| Objectives:(1)To study the infection and genetic characteristics of hantaviruses in wild rodents from the Huanggang area in Hubei province,China,and provide informations for prevention of hemorrhagic fever with renal syndrome(HFRS)in Huanggang area.(2)To study the relationship between Seoul virus(SEOV)infection and MHC-II RT1.Ba exon2 gene of Rattus norvegicus in Hubei province,China.Methods:(1)Rodents were captured in residential area and fields in Huanggang,Hubei province.during autumn and winter from 2012 to 2013.RNA was extracted from lung tissues.Partial M segments of SEOV and HTNV were detected by using specific RT-PCR.The specific product were sequenced.Phylogenetic relationship and genetic identity were analyzed by using MrBayes 3.1 and BioEdit 7.2.(2)Rodents were captured in residential area and fields in Xiangyang,Yichang,Jingzhou and Wuhan areas of Hubei province during 2014 to 2015.SEOV-IgG in serum were detected by using indirect immunofluorescence(IFA).RNA and DNA were extracted from lung tissues.SEOV S segment specific primers were designed according to the sequences in GenBank.The nested-PCR for SEOV partial S segment was established.The specific products were sequenced.Mitochondrial DNA cytochrome b gene were amplified using RT-PCR with specific primers for Rattus norvegicus and Rattus flavipectus to identify the rat species.MHC-? RTl.Ba exon2 genes of Rattus norvegicus were amplified by using RT-PCR.The specific products were sequenced.The heterozygous products of MHC-? RT1.Ba exon2 were cloned and multiple colonies were sequenced.The alleles of Norway rats MHC-? RT1.Ba exon2 genes were analyzed.Chi-square test was used to compare SEOV positive ratios of different areas in Hubei province.SEOV positive ratios were compared among Norway rats of different MHC-? RT1.Ba exon2 alleles,or of different heterozygosity.The distribution of MHC-? RT1.Ba exon2 alleles were compared among different areas.Results:(1)During autumn and winter from 2012 to 2013 in Huanggang,Hubei province,95 rodents were captured,with 75(78.94%)Norway rats.Six(8.00%)Norway rats were identified to be SEOV positive.Phylogenetic analysis showed that the Huanggang SEOV belongs to the phylogroup A.The nucleotide sequence identities between Huanggang SEOV and stain Z37 were 95.80%-96.30%,and amino acid sequence identities were 97.90%-100%.(2)During 2014 to 2015,245 rodents were captured in residential area and fields in Xiangyang,Yichang,Jingzhou and Wuhan areas of Hubei province.It included 216(88.16%)Rattus norvegicus,and 30(12.24%)Rattus flavipectus.5.71%of rodents were positive of SEOV-IgG detected with IF A,and 8.57%of rodents were positive of SEOV detected with S segment nested-PCR.The positive ratios of SEOV were different significantly among different areas in Hubei province,P<0.05.The SEOV-IgG positive rates of rodent were as follows:Xiangyang(12.05%),Wuhan(3.80%),Yichang(1.89%),Jingzhou(0.00%).The SEOV S segment positive rates of rodent were as follows:Xiangyang(13.25%),Wuhan(11.39%),Yichang(1.89%),Jingzhou(0.00%).The MHC-? RT1.Ba exon2 gene of 204 Rattus norvegicus were sequenced.Ten alleles of RT1.Ba exon2 gene gene were identified.The distribution of RT1.Ba exon2 alleles among different areas in Hubei differed significantly,P<0.05,The SEOV positive ratios did not differ significantly among different RT1.Ba exon2 alleles,P>0.05.The SEOV positive ratios did not differ significantly between Norway rats with homozygous and heterozygous RT1.Ba exon2 genes,P>0.05.Conclusions:(1)The main rodent species in Huanggang was Rattus norvegicus.The main hantaviruses carried by these rodents was SEOV,which belonged to phylogroup A,and were closely related with strain Z37.(2)The positive ratios of SEOV of four areas in Hubei province were statistically different.The SEOV positive ratio of Xiangyang is the highest.The distribution of RT1.Ba exon2 alleles differed among the four areas in Hubei province.The SEOV positive ratios were irrelevant with the alleles and heterozygosity of MHC-? RT1.Ba exon2 gene. |
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