Assessment of oral ivermectin versus shampoo in the treatment of pediculosis (head lice infestation) in rural areas of Sine-Saloum, Senegal.

Reports of treatment failure and the emergence of resistance to topical head lice treatments have become increasingly common, driving the need for continued development of new therapeutic options for pediculosis. Ivermectin has been proposed as a potential alternative for the treatment of pediculosis but has not been sufficiently evaluated. In this study, the effectiveness of oral ivermectin versus shampoo in the treatment of pediculosis in Senegal was compared. The study was conducted in two neighbouring villages of Sine-Saloum, Senegal: Dielmo (ivermectin trial group; 201 female participants) and Ndiop (shampoo trial group; 239 female participants). In the ivermectin group, patients received two doses of oral ivermectin (400 µg/kg body weight; Mectizan®) 7 days apart. In contrast, the shampoo group received a shampoo treatment based on d-phenothrin (0.23%; Hégor®). At the beginning of the study, 70 (34.8%) of 201 participants in the ivermectin group were infested by head lice versus 145 (60.7%) of 239 participants in the shampoo group. At Day 15 post-treatment, the efficacy of the treatment against head lice reached 41/53 (77.4%) in the ivermectin group (53 patients were tested in this group) versus 42/130 (32.3%) in the shampoo group (130 patients were tested in this group) (P <10-7). However, 4 (7.5%) of the 53 females in the ivermectin group exhibited probable ivermectin treatment failure, suggesting the emergence of ivermectin-resistant lice. This study demonstrates that oral ivermectin is highly effective for the treatment of pediculosis compared with shampoo, but also suggests that ivermectin resistance may emerge during treatment.