Equine infectious anaemia

EQUINE INFECTIOUS ANAEMIA (EIA)

Field diagnosis

  • Field diagnosis is based on the Coggins test. Since, no vaccines are available against EIAV, presence of antibodies against EIA in the serum of horses is an indication of infection. Clinical signs and lesions also provide clue about EIA.

Isolation and identification

  • Rarely attempted since it is of no practical value. Blood samples should be collected to confirm the diagnosis using the Coggins (agar gel diffusion) test or the more recent ELISA test. Isolation of the virus from suspect horses may be made by inoculating their blood on to leukocyte cultures prepared from horses free of infection. Virus production in cultures can be confirmed by detection of specific EIA antigen by ELISA, or imunofluorescence assay.

Nucleic acid identification method

  • Recently a RT-PCR method has been developed to detect EIA proviral DNA from the peripheral blood of horses

Serology

  • Due to the persistence of EIA virus in infected equids, detection of serum antibody to EIA virus confirms the diagnosis of EIA virus infection.
    • Coggins test – (Agar gel immunodiffusion test): It is a test prescribed for International trade. Precipitating antibody is rapidly produced as a result of EIA infection, and can be detected by the AGID test. Specific reactions are indicated by precipitin lines between the EIA antigen and the test serum and confirmed by their identity with the reaction between the antigen and the positive standard serum.
    • ELISA: Competitive and non-competitive ELISAs are also used to identify antibodies against EIAV.

Differential diagnosis

  • EIA should be differentiated from purpurahaemorrhagica, babesiosis, leptospirosis, severe strongyliasis or fascioliasis, phenothiazine toxicity and auto-immune haemolyticanaemia
Last modified: Wednesday, 30 March 2011, 4:53 AM