A comparison of the role of Musca domestica (Linnaeus) and Chrysomya megacephala (Fabricius) as mechanical vectors of helminthic parasites in a typical slum area of Metropolitan Manila.

A total of 1,016 flies (508 each for Musca domestica and Chrysomya megacephala) were collected from a typical urban slum area (Barangay 51, Pasay City, Metropolitan Manila) in the Philippines and examined for the presence of helminth ova attached to their external surfaces. A significantly greater proportion of C. megacephala (41.9%) was found positive compared to M. domestica (9.4%). C. megacephala also exhibited a significantly higher average egg load (11.9 eggs per positive fly) than M. domestica (2.6 eggs per positive fly). Male and female flies were equally contaminated for both species. Only 29 out of the 2,651 eggs recovered (1.1%) were infective to man. Ascaris spp. and Trichuris trichiura ova occurred most frequently while eggs of hookworm. Taenia spp., Toxocara spp. and Capillaria hepatica were infrequent or rare. Despite the low proportion of infective eggs recovered, the role of these synanthropic flies in the transmission of certain helminthiases should not be discounted.