| Background:Emerging infectious diseases(EIDs)are a serious challenge to public health and social development in the world.Over 70%of zoonotic emerging infectious disease events originate in wild animals[1].Rodents and shrews live in close contact with humans and act as a bond among humans,domestic animals,and arthropod vectors[2].Rodents and shrews,as two common types of wild mammals,are recognized as reservoir hosts for many zoonotic pathogens,for example,Anaplasma,Babesia,spotted fever group Rickettsiae,Borrelia,and hantavirus[3,4].Rodent transmission is mainly through direct and indirect transmission,such as rat bites,eating contaminated food,and transmission through parasites such as ticks,mites and fleas.About 10%of the 2277 living rodent species are hosts for 66 zoonotic pathogens,including viruses,bacteria,fungi,worms,and protozoans[5].However,the links between these pathogens are still rarely investigated.China is a megadiversity country and harbors various rodents and shrews.The rodents and shrews belong to the RODENTIA and EULIPOTYPHLA order.Currently,there are 235 species of RODENTIA order and 92 species of EULIPOTYPHLA order in China[6].Rodents and shrews can transmit zoonotic pathogens to human directly when humans consume food,water,or air that is contaminated with feces and bodies[7]or indirectly when humans are bitten by arthropod vectors[8-13].Most of the previous studies only focus on one or a few pathogens from rodents and shrews,and the source areas of samples are also limited[14-17].In this study,we screened representative zoonotic pathogens in a great variety of rodents and shrews from four provinces in China to identify the prevalence and co-infection of zoonotic pathogens.Objectives:On the basis of previous research work,this study explored the carrying status,composition,distribution and diversity of zoonotic pathogens in rodents in four provinces,and explored the carrying status of zoonotic pathogens in rodents and shrews captured in different provinces of China,as well as the co-infection of different pathogens.Methods:In this study,rodents and shrews were collected from Guangdong,Henan,Inner Mongolia and Yunnan provinces.8 pathogens including hantavirus,Bartonella spp.,Anaplasmataceae,Babesia spp.,Leptospira spp.,SFGR.,Borrelia spp.and Coxiella burnetii were detected in the samples,and the positive sequences were analyzed.In this study,we screened representative zoonotic pathogens from a variety of rodents and shrews from four provinces in China to determine the positive rate and co-infection of zoonotic pathogens in rodents and shrews.Results:In this study,a total of 864 rodents and shrews were collected from four provinces:Guangdong,Henan,Inner Mongolia and Yunnan.Species identification showed that a total of 37 small mammals were identified in this study,of which 24(64.9%)were RODENTIA order and 13(35.1%)were EULIPOTYPHLA order.The highest species diversity of small mammals in Yunnan was 27 species,among which Apodemus ilex,Apodemus chevrieri and Rattus tanezumi were the dominant species,accounting for 28.9%,20.2%and 13.0%of captured small mammals in Yunnan,respectively.There were 8 species of rodents and shrews in Henan,and the dominant species of rodents was Rattus tanezumi.There were 5 species of rodents and shrews in Guangdong,and Suncus murinus was the dominant species.There were only 4 species of small mammals in Inner Mongolia,and Myospalax psilurus was the dominant species.The results of PCR showed that 30 samples were positive for hantavirus,the positive rate was 3.47%,of which 27 samples(90%)were from Yunnan,3 samples were from Henan,and no positive samples were detected from Guangdong and Inner Mongolia.Genotyping results showed a total of 4 genotypes:Dobrava virus,Puumala virus,Hantaan virus and Seewis virus.There were 270 Bartonella positive samples,with a positive rate of 31.3%.The positive samples were found in four provinces,and Yunnan had the largest number of Bartonella positive samples,with a total of 124.A total of 77 samples were positive for Anaplasmataceae,with an overall positive rate of 8.91%.Positive samples were detected in four provinces,and Yunnan province had the largest number of positive samples,with a total of 41.There were 36 positive samples of Babesia,with an overall positive rate of 4.17%.The positive samples were detected in four provinces,and Yunnan province had the largest positive number of Babesia with 3 1 samples.There were 34 positive samples of Leptospira spp.,and the overall positive rate was 3.94%.All the positive samples were from Henan,but no positive samples were detected in Guangdong,Inner Mongolia and Yunnan.There were 31 positive samples of Borrelia burgdorferi,and the overall positive rate was 3.59%.Positive samples were detected in four provinces,and Henan province had the largest number of Borrelia burgdorferi with 14 samples.There were 5 positive samples of Coxiella burnetii,and the overall positive rate was 0.58%.All the positive samples were from Henan,but no positive samples were detected in Guangdong,Inner Mongolia and Yunnan.A total of 30 samples were positive for spotted fever group rickettsia(SFGR),with an overall positive rate of 3.47%.Henan and Inner Mongolia had the highest number of SFGR positive samples,with 29 samples from Henan.Zoonotic pathogens were detected in 32 species,including 22 species in the RODENTIA order and 10 species in the EULIPOTYPHLA order.Rattus tanezumi harbored the highest variety of zoonotic pathogens(8 species),followed by Apodemus agrarius(6)and Niviventer confucianus(6).Statistical analysis of all samples revealed that the highest co-infection status among three pathogens was Bartonella spp.,Leptospira spp.and Anaplasmataceae with co-infection rate of 0.46%,and the top three co-infection with two zoonotic pathogens was Bartonella spp.-Anaplasmataceae(3.36%),Anaplasmataceae-Babesia spp.(2.08%),and Bartonella spp.-Leptospira spp.(1.50%).TC-14(Niviventer confucianus Yunnan)was infected with five pathogens at the same time,and the co-infection rate between other pathogens was less frequent.At the same time,there were four and five pathogens co-infected in the samples,and the same Henan social rat(sample number:SC-21-14).Phylogenetic analysis showed that a total of two Hantavirus species were identified in the samples from Yunnan province,which clustered in the same clade with Hantaan virus and CaoBang virus,but had obvious differences with them.Conclusion:In this study,we conducted an in-depth investigation of pathogen-carrying infection in rodents and shrews from Guangdong,Henan,Inner Mongolia and Yunnan by combining field investigation and laboratory detection.We found that there were significant differences in the richness of rodent species in four provinces,and different dominant species in different provinces.A variety of pathogens may exist in rodents and shrews individually or in combination.This study is the first to identify a novel CaoBang virus in mainland China,and we should strengthen surveillance of rat species that are first associated with human habitats.Our results suggested that species distribution and co-infections of zoonotic pathogens were prevalent in rodents and shrews,highlighting the necessity of active surveillance for zoonotic pathogens in wild mammals in wider regions. |
