Fatal Halicephalobus gingivalis infection in horses from Central America

Abstract Halicephalobus gingivalis is a free-living nematode that causes an opportunistic infection in animals and humans. Two fatal cases of encephalitis and nephritis caused by H. gingivalis in equines from Costa Rica and Honduras are reported. Case 1: a 6-year-old Arabian stallion, from Costa Rica, presented severe neurological signs and was treated with systemic anti-inflammatory drugs and antibiotics. Because there was no improvement, it was euthanatized. Grossly, both kidneys showed large white nodules, ranging from 0.10 to 2.50 cm. Histopathologically, both kidneys showed similar changes consisting of multiple necrotic foci with longitudinal and transversal sections of nematode larvae. In the brain, there were several foci with similar parasites, surrounded by lymphocytes and gitter cells. Case 2: an 8-year-old Spanish stallion from Honduras it was reported as depressed and would not eat or drink water. The animal was treated with antibiotics and analgesics, without response and died spontaneously three days after the onset of clinical signs. Only pieces of kidney were sent for histopathological examination and showed findings similar to those described in case 1. These findings are similar with cases already reported expanding the knowledge about the geographical distribution of H. gingivalis in horses.