International Journal of TROPICAL DISEASE & Health

Aim: This study was aimed at identifying factors that influenced the apparent decimation of tsetse fly (Diptera: Glossinidae) population, eliminated human and decreased animal African trypanosomosis in Jigawa State, within Sahel-Sudano ecological zone of Nigeria.

Study Design: On the spot physical inspection, interviews and review of data on climate change, socioeconomic, demographic, and environmental variables were collated.

Result: Among the notable factors identified included human population density that resulted in the widespread agricultural crop farming and logging activities particularly within the forest reserves and available outgrowth of natural tree covers across the state. The Glosinna morsitans belt along Hadejia, Jama’are, D. Gaya and Katagun Rivers’ natural swath of riparian forest galleries have virtually been depleted. The area lacked thick continuous vegetation cover conducive for tsetse fly breeding. The key informants interviewed were unanimous that aerial wide insecticide spray with dichlorodiphenyl-trichloroethane (DDT) eliminated tsetse flies along with game and aquatic animals. Prevalence of animal trypanosomoses in cattle in the state could be attributed to nomadic or transhumant animal management system. With reported absence of tsetse fly and no case of human African trypanosomoses for over two decades in the state corroborated the negative impact of climate change and anthropogenic activities on normalized vegetation index in the extinction of tsetse fly population in the Hadejia-Jama’are primordial sleeping sickness focus.

Conclusion: Extrapolated climate change data analysed over a longer period showed that tsetse suitability index in the area tends to zero due to a combination of high temperature and increased aridity and desertification. These factors in conjunction with past area wide insecticidal control have contributed to absence of tsetse fly and human African trypanosomiasis or sleeping sickness in a  known primordial endemic foci. The documented cases of the disease in livestock have been attributed to the nomadic or transhumant animal management system.