Intradermal reactivity of excretory and secretory products of onchocercal microfilariae.

The intradermal reactivity of excretory and secretory (ES) products derived from the in vitro cultivation of onchocercal microfilariae was evaluated. The ES products from Onchocerca volvulus were highly sensitive in the detection of active onchocerciasis in both Liberian and Guatemalan subjects. A low level of cross-reactivity occurred in patients with loaisis and in dogs with Dipetalonema reconditum, but not in dogs with Dirofilaria immitis. ES products from O. gutturosa evoked reactions in Guatemalan subjects, but were not as sensitive as those from O. volvulus.