupted – levels of drug in the body are insufficient to kill 100% of bacteria Spread from person to person as readily as drug-sensitive TB and in the same manner 31 12/09/2015

32. CONT. Most commonly develops in the course of TB treatment, I nappropriate treatment M issing doses or F ailing to complete their treatment Multidrug-resistant strain can transmit TB if pathogens are alive & patient coughing TB strains –often less fit & less transmissible & outbreaks occur more readily in people with weakened immune systems ( HIV ) 32 12/09/2015

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35. EXTENSIVELY DRUG RESISTANT XDR-TB is defined as TB that has developed resistance to at least rifampicin and isoniazid , as well as to any member of the quinolone family and at least one of the following second-line anti-TB injectable drugs : Kanamycin Capreomycin Amikacin 35 12/09/2015

36. CONT. If TB bacteria are found in the sputum – diagnosis of TB can be made in a day or two, but can’t distinguish bet. drug-susceptible & drug-resistant TB. To evaluate drug susceptibility, bacteria need to be cultivated & tested in a suitable laboratory. Final diagnosis in this way for TB, & especially for XDR-TB, may take from 6 to 16 weeks The original method used to test for MDR-TB & XDR-TB – Drug Susceptibility Testing (DST). DST is capable of determining how well four primary ATT drugs inhibit the growth of Mycobacterium Tuberculosis 36 12/09/2015

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38. Prevention & control Primary prevention- health education & specific protection Population strategy & high risk strategy Secondary prevention- early diagnosis & specific treatment Tertiary prevention- rehabilitation & disability limitation 38 12/09/2015

39. PREVENTION & CONTROL OF TB 12/09/2015 39 Early diagnosis and treatment, particularly of sputum smear positive cases – cornerstone of tuberculosis control The Revised National Tuberculosis Control Programme (RNTCP) has focused on achieving high cure rates The protective efficacy of BCG has ranged between 0 to 80% in different studies

40. BCG-VACCINE The first human was vaccinated by the intradermal technique in 1927 BCG is the only widely used live bacterial vaccine. It consists of living bacteria derived from an attenuated bovine strain of tubercle bacilli The WHO has recommended the "Danish 1331" strain for the production of BCG vaccine Since January 1967, the BCG Laboratory at Guindy , Chennai, has been using the "Danish 1331" strain for the production of BCG vaccine 12/09/2015 40

41. CONT.. There are two types of BCG vaccine - the liquid (fresh) vaccine and the freeze dried vaccine . For vaccination. the usual strength is 0.1 mg 0.1 ml volume. The dose to newborn aged below 4 weeks is 0.05 ml . 12/09/2015 41

42. RNTCP Need for a Revised Strategy India has had an on-going National TB Program, NTP since 1962. Program reviews showed that only 30% of estimated tuberculosis patients were diagnosed & treated successfully. Based on the findings & recommendations of the review in 1992, the GOI evolved a revised strategy and launched the Revised National TB Control Programme (RNTCP) in the country. 42 12/09/2015

43. COMPONENTS OF RNTCP The directly observed treatment , short-course DOTS strategy along with the other ingredients of the Stop TB Partnership are implemented as a comprehensive package for TB control. 12/09/2015 43

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45. MANTOUX TEST The Mantoux test OR Mendel- Mantoux test OR the Mantoux screening test OR tuberculin sensitivity test OR Pirquet test OR PPD test for purified protein derivative-screening tool for TB Tuberculin is a glycerol extract of the tubercle bacillus. PPD tuberculin - precipitate of species-nonspecific molecules obtained from filtrates of sterilized, concentrated cultures A standard dose is 5 tuberculin units (TU - 0.1 ml) is injected intradermally (between the layers of dermis) and read 48 to 72 hours later 45 12/09/2015

46. CONT. The reaction is read by measuring the diameter of induration (palpable raised, hardened area) across the forearm (perpendicular to the long axis) in millimeters 46 12/09/2015

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49. SUMMARY Despite all these national programmes & efforts from govt of India , TB still continues to be a major socio-economic burden of the country Still there is need to create awareness among health care professionals, and the community 12/09/2015 49

50. REFERENCES WHO., Tuberculosis, URL available http://www.who.int/topics/tuberculosis/en/ [Last accessed on 20 feb 2015 Park.K , Park’s Textbook of Preventive and Social Medicine, 22 nd ed. Jabalpur: Banarsidas Bhanot Publishers;2013 12/09/2015 50

51. TAKE HOME MESSAGE 12/09/2015 51

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