Tsetse Control and Gambian Sleeping Sickness; Implications for Control Strategy

Area of Science:

• Medical Entomology
• Tropical Public Health
• Vector-Borne Disease Control

Background:

• Human African trypanosomiasis (HAT), or sleeping sickness, is primarily controlled through case detection and treatment, reaching only about 75% of the population.
• Vector control can interrupt HAT transmission but is often deemed too costly and logistically challenging for resource-poor settings.
• A refined vector control technology using tiny targets was field-tested to assess its utility in controlling Gambian HAT.

Purpose of the Study:

• To evaluate the efficacy of a refined tiny target technology for controlling the tsetse fly vector of Gambian HAT.
• To determine the feasibility and cost-effectiveness of implementing this vector control method in endemic areas.

Main Methods:

• Preliminary trials determined the optimal density of tiny targets to achieve over 90% reduction in Glossina fuscipes populations.
• A 500 km2 field trial was conducted in two HAT foci in Northern Uganda, deploying targets at a density of 5.7/km2.
• A published HAT transmission model was used to assess the required tsetse population reduction for disease interruption.

Main Results:

• Tsetse fly populations (Glossina fuscipes) declined by over 90% within 12 months of deploying tiny targets.
• The study demonstrated that a 72% reduction in tsetse populations is sufficient to stop HAT transmission in the studied settings.
• The cost of one year of vector control was estimated at US$42,700, significantly less than active case detection.

Conclusions:

• Tiny target vector control is a highly effective and cost-efficient method for reducing tsetse fly populations.
• This vector control strategy can completely interrupt Gambian HAT transmission.
• Integrating tiny target vector control with case detection and treatment presents a strong, feasible approach to controlling HAT in endemic regions.