Tuberculosis basics

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Tuberculosis basics


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Tuberculosis basics Dr.T.V.Rao MD:

Tuberculosis basics Dr.T.V.Rao MD Dr.T.V.Rao MD 1

HISTORY of Tuberculosis:

HISTORY of Tuberculosis Tuberculosis Is an Ancient Disease Spinal Tuberculosis in Egyptian Mummies History dates to 1550 – 1080 BC Identified by PCR Dr.T.V.Rao MD 2

Robert Koch Discoverer of Mycobacterium Tuberculosis:

Robert Koch Discoverer of Mycobacterium Tuberculosis Dr.T.V.Rao MD 3

What are Mycobacteria? :

What are Mycobacteria? Obligate aerobes growing most successfully in tissues with a high oxygen content, such as the lungs. Facultative intracellular pathogens usually infecting mononuclear phagocytes (e.g. macrophages). Dr.T.V.Rao MD 4

Classification of Mycobacteria:

Classification of Mycobacteria Tubercle bacilli Human – MTB Bovine – M. bovis Murine – M. microti Avian – M. avium Cold blooded – M. marinum Lepra bacilli Human – M. leprae Rat – M. leprae murium Mycobacteria causing skin ulcers M. ulcerans M. belnei Atypical Mycobacteria (Runyon Groups) Photochromogens Scotochromogens Nonphotochromogens Rapid growers Johne’s bacillus M. paratuberculosis Saprophytic mycobacteria M. butyricum M. phlei M. stercoralis M. smegmatis Others Dr.T.V.Rao MD 5

Mycobacterium differ from other routinely isolated Bacteria:

Mycobacterium differ from other routinely isolated Bacteria Slow-growing with a generation time of 12 to 18 hours (c.f. 20-30 minutes for Escherichia coli ). Hydrophobic with a high lipid content in the cell wall. Because the cells are hydrophobic and tend to clump together, they are impermeable to the usual stains, e.g. Gram's stain Dr.T.V.Rao MD 6

Acid fast bacilli:

Acid fast bacilli Known as “Acid-fast bacilli" because of their lipid-rich cell walls, which are relatively impermeable to various basic dyes unless the dyes are combined with phenol. Dr.T.V.Rao MD 7

How they are Acid fast:

How they are Acid fast Once stained, the cells resist decolourization with acidified organic solvents and are therefore called "acid-fast". (Other bacteria which also contain mycolic acids, such as Nocardia , can also exhibit this feature.) Dr.T.V.Rao MD 8

Mycobacterium tuberculosis complex:

Mycobacterium tuberculosis complex Includes Human and Bovine mycobacterium M .Africanism Tropical Africa M.microti do not cause human infections but in small mammals Dr.T.V.Rao MD 9


M.bovis Primarily infection among the cattle M.bovis infects Tonsils, Cervical nodes, can produce Scrofula. Enter through Intestines – infects the Ileocecal region. Dr.T.V.Rao MD 10

What are atypical Mycobacterium:

What are atypical Mycobacterium Infects birds, cold blooded animals worm blooded animals Present in environment Opportunistic pathogens Others – Saprophytic bacteria M butryicum present in butter M.phlei M smegmatis – present in Smegma Dr.T.V.Rao MD 11

Atypical Mycobacterium:

Atypical Mycobacterium 1 Photochromogens 2 Scotochromogens 3 Non Photochromogens 4 Rapid growers Dr.T.V.Rao MD 12


MOST IMPORTANT AMONG INFECTIOUS DISEASES Tuberculosis (TB) is the leading cause of death in the world from a bacterial infectious disease. The disease affects 1.8 billion people/year which is equal to one-third of the entire world population. Dr.T.V.Rao MD 13

Poverty and Crowded living spreads Tuberculosis:

Poverty and Crowded living spreads Tuberculosis Dr.T.V.Rao MD 14

Tuberculosis infects Famous people too:

Tuberculosis infects Famous people too Dr.T.V.Rao MD 15

What are Mycobacteria? :

What are Mycobacteria? Obligate aerobes growing most successfully in tissues with a high oxygen content, such as the lungs. Facultative intracellular pathogens usually infecting mononuclear phagocytes (e.g. macrophages ). Dr.T.V.Rao MD 16

General characters of the genus:

General characters of the genus Slender rods Resist staining but once stained, resist decolonization by dilute mineral acids; hence called ACID FAST BACILLI (AFB) Aerobic, Non-motile, Non-sporing, Non-capsulated. Growth generally slow Genus includes Obligate parasites Opportunist pathogens Saprophytes Dr.T.V.Rao MD 17

Morphology of Mycobacterium tuberculosis:

Morphology of Mycobacterium tuberculosis Straight, slightly curved Rod shaped 3 x 0.3microns May be single, in pairs or in small clumps On conditions in growth appears as filamentous, club shaped, or in Branched forms. Dr.T.V.Rao MD 18


ACID FAST BACILLI Known as “ Acid-fast bacilli" because of their lipid-rich cell walls, which are relatively impermeable to various basic dyes unless the dyes are combined with phenol. Dr.T.V.Rao MD 19

Important Mycobacterium:

Important Mycobacterium Mycobacterium tuberculosis , along with M. bovis , M. africanum , and M. microti all cause the disease known as tuberculosis (TB) and are members of the tuberculosis species complex. Each member of the TB complex is pathogenic, but M. tuberculosis is pathogenic for humans while M. bovis is usually pathogenic for animals Dr.T.V.Rao MD 20

Avian Tuberculosis:

Avian Tuberculosis T ransmitted by ingestion and inhalation of aerosolized infectious organisms from feces. Oral ingestion of food and water contaminated with feces is the most common method of infection. Once ingested, the organism spreads throughout the bird's body and is shed in large numbers in the feces. If the bacterium is inhaled, pulmonary lesions and skin invasions may occur transmission of avian TB is from bird to human not from human to human. Dr.T.V.Rao MD 21

Acid Fast Bacilli seen in a specimen of Sputum:

Acid Fast Bacilli seen in a specimen of Sputum Dr.T.V.Rao MD 22

Acid fast Bacilli seen as in Florescent Microscope:

Acid fast Bacilli seen as in Florescent Microscope After staining with Ziehl Neelsen method or Fluorescent method ( Auramine or Rhodamine they resist decolonization by 20% Sulphuric acid and absolute alcohol for 10 mt, So called as Acid and Alchool fast. Dr.T.V.Rao MD 23

Why they are Acid Fast:

Why they are Acid Fast The character of Acid fastness is due to presence of Unsapnofiable wax ( My colic acid and semi permeable membrane around the cell) Dr.T.V.Rao MD 24

MTB : Cultural characters:

MTB : Cultural characters Grow slowly. Generation time 14-15 hrs Colonies appear after 2 weeks or at 6-8 weeks MTB - Obligate aerobe MTB grows more luxuriantly (eugonic) than M. bovis (dysgonic). Addition of 0.5% Glycerol supports growth of human strains. No effect or inhibitory effect on bovine strains. Dr.T.V.Rao MD 25

Culturing Acid Fast Bacilli:

Culturing Acid Fast Bacilli Slow to grow , Generation time is 14 – 15 hours > 2 weeks minimal required period Grows at 37 0 c do not grow below 25 0 c Ph between 6.4 to 7.0 Dr.T.V.Rao MD 26

PowerPoint Presentation:

Eight Week Growth of Mycobacterium tuberculosis on Lowenstein-Jensen A gar Dr.T.V.Rao MD 27

Nature of Media Used:

Nature of Media Used Helps the growth needs Solid Medium is commonly used Lowenstein Jensen’s medium Petrangini Middle brook medium Dr.T.V.Rao MD 28

Lowenstein Jensen’s Medium:

Lowenstein Jensen’s Medium Contain coagulated egg Mineral salt solution Asparagine's Malachite green Agar Dr.T.V.Rao MD 29

Other Medium:

Other Medium Middle brook Sula's medium But not routinely used Dr.T.V.Rao MD 30

Nature of Growth Characters:

Nature of Growth Characters M tuberculosis is obligate aerobe M.bovis Microaerophilic M.tuberculosis growth luxierently M.tuberculosis eugonic M bovis is dysgonic When grown on 0.5% glycerin M tuberculosis growth improves Sodium pyruvate improves the growth of both organism. Dr.T.V.Rao MD 31

On L J Medium:

On L J Medium M.tuberculosis appear dry, rough raised irregular colonies Appear wrinkled They appear creamy white Become yellowish M.bovis appear as flat smooth, moist, white and break up easily Dr.T.V.Rao MD 32

PowerPoint Presentation:

Lowenstein Jensen Medium – Selective. Always in screw capped bottle. Bluish Green. Contains – Egg protein – Solidifying agent Mineral salts – Mg Sulphate, Mg citrate Asparagine Malachite Green – Selective agent Sterilized by - Inspissation Dr.T.V.Rao MD 33

On Liquid Medium:

On Liquid Medium Appear as long serpentine cords in liquid medium Virulent strains grow in a more dispersed manner. Dr.T.V.Rao MD 34

Resistance of Mycobacterium:

Resistance of Mycobacterium Mycobacterium are killed at 60 0 c in 15 – 20 mt In sputum they survive for 10 – 30 mt Relatively resistant to several chemicals including Phenol 5 % Sensitive to Glutaraldehyde and Formaldehyde Ethanol is suitable application to superficial surfaces and skin gloves Dr.T.V.Rao MD 35

Resistance to several agents:

Resistance to several agents Bacilli survive in Droplets for 8 – 10 days Survive in 5% phenol, 15% Sulphuric acid 3% Nitric acid,5% oxalic acid, 4% Sodium hydroxide Dr.T.V.Rao MD 36

Biochemical Tests on Mycobacterium spp:

Biochemical Tests on Mycobacterium spp Niacin test – 10% cyanogen's bromide and 4% Aniline in 96% ethanol are added to suspension of – C canary yellow color indicates positive test. Dr.T.V.Rao MD 37

Other Tests:

Other Tests Aryl sulphatase test – Positive in Atypical Mycobacterium Bacilli grown in 0.001 tripotassium phenolpthalein disulphide / 2 N. Sodium hydroxide added drop by drop a pink color develops Catalase peroxidase test – Differentiates Atypical from Typical Most Atypical are strongly Catalase positive Tubercle bacilli are weakly positive Tubercle bacilli are peroxidase positive – not atypical INH resistant strains are negative for test Dr.T.V.Rao MD 38

Catalase Test:

Catalase Test 30 Vol of H 2 O 2 and 0.2 % alcohol in distilled water is added to 5 ml of test culture Effervescence indicates Catalase positive Other test Amidase test Nitrate reduction test Dr.T.V.Rao MD 39

Antigenic Characters:

Antigenic Characters Group specificity due to Polysaccharides Type specificity to protein antigens Delayed hypersensitivity to proteins Related to each other species Some relation between lepra and tubercle bacilli Serology – Tests not useful Antigenic homogeneity between < bovis and M.microti Dr.T.V.Rao MD 40


Bacteriophages There are 4 Bacteriophages A B C D A worldwide B. Europe and -American C rare I type nature between A and B and common in India Phage 33 D M tuberculosis and not in BCG strains Dr.T.V.Rao MD 41

Molecular Typing:

Molecular Typing DNA finger printing differentiates different strains of Mycobacterium species Treating the organism with Restriction endonuclease yields Nucleic acid fragments of varying length and strain specific Use in epidemiological studies Dr.T.V.Rao MD 42

Finger printing Methods:

Finger printing Methods Finger printing is done with Chromosomal insertion sequence IS 6110 present in most strains of Tubercle bacilli Now entire genome of M tuberculosis is sequenced Several Molecular methods are available for studies Dr.T.V.Rao MD 43

Genome of Mycobacterium tuberculosis:

Genome of Mycobacterium tuberculosis Dr.T.V.Rao MD 44

How tuberculosis spreads:

How tuberculosis spreads Tuberculosis (TB) is a contagious disease. Like the common cold, it spreads through the air. Only people who are sick with TB in their lungs are infectious. When infectious people cough, sneeze, talk or spit, they propel TB germs, known as bacilli, into the air. A person needs only to inhale a small number of these to be infected. Dr.T.V.Rao MD 45

Tuberculosis spread by Respiratory route:

Tuberculosis spread by Respiratory route Dr.T.V.Rao MD 46

Tuberculosis highly Communicable Disease.:

Tuberculosis highly Communicable Disease. Someone in the world is newly infected with TB bacilli every second. Overall, one-third of the world's population is currently infected with the TB bacillus. 5-10% of people who are infected with TB bacilli (but who are not infected with HIV) become sick or infectious at some time during their life. People with HIV and TB infection are much more likely to develop TB. Dr.T.V.Rao MD 47

Pathology and Pathogenesis of Tuberculosis:

Pathology and Pathogenesis of Tuberculosis Source of Infection – Open case of Pulmonary Tuberculosis. Every open case has potential to infect 20 – 25 healthy persons before cured or dies Coughing , Sneezing, or Talking. Each act can spill 3000 infective nuclei in the air, Infective particles are engulfed by Alveolar Macrophages. Dr.T.V.Rao MD 48

Spread of Tuberculosis:

Spread of Tuberculosis Dr.T.V.Rao MD 49

Generation of Droplet Nuclei:

Generation of Droplet Nuclei One cough produces 500 droplets The average TB patient generates 75,000 droplets per day before therapy This falls to 25 infectious droplets per day within two weeks of effective therapy Dr.T.V.Rao MD 50

PowerPoint Presentation:

Dr.T.V.Rao MD 51

Predisposing Factors:

Predisposing Factors Genetic basis, Age Stress, Nutrition, Co existing infections Eg HIV Dr.T.V.Rao MD 52

Mechanisms of Infection :

Mechanisms of Infection Mycobacterium do not produce toxins. Allergy and Immunity plays the major role. Only 1/10 of the infected will get disease. Cell Mediated Immunity plays a crucial role. Humoral Immunity – not Important. CD 4 Cell plays role in Immune Mechanisms . Dr.T.V.Rao MD 53

Mechanisms of Infection:

Mechanisms of Infection Within 10 days of entry of Bacilli clones of Antigen specific T Lymphocytes are produced Can actively produce Cytokines, Interferon γ which activate Macrophages form cluster or Granuloma Dr.T.V.Rao MD 54

PowerPoint Presentation:

Dr.T.V.Rao MD 55

Tubercle with Caseous Necrosis:

Tubercle with Caseous Necrosis Giant cells Tubercle bacilli Partially activated macrophage Lymphocyte Fully activated macrophage Dr.T.V.Rao MD 56

Basis of Tubercle formation.:

Basis of Tubercle formation. Tubercle is a Avascular granuloma Contain central zone of giant cells with or without caseation and peripheral zone of Lymphocytes and Fibroblasts. Produce lesions may be Exudative or Productive Dr.T.V.Rao MD 57

PowerPoint Presentation:

Diagram of a Granuloma NOTE: ultimately a fibrin layer develops around granuloma (fibrosis) , further “walling off” the lesion. Typical progression in pulmonary TB involves caseation , calcification and cavity formation . Dr.T.V.Rao MD 58

Tubercle discharging:

Tubercle discharging Bronchial tree TNF- a TNF- a Dr.T.V.Rao MD 59

Immunity in Tuberculosis.:

Immunity in Tuberculosis. CD 4 T Lymphocytes with Th 1 or Th 2 secrete - 1 Cytokines,2 Interleukin 1,and 2 , 3 Interferon's γ ,4.Tumor necrosis factor. The mechanisms with Th 1 secrete Cytokines Activate Macrophages Results in protective Immunity, and contain Infection. Th 2 manifests with Delayed Hypersensitivity DTH causes Tissue destruction. and disease will progress. . Dr.T.V.Rao MD 60

Immunity in Tuberculosis :

Immunity in Tuberculosis Activated Macrophages - Epitheliod cells Forms cluster a granuloma Activated macrophages turn into Giant cells. Granuloma contains necrotic tissue Dead macrophages cheese like caseation. Apoptosis of bacteria laden cells Contribute to protective immunity. Dr.T.V.Rao MD 61

Lesions in Tuberculosis:

Lesions in Tuberculosis Exudative – and Productive Exudative – Acute inflammatory reaction with edema fluid – contains Polymorphs- Lymphocytes – later Mononuclear cells. Bacilli are virulent - Host responds with DTH Injurious. Productive Type protective Immunity Dr.T.V.Rao MD 62

Primary Tuberculosis:

Primary Tuberculosis Initial response In Endemic countries Young children Events of Primary complex 1 Bacilli are engulfed by Alveolar Macrophages 2 Multiply and give raise to Sub pleural focus of Tuberculosis,Pneumonia,involve lower lobes and lower part of upper lobes. Called as Ghon’s focus. The Hilar Lymph nodes are also involved Dr.T.V.Rao MD 63

Primary complex:

Primary complex This is known as the primary complex or primary infection . The patient will heal and a scar will appear in the infected loci. There will also be a few viable bacilli/spores may remain in these areas (particularly in the lung). The bacteria at this time goes into a dormant state, as long as the person's immune system remains active and functions normally this person isn't bothered by the dormant bacillus. Dr.T.V.Rao MD 64

Primary complex:

Primary complex Ghon’s focus with Enlarged lymph nodes appear after 3- 8 weeks after infection. Heals in 2 – 6 months calcified, Some bacteria remain alive and produce latent infections. Infection activated in Immunosuppressed conditions Eg. HIV infections and AIDS Can produce Meningitis, Miliary tuberculosis, other disseminated Tuberculosis. Dr.T.V.Rao MD 65

Reactivation of Tuberculosis:

Reactivation of Tuberculosis When a person's immune system is depressed., a secondary reactivation occurs. 85-90% of the cases seen which are of secondary reactivation type occurs in the lungs. Dr.T.V.Rao MD 66

Koch’s Phenomenon:

Koch’s Phenomenon Tuberculosis infected Guinea pig if injected with Living Tubercle bacilli The site around the injection becomes necrotic. Koch found the same reaction when injected with old Tuberculin ( heated and concentration of the tubercle bacilli ) It has produced the same reaction This is called as Koch’s Phenomenon. Dr.T.V.Rao MD 67

Post Primary Tuberculosis:

Post Primary Tuberculosis Mainly occurs due to Reactivation of Latent infection. May also due to Exogenous reinfection Differs from Primary Infection. Leads to – Cavitation's of Lungs, Enlargement of Lymph nodes, Expectoration of Bacteria laden sputum Dissemination into Lungs and other extra pulmonary areas. Dr.T.V.Rao MD 68

Majority of the Tuberculosis are Pulmonary:

Majority of the Tuberculosis are Pulmonary Dr.T.V.Rao MD 69

Multiorgan Involvement in Tuberculosis.:

Multiorgan Involvement in Tuberculosis. Dr.T.V.Rao MD 70

Complication of Tuberculosis.:

Complication of Tuberculosis . Meningitis. Pleurisy, Involvement of Kidney, Spine ( Potts spine ) Bone Joints, Miliary tuberculosis Dr.T.V.Rao MD 71

Symptoms and Sings of Tuberculosis:

Symptoms and Sings of Tuberculosis Dr.T.V.Rao MD 72

PowerPoint Presentation:

Dr.T.V.Rao MD 73

Clinical Illness with Tuberculosis:

Clinical Illness with Tuberculosis Pulmonary Disease – Major manifestation with involvement of Lungs Hemoptysis, Chest pain Fever sweets Anorexia Cavity formation in Lungs Dr.T.V.Rao MD 74

Tuberculosis - Pneumothorax:

Tuberculosis - Pneumothorax Dr.T.V.Rao MD 75

Extra pulmonary Tuberculosis:

Extra pulmonary Tuberculosis Bacteria on circulation leads to bacteremia leads to involvement of GUT, Genito urinary system, Meningitis Gastro Intestinal system, skin, Lymph nodes Bone marrow. Spinal infection Potts spine, Arthritis Dr.T.V.Rao MD 76

Tuberculosis - Lymphadenitis:

Tuberculosis - Lymphadenitis Dr.T.V.Rao MD 77


Epidemiology An ancient disease, called as white plague 1/3 of the world population is infected 2 billion infected Each year 9 lakhs to 1 million are infected Poor nations phase the burnt of the disease. In developing world > 4o% of the population is effected 15 million suffer the disease 3 million are highly infective. Dr.T.V.Rao MD 78

Diagnosis of Tuberculosis :

Diagnosis of Tuberculosis Dr.T.V.Rao MD 79

PowerPoint Presentation:

Types of specimens: -Sputum. - BAL. -Pleural effusions - Urine - Stool -CSF -Aspiration ( gastric – cold abscess) - Blood in case of haematogenous TB Dr.T.V.Rao MD 80

Laboratory Diagnosis:

Laboratory Diagnosis 1- Sputum smears stained by Z-N stain Three morning successive mucopurulent sputum samples are needed to diagnose pulmonary TB . Advantage : - cheap – rapid - Easy to perform - High predictive value > 90% - Specificity of 98% Disadvantages: - sputum ( need to contain 5000-10000 AFB/ ml.) - Young children, elderly & HIV infected persons may not produce cavities & sputum containing AFB. Dr.T.V.Rao MD 81

PowerPoint Presentation:

2 - Detecting AFB by fluorochrome stain using fluorescence microscopy : The smear may be stained by aura mine-O dye. In this method the TB bacilli are stained yellow against dark background & easily visualized using florescent microscope . Advantages: - More sensitive - Rapid Disadvantages: - Hazards of dye toxicity - more expensive - must be confirmed by Z-N stain Dr.T.V.Rao MD 82

3- Cultures on L J media Lowenstein –Jensen medium is an egg based media with addition of salts, 5 % glycerol, Malachite green & penicillin. :

3- Cultures on L J media Lowenstein –Jensen medium is an egg based media with addition of salts, 5 % glycerol, Malachite green & penicillin. Advantages : - Specificity about 99 % - More sensitive ( need lower no. of bacilli 10-100 / ml) - Can differentiate between TB complex & NTM using biochemical reactions - Sensitivity tests for antituberculous drugs ( St, INH, Rif., E) Disadvantages : Slowly growing ( up to 8 weeks ) Dr.T.V.Rao MD 83

Tuberculin Test:

Tuberculin Test Interpretation: * A positive test indicates previous exposure and carriage of T.B. * A negative tuberculin test excludes infection in suspected persons * Tuberculin positive persons may develop reactivation type of T.B. * Tuberculin negative persons are at risk of gaining new infection * False positive reactions are mainly due to: - Infection with nontuberculous mycobacteria * False negative reactions may be due to: - Sever tuberculosis infection (Miliary T.B.) - Hodgkin’s disease - Corticosteroid therapy - Malnutrition - AIDS * Children below 5 years of age with no exposure history: - Positive test must be regarded suspicious Dr.T.V.Rao MD 84

Tuberculin Testing - Limitations:

Tuberculin Testing - Limitations False positive reactions are mainly due to: - Infection with nontuberculous mycobacteria * False negative reactions may be due to: - Sever tuberculosis infection (Miliary T.B.) - Hodgkin’s disease - Corticosteroid therapy - Malnutrition - AIDS * Children below 5 years of age with no exposure history: - Positive test must be regarded suspicious Dr.T.V.Rao MD 85

Recent Methods for Diagnosis:

Recent Methods for Diagnosis I – BACTEC 460 ( rapid radiometric culture system ) specimens are cultured in a liquid medium (Middle brook7H9 broth base )containing C 14 – labeled palmitic acid & PANTA antibiotic mixture. Growing mycobacteria utilize the acid, releasing radioactive CO 2 which is measured as growth index (GI) in the BACTEC instrument. The daily increase in GI output is directly proportional to the rate & amount of growth in the medium. Dr.T.V.Rao MD 86

III Polymerase Chain Reaction (PCR) & Gene probe:

III Polymerase Chain Reaction (PCR) & Gene probe Nucleic acid probes & nucleic acid amplification tests in which polymerase enzymes are used to amplify ( make many copies of specific DNA or RNA sequences extracted from mycobacterial cells. Advantages: - Rapid procedure - High sensitivity (1-10 ( 3 – 4 hours) bacilli / ml sputum) Dr.T.V.Rao MD 87

Tuberculosis and HIV infection:

Tuberculosis and HIV infection HIV association has become a threat to the developed countries too HIV association will lead to rapid spread of tuberculosis Dr.T.V.Rao MD 88

HIV Considerations:

HIV Considerations HIV is the strongest risk factor for progression to active disease HIV kills CD4 + T Helper cells which normally inhibit M. tuberculosis HIV interferes with PPD skin test Protease inhibitors interfere with rifampin Dr.T.V.Rao MD 89

MDR tuberculosis:

MDR tuberculosis Multidrug resistant tuberculosis has become a global threat. In 1993 WHO declared Tuberculosis a Global emergency Animals shed the bacilli in Milk, human’s get infected after drinking the unsterilized Milk Pasteurization has reduced the incidence of Bovine tuberculosis. Dr.T.V.Rao MD 90

Why Tuberculosis continues to be Important :

Why Tuberculosis continues to be Important Someone in the world is newly infected with TB bacilli every second. Overall, one-third of the world's population is currently infected with the TB bacillus. 5-10% of people who are infected with TB bacilli (but who are not infected with HIV) become sick or infectious at some time during their life. People with HIV and TB infection are much more likely to develop TB. Dr.T.V.Rao MD 91


Treatment Drugs used : 1- First line drugs : - Isoniazid - Rifampicin - Pyrazinamide - Ethambutol - Streptomycin 2- Second line drugs (more toxic and less effective): - Kanamycin - capreomycin - Cycloserin - ethionamide - ciprofloxacin - Ofloxacin * Noncompliance (failure to complete the course): Directly observed therapy (DOT) Health care workers observe the medication Dr.T.V.Rao MD 92

Immuno-prophylaxis :

Immuno-prophylaxis Intradermal injection of live attenuated vaccine Bacille Calmette-Guerin (BCG). The strain causes self limited lesion and induces hypersensitivity & immunity. Coverts tuberculin negative person to positive reactor. Immunity lasts for 10-15 years. Immunity 60-80% Some studies proved BCG is doubtful value in prevention of Tuberculosis Dr.T.V.Rao MD 93


BCG Given at birth without tuberculin testing Protects against TB, the disease runs milder course in protected, prevents skeletal, meningeal & miliary forms. Also found useful in leprosy, leukaemias and other malignancies by non-specific stimulation of RE system. Dr.T.V.Rao MD 94

PowerPoint Presentation:

Programme created by Dr.T.V.Rao MD for Medical and Paramedical students in the Developing World Email Dr.T.V.Rao MD 95

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