Epidemiologic and phylogenetic study on hemorrhagic fever with renal syndrome in Hunan province from 2007 to 2010

Objective To study the epidemiological features of hemorrhagic fever with renal syndrome(HFRS) and to analyze the molecular evaluation of the virus M gene.Methods Descriptive epidemiology was applied to analyze the epidemic data collected from both the national notifiable disease reporting system and the local surveillance records of HFRS including human and rodent endemics.IFA and RT-PCR were used to determine the etiology from blood samples of patients and lung tissues of rodents.Meanwhile the virus M gene was sequenced and analyzed by bioinformatics.Results A total of 2 115 HFRS cases reported from 2007 to 2010 in 14 areas of Hunan province with the mortality of 1.28%.Most of the cases were from Loudi and Shaoyang counties and 67.19% of patients were farmers.Also IFA test revealed that 2.18% of all the captured mice were found to be Hantavirus positive in their lung tissues,and apodemus agrarius was the major host of the virus in this endemic area.PCR products of two blood samples and one mouse lung tissue were positive with both HTNV general primers and specific typing primers.The phylogenetic tree showed that these three isolated viruses had a high homogeneity with 84Fli strain,which were classified as H5 subtype of HTNV.Conclusions The overall downward trend of HFRS epidemics in Hunan province could be related to the successful control strategies,but in some areas the epidemic situation is still serious,and the M gene ofHantavirus has not changed a lot compared with others.