Studies on Dictyocaulus filaria. III. The migration of the immature stages applied to an anthelmintic test

Abstract

The larvae of Dictyocaulus filaria (Rudolphi, 1809) develop to the 5th stage in the mesenteric lymph nodes within 6 to 8 days of infestation. The migration of the 5th stage to the lungs commences on the 7th or 8th day and is almost complete by the 13th day. The adult females start laying eggs in the bronchi from the 28th day. Controlled anthelmintic tests on two groups of sheep are described. Levamisole was dosed intraruminally at 7,5 mg/kg. It was tested against the 3rd and 4th stage larvae in the lymph nodes in the 1st group and against the 5th stages in the lungs in the 2nd group of animals. In both cases data assessed by the non-parametric statistical method showed that levamisole could be classified in Class B, i.e. it was more than 60 per cent effective in more than 60 per cent of the treated flock.