Prevalence of Gasterophilus larvae (Diptera : Gasterophilidae) in slaughter horses in North-Eastern Germany

Stomach and duodenum of 620 horses slaughtered between January 1996 and Apr il 1997 originating most from the Federal States of Brandenburg and Mecklen burg-Vorpommern were examined for Gasterophilus larvae. 47.9 per cent of th e horses harboured Gasterophilus larvae in their stomachs. A total of 12,88 6 larvae were collected belonging exclusively to the species G. intestinali s. The intensity of infestation showed a great individual variation, rangin g from some to more than 400 larvae. Second-stage larvae were recorded from September to March, third-stage larvae from October to July, in one case e ven in August. Maximal larvae counts were recorded from December to April. Compared to a study conducted 20 years ago in the same region, a considerab le increase of the prevalence of G. intestinalis was found, while the inten sity of infestation remained nearly unchanged.