Equine Viral Arteritis (EVA)
Equine Viral Arteritis is a sexually transmitted viral disease caused by an Arterivirus .
It is considered a venereal disease, though it can be spread through the respiratory system or passed from a mare to the foal in utero. Contact between infected semen, vaginal secretions or respiratory secretions and the mucus membrane allows the virus entry to the body. The virus infects the local ________________, which transport the virus to the lymph nodes. In the lymph nodes the virus spreads to other types of leukocyte and uses these leukocytes to spread throughout the body. Once the virus is freely circulating in the blood it preferentially infects the cells of the vascular __________________ causing inflammation, weakening of the vessel wall, neutrophilia and necrosis of the tunica media of the blood vessel. This causes increased permeability of the vessel walls, weakening of the vessel walls and the formation of microthrombi which all predispose for haemorrhage into the tissues and edema of the tissues. Animals that are used for breeding, especially those who are bred using _____________ are at an increased risk of contracting EVA. The reuse of instruments used in artificial insemination may also be a vector for disease transmission. Some stallions enter a subclinical carrier state, where they show no outward sign of disease, but shed virus into their ejaculate, making it difficult to control the spread of disease. EVA is seen clinically as pyrexia, leukopenia, depression, anorexia, _____________ , swelling of the hind limb, conjunctivitis, perioccular edema, nasal discharge, urticaria, ventral edema, stiffness, ataxia, icterus, and _____________ . 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.
Anemia
Anemia is defined as a decrease in the circulating amount of __________________.
It can be caused by a decrease in erythropoiesis, dietary ______________ deficiency, excessive haemorrhage or erythrolysis. Whatever the cause, a decrease in the amount of circulating haemoglobin results in systemic hypoxemia, hypoxia and hypoxic necrosis of the tissues. The very young and the very old are at a greater risk of developing anemia, as are horses suffering from gastrointestinal disease or exercise induced pulmonary haemorrhage.
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