Submitted to: American Society of Tropical Medicine and Hygiene
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 14, 1999
Publication Date: December 1, 1999
Interpretive Summary: The infectious stage of Cryptosporidium parvum, the oocyst, is transmitted by the feacl oral route via food and water. This zoonotic anthroponotic parasite contributes to morbidity and mortality in animals and humans. As few as 30 oocysts werefound to intiiate infection in immunocompetent people. Refuse and promiscuous-landing flies are known transport hosts for a variety of pathogens of public health concerns. In the present study maggots, pupae, and adult flies exposed to bovine feces seeded with oocysts of Cryptosporidium parvum. were found to serve as transport hosts for oocysts.
The oocyst of the parasite Cryptosporidium is the stage that upon ingestion with food or water initiates infection in humans and animals. How this stage is spread through the environment is a question of great concern with respect to control of the disease. Because the oocyst is excreted in the feces of infected animals and persons, and because flies lay eggs in manure and are otherwise asssociated with manure this study was undertaken to determine if they might serve as mechanical transporters of oocysts. Flies and fly larvae examined microcopically after exposure to oocyst contaminated feces were found to harbor oocysts in the gut, on wings and under hairs on legs. These findings suggest that fly control in and around animal feeding and rearing operations should be considered part of a good animal management strategy that could help reduce transmission of Cryptosporidium to other animals and humans.