be found in the epithelium of certain tissues, particularly the adrenals, seminiferous tubules, thyroid, and liver.
Transmission is through respiratory or venereal routes either direct or indirectly.
Predispositions are horses under stress in close contact & breeding stock. Standardbreds and Warmbloods are most commonly affected breeds.
Typical cases are characterized by fever, depression, anorexia, leukopenia, vasculitis, ventral edema (especially of the lower hind extremities, scrotum, and prepuce in the stallion), conjunctivitis, supra- or periorbital edema, nasal discharge, respiratory , skin rash, temporary subfertility in affected stallions, abortion, and infrequently, illness and death in young foals. Some stallions enter a subclinical state, where they show no outward sign of disease, but shed virus into their ejaculate, making it difficult to control the spread of disease. Diagnosis of EVA is made through nasal swab, serology and tissue biopsy revealing infection with the equine viral arteritis virus.
Treatment is mainly supportive including anti-viral medications, NSAID’s and IV fluids.
Prognosis is guarded, and abortion is likely in infected mares.
Strangles (Equine Distemper)
Strangles, or equine distemper, is the name given to the infection of the mandibular & retropharyngeal lymph nodes with the Gram positive bacteria . The bacteria invade the upper respiratory tract and the pharyngeal mucosa where they replicate. The bacteria release and enzymes that cause inflammation and irritation of the endothelium. The inflammation makes the respiratory endothelium more susceptible to infection and allows the bacteria to spread to the local lymph nodes. Once inside the lymph nodes the bacteria continue to replicate and continue to release toxins and enzymes resulting in . The immune cells inside the lymph nodes attack the bacteria and the infected lymph cells resulting in the formation of abscesses filled with purulent materials. These abscesses may rupture externally resulting in an ulcerated lesion exuding purulent material, or they may rupture internally leading to bacteremia, pleuritis, bacterial pneumonia or infection of the lymph nodes of the thorax or abdomen. The internal rupture of strangles abscesses is commonly called “ ”. Strangles is transmitted through the inhalation or ingestion of the purulent discharge exuding from an infected lymph abscess. This can be through direct or indirect contact.
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