Epidemiological Survey And Analysis Of The Neurotropic Virus In Brain Tissue Samples From Rat-like Animals In Guangzhou,Xiamen And Shenzhen

1 Background and objectiveA lot of rat-like animals are the reservoirs of many emerging zoonosispathogens.which live in the human living environment.Several neurotropic viruses from brain tissue of rat-like animals had been detected,including Borna virus,Rabies virus and Tick-borne encephalitis virus.However,there is little information from South China.In this study,we collected brain tissue of rat-like animals and detected four neurotropic viruses in these samples.We aimed to understand the prevalence of viruses and explore whether the rat-like animals are potential sources of zoonosis infections caused these viruses.2 Methods2.1 Sample collectionRat-like animals were trapped in residential areas,city parks,hospitals,markets and schools,with iron cage which had baits(peanuts and fried breadstick),in Xiamen.Shenzhen and Guangzhou between January 2013 and June 2016.The catched sites included corner of wall,grass,garbage can.and drain.Species identification of rat-like animals was verified by amplification and sequencing of the cytochrome B(cytB)gene,in combination with morphological.Brain tissue samples of trapped rat-like animals were collected by sterilization craniotomy in the laboratory under anesthesia with diethyl ether and preserved in tubes containing RNAlater.All the samples were stored at-80? until use.2.2 Detection of four neurotropic virusesThe DNAs/RNAs of brain tissue samples from rat-like animals were extracted.RNAs were reversed into cDNAs.A RT-PCR of the cDNAs was amplified to detect Chikungunya virus and Zika virus.The Real-time PCR and RT-PCR of the cDNAs were amplified for detecting Japanese encephalitis virus.Suckling mice and BHK-21 cell was inoculated to verify and isolate-virus if found the suspiciously positive.The Nested-PCR of the DNAs was amplified to detect Herpesvirus.PCR products were analyzed by electrophoresis on 1%agarose gels,sending the product of objective strap Gene sequencing.The positive rate was calculated and the phylogenetic analysis was conducted.3 Results3.1 Basic information of rat-like animalsTotally 1092 rat-like animals were trapped in Xiamen,Shenzhen and Guangzhou between January 2013 and June 2016,which belonged to 7 species,3 genera,2 families,2 orders,including Rattus norvegicus(593),Rattus flavipectus(76),Rattus rattus(3)Suncus murinus(319),Rattus losea(99),Rattus coxingi(1)and Bandicota indica(1).3.2 Detection of four neurotropic virusNo detectable Chikungunya virus,Zika virus and Japanese encephalitis virus was found in the 1092 brain tissue samples of rat-like animals.There were 29 herpesviruses(2.66%)in the 1092 brain tissue samples of rat-like animals.Phylogenetic analysis based on nucleotide sequences of herpesvirus found that the rat-like animal herpesviruses in brain tissue samples cluster in genus Rhadinovirus,subfamilies Gammaherpesvirinae.4 Conclusions1.All brain tissue samples of rat-like animals in Xiamen,Shenzhen and Guangzhou City collected in this study were negative for Chikungunya virus,Zika virus and Japanese encephalitis virus.The result indicted that there is a less possibility that rat-like animals in Xiamen,Shenzhen and Guangzhou City act as infectious sources of human chikungunya fever infections,Zika virus infections and Japanese encephalitis,however,large samples and more studies are need still need.2.There was a low positive detection rate of Herpesvirus in the brain tissue samples.There viruses clusterd in genus Rhadinovirus,subfamilies Gammaherpesvirinae.This shows that there are differences in the rat-like animals and human herpesviruses.There is a low possibility that rat-like animals transmit herpesvirus to humans.