The surveys were carried out in the districts of Kiang West, Niamina East and Nianija in The Gambia. The Kiang West district is situated in the Lower River Division 100km from the Atlantic coast. It encompasses the largest national park in the Gambia. The vegetation, which is the savannah woodland type, is known to be one of the thickest in the country and an important quantity of wood fuel sales in the capital originate from this district. The tsetse challenge is considered as medium. Kiang West is known to be the district with the lowest population density in the Gambia.
The Niamina East district is located in the Central River Division South 200km from the Atlantic coast. Vegetation is characterised by woodlands interspersed with open savannah and fresh water swamp. The area is known to have an important cattle population. During the dry season, the abundant vegetation in the swamp attracts numerous transhumant herds from other districts in search of feed and water. Past surveys ranked this district as an area of high tsetse challenge.
The district of Nianija is situated in the northern part of the Central Rivers Divisions 200km from the Atlantic coast. Niamina East is dominated by open savannah vegetation. Precipitation values in this district are the lowest in the Gambia.