Surveillance of hemorrhagic fever with renal syndrome in Gansu, 2006-2011

Objective To understand the incidence trend of hemorrhagic fever with renal syndrome (HFRS) and the density and hantaan virus carriage of rats in Gansu province from 2006 to 2011. Methods The human HFRS incidence data were collected from national disease surveillance information system. Rats were captured by using traps. Rat’s Hantaan virus carriage was detected by using immunofluorescence assay and rat’s serum hantan virus antibodies were detected by using ELISA. Results From 2006 to 2011, the annual case number of HFRS was 35, 10, 25, 13, 6 and 5 respectively. The cases were distributed sporadically in 9 municipalities (prefecture), but mainly in Ganan (30), Pingliang (25) and Tianshui (15). The cases were mainly young male farmers or herdsmen. Totally 1090 rats (10 species) were captured. The captured rat number was highest in 2006. Apodemus agrarius was the predominated species in open country (47.64%), while Rattus norvegicus was the indoor predominated species (65.12%). The rat virus carriage rate was 1.01% (11/1090). Ten rats carrying virus were mainly Apodemus agrarius (10/11). Conclusion The incidence of HFRS was low in Gansu. Apodemus agrarius is the major infection source and host in the mixed type foci. It is important to strengthen the surveillance of the epidemic in rats to prevent and control HFRS.