Coggins testing diagnoses a horse with equine infectious anemia (EIA). EIA is a potentially fatal virus that only infects horses. The disease is highly contagious and many of the symptoms are often mistaken for other fever-related illnesses like anthrax, influenza, and equine encephalitis. Unlike these other diseases, EIA contaminates the DNA of red blood cells, potentially causing death within 2-3 weeks. In addition, some horses may not show any signs of having EIA if their contraction is ‚Äúin-apparent,‚Äù but they are still contagious and a danger to other horses.