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==Description==

==Description==

Equine Infectious Anaemia (EIA) is an exotic viral disease affecting horses, donkeys and mules. It is caused by Equine Infectious Anaemia Virus (EIAV), an equid-specific lentivirus in the retrovirus family that is closely to related to HIV in humans. EIA occurs in acute and subacute forms in susceptible animals but more commonly assumes a chronic course. Affected horses that recover from EIA may become lifelong carriers, and relapse of the disease may occur during times of stress or illness.

Equine Infectious Anaemia (EIA) is an exotic viral disease affecting horses, donkeys and mules. It is caused by Equine Infectious Anaemia Virus (EIAV), an equid-specific lentivirus in the retrovirus family that is closely to related to HIV in humans.  

Cases of EIA in the UK are extremely rare and have previously occurred in horses that have travelled abroad or have been imported from areas of endemic disease. The disease is notifiable and confirmed cases must be humanely destroyed.

Cases of EIA in the UK are extremely rare and have previously occurred in horses that have travelled abroad or have been imported from areas of endemic disease. The disease is notifiable and confirmed cases must be humanely destroyed.

==Pathogenesis==

==Pathogenesis==

EIA occurs worldwide but most commonly in countries with warm climates. The virus is usually transmitted via mechanical innoculation of blood from large biting flies such as horseflies (''Tabanid'' spp) or stable flies (''Stomoxys calcitrans''). Additionally, transmission of the virus may occur through saliva, milk, body secretions or via contaminated needles and blood products. The virus may also be passed from pregnant mares to their foals across the placenta.

EIA occurs worldwide but most commonly in countries with warm climates. The virus is usually transmitted via mechanical innoculation of blood from large biting flies such as horseflies (''Tabanid'' spp) or stable flies (''Stomoxys calcitrans''). Additionally, transmission of the virus may occur through saliva, milk, body secretions or via contaminated needles and blood products. The virus may also be passed from pregnant mares to their foals across the placenta.

==Clinical signs==

==Clinical signs==

The incubation period of the disease ranges from 10 to over 45 days and the clinical presentation is highly variable. A large number of affected horses do not display any clinical signs. Animals may be affected acutely, chronically or sub-clinically and clinical signs vary according to the stage of the disease. Inapparent carriers may be clinically normal. In the acute stages, clinical signs may include mucosal petechial and ecchymotic haemorrhages, depression, lymphadenopathy, fever, lethargy and inappetance. Horses that have been infected for thirty days or may display the characteristic signs of EIA including ventral and limb oedema, anemia, icterus, pyrexia and cachexia.

The incubation period of the disease ranges from 10 to over 45 days and the clinical presentation is highly variable. EIA occurs in acute and subacute forms in susceptible animals but more commonly assumes a chronic course. However, a large number of affected horses do not display any clinical signs and inapparent carriers may be clinically normal.  

 

In the acute stages, clinical signs may include mucosal petechial and ecchymotic haemorrhages, depression, lymphadenopathy, fever, lethargy and inappetance. Horses that have been infected for thirty days or may display the characteristic signs of EIA including ventral and limb oedema, anemia, icterus, pyrexia and cachexia.

==Diagnosis==

==Diagnosis==

*Higgins, A., Snyder, J. R. (2006) '''The Equine Manual''' ''Elsevier Health Sciences''

*Higgins, A., Snyder, J. R. (2006) '''The Equine Manual''' ''Elsevier Health Sciences''

*Jain, N. C. (1993) '''Essentials of Veterinary Haematology''' ''Wiley-Blackwell''

*Jain, N. C. (1993) '''Essentials of Veterinary Haematology''' ''Wiley-Blackwell''

*Lavoie, J. P., Hinchcliff, K. W. (2009) '''Blackwell's Five-Minute Veterinary Consult: Equine''

*Lavoie, J. P., Hinchcliff, K. W. (2009) '''Blackwell's Five-Minute Veterinary Consult: Equine''' ''John Wiley and Sons''

[[Category:Lentiviruses]][[Category:Horse Viruses]]

[[Category:Lentiviruses]][[Category:Horse Viruses]]