Species and Incidence of Dipterous Larvae Concerned in Wound Myiasis

Abstract

It is known that a number of species of Diptera, principally in the family Calliphoridae, and to a lesser extent in the family Sarcophagidae and other families, are concerned in the production of myiasis in domesticated animals. Information available in the literature as to the species implicated and the comparative incidence of each is limited. Since the discovery, by Cushing and Patton (2), that the screwworm, Cochliomyia americana C. and P., has been confused with Cochlionmyia macellaria Fab., there has been a greater interest in determining the importance of the various species of myiasis-producing Diptera. Bishopp (I) discusses several species of Calliphoridae which cause myiasis in man and animals, namely, C. macellaria Fab., Phormia regina Meig., Lucilia sericata Meig., L. illustris Meig.,2 Calliphora erythrocephala Meig., and Cynomyia cadaverina Desv. Parish and Laake (4) record the species of flies concerned in the production of myiasis in Menard County, Texas, as based on the rearing of 46,242 adults. The number of infested animals from which these adults were reared is not mentioned. From these flies, which were reared at different times over a period of three years, it was found that Cochliomyia spp. (no differentiation was made between the two species, i.e., C. americana and C. macellaria) constituted approximately 94 per cent of all flies reared, whereas approximately 6 per cent of the flies were Phormia regina. Two specimens of Sarcophaga plinthopyga Wied. and two of Sarcophaga sp. were also reared. Laake, Cushing, and Parish (3) record the number of species of flies reared from 114 cases of myiasis in all classes of range livestock on one ranch near Sonora, Tex. An analysis of these shows 79.8 per cent of the cases involved the primary screwworm, C. americana, in pure culture, Io.5 per cent were mixed cultures of C. americana and secondary species,3 such as C. macellaria, P. regina, L. sericata, and S. plinthopyga, whereas 9.6 per cent were pure cultures of secondary species involving the same species as those mentioned. The primary