Study on the molecular characteristic of natural infection of rodents with Hantaviruses in Shenzhen city / 中华预防医学杂志

<p><b>OBJECTIVE</b>In order to investigate Hantavirus (HV) infection of captured rodents and to understand the genotypes and the molecular characteristic of Hantaviruses in Shenzhen.</p><p><b>METHODS</b>The captured rodents were classified and the density of distribution was calculated. A total of 472 animals were captured, among which Rattus norvegicus was the dominant group. The total viral RNA was extracted from the lung tissues positive with HV antigens by immunofluorescent assay and gene sequence of M fragment was amplified with RT-nested-PCR by using the Hantavirus genotype specific primers. The amplified genes were then sequenced, and subjected to genotyping and homology analysis.</p><p><b>RESULTS</b>The results of genotype analysis showed that the Hantaviruses taken from twenty-one lung specimens in Rattus norvegicus in Shenzhen city belonged to the Hantavirus type II (SEOV). Results in homology analysis suggested that the homology among twenty-one samples should be rather high with 95.4% of nucleotide sequence identity and they belonged to the same subtype. Phylogenetic tree analysis showed that they were branched into at least six different lineages, and were highly homologized with SZ2083. We also found that these virus strains had not shown more highly homology of nucleotide sequence in nearest district, whereas revealed consistency in farther district.</p><p><b>CONCLUSION</b>The major hosts of Hantaviruses in Shenzhen city were Rattus norvegicus and the epidemic strains were genotyped as SEO-type. Nucleotide sequence and deduced amino acid sequence from different rodents were highly homologous, while nucleotide mutation had also been observed. Further studies are required to explore the possible viruses' sequence mutation.</p>

Surveillance on natural infection of rodents with hantavirus in Shenzhen city and identification of a hantavirus strain SZ2083 / 中华流行病学杂志

<p><b>OBJECTIVE</b>For clarifying the situation of the natural infection of rodents having hemorrhagic fever with renal syndrome (HFRS) virus and to type Hantavirus (HV) using molecular technique in Shenzhen city in 2005, and offering guidance for prevention and control of HFRS.</p><p><b>METHODS</b>Data on the host animals was collected from the city of Shenzhen. ELISA and indirect immunofluorscent antibody(IFA) test were applied to the specific antibodies against HV in the sera of captured rats. Direct immunofluorscece assay was adopted to determine HFRS antigens and the lung tissues of the HV infected rats were inoculated into Meriones unguiculata to isolate HV. The whole viral RNA was extracted from the lung tissues of the HV infected rats and amplified the partial M fragments with RT-nested-PCR, using the HV genotype specific primers. The amplified genes were then sequenced, and subjected to genotyping and homology analysis.</p><p><b>RESULTS</b>472 rodents were captured from Shenzhen in 2005. Surveillance on rats demonstrated 9.96% rats carrying HV (with a density of 8.25%) and the main host was Rattus norvegicus. In the blood samples of rats, anti-HV IgG antibodies were detectable in 56 cases by IFA, and proved to be positive in 76 cases by ELISA. We successfully isolated a HV strain designated as SZ2083 from Rattus norvegicus for the first time in Shenzhen and was identified to SEO type by RT-nested-PCR. Compared with the coding region of the M gene of HV L99 virus strain, the homologies of nucleotide among them were 97%, but the homology was 76% of the SZ2083 with HTN 76-118 virus strain.</p><p><b>CONCLUSION</b>Results showed the existence of natural epidemic areas of HFRS in Shenzhen city. Based on the results of sequencing, it is possible that the Seoul strain of HV might be the predominant serotype of virus harbored.</p>