The Itwara focus is located around the Itwara forest reserve, about 25 km to the north of Fort Portal in Uganda. The climate is characterized by a humid heat and all-year-round rains. The area is drained by three rivers:
- the Sogohi river and its tributaries (Wamise, Nyakibuguta, Kanaba and Kafunda)
- the Siisa river and its tributaries (Kyasa and Mohabura)
- the Aswa river.
The total population of the Itwara focus is over 80 000 people. Onchocerciasis is transmitted by Simulium neavei.
Large-scale ground larviciding has resulted in Simulium naevei being eliminated in the Itwara focus since 1999.
Reinforcement of community-directed treatment with ivermectin is expected to lead to rapid elimination of onchocerciasis.