Comparative efficacy of standard antihookworm drugs against various test nematodes.

The chemotherapeutic responses of three test nematodes, Nippostrongylus brasiliensis, Nematospiroides dubius and Ancylostoma ceylanicum to standard antihookworm drugs were assessed in order to select a suitable host-parasite system for the primary screening of potential antihookworm compounds. N. dubius behaved inconsistently and, with some infections, required more drug to achieve 100% clearance. Nippostrongylus brasiliensis was found to be sensitive to thiabendazole, tetramisole and levamisole but the broad spectrum anthelmintic mebendazole was ineffective. A. ceylanicum was very sensitive to mebendazole, sensitive to tetramisole and levamisole and refractory to thiabendazole. In vitro, none of the compounds had any lethal effect against any of the nematodes, except mebendazole against A. ceylanicum. A. ceylanicum does occur in man and its chemotherapeutic reactions are similar to those of target hookworm infections of economic importance. As such, although not equally sensitive to standard anthelmintics, it is recommended for routine primary screening.