Changes

====Pathogenesis====

====Pathogenesis====

The virus is usually transmitted through large biting flies such as horseflies (Tabanid spp) or stable flies (Stomoxys calcitrans). Blood is transferred from infected horses when the flies feed, Infection with EIA results in an acute phase of infection followed by recurrent episodes that usually susbide after a period of time. Affected horses become persistently infected, lifelong carriers of the disease.

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). Transmission of the virus can also occur when a nursing foal ingests milk from a carrier mare or iatrogenically via contaminated needles.

 

*'''Type III Immune complex disease''' develops

Following coating of erthrocytes and thrombocytes by the virus and the development of a Type III immune complex reacion, lysis of erthrocytes occur. Infection with EIA results in an acute phase of infection followed by recurrent episodes that usually susbide after a period of time. Affected horses become persistently infected, lifelong carriers of the disease. EIA may be induced by stress, disease or immunosuppressive drugs.

====Epidemiology====

====Epidemiology====

==Clinical signs==

==Clinical signs==

The incubation period of the disease ranges from 10 to over 45 days and initial clinical signs may be vague or unnoticed. 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 haemorrhages, depression, 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, 'spiking' fever and cachexia.

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 haemorrhages, depression, 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, 'spiking' fever and cachexia.

==Diagnosis==

==Diagnosis==

The 'gold standard' for diagnostic confirmation is an agar gel immunodiffusion test (the Coggins test) which detects serum antibodies against the EIA virus. False positives may be obtained from foals that have absorbed colostrum from affected mares and false negatives may occur during acute stages of EIA. The Coggins test may be performed in combination with an ELISA in order to increase the test sensitivity.  

The 'gold standard' for diagnostic confirmation is an agar gel immunodiffusion test (the Coggins test) which detects serum antibodies against the EIA virus. False positives may be obtained from foals that have absorbed colostrum from affected mares and false negatives may occur during acute stages of EIA. The Coggins test may be performed in combination with an ELISA in order to increase the test sensitivity.  

==Control==

==Control==

*2 clear Coggins tests of all horses before movement allowed

*2 clear Coggins tests of all horses before movement allowed

*Vector control: stabling, etc.

*Vector control: stabling, etc.

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

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

[[Category:To_Do_-_Clinical/Viruses]]

[[Category:To_Do_-_Clinical/Viruses]]