The house fly (Musca domestica) as a potential vector of metazoan parasites caught in a pig-pen in Germany.

In the present study a total of 224 specimens of the synanthropic house fly (Musca domestica) were caught in a pig-pen of an organic farmer in Dormagen (Germany). The flies were examined for their potential as a carrier of metazoan parasites. On the exoskeletons and in the intestines of the flies the eggs and/or larvae of four endoparasite nematode species of domestic pigs (Ascaris suum, Strongyloides ransomi, Metastrongylus sp., undetermined Strongylida) were isolated. Also one ectoparasite species, the hog louse (Haematopinus suis), was detected on the exoskeleton of one fly. The analysis of the pig faeces as potential source revealed many eggs and larvae of nematodes. A high number of A. suum eggs (62.0% of all found nematode eggs), many eggs of strongylid nematodes (21.0%), some eggs of S. ransomi and few eggs of Trichuris suis were detected. However Metastrongylus sp. could not be identified in the faeces. Further laboratory experiments verified the potential of the house fly as a transmitter of the pig parasites A. suum and T. suis. In the intestines of 59 flies (49.2%) from 120 experimentally used house flies, nematode eggs of both nematode species were detected. The present study clearly demonstrates the potential of the house fly as a vector of metazoan pig parasites.