the vascular endothelium, causing vasculitis, disseminated intravascular coaggulopathy, haemorrhage and abortion. kept in close proximity to other horses are at increased risk of contracting equine viral rhinopneumonitis. Young racehorses are often infected when they are first brought to a racing stable for training. Transmission of equine viral rhinopneumonitis occurs through the direct or indirect contact with infected nasal discharge, or the aborted fetus, the placenta or the placental fluids from an infected mare. The incubation period for equine viral rhinopneumonitis is two to ten days. Most horses present with a fever of 39 to 42 ºC followed by serous nasal and lacrimal discharge, pharyngitis, cough, enlarged lymph nodes, lethargy anorexia and depression. Pregnant mares infected with EHV type I may experience spontaneous abortion in the third trimester. The aborted fetus is fresh, and there tends to be epidemic abortion in broodmare herds. Occasionally some individuals infected with EHV type I may exhibit central nervous system signs including dementia, head pressing, ataxia, blindness and seizures. Diagnosis of equine viral rhinopneumonitis is made through the clinical signs and symptoms, endoscopy revealing hyperemia, ulceration and necrosis if the respiratory endothelium and through nasal swab revealing cells infected by the equine herpes virus. Treatment involves supportive & nursing care. This includes , rest, antipyretics, IV fluids, NSAIDs, bronchiodilators and antibiotics if secondary bacterial infection occurs. Individuals displaying CNS signs should be treated with antiviral medications and immune system stimulators.
Prevention is vaccine.
Equine Influenza
Equine influenza is commonly called the “flu” or the “flu virus”.
It is caused by , also called the equine influenza virus type II (AE-2). Equine influenza virus type I does exist and is recognized to cause equine influenza but the type I strain has not been isolated in a horse for over twenty years. The influenza virus attacks the endothelium of the airways in much the same manner as the equine herpes virus. It uses the host cells to replicate viral clones until the host cell is full, then causes the lysis if the host cell to free the new viruses. The respiratory endothelium becomes inflamed and ulcerated. This is seen as pharyngitis. Inflammation of the endothelium triggers an increase in mucus production which cannot be cleared as the mucocilliary transport system is
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