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Paratuberculosis or Johne's disease is a contagious, chronic and sometimes fatal infection that primarily affects the small intestine of ruminants. It is caused by the bacterium ''Mycobacterium avium'' subspecies ''paratuberculosis''. Infections normally affect ruminants (mammals that have four compartments of their stomachs, of which the rumen is one), but have also been seen in a variety of nonruminant species, including rabbits, foxes, and birds. Horses, dogs, and nonhuman primates have been infected experimentally. Paratuberculosis is found worldwide, with some states in Australia (where it is usually called bovine Johne's disease or BJD) as the only areas proven to be free of the disease.〔Collins M. and Manning E. "Johne's Information Center" The University of Wisconsin-School of Veterinary Medicine. 13 March 2003.〕 Some sources define "paratuberculosis" by the lack of ''Mycobacterium tuberculosis'', rather than the presence of any specific infectious agent, leaving ambiguous the appropriateness of the term to describe Buruli ulcer or Lady Windermere syndrome. ==Bacterium== The disease, discovered by Heinrich A. Johne, a German bacteriologist and veterinarian, in 1905, is caused by a bacterium named ''Mycobacterium avium'' subspecies ''paratuberculosis'', an acid-fast bacillus, often abbreviated MAP. MAP is akin to, but distinct from, ''Mycobacterium tuberculosis'', the main cause of tuberculosis in humans, and ''Mycobacterium bovis'', the main cause of tuberculosis in cattle and occasionally also in humans. MAP is 99% genetically related to ''Mycobacterium avium'', but has different phenotypic characteristics, such as: * slower growth * requires the addition of an iron transport chemical known as mycobactin when grown ''in vitro'' * forms a rough colony when grown on a solid agar medium * Infects mammals instead of birds Also, the environmental distribution of MAP is markedly different from that of ''M. avium'', which can produce mycobactin, so can grow and multiply outside the body. 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「paratuberculosis」の詳細全文を読む スポンサード リンク
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