Isolation And Gene Expression Analysis Of Ivermectin-resistant Strain And Sensitive Strain Of Haemonchus Contortus

Due to the emergence of drug-resistant strains,an series of problems followed,such as increased treatment costs,excessive drug residues and environmental pollution.Therefore,the study of the mechanism of resistance of Haemonchus contortus to antiparasitic drugs has a great significance.There were a few studies on the expression level of ivermectin-related genes in China.Therefore,the aim of present research was to study the genes related to ivermectin-resistant Haemonchus contortus using RT-qPCR.The results obtained were as follows:(1)By comparing the hatching rate of eggs and larvae development rate,the media of eggs hatching and larvae development of Haemonchus contortus were screened;the effects of newborn bovine serum on the hatching eggs and the larvae development as well as of E.coli on the development of larvae were also studied.It was confirmed that there was no statistical difference in the effects of different media solutions on eggs hatching,but 17.5%NCTC-109 could be as the optimum medium for larvae development.Newborn bovine seram had inhibited eggs hatching and larvae development,while E.coli could promote larvae development.(2)The Ivermectin-resistant and susceptible strains of Haemonchus contortus were screened,isolationed and purificationed by the tecal egg reduction test,larval development inhibition test,and parasitological dissection.A susceptible strain(YC-S)and a drug-resistant strain(WS-R)were respectively obtained from Yuci city of Shanxi and Wushen banner of Inner Mongolia.(3)RT-qPCR technique was used to study 9 IVM resistance-related genes in female and male Haemonchus contortus.Hco-Pgp-2,Hco-Pgp-9,Hco-glc-2,Hco-glc-3.Hco-glc-4,Hco-unc38,Hco-acr-8b Hco-avr-14a and Hco-avr-14b were tested and compared.It was found that the expression of these 9 genes all had a very significant difference between female and male(P<0.01).For the resistant strains WS-R,the expression in females were lower than that in males(P<0.01),while the expression in females of sensitive strains YC-S was higher than that in males(P<0.01).At the same time,the expression of these 9 genes was significantly different between the resistant strain WS-R and the sensitive strain YC-S(P<0.01):for females,the expression level in resistant strain WS-R was lower than that in sensitive strain YC-S;for males,the expression in WS-R was opposite.The above results indicated that the expression of ivermectin-resistance genes of Haemonchus contortus was affected by the sex of the worm,so the gender factor needs to be considered when detecting the resistance of the worm.The results provide basic data for the detection of ivermectin resistance of Haemonchus contortus,and it has great significance for the study of drug resistance of worms.