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Swine brucellosis is a zoonosis affecting pigs, caused by the bacterium ''Brucella suis''. The disease typically causes chronic inflammatory lesions in the reproductive organs of susceptible animals or orchitis, and may even affect joints and other organs.〔Fretin, D. A.-B. (2008). Brucella suis identification and biovar typing by real-time PCR. Veterinary Microbiology , 131 (2-4), 376-385.〕 The most common symptom is abortion in pregnant susceptible sows at any stage of gestation.〔Godfroid, J. A.-B. (2005). From the discovery of the Malta fever's agent to the discovery of a marine mammal reservoir, brucellosis has continuously been a re-emerging zoonosis. Veterinary Research , 36, 313-326.〕 Other manifestations are temporary or permanent sterility, lameness, posterior paralysis, spondylitis, and abscess formation. It is transmitted mainly by ingestion of infected tissues or fluids, semen during breeding, and suckling infected animals.〔The Merck Veterinary Manual. (2011). Brucellosis in Pigs. Retrieved 4 20, 2011, from http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/110505.htm〕 Since brucellosis threatens the food supply and causes undulant fever,〔Wilson, G. S. (1955). Topley and Wilson’s principles of bacteriology and immunity. London, England: Edward Arnold Publishers Ltd.〕 ''Brucella suis'' and other ''Brucella'' species (''B. melitensis, B. abortis, B. ovis, B. canis'') are recognized as potential agricultural, civilian, and military bioterrorism agents.〔Halling, S. M.-B.-L. (2005). Completion of the Genome Sequence of Brucella abortus and Comparison to the Highly Similar Genomes of Brucella melitensis and Brucella Suis. Journal of Bacteriology , 187, 2715-2726.〕 ==Etiology== ''B. suis'' is a Gram-negative, facultative, intracellular coccobacillus, capable of growing and reproducing inside of host cells, specifically phagocytic cells.〔Liautard, J. P., A. Gross, J. Dornand, and S. Kohler. "Interactions between professional phagocytes and Brucella spp." Microbiologia 12 (1996): 197-206.〕 They are also not spore-forming, capsulated, or motile.〔Liautard, J. P., A. Gross, J. Dornand, and S. Kohler. "Interactions between professional phagocytes and Brucella spp." Microbiologia 12 (1996): 197-206.〕 Flagellar genes, however, are present in the ''B. suis'' genome, but are thought to be cryptic remnants because some were truncated and others were missing crucial components of the flagellar apparatus.〔DelVecchio, V.G., Kapatral, V., Elzer, P., Patra, G., and. "The genome of Brucella melitensis." Veterinary Microbiology 90 (2002): 587-592.〕〔Moreno, E., and Moriyon, I. "Brucella melitensis: a nasty bug with hidden credentials for virulence." Proceedings of the National Academy of Science of USA 99 (2002): 1-3.〕 Interestingly, in mouse models, the flagellum is essential for a normal infectious cycle, where the inability to assemble a complete flagellum leads to severe attenuation of the bacteria.〔Fretin, D., A. Fauconnier, S. Kohler, S. Halling, S. Leonard, C. Nijskens, J. Ferooz, P. Lestrate, R.-M. Delrue, I. Danese, J. Vandenhaute, A. Tibor, X. DeBolle and J.-J. Letesson. "The sheathed flagellum of Brucella melitensis is involved in persistence in a murine model of infection." Cellular Microbiology 7.5 (2005): 687-698.〕 ''B. suis'' is differentiated into five biovars (strains), where biovars 1-3 infect wild boar and domestic pigs, and biovars 1 and 3 may cause severe diseases in humans.〔Fretin, D., A. M. Whatmore, S. A. Dahouk, H. Neubauer, B. Garin-Bastuji, D. Albert, M. Van Hessche, M. Menart, J. Godfroid, K. Walravens, P. Wattiau. "Brucella suis identification and biovar typing by real-time PCR." Veterinary Microbiology 131.2-4 (2008): 376-385. 〕 In contrast, biovar 2 found in wild boars in Europe shows mild or no clinical signs and cannot infect healthy humans, but does infect pigs and hares.〔Lagier, A., S. Brown, A. Soualah, I. Julier, B. Tourrand, D. Albert, J. Reynes and B. Garin-Bastuji. "Brucellose aigue a B. suis biovar 2 chez un chasseur de sanglier." Med. Mal. Infect 35 (2005): 185.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Swine brucellosis」の詳細全文を読む スポンサード リンク
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