Epidemiology of hemorrhagic fever with renal syndrome in Liaoning

Objective To understand the epidemiological features of hemorrhagic fever with renal syndrome (HFRS) in Liaoning and provide evidence for the prevention and control of HFRS. Methods Descriptive epidemiological analysis of HFRS epidemic was conducted and host animal surveillance was carried out to detect rat density and virus carrying rate. Results A total of 53 525 HFRS cases were reported from 1962 to 2008, including 1042 deaths. The average annual incidence was 2.85/lakh and case fatality was 1.95%. Both rattus type endemic area and mixed type endemic area increased gradually. The cases were distributed in only 4 areas in 1980s, but now in 90% of the counties (district) in 14 municipalities in the province. The incidence peaked during March-June and November-January. The cases were aged 15-60 years and most of them were farmers (70%). Conclusion The incidence of HFRS once increased rapidly at beginning of this century, but the epidemic had been under effective control since 2005 when mass vaccination among the population in risk areas started.