[Genetic characteristics of hantavirus detected in rodents in Shenzhen]

Objective: To study the molecular epidemiological characteristics and genotypes of hantavirus carried by rodents in Shenzhen. Methods: Rodents were captured, and their lung samples were collected and grinded for RNA extraction. The hantavirus positive samples were classified by real-time fluorescence PCR. Rat lung nucleic acid samples were selected to amplify the nucleotide sequences of partial M fragments (G2 segment) and S fragments by reverse transcription-nested polymerase chain reaction (RT-nested PCR). The PCR products were then sequenced and homology and phylogenetic tree analyses were conducted. Results: A total of 200 rodents were captured, including 189 Rattus norvegicus, 9 Rattus flavipectus and 2 Mus musculus. The positive rate of hantavirus was 21.0% (42/200), all of the isolates were seoul virus (SEOV) strains. The positive rate of hantavirus in Bao'an district was highest (45.7%), and the difference in detection rate among districts were significant (χ²=25.60,P<0.05). A total of 25 G2 segment sequences and S fragment sequences of SEOV were obtained by virus gene sequencing, and their nucleotide homology was 95.3%-100.0% and 97.6%-100.0%, respectively. Compared with other reference sequences of S2 subtype, the nucleotide homology between the sample sequence and the reference sequence from Guangzhou was high. Analysis on nucleotide homology and phylogenetic tree showed that hantavirus carried by the rodents captured in Shenzhen belonged to SEOV S2 subtype. Analysis on amino acid variation sites revealed that there was a variation in the nucleocapsid protein encoded by S gene from Alanine to Threonine at the 973 position of BA-111. Conclusion: Hantavirus carried by rodents in Shenzhen belongs to S2 subtype of Seoul virus, which have little variation compared with the hantavirus strains obtained in other years in Shenzhen and surrounding provinces.