Mycobacterium bovis

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iMycobacterium bovis

Scientific classification

Kingdom:	Bacteria
Phylum:	Actinobacteria
Order:	Actinomycetales
Suborder:	Corynebacterineae
Family:	Mycobacteriaceae
Genus:	Mycobacterium
Species:	M. bovis

Binomial name

Mycobacterium bovis
Karlson & Lessel 1970

Mycobacterium bovis is a slow-growing (16 to 20 hour generation time), aerobic bacterium and the causative agent of tuberculosis in cattle. Related to M. tuberculosis—the bacteria which causes tuberculosis in humans—M. bovis can also jump the species barrier and cause tuberculosis in humans.

1 Pathogenesis
2 Epidemiology
3 Treatment
4 References

[edit] Pathogenesis

It has been estimated that, during the first half of the 20th century, M. bovis was responsible for more losses among farm animals than all other infectious diseases combined. Infection occurs if the bacterium is ingested.

M. bovis is usually transmitted to humans via infected milk, although it can also spread via aerosol droplets. However, actual infections in humans are rare. This is mostly due to pasteurisation killing any bacteria in infected milk; as well, cattle are randomly tested for the disease and immediately destroyed if infected.

[edit] Epidemiology

In the 1930's, 40% of cows in the UK were infected with M. bovis and there were 50,000 new cases of human M. bovis infection every year.<ref>Reynolds D (2006). "A review of tuberculosis science and policy in Great Britain". Vet Microbiol 112 pages=119–126. PMED 16343818.</ref> Since 1990, only one case of human M. bovis infection acquired from an animal source has been documented in the UK. In 2004, 5.6% of herds were affected by restrictions because of M. bovis infection.

Badgers (Meles meles) were first identified as carriers of M. bovis 30 years ago, but it was the report of an independent review committee in 1997 which concluded that badgers made an important contribution to the spread of M. bovis between herds of cattle.<ref>Krebs JR, Anderson T, Clutton-Brock WT, et al. (1997). Bovine tuberculosis in cattle and badgers: an independent scientific review. Ministry of Agriculture, Fisheries and Food.</ref> This was the major cause of the current battle between animal conservationists (keen to save the badger) and farmers (keen to cull badgers, to reduce livestock losses). There are on-going trials to determine whether badger culling actually affects the spread of M. bovis; preliminary results have been published and are equivocal.

It should be noted that in the UK, other animals that carry M. bovis include deer and the red fox. In Australia, important carriers of M. bovis are the water buffalo and opossum.