Prevalence of Hantavirus infections in humans and animals in Wenzhou city.

Objective The prevalence of hemorrhagic fever with renal syndrome(HFRS) was monitored and analyzed to reveal the epidemiologic characteristics of HFRS in Wenzhou,in order to provide the basis for development of the control and prevention strategies for HFRS.Methods A descriptive epidemiologic approach was employed to analyze the prevalence of HFRS in humans in Wenzhou from 1981 to 2008.Cage traps were used to capture small mammals for investigation of the species composition of animal hosts.The indirect immunofluorescence assay was used to detect the Hantavirus(HV) antigens in animal lungs,which were then genotyped by PCR.Results A total of 383 cases were reported from 1981 to 2008 with an average incidence rate of 0.20/105.There were 13 death cases,with a fatality rate of 3.39%.The cases were distributed in all the ten counties(cities,districts) of the city,particularly in Ruian,where the number of cases accounted for 53.78%.Significant seasonality was observed as the prevalence peaked in winter(from November to January of the following year) when the number of cases accounted for 41.25%.Most cases were 20 to 50 years,accounting for 74.76% of the total number.In regard to the monitoring of host animals,the outdoor capture rate was 7.16% and the indoor one was 7.88%.The dominant species outdoors was Niviventer confucianus,followed by Rattus losea;the dominant species indoors was R.norvegicus,followed by R.tanezumi.A total of 422 rat lungs were investigated,resulting in nine HV antigen-positive specimens with the positive rate of 2.13%.The sole genotype of the extract of viral RNA in the HV antigen-positive rat lung tissues was SEOV.Conclusion Comprehensive prevention and control measures,including strengthened monitoring,deratization and vaccination shall be implemented to effectively prevent HFRS epidemic.