Equine infectious anemia causes a low red blood cell count in horses, according to the North Carolina Department of Agriculture and Consumer Services. This is a contagious viral disease that can result in death.
A disease caused by the EIA virus causes horses to have red blood cell counts, the North Carolina Department of Agriculture and Consumer Services says. It only attacks animals of the equine family, such as mules, ponies, donkeys and horses. The virus is contracted through infected blood and manifests in subacute, acute or chronic forms. Although there is no vaccine or cure for the disease, it is only fatal in the chronic form. Any horses that show symptoms of EIA need to be isolated from other horses.
Horses also suffer from low red blood cell levels due to a lack of iron, resulting in anemia, explains Kentucky Equine Research. This condition is normally not fatal and fairly rare. Horses that graze have good levels of iron and normal red blood cell counts because they receive plenty of minerals in the grass and soil that they consume. Racehorses are more prone to this issue because their diets are strictly monitored. As a result, most are on iron supplements. Horses that do contract anemia show signs of weakness, lethargy, depression and loss of appetite.