Hantaviruses in small mammals and humans in the coastal region of Zhejiang Province, China.

To gain more insights into the epidemiology of hantaviruses in the coastal region of Zhejiang Province, China, the morbidity and mortality of hemorrhagic fever with renal syndrome (HFRS) were analyzed in two coastal areas: Cixi (hilly terrain) and Wenzhou (mountainous terrain). More HFRS cases have been reported in Cixi than in Wenzhou. Annual incidence rate of HFRS in Cixi had been on the level of approximately 1.5/100,000 from 1968 (when the first HFRS case was reported) to 2007, with the highest incidence rate of 8.54/100,000 in 1999. The annual incidence rate in Wenzhou has been relatively low, less than 0.5/100,000 since the first HFRS case was reported in 1981. A total of 461 rodents and 199 shrews were captured in these two areas. Hantavirus antibodies were detected in 16 of 241 (6.64%) Rattus norvegicus and 13 of 122 (10.66%) R. flavipectus. Interestingly, hantavirus antigens were identified in 6 of 196 (3.06%) Suncus murinus. Genetic analysis showed that partial M and S segment sequences recovered from rats in the two regions belong to Seoul virus (SEOV) and can be assigned into two genetic lineages. SEOV variants that belong to these two lineages of viruses are distributed widely in China and have been found outside China. As most trapped rodents were rats and SEOV was the only hantavirus detected, these results suggested that SEOV plays an important role in human hantavirus infections. They also reinforce the need for vigilance in preventing HFRS caused by hantaviruses in the coastal region.

[Study on the feasibility of a cell-culture inoculation test in the detection and isolation of street rabies virus].

OBJECTIVE: Feasibility of using MNA cell-culture inoculation test to detect and isolate the street rabies virus. METHODS: Using MNA cell-culture inoculation test, fluorescent antibody test (FAT) and sandwich ELISA with double-antibodies to detect 33 specimens of street rabies virus, 20 specimens of negative canine brains and 4 specimens of healthy mice brains. RESULTS: 33 specimens of street rabies virus were positive to the cell-culture inoculation test but the others were negative. The concordances of MNA cell-cultured inoculation test with FAT and sandwich ELISA with double-antibodies were both 100%. CONCLUSION: MNA cell-culture inoculation test appeared to be both highly sensitive and specific in detecting the street rabies virus, and could be used in detection and isolation of the virus.

[Study on the molecular epidemiology of hantavirus carried by rodent hosts in Cixi, Zhejiang province].

OBJECTIVE: To collect more data on the epidemiology of hantavirus in rodents in Cixi, Zhejiang province. METHODS: Rodents were captured in Cixi, where hemorrhagic fever with renal syndrome (HFRS) appeared endemic. Hantavirus antigens in the rat lungs were detected by immunofluorescence assay. Partial S segment sequences were amplified by reverse transciption-polymerase chain reaction (RT-PCR) and then sequenced. The phyologenetic trees were constructed by maximum likelihood method to detect the genetic characteristics of hantavirus. RESULTS: A total of 243 rodents were trapped in the epidemic areas, and hantavirus antigens were identified in 7 out of these lung samples (2.88%). Partial S segment sequences (620-999 nt) were recovered from 6 samples and sequenced. Data from phylogenetic analysis of these S segment sequences indicated that all viruses belonged to Seoul virus (SEOV), despite the origins of sources were either from Rattus norvegicus or from R. flabipectus. These viruses could further be divided into two distinct lineages but the viruses carried by R. norvegicus were different from those carried by R. flabipectus. CONCLUSION: Two distinct lineages of SEOV had been cocirculating in rodents in Cixi.