Flies are frequent carriers of helminthes.
Several nematodes, like Parafilaria bovicola, Thelazia spp. and Heterotylenchus automnalis are found in various fly species and especially in the face fly (Bech-Nielsen, 1982, Chirico, 1994, Geden, 1982, O'Hara, 1989).
Thelaziosis, an eyeworm infection affecting cattle, sheep, horses and goats, is mainly transmitted by the face fly Musca automnalis (Greenberg, 1973, Lancaster, 1986, O'Hara, 1991, Stork, 1979).
Several fly species have also been found carrying eggs of Ascaris, Trichuris and Ancylostoma and may therefore play a role in the transmission of these helminthiasis (Dipeolu, 1982, Monzon, 1991, Oyerinde, 1976, Umeche, 1989).
The house fly is a vector of cestodosis in poultry (Abrams, 1976). In poultry, coccidiosis can be transmitted by flies as well, although this is not the major way of spreading of the disease (Greenberg, 1973, Milushev, 1978).
