Tukuyu, United Republic of Tanzania
The Tukuyu focus is situated on the border between the United Republic of Tanzania and Malawi. It covers an area of 3000 km2. The climate is characterized by a dry season (June to October) and a rainy season (November to May). The vegetation varies from the savannah to degenerated forest.
The area is crossed by three main rivers: the Kiwira, the Mbaka and the Lufilyo, where the blackfly vector breeds. Outside Tukuyu in northern Malawi is the river Songwe, which is a potential source of blackfly re-invasion. A second potential source of re-invasion is the Songea focus located 150 km from Tukuyu.
Onchocerciasis is transmitted by Simulium thyolense (Simulium damnosum, Kiwira form) and takes place mainly during the dry season.
Large-scale ground larviciding was carried out in 2003 and 2005. This resulted in a drastically reduced biting rate of Kiwira form).
Ivermectin has been distributed across the entire zone since July 1994. Reinforcement of community-directed treatment with ivermectin is expected to lead to rapid elimination of onchocerciasis.