The effect of deltamethrin pour-on applied to cattle on the transmission of bovine trypanosomosis

Abstract

A trial to evaluate the effect of monthly deltamethrin pour-on treatments on the tsetse’s feeding response and, consequently, the incidence of tsetse-transmitted trypanosomosis in deltamethrin-treated and untreated cattle was conducted in Zambia. During a period of 14 consecutive weeks the two-weekly trypanosomosis incidence and packed cell volume of deltamethrin-treated and untreated herds, herded in the same area, were compared. No significant differences were found. It is concluded that the reported effects of deltamethrin treatments on trypanosomosis incidence are a result of reduced tsetse challenge due to a decline in tsetse density in surrounding areas and not of the direct effect of deltamethrin treatments on the tsetse’s feeding response. This control method will, therefore, be most effective in those areas where the tsetse population density can be sufficiently reduced to significantly affect disease transmission.