Postnatal neosporosis in dairy cattle in northeast Thailand

A total of 83 dairy cows in Loei Province (Muang) and Nong Bua Lamphu (NBL) Province, northeast Thailand were sampled three times within 6 months in 1 998 and their sera were examined for antibodies to Neospora caninum at a di lution of 1:100 in the indirect fluorescent antibody test (IFAT). In Muang the seroprevalence of N. caninum was 37.5% (June), 60% (August), and 62.5% (November). In NBL the prevalence was 50% (August) and 70% (November). In b oth areas abortions were observed between 1 and 3 months after the introduc tion of these cattle from another area. Nine of 14 and seven of 17 calves w ere descendants of seropositive dam, of which only two calves from Muang an d two calves from NBL were positive for N. caninum antibodies. These findin gs suggest postnatal N. caninum transmission. (C) 2001 Elsevier Science B.V . All rights reserved.