Louping Ill Ovine Encephalomyelitis, Infectious Encephalomyelitis of Sheep, Trembling–Ill
Louping ill is a tick-borne, zoonotic, viral disease that is most important in sheep and red grouse. Severe clinical signs can be seen in naive sheep flocks moved into endemic areas. Many animals may develop neurological disease, and up to 60 % of the flock can die. In endemic areas, most losses occ...
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| Format: | Text |
| Language: | English |
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2009
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.180.5360 http://www.cfsph.iastate.edu/Factsheets/pdfs/louping_ill.pdf |
| Summary: | Louping ill is a tick-borne, zoonotic, viral disease that is most important in sheep and red grouse. Severe clinical signs can be seen in naive sheep flocks moved into endemic areas. Many animals may develop neurological disease, and up to 60 % of the flock can die. In endemic areas, most losses occur among unvaccinated younger sheep that are no longer protected by maternal antibodies. Louping ill is a serious problem in red grouse populations; few chicks may survive in some endemic areas. The mortality rate can be as high as 80 % in experimentally infected birds. Cases of louping ill are also reported occasionally in other species including goats, llamas, alpacas, swine, horses and deer. Humans can develop flu-like symptoms or neurological signs after exposure, but the illness is rarely fatal. Etiology Louping ill results from infection by louping ill virus, a member of the genus Flavivirus in the family Flaviviridae. This virus is closely related to tickborne encephalitis virus (TBEV) and is a member of the same viral complex. Four subtypes of louping ill virus – the British, Irish, Spanish and Turkish subtypes – have been identified; however, a recent genetic analysis suggests that the Turkish subtype (Turkish sheep encephalitis virus) is more closely related to TBEV than louping ill virus, and should be reclassified. Species Affected Sheep are the most important hosts for louping ill virus. Clinical cases have also been documented in other mammals including cattle, goats, horses, llamas, alpacas, pigs, dogs, deer and European elk. Fatal cases have been reported among grouse and their relatives, including experimentally infected ptarmigan (Lagopus mutus) and willow grouse (Lagopus lagopus), and naturally or experimentally infected red grouse (Lagopus lagopus scoticus). Louping ill virus can also infect a number of small mammals including shrews, wood mice, voles, rats, hares and rabbits. Humans seem to be accidental hosts. Sheep appear to be the most important reservoir hosts, but grouse can also amplify ... |
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