Laboratory investigations into the role of Musca vicina and Musca domestica in the transmission of parasitic helminth eggs and larvae.

Musca vicina and M. domestica were induced to feed on stools containing eggs of hook worm and Ascaris lumbricoides and on infective larvae of the parasites. The development periods of the regurgitated eggs were observed while attempts were made to recover the ingested larvae through regurgitation. Results showed no difference between the developmental periods of eggs of hookworm and A. lumbricoides recovered from the houseflies up to 2 hours post ingestion and eggs of the same parasites which were not fed to the houseflies. In the case of infective larvae of hookworm, almost all experimental flies regurgitated infective larvae up to 8 hours post ingestion; the number of flies with this ability dropped very drastically as from the 9th hour. In addition, the number of larvae recovered decreased steadily as from the 5th hour post ingestion until it almost seized by the 9th hour. Such decreases in number of houseflies from which larvae were recovered and in the number of larvae recovered were not experienced with A. lumbricoides.