Equine Infectious Anemia
Equine Infectious Anemia, also called swamp fever, transmitted by bloodsucking insects infects horses and is cause by a retrovirus. It is endemic in the Americas, parts of Europe, the Middle and Far East, Russia, and South Africa. It is a lentivirus, similar to HIV.
EIA can be transmitted through blood, saliva, milk, and bodily secretion. Normally transmission comes from biting flies like the horse-fly and deer-fly. Along with biting animals the disease can be transmitted through contaminated surgical equipment.
When the disease suddenly occurs at full force it is in its acute form, where as a slower progression of the disease is subacute. In Chronic cases the horse may have recurring fever and anemia and can relapse into the subacute or acute form even years after an original attack.
It is also possible for a horse to not show any symptoms yet still test positive for EIA antibodies which means the horse is still contagious.
EIA can abort the fetus in pregnant mares at any time during the pregnancy. A vaccine, developed in China, and used there since 1983 is available. The disease can be transferred through syringes and needles. Horses that test positive are sent to research facilities. The United States does not have an eradication program since there are few incidences of the virus. Most countries require testing before a horse is imported.