Seroprevalence of hantaviruses in small wild mammals trapped in South Korea from 2005 to 2010.

The seroprevalence of Hantaan virus (HTNV) in wild rodents in South Korea was analyzed. Wild rodents were trapped in 18 cities in eight provinces during 2005-2007 and on three islands and four mountains during 2008-2010. Sera were collected from 629 out of 933 trapped wild animals and examined for immunoglobulin G antibodies to HTNV using indirect immunofluorescence assays. Apodemus agrarius (80.1%) was the most frequently captured species at almost all trapping sites. The overall prevalence of HTNV antibodies was 0.26 (162/629). Seropositive individuals were more frequent in cities (32.2%, n=410) than on islands (14.0%, n=57) or mountains (13.6%, n= 162). HTNV antibody-positive rate was higher in the fall (29.6%, n=253) than in the spring (23.1%, n=376). A. agrarius had the highest prevalence of HTNV antibodies (26.9%, n=561) of all tested species. Considering all the individuals, the prevalence of HTNV antibodies was higher in males (29.2%, n=250) than in females (22.3%, n=305). Our results show that HTNV is widely distributed throughout South Korea, and that HTNV infection of wild rodents is affected by their habitat, species, sex, and season.

Prevalence of hantavirus infection in wild rodents from five provinces in Korea, 2007.

Hemorrhagic fever with renal syndrome (HFRS) is an infectious disease caused by hantaviruses of the family Bunyaviridae. Among them, Hantaan virus (HTNV) is most widely distributed in Korea. The striped field mouse, Apodemus agrarius, is the natural host of HTNV in rural Korea. We trapped 766 small mammals of three species (1 Eothenomys regulus, 13 Crocidura suaveolens, and 752 Apodemus agrarius) in five provinces in Korea from January to December 2007. We tested 542 rodent sera for HTNV antibodies by an indirect immunofluorescent assay (IFA), finding antibody prevalences of 4 to 29% among the five provinces. Peaks in monthly antibody prevalence occurred in spring and fall. Antibody prevalence during the second peak coincided increased HFRS incidence in autumn. We used multiplex reverse transcription polymerase chain reaction (RT-PCR) to detect the partial S segment of Hantaan, Seoul, and Puumala viruses in 766 lung samples of all captured animals and found HTNV RNA in 25 A. agrarius. Two isolates of HTNV were obtained from PCR-positive A. agrarius by cultivation in Vero E6 cells. This first systemic survey of monthly antibody prevalence in hantavirus hosts in wide regions in Korea could provide useful information for other researchers studying environmental and ecological factors affecting HFRS.