Effect of Deltamethrin Aerial Spraying in Controlling African Animal Trypanosomosis in Cattle in the Sesheke and Shang'ombo Districts of Western, Zambia

Trypanosomosis is a vector-borne zoonotic disease transmitted by the tsetse fly (Glossina species). The condition is caused by protozoa known as Trypanosomes. In ۲۰۰۹, large-scale aerial spraying with deltamethrin at ۰.۲۶-۰.۳ g/ha, was undertaken in ۵۰۰۰ km۲ covering parts of the Sesheke and Shang’ombo districts to control tsetse flies animal trypanosomosis in cattle in the area. Cattle were sampled for prevalence and incidence of trypanosomosis before, during, and, after aerial spraying as a circuitous way of detecting the presence of the primary vector (tsetse flies). Buffy coats, thick and thin dry smears were applied in the parasitological tests. In the baseline survey, ۱,۸۶۶ cattle were presented, and ۲۵.۷% (n = ۴۸۱) were sampled and examined. Trypanosoma spp. was detected in ۱.۹% (n = ۹) of animals. Six sentinel herds (four treatments and two controls) with ۲۰ animals per herd were monitored for the incidence of AAT during and after aerial spraying, and prevalence was compared among the three phases. The results showed that no new case of trypanosomosis was detected in the treatment herd during the aerial spraying and three months into the post-aerial spraying period except ۰.۸۳% (n = ۱) in the control herd [Mid-P exact; p-value = ۰.۱۶۷ (۱-tailed)]. This suggests an association between deltamethrin aerial spraying and trypanosomosis. In conclusion, there was a significant reduction in trypanosomosis prevalence following the aerial spraying operation. This indicates that aerial spraying significantly reduced the tsetse population and subsequently reduced disease transmission to cattle in the area. Furthermore, it indicates that aerial spraying was an effective method of controlling trypanosomosis in cattle. There is a need to extend this operation to other tsetse-infested areas in the country.