Cross-infections between fallow deer and domestic ruminants with large lungworms (Dictyocaulus spp.).

Groups of four deer each were experimentally infected with larvae of Dictyocaulus (D.) eckerti (from fallow deer) or D. viviparus (from cattle) or D. filaria (from sheep), groups of four cattle each with D. viviparus or D. eckerti and groups of 4 lambs each with D. filaria or D. eckerti. The animals were daily examined coprologically following the 16th day post infectionem. The animals were slaughtered at different times and the lungs were dissected. With the exception of the infection of the sheep with D. eckerti from fallow deer, the mutual infections of the different hosts with the lungworm species became patent. Lungworms could be isolated. Fallow deer proved to be more susceptible to an infection with D. viviparus than cattle to an infection with D. eckerti. The large lungworms which naturally infest fallow deer and cattle, D. eckerti and D. viviparus respectively, can be distinguished according to the morphology of their mouth capsules, especially in the structure of the buccal ring. These features were also present after infection of the heterologous hosts.