ZOONOTIC IMPORTANCE
ZOO-1008
Submitted to
Dr. Shakera Sadiq Gill
Submitted by
Syeda Anum Hadi
2013-mphil-1063

 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

 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

 Mycobacterium
 Gram positive
 Acid-fast bacterium (AFB)
 Family Mycobacteriaceae.
 Mycobacterium tuberculosis- human
 Mycobacterium bovis- zoonoticTB
 Mycobacterium capare- zoonoticTB (rarely)
 Mycobacterium canis- dog
4

5

 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

Maintenance hosts
UL: Brush tailed
opossums
UR: Badger
LL: Bison
LR: Elk
CL:African
Buffalo
CR: Kudu
7

 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

9

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

11

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

13

14

 Several months
 Cold, dark, moist conditions
 12-24C… 18-332 days
 Susceptible to sunlight
15

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

 Poor sanitation
 Lack of access to clean water
 Over-crowding
 Poor housing
 Absence of health care
17

 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

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

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

 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

22

 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

 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

25

 Samples from Live animal:
Sputum and other body fluids
Blood samples
 Samples at necropsy:
Abnormal lymph nodes
Lungs
Liver
Spleen
26

 Contagious bovine pleuropneumonia
 Pasteurella
 Corynebacterium pyogenes pneumonia
 Aspiration pneumonia
 Traumatic pericarditis
 Caseous lymphadenitis
 Liver fluke infestation
27

 Isoniazid
 Rifampicin
 Ethambutol
 Pyrazinamide
 Streptomycin
 6months
 MDRTB… 2 years Rx… 3lakh/year expense
28

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

 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

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

 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

 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

 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

35