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Mycobacterium bovis

(Tuberculosis)

Note for Pet Owners:

This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Mycobacterium bovis is a very important zoonosis which causes tuberculosis in humans and many other species, and is of major concern and a cause of losses significant financial losses for agriculture worldwide

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Description
In humans tuberculosis usually causes debilitating respiratory or gastrointestinal signs. 


Cause
Tuberculosis is caused by an aerobic acid-fast bacterium called Mycobacterium bovis


Occurrence
M.bovis  has a worldwide distribution except for a few countries (e.g. Australia) and transmission to humans is usually via  ingestion of unpasteurised milk or dairy products, direct contact, and sometimes by aerosol droplets or contact with infected sputum, urine or faeces 

Species that can be infected include humans, cattle, deer, elk, goats, pigs, domestic cats, llamas, foxes, coyotes, mustelids, badgers, possums, raccoons and rodents. Some species (e.g. sheep and horses) are rarely infected.  In many countries wild mammals act as a reservoir for infection (e.g. opossums in New Zealand and badgers in the UK) which has prompted control measures to control their numbers 

There is one report in the literature of infection in a household involving human and canine patients with clinical signs and a latent human carrier (Shrikrishna et al 2009) 


Signs

Infected animals may be asymptomatic, or develop a chronic disease that usually involves the lungs, lymph nodes and other organs showing signs including fever, weight loss or respiratory signs such as coughing. Other signs may gastrointestinal and cattle may develop mastitis.


Complications
None


Diagnosis
In cattle  a single comparative intradermal skin test (SICTT) has  typical  specificity greater than 99.9%. BUT sensitivity remains moderate in the range 50-60%  Nevertheless it is the best single test currently available for the diagnosis of bovine tuberculosis. 

Other diagnostic tests are available and the organism can be isolated at post-mortem . 


Treatment

Treatment involves administration of  isoniazid and rifampicin for 9 months

There are experimental vaccinations available . 

Other preventive measures include controlling wild animal reservoirs, and the routine pasteurisation of milk.


Prognosis
If untreated infections with M.bovis can prove fatal 

Reference

Shrikrishna D et al (2009) Human and canine pulmonary Mycobacterium bovis infection in the same household - re-emergence of an old zoonotic threat ?  Thorax 64 89-91

 

 

Updated September 2014