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''Brucella'' is a genus of Gram-negative bacteria, named after David Bruce (1855-1931). They are small (0.5 to 0.7 by 0.6 to 1.5 µm), non-encapsulated, flagellated, facultatively intracellular coccobacilli. ''Brucella'' is the cause of brucellosis, which is a zoonosis. It is transmitted by ingesting contaminated food (such as unpasteurized milk products), direct contact with an infected animal, or inhalation of aerosols. Transmission from human to human, for example through sexual intercourse or from mother to child, is exceedingly rare, but possible.〔(【引用サイトリンク】title=Diagnosis and Management of Acute Brucellosis in Primary Care )〕 Minimum infectious exposure is between 10 - 100 organisms. The different species of ''Brucella'' are genetically very similar, although each has a slightly different host specificity (see below). Hence, the NCBI taxonomy includes most ''Brucella'' species under ''Brucella melitensis''. The many names of brucellosis include (human disease/animal disease): * Malta fever/Bang’s disease * Undulant fever/enzootic abortion * Mediterranean fever/epizootic abortion * Rock fever of Gibraltar/slinking of calves * Gastric fever/ram epididymitis * Contagious abortion/spontaneous abortion〔Xavier.M.N, Paixão.T.A,"Pathogenesis of'' Brucella'' spp." ''The Open Veterinary Science Journal'', 2010, 4, 109-118〕 == Human brucella == Sir David Bruce isolated ''B. melitensis'' from British soldiers who died from Malta fever in Malta. After exposure to ''Brucella'', humans generally have a two- to four-week latency period before exhibiting symptoms, which include acute undulating fever (>90% of all cases), headache, arthralgia (>50%), night sweats, fatigue, and anorexia. Later complications may include arthritis or epididymoorchitis, spondylitis, neurobrucellosis, liver abscess formation, and endocarditis, the latter potentially fatal. Human brucellosis is usually not transmitted from human to human; people become infected by contact with fluids from infected animals (sheep, cattle, or pigs) or derived food products, such as unpasteurized milk and cheese. Brucellosis is also considered an occupational disease because of a higher incidence in people working with animals (slaughterhouse cases). People may also be infected by inhalation of contaminated dust or aerosols, and as such the CDC has labeled ''Brucella'' species as highly weaponizable. Human and animal brucellosis share the persistence of the bacteria in tissues of the mononuclear phagocyte system, including the spleen, liver, lymph nodes, and bone marrow. ''Brucella'' can also target the male reproductive tract. Globally, an estimated 500,000 cases of brucellosis occur each year. Malta fever was a major health problem to British troops in Malta in the 19th and early 20th centuries, resulting in over 6000 cases and 574 deaths.〔Ariza.J , Bosilkovski.M , "Perspectives for the Treatment of Brucellosis in the 21st Century:The Ioannina Recommendations",2007, PLoS Medicine, Volume 4 ,Issue 12 , 317〕 In 1860, J.A. Maraston, assistant surgeon in the British Army in Malta, gave the first accurate description of the disease he called “Mediterranian gastric remittent fever”. In 1897, A.E. Wright, a pathologist in British army, developed the agglutination test, diagnostic of the disease. In 1905, Zammit, a Maltese physician, identified goats as the source of infection. E. Bang, a Danish veterinarian, described the intracellular pathogen causing abortion in cattle in 1897, and named it ''Bacillus abortus''. In 1918, A. Evans, an American microbiologist, made the connection between'' B. abortus'' and'' Micrococcus melitensis'', and placed them in the Bacteriaceae. In 1914, Mohler isolated an organism from the liver and spleen of pigs, ''B. suis''. ''B. neotome'', ''B. ovis'', and ''B. canis'' were described in 1957, 1963, and 1966, respectively.〔 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「Brucella」の詳細全文を読む スポンサード リンク
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