also inflamed and infected and is therefore compromised. Ulceration of the respiratory endothelium predisposes the respiratory tract to secondary bacterial infection. Equine influenza is transmitted through the direct or indirect contact with infected respiratory secretions, or the inhalation of those secretions in aerosol forms. Equine influenza is most commonly seen in horses one to five years of age, or in weanlings in close contact with other horses. horses and those with compromised immune systems are also at higher risk of developing equine influenza. The clinical presentation of equine influenza begins one to three days after infection. Clinical signs and symptoms include fever of 39 to 42 ºC that lasts for one to five days, cough, lacrimal discharge, serous nasal discharge that may turn purulent if bacterial infection occurs, myalgia, edema of the lower limbs, lethargy, anorexia and depression. Laminitis or exertional rhabdomyolysis may occur as a consequence of influenza infection. Diagnosis of equine influenza is made through the clinical signs and symptoms as well as nasal swab resulting in the isolation of influenza virus. Treatment involves supportive & nursing care. This includes isolation, rest, antipyretics, IV fluids, NSAIDs, bronchiodilators and antibiotics if secondary bacterial infection occurs. In healthy horses the disease is self-limiting and clears within 2-3 weeks. against equine influenza may provide some degree of protection against infection. Immunity is not guaranteed as the influenza virus mutates readily and regularly and immunity to one strain does not necessarily provide protection against all strains of influenza virus. Prognosis for most horses infected by equine influenza virus is good with most returning to athletic performance within two weeks of infection. Some animals that are very young, very old or are otherwise immunocompromised may die as a result of equine influenza virus infection or as a result of secondary bacterial infection of the respiratory tract.
Equine Viral Arteritis
Equine viral arteritis (EVA) is an acute, contagious, viral disease caused by equine arteritis virus (EAV) an RNA virus of the Arterivirus family.
After exposure, EAV invades the upper and lower respiratory tract and multiplies in nasopharyngeal epithelium and tonsillar tissue and in bronchial and alveolar macrophages. Infected WBC transport the virus to the regional lymph nodes, where it undergoes a further cycle of replication before being released into the bloodstream. The virus localizes in the vascular endothelium, especially the , and causes vasculitis. It can also
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