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Inclusion Body Disease (IBD) in the boid family of snakes, particularly ''Boa constrictor'', has been recognized since the mid-1970s. It is so named because of the characteristic intracytoplasmic inclusions which are observed in clinical examinations in epidermal cells, oral mucosal epithelial cells, visceral epithelial cells, and neurons. In the 1970s and 1980s the disease was most commonly observed in Burmese pythons, ''Python molurus bivittatus''. From the 1980s till the present day, it has been most commonly observed in boa constrictors, ''Boa constrictor'' from S. America. All boid snakes should be considered susceptible to the disease. Many zoos quarantine boas specifically as a result of this high risk before introducing them into their permanent collections and (breeding) programs. While the disease has not been identified in non-boid snakes, it is yet unknown whether non-boid snakes harbour the virus. The primary host of this virus has not yet been identified but mites are thought to be primary hosts or at least a contributory factor. Its distribution is worldwide, specifically in captive boid snakes. Its occurrence in the wild is unknown. Strangely enough, the disease has only been identified in adult and sub-adult specimens. Even so, all age groups are considered susceptible. There are also anecdotal reports of the infection in neonates. A retro-like virus infection was suspected as the causative agent of IBD, but identification of highly divergent arenavirus sequences from Boa constrictors with IBD (Stenglein et al., 2012; Bodewes et al., 2013) suggested arenaviruses to be the etiological agent of IBD. Cell culture isolation of several arenaviruses from boid snakes with IBD further solified, but did not yet confirm, the etiological relationship between IBD and arenaviruses (Hetzel et al., 2013). == Clinical signs == Clinical signs may vary, regurgitation and neurological symptoms being the most prominent in the early and later stages of its progression. In boa constrictors, the first signs may include off and on regurgitation, and some develop head tremors. Dysecdysis (abnormal shedding) may occur. Some develop chronic regurgitation and anorexia (of appetite or refusal to feed ). However, not all infected snakes may regurgitate. Boas lose weight and may develop clogged nares (nostrils), stomatitis or secondary pneumonia. The disease can rapidly progress to produce nervous system disorders, such as disorientation, ''corkscrewing of the head'' and neck, holding the head in abnormal and unnatural positions, rolling onto the back or ''stargazing''. Stomatitis, pneumonia, undifferentiated cutaneous sarcomas, lymphoproliferative disorders, and leukemia have all been observed in affected specimens. Burmese pythons generally show signs of central nervous system disease without manifestation of other clinical signs and regurgitation is not seen in Burmese pythons, only in boas. These are symptoms similar to those seen in specimens infected by Chlamydia–specifically Chlamydophila psittaci, the so-called parrot's disease. Several snakes have been seen with proliferative pneumonia, while inclusions are commonly seen in the liver, kidney, and pancreas. Cases have also been observed where there are only very few inclusions. In a few snakes with signs of central nervous system disease, and with a severe encephalitis, no inclusions have been seen in any cells. While the presence of characteristic inclusions is diagnostic for the disease, the absence of such inclusions does not necessarily indicate that the snake is not diseased or is free from the IBD virus. While cells having inclusions may show mild degenerative changes, inflammation is rarely seen in visceral tissues. In the brain, mild to severe encephalitis occurs, with lymphocytic perivascular cuffing. Several snakes with lymphoproliferative disorders have been identified with lymphoid infiltrates in multiple organs. 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「Inclusion Body Disease」の詳細全文を読む スポンサード リンク
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