Control of Glossina longipennis (Diptera: Glossinidae) by insecticide-treated targets at Galana Ranch, Kenya, and confirmation of the role of G. longipennis as a vector of cattle trypanosomiasis

• Published in: Bulletin of entomological research 2000-10, Vol.90 (5), p.397-406
• Main Authors: Makumi, J.N., Stevenson, P., Green, C.H.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cattle; Cattle Diseases - parasitology; Cattle Diseases - prevention & control; Disease Vectors; Female; Fundamental and applied biological sciences. Psychology; Glossina longipennis; Glossinidae; Incidence; Insect Control - methods; Insecticides; Kenya; Kenya - epidemiology; Male; Medically important nuisances and vectors, pests of stored products and materials: population survey and control; Nitriles; Pesticide Residues; Pyrethrins; Rain; Trypanosoma congolense - isolation & purification; Trypanosoma vivax - isolation & purification; trypanosomiasis; Trypanosomiasis, African - epidemiology; Trypanosomiasis, African - parasitology; Trypanosomiasis, African - veterinary; Tsetse Flies - parasitology; Vectors. Intermediate hosts
• ISSN: 0007-4853; 1475-2670
• DOI: 10.1017/S0007485300000535

Glossina longipennis Corti was studied in Galana Ranch, Kenya over a four year period, in two areas (Tank E and Lali) where the species was abundant and other species were absent or scarce. There was active transmission of trypanosomiasis to cattle in both areas, the parasite species being Trypanosoma vivax Ziemann and T. congolense Broden. Mean infection rates of the G. longipenniswere 1.1% and 0.55% for T. vivax and T. congolenserespectively at Tank E, and 0.88% and 0.15% at Lali. Experimental transmission studies showed that cattle in fly-proof enclosures challenged with wild G. longipennis collected from Galana became infected with both trypanosome species. A tsetse control operation in one area (Tank E) using targets impregnated with deltamethrin in an oil formulation reduced the population of G. longipennisby 98% over one year, despite evidence of re-invasion. Populations of G. longipennis in the other area (Lali) were relatively stable over the whole study period. The effect of tsetse control on the incidence of cattle trypanosomiasis at Tank E was less clear than that on tsetse numbers, probably due to the lack of a sustained reduction in tsetse numbers. However, a significant relationship was demonstrated between fortnightly incidence measurements and electric net catches of G. longipennisat Tank E. A further significant predictor of incidence was rainfall in the previous four to seven weeks. This study confirms the importance of G. longipennisas a vector of bovine trypanosomiasis in areas where it is the predominant tsetse present.