Bluetongue disease
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Bluetongue disease (also called catarrhal fever) is a non-contagious, arthropod-borne viral disease of ruminants, mainly sheep and less frequently of cattle, goats, buffalo, deer, dromedaries and antelope. There are no reports of human transmission. It is caused by the Bluetongue virus.
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[edit] Pathogen
The pathogenic virus, Bluetongue virus of the genus Orbivirus is a member of the Reoviridae family. There are 24 serotypes. It is transmitted by a midge, Culicoides imicola and other culicoid species.
[edit] Epidemiology
Bluetongue has been observed in Australia, the USA, Africa, the Middle East, Asia and Europe. Its occurrence is seasonal in the affected Mediterranean countries, subsiding when temperatures drop. It has been spreading northward since October 1998, perhaps as a result of global warming.[1] In August 2006 cases of bluetongue were found in the Netherlands, then Belgium, Germany, Holland, and Luxembourg.[2][3]
[edit] Symptoms
Major signs are high fever, excessive salivation, swelling of the face and tongue and cyanosis of the tongue. Swelling of the lips and tongue gives the tongue its typical blue appearance, though this sign is confined to a minority of the animals. Recovery is very slow.
The incubation period is 5–20 days, and all signs usually develop within one month. The mortality rate is normally low, but is high in susceptible breeds of sheep. In cattle and wild ruminants infection is usually asymptomatic despite high virus levels in blood.
[edit] Treatment
There is no efficient treatment. Prevention is effected via quarantine, inoculation with live modified virus vaccine and control of the midge vector, including inspection of aircraft.
Although the tongues of human patients with some types of heart disease may be blue, this sign is not related to bluetongue disease.
[edit] Related Diseases
African Horse Sickness is related to Bluetongue and is spread by the same midge (Culicoides species). It can kill up to 90% of the horses it infects.[4]
[edit] References
- ^ Purse, Bethan V.; Mellor, Philip S.; Rogers, David J.; Samuel, Alan R.; Mertens, Peter P. C.; and Baylis, Matthew (February 2005). "Climate change and the recent emergence of bluetongue in Europe". Nature Reviews Microbiology 3 (2): 171-181. DOI:10.1038/nrmicro1090. Retrieved on 2006-07-26.
- ^ European Commission (2006-08-21). Blue Tongue confirmed in Belgium and Germany. Press release. Retrieved on 2006-08-21.
- ^ Wikt:Unknown (2007-03-28). Lethal horse disease knocking on Europe's door. Press release. Retrieved on 2007-03-27.
- ^ wikt:Unknown (2007-03-28). Lethal horse disease knocking on Europe's door. Press release. Retrieved on 2007-03-27.
