APHIS, the Animal and Plant Inspection Service of the U.S. Department of Agriculture, suggests steps to prevent and reduce the risk of infection with equine infectious anemia (EIA), a potentially fatal disease caused by a retrovirus transmitted by insects and sometimes contaminated syringes or needles. Ill mares transmit the disease to their foals. The disease, also known as "swamp fever," can be acute or chronic.
In its most dangerous form, the disease can kill in two to three weeks. In its chronic form, it causes equine depression, weight loss, swelling, fevers, hemorrhaging into the mucous membranes and anemia.
There is no vaccine and APHIS recommends testing to safely quarantine infected horses from others. Federal regulations require labs to report horses that test positive.
According to APHIS, one-fifth of a teaspoon of blood from a chronic case during a feverish episode contains enough virus to infect another 10,000 horses.
"The horse with chronic EIA is the classic 'swamper' who has lost condition, is lethargic and anorexic, has a low hematocrit, and demonstrates a persistent decrease in the number of blood platelets, especially coincident with fever induced by EIA," APHIS states.
Since EIA is considered a bloodborne infection, APHIS suggests horse owners take the following steps to reduce the risk of transmission:
- Implement insect controls. Your veterinarian can provide information about approved insecticides and other insect-control measures. Avoid keeping standing water or maintaining habitats favorable to insect survival.
- Minimize or eliminate horse contact with the secretions, excretions and blood of EIA-infected horses. This can be done by testing and segregating. Do not intermingle infected and healthy animals and isolate all new horses, mules and donkeys brought to the premises until they have been tested for EIA.
- Also important, follow the rule of one horse-one needle. Use disposable syringes; clean and sterilize all instruments thoroughly after each use; keep stables and immediate facilities clean and sanitary. Remove manure and debris promptly, and ensure that the area is well- drained.
- Obtain the required certification of negative EIA test status for horse shows, county fairs, race tracks and other places where many animals are brought together.
For more on EIA, visit www.aphis.usda.gov/vs/nahss/equine.