The Investigation Of Conventional Anthelmintic Drug Resistance Of Sheep Gastrointestinal Nematodes In Chayouhouqi Area

Gastrointestinal nematodosis is a major parasitic disease that endangers the healthy development of the sheep industry,and it caused the huge economic losses.Some antiparasitic drugs that have been used for many years have shown certain degrees of resistance in many areas.In addition,the lack of veterinary clinical resistance testing methods has made sheep gastrointestinal nematodes still in a high infection state.In order to understand the prevalence of sheep gastrointestinal nematodes and the resistance to commonly used anthelmintic drugs in Chayouhouqi area of Inner Mongolia.In this study,the infection level of sheep gastrointestinal nematodes and resistance to four kinds of anthelmintic drugs in eight townships under the jurisdiction of Chayouhouqi Area were investigated And explored the method for larval viability detection by staining method.The results were as follows:(1)The investigation of the epidemic situation of Gastrointestinal neinatodosis about 2220 stocking sheep in eight townships in Chayouhouqi was performed,the results showed that five species of nematodes,Haemonchus contortus,Nematodirus spp.,Burtostomum trigonocephalum,Trichuris ovis,and Trichostrongylus spp.were detected in the sheep in this area,the total infection rate was 63%.The maximum infection intensity was EPG 21400 and the dominant species was Haemonchus contortus(infection rate of 63%).(2)800 sheep with Gastrointestinal nematode infection intensity EPG>300,were selected in the eight townships,at the same time,four drugs,Ivermectin,Albendazole,Closantel Sodium,and Levamisole,were selected and used for faecal egg count reduction test.The results showed that the gastrointestinal nematodes of sheep in Chayouhouqi area were the most sensitive to Levamisole,and had different degrees of resistance to Ivermectin,Albendazole and Closantel Sodium.(3)Methylene blue(C16H18C1SN3,MB),trypan blue(C34H24N6Na4014S4,TB)and gentian violet(C25H30C1N3,GV),the three different types of dyes were used to stain larvae,in order to compare the staining effects of larvae cultured in different concentrations of albendazole culture solution and establish a method of detecting the larval viability of gastrointestinal nematodes in sheep.The results showed that the low-viability or dead larvae were light blue or blue using MB staining,and the high-viability larvae were colorless.Also,the larval staining rate was increased with the increase of the concentration of albendazole.However,There was no significant difference in the different viability larvae after using TB staining and GV staining.Therefore,MB staining could be used as an effective method to detect the drug resistance of gastrointestinal larvae.