Albendazole Resistance in Gastrointestinal Nematode Parasites of Cattle in Bangladesh

Tropical Animal Health and Production -     

Economics of Prophylaxis against Peste des Petits Ruminants and Gastrointestinal Helminthosis in Small Ruminants in North Cameroon

Data on reproduction and mortality were collected over one year from 5100 sheep and 13 300 goats in treated and control flocks. The treated animals received vaccination against peste des petits ruminants (PPR) and anthelmintics twice a year. Productivity parameters (fecundity and mortality rates) obtained with and without prophylaxis were fitted into a benefit–cost economic analysis model and run for project lifespans varying from one to five years. At a 7% discount rate, the overall benefits for a project lifespan of five years were estimated as over 15 million FCFA and 11 million FCFA for sheep and goats, respectively. The benefit–cost ratio ranged from 2.26 to 3.27 in goats and 3.01 to 4.23 in sheep, depending on the project lifespan. It was concluded that PPR and gastrointestinal helminthosis are important causes of economic losses in small ruminants in Cameroon. A national or even a regional vaccination campaign against PPR and strategic anthelmintic treatment of small ruminants are recommended.     

A Field Study on the Effect of Some Anthelmintics on Cyathostomins of Horses in Sweden

The objective of the study was to investigate different aspects on the efficacy of three anthelmintics on cyathostomin nematodes of Swedish horses. A faecal egg count reduction (FECR) test was performed on 26 farms. Horses were treated orally with recommended doses of ivermectin, pyrantel pamoate or fenbendazole. Faecal samples were collected on the day of deworming and 7, 14 and 21 days later. No resistance was shown against ivermectin; the FECR was constantly >99%. The effect of pyrantel was assessed as equivocal in 6 farms 14 days after treatment; the mean FECR was 99%. As many as 72% of the fenbendazole-treated groups met the criteria for resistance; the mean FECR was 86%, ranging from 56% to 100%. A re-investigation of two farms where pyrantel resistance had been suspected clearly revealed unsatisfactory efficacy of pyrantel on one of these farms; the FECR varied from 72% to 89%. Twenty-six of the horses previously dosed with pyrantel or fenbendazole, and which still excreted ≥150 eggs per gram of faeces 14 days after treatment, were dewormed with ivermectin and fenbendazole or pyrantel in order to eliminate the remaining cyathostomins. A total of 13 cyathostomin species were identified from horses that initially received fenbendazole and seven species were identified from pyrantel-treated individuals. The egg reappearance period (ERP) following treatment with ivermectin and pyrantel was investigated on two farms. The shortest ERP after ivermectin treatment was 8 weeks and after pyrantel was 5 weeks. We conclude that no substantial reversion to benzimidazole susceptibility had taken place, although these drugs have scarcely been used (<5%) in horses for the last 10 years. Pyrantel-resistant populations of cyathostomins are present on Swedish horse farms, but the overall efficacy of pyrantel is still acceptable.     

Rintal片驱除绵羊消化道线虫的试验

用Ｒｉｎｔａｌ片进行了驱除绵羊消化道线虫试验。结果表明当５ｍｇ／ｋｇ体重剂量时对捻转血矛线虫、哥伦比亚线虫、羊仰口线虫、细预属线虫和奥斯特线虫等绵羊消化道线虫的虫卵减少率,虫卵转阴率、虫卵孵化第三期幼虫减少率和第三期幼虫转阴率均可达到１００％,且安全,无任何毒副作用。     

Rintal颗粒剂对绵羊消化道寄生虫的驱虫效果试验

用Rintal颗粒剂对绵羊进行了消化道线虫驱虫试验。结果表明当前剂量为5.0mg/kg体重时,Rintal颗粒剂对绵羊食道口线虫、细颈属线虫、毛圆线虫、夏伯特线虫、奥斯特线虫以及肺丝虫等虫卵减少率,虫卵转阴率、虫卵孵化第3期幼虫减少率和第3期幼虫转阴率均为100%,而且安全,使用方便,易于保管运输。     

Ionophore and Anthelmintic Activity of PF 1022A,a Cyclooctadepsipeptide,Are Not Related

PF 1022A, a 24-membered cyclooctadepsipeptide and a potent anthelmintic drug, is active against nematodes but not against arthropods. Muscle cells of Ascaris suum generate autorhythmic spikes in electrophysiological control experiments. Exposure of the worm to PF 1022A leads to flaccid paralysis and in parallel to the disappearance of these spike events. Results of such experiments in vitro were compared with those from experiments using planar lipid bilayer membranes incorporating PF 1022A, a related linear octadepsipeptide and other cyclodepsipeptides. Whereas PF 1022A acts both as an ionophore in lipid bilayers, similar to other cyclodepsipeptides like valinomycin and enniatin A, and as a paralysing drug in worms, some of the series of depsipeptides examined have only an ion carrier function, while others exhibit only nematocidal activity. It is concluded that the ion carrier property of PF 1022A is not responsible for its paralyzing effect on nematodes and that there is a specific binding site for PF 1022A in nematodes. Binding may trigger the lethal reaction cascade, which is responsible for anthelmintic activity.     

Anthelmintic Resistance in Pashmina (Cashmere) Producing Goats in India

Veterinary Research Communications -