Clinical aspects of 27 cases of neosporosis in dogs.

Twenty-seven cases of neosporosis in European dogs are described. The disease was confirmed by immunohistochemistry, electron microscopy, or a favourable response to treatment in the dogs with appropriate clinical signs, and by the presence of antibodies to Neospora caninum but not to Toxoplasma gondii. The affected dogs were two days to seven years old, and of 13 different breeds. Both sexes were affected and in most cases littermates remained normal. Twenty-one cases had an initial hindlimb paresis or ataxia, in which muscle atrophy was the most consistent clinical sign. Rigid hyperextension developed in approximately half of the cases. Anorexia and pyrexia were rare. Other clinical signs included forelimb ataxia, head tremors with tetraparesis and sudden collapse due to myocarditis. Titres of > or = 1:800 in the N caninum indirect fluorescent antibody test were detected in the 20 cases from which serum samples were taken. Such high titres are rare in healthy dogs and strongly suggest a diagnosis of neosporosis. Sixteen of the dogs received appropriate antiprotozoal treatment with clindamycin, potentiated sulphonamides and/or pyrimethamine; 10 made a full or functional recovery. Recovery was less likely in peracute cases with severe clinical signs, and when the treatment was delayed.