Anthelmintic Efficacy Of Ivermectin Research Articles

Anthelmintic efficacy of ivermectin and abamectin, administered orally for seven consecutive days (100 µg/kg/day), against nematodes in naturally infected pigs

The present study aimed to evaluate ivermectin and abamectin, both administered orally in naturally infected domestic swine, as well as analysing if the EPG (eggs per gram of faeces) values were equivalent with the ivermectin and abamectin efficacy obtained by parasitological necropsies. The animals were randomly selected based on the average of three consecutive EPG counts of Strongylida, Ascaris suum and Trichuris for experiment I, and of Strongylida and Trichuris for experiment II. After the random draw, eight animals were treated, orally, during seven consecutive days with 100 µg/kg/day ivermectin (Ivermectina® premix, Ouro Fino Agronegócios), eight other animals were treated, orally, during seven consecutive days with 100 µg/kg/day abamectin (Virbamax® premix – Virbac do Brasil Indústria e Comércio Ltda.), and eight pigs were kept as controls. EPG counts were performed for each individual animal at 14th day post-treatment (DPT). All animals (control and treatment) were necropsied at the 14th DPT. The results from both experiments demonstrate that both ivermectin and abamectin, administered orally for a continuous period of seven days, at a daily dosage of 100 µg/kg, were highly effective (>95%) against Hyostrongylus rubidus, Strongyloides ransomi, Ascaris suum and Metastrongylus salmi. Against Oesophagostomum dentatum, abamectin presented over 95% efficacy against both evaluated strains, while ivermectin reached other strain as resistant. Regarding T. suis, both ivermectin and abamectin were effective (efficacies >90%) against one of the tested strains, while the other one was classified as resistant. Furthermore, the EPG values were equivalent with the ivermectin and abamectin efficacy obtained by parasitological necropsies.

The efficacy of ivermectin against the eyeworm, Thelazia skrjabini, in experimentally infected cattle

The anthelmintic efficacy of ivermectin (administered subcutaneously at 200 μg kg −1 body weight) was assessed for control of Thelazia skrjabini in experimentally infected calves. Twenty-four uninfected male Holstein calves, 1–2 weeks old, were artificially infected with Thelazia skrjabini by placing 15 third-stage larvae under the third eyelid of calves. The challenge larvae were recovered from naturally infected face flies, Musca autumnalis. The exposed calves were randomly assigned to either an ivermectin treatment group or a control within pairs ranked by weight. Equal numbers of calves were housed in each of four indoor fly-free rooms. The calves were treated with ivermectin or saline 35 days post-infection, then slaughtered 14 days later to determine eyeworm numbers. All eyes and associated tissues (including the lacrimal glands and ducts) were removed and examined for total numbers, species and viability of eyeworms. Thelazia skrjabini was found in the control group of calves only. The efficacy of ivermectin against Thelazia skrjabini was thus shown to be 100%.

A field evaluation of anthelmintics for control of cyathostomes of horses in Brazil

The anthelmintic efficacy of ivermectin (IVM), piperazine citrate (PPZ) and fenbendazole (FBZ) alone, and combinations of FBZ with varying dosages of PPZ, was evaluated for the control of strogyles of Mangalarga equids. In all cases of positive strongyle egg counts per gram of faeces (EPG) before and after treatment, pure populations of cyathostome larvae with eight gut cells were consistently observed in faecal cultures. The faecal egg count reductions (FECR) were evaluated between Day 7 and Day 56 post-treatment. Significant differences ( P⩽0.05) were found between Day 7 and Day 49 when comparing the mean EPG values of IVM with those of the other anthelmintics. PPZ alone and the combination of FBZ (7.5 mg kg −1) and PPZ (55 mg base kg −1) did not show significant differences during the trial; both groups exhibiting an FECR of > 90% between Day 7 and Day 30. Horses treated with the combinations of FBZ (7.5 mg kg −1) and PPZ at either 40 or 25 mg base kg −1, and with FBZ alone at either 7.5 or 15 mg kg −1, showed an FECR of <90% 2 weeks after treatment. The emergence of a degree of resistance of strongyles to FBZ and PPZ in a segment of the cyathostomes in this population is suggested.

Estudo comparativo da eficiência de Ivermectina, de Fenbendazole, de Mebendazole e de Mebendazole associado ao Citrato de Piperazina.no controle de ciatostomíneos de eqüinos da raça Mangalarga Paulista

The anthelmintic efficacy of Ivermectin, Fenbendazole, Mebendazole and Mebendazole combined with Piperazine Citrate for the control of cyathostomes of Mangalarga Paulista equids were analyzed. In all cases of positive eggs per gram (epg) counts before and after treatment, pure populations of cyathostome larvae with eight gut cells in faecal cultures were consistently observed. The percentages of efficacy were evaluated between the 7th and 72nd days post-treatment. Confronting the epg mean values of Ivermectin in respect of the others anthelmintics, significant differences were found between the 7th and 57th days; Fenbendazole and Mebendazole did not show significant differences during the experiment. The association of Mebendazole combined with Piperazine Citrate indicated a significantly higher efficacy than Fenbendazole and Mebendazole between the 7th and 30th days.

北海道の育成牛における消化管内線虫に対するイベルメクチンの駆虫効果

北海道の育成牛における消化管内線虫に対するイベルメクチンの駆虫効果

The anthelmintic efficacy of ivermectin in experimentally infected cattle

The 22,23-dihydro derivative (ivermectin) of the major B 1 components of the avermectins was evaluated, by oral and parenteral routes, for anthelmintic activity in cattle experimentally infected with 7 gastro-intestinal nematode species and lungworm. Treatment at three dosage levels was administered when the parasites were in the L 4 developmental stage or when adult. The dosage expected to remove 95% of the nematodes (ED 95) by each route of administration against the various developmental stages of each species of parasite was calculated by methods of linear regression to choose dose levels to be used in subsequent developmental field trials. Parenterally, efficacy against L 4 stages of Haemonchus placei, Ostertagia ostertagi, Trichostrongylus axei, T. colubriformis, Cooperia oncophora, C. punctata, Oesophagostomum radiatum and Dictyocaulus viviparus exceeded 99% with treatment at 0.2 mg ivermectin/kg. Parenteral treatment of the adult parasites resulted in at least 98% reduction of worm burdens, except ≊ 90% for T. colubriformis, with 0.2 mg/kg. Oral treatment of L 4 stages of development with 0.2 mg/kg resulted in at least a 95% reduction in worm burdens of each of the 8 species of parasite. Oral treatment of the adult worms with 0.1 mg ivermectin/kg produced at least a 98% decrease in each parasite species, except for T. colubriformis (90% reduction) for which dose-response calculations suggest 95% efficacy with oral treatment at 0.2 mg/kg.