Equine Infectious Anemia (EIA) is a retroviral disease in equids that can be characterised by acute and/or chronic intermittent clinical symptoms including fever, anaemia, edoema and cachexia in some species. Most horses have very weak or inapparent symptoms at first exposure and bear this infection subclinically. It is unlikely that the owners of these animals will know that they are contaminated until serological laboratory testing is carried out. Both infected horses, including those who are asymptomatic, become vectors and are life-threatening. Infected animals must either be slaughtered or completely separated from other equines in order to avoid infection.
Phases of Equine Infectious Anemia (EIA)
Equine Infectious Anemia (EIA) has three stages:
- Acute-the virus is alive, multiplying and harmful to the immune system during this process. The acutely ill horse has a high concentration of the virus in its bloodstream.
- Chronic-The animal has elevated amounts of the virus in its blood but can alternate between remission and disease.
- Inapparent Carrier-The horse bears the infection but does not exhibit any outward symptoms of disease. Stress or sickness may lead to an acute episode.
There is no remedy or cure for a horse that has developed EIA at this time. There is still no vaccine available to protect a horse from the EIA virus.
How Do Horses Get EIA?
The EIA virus spreads by blood from one horse to another. Biting flies, such as horseflies, deer flies and stable flies, may be spread after feeding to an EIA infected horse. If someone affects a horse’s meal— it returns to the same horse if no other horses are around. When a pasture mate happens to be walking up to a horse that was recently fed, there is a possibility that the illness may come from the fly.
Other methods in which horses can get the EIA are as follows:
- Reuse of needles and syringes on several horses
- Infection in multi-dose vials by injecting a discarded needle and/or syringe that deposits blood (virus) into the container.
- Reuse of IV tubing
- The use of unlicensed blood or plasma materials
- Insufficient washing and sterilization of lip tattoo equipment
How is equine infectious anemia treated?
There is no EIA treatment. If you believe that your horse might be sick, contact the veterinarian promptly, travel at least 200 yards away from other horses and reduce the exposure to biting flies. Equine infectious anemia is a known condition. Positive cases must be notified to local state or federal animal welfare authorities by the research facility within two days of the diagnosis.
What can I do to protect my horse from Equine Infectious Anemia (EIA)?
In order to avoid EIA transmission, owners of horses are advised to:
- Require evidence of latest negative Coggins test and EIA test for horses who have lived in the premises where EIA-positive horses have been identified.
- Only take part in events that include proof of a negative Coggins test for each horse attending the event to discourage the initiation and dissemination of disease.
- Exercise good flies protection by frequent mucking of stalls, careful handling of manure away from horse stall areas, and use of fly sprays or natural predators to reduce the presence of birds.
- Use a sterile needle and syringe for every injection or procedure.
- Clean all surgical or dental instruments properly between horses. Remove all residue and blood from soap and water until disinfection.
- Use a clean needle every time a multi-dose bottle of drug is punctured. Consult a veterinarian to explain how to use a sterile procedure while producing medicines.
- Isolate horses with fever, decreased feed consumption and/or lethargy from other horses, and call the veterinarian.
By adopting these biosafety steps, horse parents are protecting the health of their animals and the health of the entire equine population.
