The known geographical distribution of soil-transmitted helminths in East Africa. The geographical distribution of (A) hookworm, (B) Ascaris lumbricoides, and (C) Trichuris trichuira, based on available survey collected between 1980 and 2009, and categorized according to WHO prevalence thresholds (n = 1,948). First-level administrative boundaries are indicated in grey. The relatively wide distribution of hookworm is apparent in most surveyed areas in East Africa, except in northern Kenya and northeast Uganda. The distribution of A. lumbricoides and T. trichuria infection is more restricted, with high prevalence estimates reported in Burundi and Rwanda, central and western Kenya, southeast Uganda, northeast Tanzania and Zanzibar (Pemba and Unguja).