Infectious Equine Anemia

an infectious disease characterized by constant or intermittent fever, anemia, cardiovascular lesions, and prolonged presence of virus in the animal. The causative agent is a virus that was discovered in 1904–06 by the French scientists H. Carré and H. Valleé. It was observed in Russia by M. I. Potudin in 1910, A. V. Vasil’ev in 1929, and I. V. Poddubskii, B. G. Ivanov, and Ia. E. Koliakov in 1932. The disease occurs on all continents; the incidence declined in the 1950’s and 1960’s. In the USSR, it is encountered only on isolated farms. The disease inflicts considerable economic damage because of the loss of the animals, the prolonged quarantine period, and the high cost of controlling and preventing the disease.

Under natural conditions, mostly horses contract the disease, and occasionally mules and asses. The cases tend to be isolated, although there are epidemics. An acute or subacute course of infectious equine anemia is seen in 15–25 percent of the cases and a chronic course in 75–85 percent. Diseased horses or virus carriers are the sources of the infection. Most of the new cases are recorded in the summer and fall. Since insects (horseflies, stable flies, mosquitoes) are the main factor in spreading the disease, it occurs chiefly in wooded and swampy areas with acid podzolic soils. The latent period is 5–30 days, sometimes 90 days or more.

The clinical symptoms are fever, loss of appetite, fatigability and weakness, jaundice and hemorrhage of the mucous membranes, and a loss of flesh. A biological test is the most reliable method of diagnosing the disease. No treatment has as yet been developed. Control measures include isolation and destruction of the diseased animals and establishment of quarantine, which can be lifted three months after the last case of isolation of a diseased animal.