Intestinal Parasites among Wild Rodents in Northern Gangwon-do, Korea

To determine geographical patterns of natural parasite infections among wild rodents, a total of 46 wild rodents from 3 different localities in northern Gangwon-do (Province), Korea were examined for intestinal parasite infections. Along with nematodes such as hookworms and Syphacia spp., Plagiorchis muris (2 specimens) (Trematoda) were collected from striped field mice, Apodemus agrarius. In a Korean wood mouse, Apodemus peninsulae, the overall nematode infections were similar to A. agrarius, but an adult worm of Echinostoma hortense (Trematoda) was collected. In addition, 2 species of cestodes, i.e., Hymenolepis nana and Hymenolepis diminuta, were collected from A. agrarius. Through this survey, A. agrarius and A. peninsule were confirmed as the natural definite hosts for zoonotic intestinal helminths, i.e., P. muris, E. hortense, H. nana, and H. diminuta, in northern Gangwon-do, Korea. Considering increased leisure activities around these areas, seasonal and further comprehensive surveys on wild rodents seem to be needed to prevent zoonotic parasite infections.

Nucleotide Sequence and Phylogenetic Analysis of M and L Segment of Soochong Virus

Hantaan virus (HTNV) and Seoul virus (SEOV) have mainly been known as the cause of hemorrhagic fever with renal syndrome (HFRS) in Korea since HTNV has been isolated from Korean field mouse, Apodemus agrarius in 1976 and SEOV has been isolated from Rattus norvegicus in 1980. Soochong virus-1, -2, -3, -4 (SOOVs) were isolated from lung tissues of four Apodemus peninsulae captured on August 1997 at Mt. Gyebang in Hongcheon-gun, Mt. Gachil, Inje-gun, Gangwon Province, and in September 1998 at Mt. Deogyu, Muju-gun, Jeollabuk Province. Apodemus peninsulae is the second-most dominant field rodent species found throughout Korea. To determine phylogenetic analysis of SOOVs, we entirely identified nucleotide sequences of M and L segments. The length of M segment was 3,615 bp and L segment was 6,533 bp. SOOVs were diverged from HTNV by 22.7~23.3% and SEOV by 36.3~37.2%, in M segment. In addition, L segment was diverged from HTNV by 21.8~22.0% and SEOV by 30.3~30.5%. SOOVs sequence compared with Amur virus (AMRV) in M segment showed that SOOVs were different with AMRV about 14.6~16.2% in nucleotide sequences. Neighbor-joining phylogenetic analysis based on entire sequences of the M and L segment indicated that the SOOVs sequences present a separate lineage with HTNV, SEOV and AMRV. SOOVs constituted an individual cluster on the phylogenetic tree and they composed a phylogenic lineage separately. According to these data, SOOVs could be classified as a new hantavirus.

Seroprevalence and Phylogenetic Analysis of Orientia tsutsugamushi from Apodemus peninsulae in Korea

To investigate the seroprevalence of the Orientia tsutsugamushi infection of Apodemus peninsulae and genomic variations in O. tsutsugamushi isolates, 246 A. peninsulae were trapped in 14 mountainous areas approximately 500 meter above sea level in Korea during the period of 1997 and 2000. Seropositive rate of O. tsutsugamushi among A. peninsulae was 31.8% in Kyunggi, 8.2% in Chunbuk and 7.1% in Kangwon provinces by microimmunofluorescent test. The 56 kDa protein gene was amplified by PCR in the spleens of seropositive A. peninsulae. Two amplicons from seropositive A. peninsulae were sequenced and their phylogeny was analysed on the basis of sequence homology. The 56 kDa genes of A. peninsulae 98-12 strain and A. peninsulae 98-16 strain showed 98.7% nucleotide homology and 96.6% amino acid similarity. A. peninsulae 98-12 and A. peninsulae 98-16 strain were related to Kuroki, Boryong and Karp strains showing 93.3~92.2%, and 87.1~84.6% homologies in nucleotide and amino acids levels, respectively. In the phylogenetic analysis, A. peninsulae 98-12 and A. peninsulae 98-16 strain formed a distinct group with Boryong, Kuroki and Nishino strains and were clearly distinguished from other genetic groups. The results suggest that A. peninsulae might be an important reservoir of O. tsutsugamushi in Korea.

Seroepidemiological Study on Hantavirus Infection of Wild Fodents Captured in the Moutainous Areas of Korea

Hantaan virus is widely distributed among rodent populations in Korea. Two antigenically distinct hantaviruses were isolated from Apodemus agrarius in 1976 and Rattus norvegicus in 1980 in Korea. This study was designed to investigate the serological evidence of hantavirus infection among indegenous wild rodents, which were captured in 11 mountains located in Kyunggi, Kangwon, Chungnan, Chunbug and Kyungnam province of South Korea. A total 252 wild rodents of 3 species were trapped from Myungsung Mt., Chumbong Mt., Kali Mt., Hansuk Mt., Chachil peak, Kyebang Mt., Odae Mt., Kyerong Mt., Kaya Mt., Togju Mt. and Chiri Mt. in 1997. Serologic test for hantavirus infection was performed using hantavirus antigens by indirect immunofluorescent antibody technique. Among 122 Apodemus agrarius, 88 Apodemus peninsulae and 42 Eothenomys regulus; 18 A. agrarius (14.8%), 12 A. peninsulae (13.6%) and 4 E. regulus (9.5%) were immunofluorescent antibody (IFA) positive against hantaan virus. IFA titers 3 Eothenomys regulus sera were higher against puumalavirus than hantaan virus. These data imply that above three species of rodent might be natural reservoirs of hantaviruses in Korea.