Brucella Abortus gram-negative bacterium - TvAgro By Juan Gonzalo Angel
Channel: TvAgro Channel
Date: 2017-12-27

Bovine brucellosis, caused by the bacterium Brucella abortus, is an economically
important cause of abortions in cattle. B. abortus also affects other species including
bison, buffalo and elk; some species are maintenance hosts for this organism. Infections
in wildlife can hinder eradication efforts in cattle. In addition, B. abortus is a human
pathogen. In humans, brucellosis can be a serious, debilitating and sometimes chronic
disease that may affect a variety of organs. Most cases are the result of occupational
exposure to infected animals, but infections can also occur from ingesting contaminated
dairy products. In addition, B. abortus could be used in a bioterrorist attack. 
In cattle, bison and buffalo, brucellosis is mainly caused by Brucella abortus, a
Gram-negative coccobacillus or short rod. This organism is a facultative intracellular
pathogen. Up to nine B. abortus biovars (1-9) have been reported, but some of these
biovars differ only slightly and their status is unresolved. Other Brucella species
uncommonly associated with disease in cattle include Brucella melitensis and B. suis.
(For information on B. suis or B. melitensis, see the factsheets titled “Porcine
Brucellosis” and “Ovine and Caprine Brucellosis,” respectively.)
Genetic and immunological evidence suggests that all members of the genus
Brucella are closely related, and some microbiologists have proposed that this genus
be reclassified into a single species (B. melitensis), which contains many biovars. This
proposal is controversial, and both taxonomic systems are currently in use. The
multiple species nomenclature is used in this factsheet
Most species of Brucella are primarily associated with certain hosts; however,
infections can also occur in other species, particularly when they are kept in close
contact. Maintenance hosts for Brucella abortus include cattle, bison (Bison spp.)
water buffalo (Bubalus bubalus), African buffalo (Syncerus caffer), elk and camels. A
feral pig population has recently been reported to maintain B. abortus. A variety of
other species can become "spill-over" hosts where this organism is enzootic. B.
abortus has been reported in horses, sheep, Rocky Mountain bighorn sheep, goats,
chamois, pigs, raccoons, opossums, dogs, coyotes, foxes, wolves and other species.
Moose and llamas can be infected experimentally. 

Source: http://www.cfsph.iastate.edu/Factsheets/pdfs/brucellosis_abortus.pdf
 Juan Gonzalo Angel Restrepo
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