Evaluation of broad-spectrum anthelmintic activity in a novel assay against Haemonchus contortus, Trichostrongylus colubriformis and T. sigmodontis in the gerbil Meriones unguiculatus.

The gerbil Meriones unguiculatus, infected with three species of nematodes, each located in a separate part of the gastrointestinal tract, provided a reliable laboratory assay for the evaluation of broad-spectrum anthelmintic activity. Gerbils harbouring 6-day-old infections of Haemonchus contortus, Trichostrongylus colubriformis and T. sigmodontis were given selected broad-spectrum anthelmintics by gavage. Three benzimidazoles, thiabendazole, oxfendazole and albendazole, a tetrahydropyrimidine, morantel, an imidazothiazole, levamisole hydrochloride, a macrocyclic lactone, ivermectin and an experimental natural product, paraherquamide, were active against all three nematodes at various dosages. Trichostrongylus colubriformis was most sensitive to levamisole hydrochloride, morantel, thiabendazole and paraherquamide whereas ivermectin, oxfendazole and albendazole were more effective against H. contortus. All compounds were active against the caecal nematode T. sigmodontis although it was less sensitive than T. colubriformis. Haemonchus contortus was more sensitive than T. sigmodontis to all anthelmintics tested except thiabendazole.

Efficacy of caspofungin against Aspergillus flavus, Aspergillus terreus, and Aspergillus nidulans.

The echinocandin caspofungin is a potent inhibitor of the activity of 1,3-beta-D-glucan synthase from Aspergillus flavus, Aspergillus terreus, and Aspergillus nidulans. In murine models of disseminated infection, caspofungin prolonged survival and reduced the kidney fungal burden. Caspofungin was at least as effective as amphotericin B against these filamentous fungi in vivo.

Determination of poultry feed-through insecticide activity in an in vivo anticoccidial assay.

The ability of an in vivo anticoccidial assay to identify potential feed-through insecticides was demonstrated using first-instar Lucilia sericata on droppings from chicks fed medicated diets. Cyromazine, a commercially available feed-through insect growth regulator, ivermectin, diflubenzuron, fipronil, permethrin, and 2 experimental compounds were effective in varying degrees in killing L. sericata larvae. Eleven coccidiostats were effective against the protozoan parasites (Eimeria spp.) at commercially used levels, whereas they were ineffective against Lucilia larvae.