The Study Of Efficacy And Action Mode Of Ivermectin On Dengue Virus Type 2 In Aedes Albopictus

Objective:To confirm the antivirus effectiveness of ivermectin on dengue virus type 2(DENV-2)in Aedes albopictus,and then explore its potential action mode,providing alternative tools in the combating to the dengue epidemics.Methods:Firstly,the experiments on artificial infection ofAe.albopictus with DENV-2 were performed,to determin several variables of vectoral capacity,including the infection rate,virus loads,and the tends changing with rearing time,etc.At the same time the impact factors of the infection were also observed,such as experimental targets,virus types,way of artificial infection,virus loads in blood feeding,the temperature and moisture of the artificial infection and breeding environment,etc.By understanding these factors,the idea animal modal for artificial infection of Ae.albopictus with DENV-2 was established(n=20,with three replicates).Second,by using the infection mode,Ae.albopictus were infected with DENV-2 in human whole blood,and the mosquitoes were fed with ivermectin at two intervention points,namely at the ingesting time(n?30)and at the fourth day after infecting(n=20,with three replicates),respectively.After 10 days of infection,the infection rate and virus loads were detected for each group.The change patterns of infection rate and virus loads in mosquito with the IVM concentration were analized.Thirdly,a total of 11 miRNA,including miR-4448,miR-1767,miR-276-3P,miR-622,miR-956-3P,miR-2951-5P,miR-4728-5P,miR-956-5P,miR-1174,miR-6134,miR-6668-3p in mosquitoes grouped(n)20)by DENV 2 loads dropping down/turning negative,increasing/remain unchanged were detected and analyzed,and then the miRNA with different expression levels were detected and compared between ivermectin treated group and non-treated group(n=30),in order to explore the possible action mode of antivirus effectiveness in Ae.albopictus by IVM in combination with IVM molecular characteristics and current knowledge in this field.Results:Firstly,the infection model of Ae.albopictus with IVM was successfully established.The DENV 2 loads were about 1.06x108pfu/ml and led to about 80%infection rates in Ae.albopictus.Secondly,compared with control group,the infection rates and virus load in Ae,albopictus were reduced by ivermectin at both intervention points,which furthermore continually descending with increasing of ivermectin concentration.The infection rate of DENV-2 and the maximum virus loads were significantly reduced up to 86.56%and 99.99%,respectively.Thirdly,it was found that miR-4728-5P,miR-956-5P,miR-1174,miR-6134,miR-6668-3P were higher expressed in Ae.albopictus with virus loads increasing.Furthermore,significant different levels of miR-1174 and miR-6668-3P were detected between ivermectin treated and non-treated mosquitoes.Conclusion:Ivermectin can inhibit DENV-2 propagation in Ae.albopictus.With increase of the ivernectin concentration,the DENV-2 inhibiting effectiveness changes significantly.Moreover,the expression of miR-1174 and miR-6668-3P were elevated by ivermectin ingestion in Ae.albopictus,giving some hint for the further study about ivermectin action mode.The results are promising for farther study to explore the new avenue in combating dengue epidemics.