Isolation and identification of bacteria associated with the screwworm fly Cochliomyia hominivorax, coquerel and its myiasis.

We studied eight different myiasis of sheep caused by screwworm flies under laboratory conditions. Swabs were taken from the wound, before, during, and after the myiasis. Seven hundred and thirty-one samples were streaked on different bacteriological media. All samples were identified by Api System (bioMerieuex). We found thirty-eight different bacterial species in the exudates from the myiasis (before, during, and after the parasitic cycle). The analysis of bacterial flora of the screwworm showed, on larvae stage 1, 10 different bacterial species, on larvae 2, 12 bacterial species; larvae 3, 15 bacterial species; crawl off, 15 bacteria species, pupa, 9 bacterial species; and adults, 2 bacterial species and on the pioneer fly, 14 different bacterial species were isolated and identified.

The role of botfly myiasis due to Dermatobia hominis L.Jr. (Diptera:Cuterebridae) as a predisposing factor to New World screwworm myiasis (Cochliomyia hominivorax coquerel) (Diptera:Calliphoridae).

In the tropics, the botfly Dermatobia hominis and the NWS Cochliomyia hominivorax are the most important myiasis agents in cattle. It is frequently reported that furuncular lesions due to D. hominis are a predisposing cause for screwworm myiasis. Our results pointed out that only 5.2 to 7.4% of C. hominivorax gravid females oviposited in the offered furuncular lesions. Of 3242 eggs layed on botfly lesions (BFL), only 82 (2.5%) developed to second instar and died. In the flies tested, the furuncular lesions due to Dermatobia were used as food supply in 81.3% of the cases. In our opinion, the role of pH, the microflora associated with BFL, and the foruncular structure were the reasons for this lack of attraction. BFL do not serve as a predisposing factor for screwworm myiasis in the tropics.