Prevalence of onchocerciasis and epilepsy in a Tanzanian region after a prolonged community-directed treatment with ivermectin per Mushi, VP, Bhwana, D, Massawe, IS, Makunde, W, Sebukoto, H, Ngasa, W, Sengerema, J, Mhina, A, Hayuma, PM, Kimambo, H, Kidima, W, Matuja, W, Sander, JW, Cross, H, Sen, A, Colebunders, R, Newton, CR, Mmbando, BP, EPInA Study Group