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[[Image:Myxomatosis_rabbit_logo.jpg|200px|right|thumb|A European Rabbit afflicted by Myxomatosis <br> Chris Bayley, WikiMedia Commons]]

[[Image:Myxomatosis_rabbit_logo.jpg|200px|right|thumb|A European Rabbit afflicted by Myxomatosis <br> Chris Bayley, WikiMedia Commons]]

This page explains the viral cause of Myxomatosis and the associated clinical signs, pathology and pathogenesis, treatment, control and prognosis.

Myxomatosis is a highly contagious viral condition of rabbits caused by the myxoma virus and carried prinicpally by the rabbit flea,''Spilopsyllus cuniculi''. It is also transmitted by direct or indirect contact with ocular or skin discharges or by mechanical vectors. Myxomatosis is enzootic in rabbits of the genus Sylvilagus in both South and North America and in wild rabbits of the genus Oryctolagus in South America, Europe, and Australia.

===Myxoma virus===

==Clinical signs==

Clinical disease varies with virus strain and host species. Sylvilagus species are relatively resistant, and are probably the natural host of the virus.  In Sylvilagus species, infection usually results in the development of skin tumour at the site of innoculation.  The tumours appear 4-8 days after exposure and persist for up to 40 days.  Very young rabbits may succumb to generalized disease. Lepus species (hares) however are highly resistant; occasional individuals develop mild to severe generalized myxomatosis.

*Infectious myxomatosis is highly contagious and transmitted by direct or indirect contact with ocular or skin discharges or by mechanical vectors.

*Arthropod vectors such as mosquitoes and fleas provide the principal means of transmission.   

*Myxomatosis is enzootic in rabbits of the genus Sylvilagus in both South and North America and in wild rabbits of the genus Oryctolagus in South America, Europe, and Australia. 

*Following introduction into Europe and Australia, genetic modification of the myxoma virus produced markedly attenuated strains that replaced the virulent virus as the dominant virus strain.   

*The naturally attenuated viruses cause a milder disease of longer duration which favors vector transmission and persistence of the virus in nature.   

*High ambient environmental temperatures are associated with increased survival of infected animals. Some authors consider the California strains of the virus (California rabbit fibroma virus) as distinct from the myxoma virus, while others feel that the antigenic differences do not justify the separate distinction.

In the European rabbit (Oryctolagus cuniculus), infection with a virulent virus (i.e. the South American or California strains) results in severe disease with up to a 99% case fatality rate. Initial signs include oedema of the eyelids accompanied by inflammation and oedema around the anal, genital, oral, and nasal orifices.  Oedema of the head and ears, drooping ears, and bacterial infections resulting in mucopurulent conjunctivitis and pneumonia are seen.   

**In the European rabbit (Oryctolagus cuniculus), infection with virulent virus (South American or California strains) results in severe disease with up to a 99% case fatality rate.

***Initial signs include edema of the eyelids accompanied by inflammation and edema around the anal, genital, oral, and nasal orifices.   

***Edema of the head and ears, drooping ears, and bacterial infections resulting in mucopurulent conjunctivitis and pneumonia are seen.   

***The primary tumor may be evident by 3-4 days after infection.  Generalized tumors develop by 6-7 days after infection.   

***The primary tumor may be evident by 3-4 days after infection.  Generalized tumors develop by 6-7 days after infection.   

***Subcutaneous swellings become mucoid, gelatinous masses (hence the name myxomatosis).   

***Subcutaneous swellings become mucoid, gelatinous masses (hence the name myxomatosis).   

[[Category:Leporipoxviruses]][[Category:Rabbit Viruses]]

[[Category:Leporipoxviruses]][[Category:Rabbit Viruses]]

[[Category:To_Do_-_Clinical]]

[[Category:To_Do_-_SophieIgnarski]]