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Bovine tuberculosis

  1. ZOONOTIC IMPORTANCE ZOO-1008 Submitted to Dr. Shakera Sadiq Gill Submitted by Syeda Anum Hadi 2013-mphil-1063
  2.  Definition  Etiology  Species Affected by M. Bovis  Occurrence/Geographical distribution  Mode of transmission  Survivability of M. bovis  Population at risk  Incubation Period  Clinical symptoms  Postmortem lesions  Morbidity & mortality  Laboratory diagnosis  Sample Collection  Differential diagnosis  Treatment in humans  Prophylaxis/ Control  Vaccine  Outbreak reports  Public health significance  References 2
  3.  Bovine tuberculosis is a chronic bacterial disease of cattle that occasionally affects other species of mammals.  This disease is a significant zoonosis that can spread to humans, typically by the inhalation of aerosols or the ingestion of unpasteurized milk. 3
  4.  Mycobacterium  Gram positive  Acid-fast bacterium (AFB)  Family Mycobacteriaceae.  Mycobacterium tuberculosis- human  Mycobacterium bovis- zoonoticTB  Mycobacterium capare- zoonoticTB (rarely)  Mycobacterium canis- dog 4
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  6.  Primary host-cattle  Maintenance hosts  brush tailed opossums (New Zealand);  badgers (UK &Ireland);  bison and elk(Canada),  and kudu and African buffalo (Southern Africa) 6
  7. Maintenance hosts UL: Brush tailed opossums UR: Badger LL: Bison LR: Elk CL:African Buffalo CR: Kudu 7
  8.  Endemic in developing and under-developed cattle rearing countries-Africa, parts of Asia and some middle eastern countries. (RED)  Ongoing Eradication Programs in- UK, USA, NZ, Japan, Mexico, (GREEN)  TB free countries- Australia, Iceland, Denmark, Sweden, Norway, Finland, Austria, Switzerland, Luxembourg, Latvia, Slovakia, Lithuania, Estonia, the Czech Republic, Canada, Singapore, Jamaica, Barbados and Israel. (YELLOW) 8
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  10. ANIMAL-ANIMAL  HorizontalTransmission-  inhalation of aerosols(cats, badgers), by ingestion(calves, pigs, cats, ferrets), or through breaks in the skin (cats, badgers).  Shedding of bacteria in- faces, milk, discharging lesions, saliva, vaginal fluids, semen and urine. (later stages of disease)  Close, prolonged contact of healthy animals with infected animal  Intensive livestock farming;  Extensive livestock farming (vaccination centers, AI Centers, Dipping tanks, Auction markets, transportation, ponds, wells and streams, in tropical areas gathering under shady areas during hot part of the day, salt supplementing points)  Vertical transmission-Congenital infections (rare in developed countries with an effective eradication program) 10
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  12. Animal to human  PulmonaryTB- more in rural dwellers… due to inhalation of infected dust  GastrointestinalTB- more in urban dwellers… due to ingestion of unpasteurized milk and dairy products  HIV people Human to animal  Rare  Genito-urinaryTB… urination in cowsheds/ pasture … animal craving salt would prefer grazing there… INFECTION Human to human  Rare  Less efficient than M. tuberculosis  HIV infected humans are highly susceptible. 12
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  15.  Several months  Cold, dark, moist conditions  12-24C… 18-332 days  Susceptible to sunlight 15
  16. Occupational Risk  Farmers,  Abattoir workers,  Veterinarians  Laboratory technicians  Animal caretakers in zoos  Workers in animal reservations and national parks  Close association with people living with animals or working with them. Susceptible age group-  Infants,  Pregnant women,  Old. Consumption related risk factors  Nutritionally deficient people  Consumers of unpasteurized milk,  Raw meat or  Undercooked meat. Medical conditions  HIV positive humans  Diabetics  Previously incorrectly treated TB patients 16
  17.  Poor sanitation  Lack of access to clean water  Over-crowding  Poor housing  Absence of health care 17
  18.  Takes months to develop  Dormant for years and reactivating during period of stress or old age  2-5 weeks  Kittens-experimentally IP is 3 weeks. 18
  19. Humans  A bad cough that lasts 3 weeks or longer.  Pain in the chest.  Coughing up blood or phlegm from deep inside the lungs.  Weakness or feeling very tired.  Losing weight without trying.  Having no appetite.  Chills and fever.  Sweating at night or when sleeping. In Animals: Early on it remains asymptomatic Late stages  progressive emaciation,  a low–grade fluctuating fever,  weakness and  inappetence. 19
  20. Animals with pulmonary involvement  a moist cough that is worse in the morning, during cold weather or exercise,  dyspnea or tachypnea. In the terminal stages, animals may  become extremely emaciated  acute respiratory distress.  retropharyngeal or other lymph nodes enlarge and may rupture and drain.  Greatly enlarged lymph nodes can also obstruct blood vessels, airways, or the digestive tract.  If the digestive tract is involved, intermittent diarrhea and constipation may be seen. 20
  21.  granulomas (tubercles) where bacteria have localized. usually yellowish either caseous, caseo-calcareous or calcified often encapsulated.  found in the lymph nodes, particularly those of the head and thorax.  common in the lung, spleen, liver and the surfaces of body cavities 21
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  23.  Infective dose: Cattle: 1 CFU (colony forming units)=6-10 viable bacilli; Human respiratory route: 10’s to 100’s bacteria; Millions by gastrointestinal route  100% mortality if not treated. 23
  24.  Cattle:  Tuberculin skin test (screening test)  Microscopic examination of AFB  Ziehl/Neelson stain  Flourescent acid-fast stain  Isolation on selective culture media (8 weeks)  PCR  Biological safety cabinet should be used  Wildlife: Lymphocyte proliferation assay/gamma-interferon assays / ELISA (D.V. Cousins & N. FlorissonA review of tests available for use in the diagnosis of tuberculosis in non- bovine species, Rev. sci. tech. Off. int. Epiz., 2005, 24(3), 1039-1059) 24
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  26.  Samples from Live animal: Sputum and other body fluids Blood samples  Samples at necropsy: Abnormal lymph nodes Lungs Liver Spleen 26
  27.  Contagious bovine pleuropneumonia  Pasteurella  Corynebacterium pyogenes pneumonia  Aspiration pneumonia  Traumatic pericarditis  Caseous lymphadenitis  Liver fluke infestation 27
  28.  Isoniazid  Rifampicin  Ethambutol  Pyrazinamide  Streptomycin  6months  MDRTB… 2 years Rx… 3lakh/year expense 28
  29. Why control???  Risk of infection to human  Loss in productivity  Animal market restrictions set by countries with advanced eradication programs  Threat to endangered wild animal species Failure of control programs in developing countries???  Cannot shoulder the cost of eradication program and compensate for culled animals.  Limited access to education  Poor information networks  Lack of disease surveillance 29
  30.  MandatoryTest-and- slaughter strategy or test- and-segregation.  Periodic re-testing of infected herd  Quarantine  Trace back reactor and those that came in contact with them  Strong Disinfection with 5% phenol, iodine solutions, glutarldehyde and formadehyde…long contact time  Rodent control  Barrier the area to prevent wildlife interaction with domestic animals.  Pasteurization of milk  Awareness about the deleterious effects of unpasteurized milk consumption.  Proper cooking of meat.  Restricted animal movement.  Involvement of ministry of health in coalition with agriculture industry for combined efforts to reduce bovineTB. 30
  31. HumanTB  Bacillus CalamiteGuerin (BCG)  Attenuated strain of wild type of M. bovis isolate from cattle BovineTB  BCG vaccination in animals less effective.  Is under consideration in European countries, North America and some African countries. 31
  32.  TheTB-free New Zealand program is regarded as "world-leading". It has successfully reduced cattle and deer herd infection rates from more than 1700 in 1994 to fewer than 100 herds in July 2011  In USA … In 2008, 733,998 licensed deer hunters harvested approximately 489,922 white-tailed deer in attempts to control the disease spread. 32
  33.  5-10% of human tuberculosis is caused by M.bovis  Effects lymph nodes, skin, bones, joints, genitourinary system, meninges or respiratory system.  Cervical lymphadenopathy (scrofula) … in children… infected milk intake  Lupus vulgaris-chronic skin disease  Buthcer’s warts.. Localized skin disease.. Benign and self-limiting.  PulmonaryTB  Treatable disease 33
  34.  CFSPH (The Center for Food Security and Public Health). Bovine Tuberculosis. College ofVeterinary Medicine Iowa State University Ames,2007.  Center for Disease Control and Prevention. GetThe Facts About TB Disease.The New Jersey Medical School GlobalTuberculosis Institute, 2011.  OSHA's Alliance Program. Zoonotic Diseasaes Fact Sheet.  S. Ali, K.T. Jaffary, B. Zameer and Z.J.Gill, BovineTB Zoonoses; A Review; Pakistan Journal Of Science.Vol.61, No.2, June 2009  M. Borna, D. Salome, A. Silvia, H. Jan, J.M.L Cláudio, D.C.P. Sven, D.V.H. Paul, and Z. Jakob; Zoonotic Mycobacterium bovis–induced Tuberculosis in Humans; Emerging Infectious Diseases ,Vol. 19, No. 6, June 2013  D.A.Ashford, E.Whitney, P. Raghunathan & 0. Cosivi l, Epidemiology of selected mycobacteria that infect humans and other animals , Rev. sci. tech. Off. int. Epiz., 2001,20 (1), 325-337 34
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