Equine Infectious Anemia - contd.

ClinicalSigns
Clinical signs are variable and depend on the stage of the disease. Acute disease usually occurs one to four weeks after infection and is associated with high levels of viremia. Fever, anorexia, lethargy, ventral edema, and occasionally mucous membrane petechiae, epistaxis and death can characterize EIA. The acute phase is usually less than one week in duration, and is sometimes mild enough to go completely unnoticed.

Chronic disease is associated with recurrent episodes of viral replication, causing repeated bouts of the above mentioned clinical signs. The classic signs of anemia, ventral edema, and weight loss occur during the chronic phase of the disease; these horses are sometimes referred to as "swampers." With time, clinical disease episodes decrease in duration and severity, and most horses' immune systems will control the infection within one year. These horses will become inapparent carriers of the virus and will show no clinical signs.

Symptoms
Initial symptoms begin one to four weeks after infection, and can include fever, loss of appetite, listlessness, and swelling of the lower legs, brisket, and belly. Occasionally small blood spots develop on the inside of the lips and on the gums. In severe cases, bleeding from the nose and even death can occur. In contrast, the initial symptoms can be so mild in some horses that they go completely unnoticed. Over time, repeated episodes of these symptoms tend to occur in cycles, and weight loss can develop. Usually after approximately a year the symptoms stop, and most horses look completely normal.