NEOSPOROSIS AND BOVINE ABORTION IN SCOTLAND

Serum samples were collected over a two-year period from aborting cows and their fetuses from throughout Scotland; 465 maternal sera were ex amined using an immunofluorescent antibody test for IgG antibody to Ne ospora caninum and 547 fetal sera were examined for IgM and IgG antibo dy to the parasite; 355 of the maternal sera were paired with their re spective fetal samples. The maternal titres ranged from ys to 1/16,384 , with 59 per cent (275) having titres of 1/128 or 1/256, Of the 547 f etal sera, 9.9 per cent had IgM titres equal to or greater than 1/64, 11.2 per cent had IgG titres equal to or greater than 1/64 and 15.9 pe r cent had IgM and/or IgG titres equal to or greater than 1/64, It is concluded that a fetal IgM or IgG titre of 1/64 or more is evidence of fetal exposure to N caninum but that the examination of maternal sera is less reliable on an individual basis, although valuable for indica ting the degree of infection in a herd, Although fetal seropositivity does not necessarily provide proof that N caninum was the cause of dea th in a given case, the observation that 15.9 per cent of aborted fetu ses had antibody to the parasite shows that vertical transmission from dam to fetus is relatively common and may be an important cause of fe tal loss in cattle in Scotland.