EFFICACY OF NICLOSAMIDE AS A POTENTIAL TOPICAL ANTIPENETRANT (TAP) AGAINST CERCARIAE OF SCHISTOSOMA-MANSONI IN MONKEYS

A 1% (W/V) formulation of Niclosamide (2, 5-Dichloro-4-nitrosalicylani lide) (TAP) was tested on Cebus apella monkeys as a topical prophylact ic against schistosomiasis mansoni. Two experiments were conducted usi ng the same formulation. In the first experiment, the TAP provided com plete protection against schistosomiasis for 3 days. Of the 4 monkeys treated with TAP 7 days before exposure to Schistosoma mansoni cercari ae, 2 were completely protected. The remaining 2 monkeys of the 7 day treatment group had a 78% or greater reduction in adult worm burdens w hen compared to the placebo treated monkeys. The second experiment was designed to determine the time between day 3 and 7 when the TAP no lo nger provided complete protection. However, all of the TAP treated mon keys in this experiment were completely protected, even the monkeys tr eated 7 days earlier. In both experiments, all monkeys used as infecti on controls and those receiving only the placebo became infected and s howed typical experimental schistosomiasis. These results demonstrate that the TAP could provide fast acting, short-term protection to peopl e who must enter cercariae infested water.