Equine Infectious Anemia Study Guide

Overview and Clinical Importance

Equine Infectious Anemia (EIA), also known as swamp fever, is a chronic, persistent bloodborne viral disease of equids caused by the Equine Infectious Anemia Virus (EIAV), a lentivirus in the family Retroviridae. This disease is of significant veterinary importance due to its lifelong carrier state, lack of treatment or vaccine, and regulatory implications. EIA is a WOAH-notifiable disease and is reportable in all U.S. states.

The disease was first identified in France in 1843 and was one of the first animal diseases confirmed to have a viral etiology (1904). EIAV is closely related to Human Immunodeficiency Virus (HIV), making it an important model for understanding lentiviral pathogenesis and immune control.

Etiology

Viral Characteristics

EIAV Classification: Family Retroviridae, Genus Lentivirus. EIAV is an enveloped, single-stranded RNA virus with a genome of approximately 8.2 kb. It is the simplest of all lentiviruses, encoding only three accessory genes (tat, rev, S2) in addition to the standard retroviral genes (gag, pol, env).