Serological survey and first finding of Neospora caninum in Taiwan, and the detection of its antibodies in various body fluids of cattle

A serological survey for antibodies against Neospora caninum in cattle, goa ts and farm dogs in Taiwan was carried out. Sera of 613 cattle from 25 dair y farms, 24 goats from six goat farms and 13 dogs from six dairy cattle far ms were tested for antibodies against N. caninum using indirect fluorescenc e antibody test (IFAT). The same sera were also tested for antibodies again st Toxoplasma gondii using latex agglutination test. Of the 613 cattle sera , 44.9% (275/613) were found to have antibodies against N. caninum. Among t hese 275 positive cattle, 77 also possessed antibodies against T. gondii. N evertheless, 92 cattle which were negative for N. caninum showed antibodies against T. gondii. Of the 24 goat sera tested, none was found to be positi ve for N. caninum but 50% (12/24) were positive for T. gondii. Of the 13 fa rm dogs tested, three were found to possess antibodies against N. caninum, two of which tested negative for ir: gondii antibodies. Besides sera, antib odies to N. caninum in cattle could be observed in the milk, vaginal secret ion and saliva. However, the order of higher frequency of antibodies detect ion is in sera, milk, vaginal secretion and saliva. This is the first demon stration of the presence of antibodies to N. caninum in vaginal secretion a nd saliva of cattle. A 50 mu m cyst was observed in the brain of one of the 13 prednisolone-treated SPF ICR mice which had been peritoneally inoculate d 4 months earlier with the brain homogenate of a serologically N. caninum positive but T. gondii negative cattle. Thus, we have confirmed for the fir st time the presence of N. caninum in Taiwan and also observed that it is w idespread among dairy cattle and farm dogs. (C) 2000 Elsevier Science B.V. All rights reserved.