Improved survival of laboratory-reared tsetse flies Glossina morsitans morsitans (Diptera: Glossinidae) through use of homidium bromide-treated blood diet

Abstract

Homidium bromide is a broad-spectrum anti-microbial trypanocide likely to be encountered as a violative residue in blood collected from abattoirs destined for feeding laboratory-reared tsetse colonies. We investigated its effects on longevity of laboratory reared Glossina morsitans morsitans Westwood. Four steers were intra-muscularly administered with 1 mg homidium bromide/kg of body weight and blood was aseptically collected from them between 15 and 30 min post-administration. This blood was defibrinated, analysed for homidium levels, screened for bacterial contamination, frozen and warmed to 37"C before feeding to tsetse flies. Teneral male (l00) and female (220) G. m. morsitans flies were fed on homidiurn-treated diet, and control flies (99 males and 187 females) on untreated blood diet and their survival monitored for 163 days. Homidium, at 266.15ng/ml blood diet, significantly (P <0.05) improved fly survival. We concluded that homidium bromide has a beneficial effect on tsetse, probably attributable to its antimicrobial activity against unfavourable microbes mediated by the drug, and could be used as a tsetse diet additive.