pyrantel-tartrate and Haemonchiasis

The efficacy of pyrantel tartrate was evaluated in goats against induced infections with Haemonchus contortus, Teladorsagia circumcincta and Trichostrongylus colubriformis. All the strains were of sheep origin and tested for susceptibility to pyrantel tartrate in sheep at the standard dose rate (20 mg kg-1) prior to the infection of goats. Fifteen French Alpine female goats were inoculated with the three nematode species. On Day 25 post-infection, goats were randomized into an untreated control group and two pyrantel treatment groups (20 mg kg-1 bodyweight once, and 40 mg kg-1 bodyweight as two doses 24 h apart). The goats were killed and processed for worm recovery 10 days after treatment. The two dose rates achieved high and similar levels of efficacy (> 96%) against Haemonchus contortus and Teladorsagia circumcincta. Against Trichostrongylus colubriformis, however, pyrantel tartrate was less effective at both dose rates as worm reductions ranged from 55 to 62%.

Topics: Animals; Antinematodal Agents; Female; Goat Diseases; Goats; Haemonchiasis; Helminthiasis; Pyrantel Tartrate; Sheep; Trichostrongylosis

Haemonchus contortus- and Trichostrongylus colubriformis-infected jirds (Meriones unguiculatus) are useful for anthelmintic studies. With concurrent infections of these parasites established in the jird, questions of not only anthelmintic activity, but to some extent spectrum, could be assessed in a single model system. This report outlines a model using immunosuppressed (0.02% hydrocortisone in feed) jirds concurrently infected with H. contortus and T. colubriformis. Immunosuppressed jirds were inoculated with approximately 1,000 exsheathed infective larvae of each species, treated per os on day 10 postinoculation (PI), and killed on day 13 PI. Stomachs and small intestines were removed, opened longitudinally, incubated in distilled water at 37 C for 5 hr, fixed in formaldehyde solution, and stored for subsequent examination. Contents of both organs were examined using a stereomicroscope (15-45 x). Various standard anthelmintics were evaluated in the model; modern broad-spectrum ruminant anthelmintics (benzimidazoles, febantel, ivermectin, levamisole hydrochloride, and milbemycin D) are active uniformly and in most cases at doses comparable to those required for efficacy against these parasites in ruminants. This model, using worms of 2 genera living in distinct sites, allows preliminary evaluation of anthelmintic activity and spectrum for experimental compounds in a single cost- and resource-efficient experiment.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Benzimidazoles; Bithionol; Diethylcarbamazine; Gerbillinae; Guanidines; Haemonchiasis; Macrolides; Piperazine; Piperazines; Pyrantel Tartrate; Rodent Diseases; Trichostrongyloidiasis