The indiscriminate feeding of anthropophilic simulium upon man and domestic animals, and its relation to studies on the transmission of human onchocerciasis in Guatemala

Abstract

It has been known for some time that the anthropophilic species of Simulium commonly implicated as vectors of human onchocerciasis in Guatemala (S. ochraceum, S. Metalllicum, and S. callidum) will bite animals other than man. It has not been known, however, whether an individual fly will bite various species of animals during its life time and thus possibly ingest microfilariae of both human and animal origin

To establish this point, field-caught flies were captured after partially engorging on one host, and then were transferred to a host of another species. Cattle, horses, or dogs were used either before or after man as sources for blood meals. S. ochraceum showed reluctance to resume feeding on the second host in combinations wherein man alternated with cattle or dogs. Otherwise, all three species of flies readily resumed feeding on the second host, regardless of which host species was offered first(AU)