Study On Molecular Epidemiological Characteristics Of Hantavirus In China

Hantavirus(HV)is one of the most important zoonotic pathogens,belonging to the family hantavirus,the genus Orthohantavirus,it is a single-stranded negative stranded RNA virus.After infection,according to different characteristics of clinical manifestation can be divided into Hemorrhagic Fever of Renal Syndrome(HFRS)and Hantavirus Pulmonary Syndrome(HPS).Diseases caused by hantavirus are prevalent worldwide,and seriously endanger human health.It has affected more than 70 countries on five continents and become a public health issue of global concern.HFRS is one of the most serious rat-borne diseases in China with a wide range of prevalence and complex types of epidemic areas.In order to understand the molecular characteristics and genetic evolution of HV in China,this study combined with the national HFRS surveillance system and collected the host animal specimens to carry out the molecular epidemiological investigation of HV infection.A total of284 lung samples were collected,and 95 were positive by PCR,including 24 from Liaoning province and 18 were positive.70 from Yunnan province,19 were positive;20 from Hebei province,18 were positive;24 from Heilongjiang province,12 of which were positive;8 from Jiangxi province,6 were positive;103 from Anhui province,8 were positive;35 from Hunan province,14 were positive.By means of RT-PCR,a total of 50 strains of hantavirus were amplified from positive mouse lung specimens or virus strains and genotyped.These included 8 strains(SEOV)from Yunnan province,16 strains(SEOV)from Liaoning province,5 strains(SEOV)from Heilongjiang province,10 strains(SEOV)from Hebei province,3 strains(HTNV)from Anhui province,1 strain(HTNV)from Shandong province,1 strain(HTNV)from Fujian province,3 strains(HTNV)from Shaanxi province,and 3 strains(1 SEOV,2 HTNV)from Hunan province.In addition,Gc fragments of 15 HV strains were obtained,including 12 strains in Hunan province(HTNV)and 3 strains in Jiangxi province(1 SEOV and 2 HTNV).A total of 6 HV strains were isolated from the lung specimens of positive mice,including 1 SEOV(XY67)from Yunnan province,2 HTNV(2018c024-10 and 2018c024-22)from Hunan province and 3 HTNV(xc028,xc067 and xc046)from Anhui province.From GenBank and other public databases,hantavirus reference strain sequences were downloaded,including HV sequences of different species at home and abroad,and HTNV/SEOV historical strain sequences of different provinces in China,with a total of 96 strains.The software was used to analyze the nucleotide similarity between isolated strain sequences and reference sequences,and the genetic evolution tree was constructed by NJ method.The results showed that the HV sequences obtained from Liaoning,Hebei and Heilongjiang provinces in this study were all S3 genotype of SEOV,with a high similarity of 97%to the previous isolates of S3 genotype and the reference sequences of S3 genotype in all provinces.Three sequences of HTN type in Shaanxi province were H4 genotype,which were different from the historical strain 84FLi.One sequence of SEO type in Fujian province was S5 genotype which was different from the historical strain.One sequence of HTN type in Shandong province was H5 genotype,It is known that there are at least 5 genotypes of HTNV/SEOV in Shandong province.One SEOV sequence in Hunan province belongs to S3 genotype,the similarity between two HTNV sequences and other genotypes is less than 95%,and the Gc fragments of 12 HTNV strains do not branch into known genotypes.In Anhui province,three HTNV sequences were H9 genotype.Eight SEO strains in Yunnan province had large variation and split into two branches in the evolutionary tree,indicating that there may be two subtypes of viruses circulating simultaneously in the same area.The Gc fragments of one strain of SEO type and two strains of HTN type in Jiangxi province became independent branches,,with a large degree of variation and multiple genotypes.Sequence analysis of the majority of HTNV and SEOV stored on GenBank suggested that the viral genome showed a trend of more diversification,and the aggregation into more independent branches showed the characteristics of variation.In this study,the host"overflow" phenomenon of HV was also found.SEOV was detected in Rattus rattus and HTNV was detected in Mus musculus,which may be one of the important mechanisms for the formation of viral diversity in the process of natural selection.In summary,this study preliminary elucidated the molecular epidemiological characteristics of hantavirus in China,revealing the different species and geographic distribution of virus genotype and the area of the main features of the pandemic virus,analyzing the diversity of the viral genome.The HV gene sequences of the key prevalent provinces of HFRS in China were obtained.It had contributed valuable data to the research on the molecular level of HV in China,and six viral circulating strains from three different provinces were isolated,which enriched the HV virus library in our country.It is of great significance to accurately carry out the prevention and control measures of HFRS and evaluate the effect of vaccine immunization,which also lays a solid foundation for further analysis and research on the epidemic characteristics of HV in the future.