• The Journal of Korean Society of Virology
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• v.28 no.1
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• pp.11-20
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• 1998

Twenty isolates of Hantavirus were isolated from patients and reserovirs from 1988 to 1994 in Korea. Isolation rate was 1.9% (10/538) in patients, 6.2% (5/81) in Apodemus sp., 2.6% (1/38) in Rattus sp. and 0.6% (4/677) in bats. Reciprocal mean IFA titers ranged from 27.5 to 1,024 at the specimen collection. According to the growth rate and reaching peak titier of infectivity, the isolates were grouped as rapid, intermediate, and slow growing groups. All isolates were confirmed as Hantaan type by the nested RT-PCR on the G1 region of the M segment. Comparison of nucleotide sequence (Nt: 2101 - Nt: 2280) of the G2 region revealed that the sequence homology bewteen Hantaan 76/118 virus and the isolates was more than 90%. Several nucleotide positions of the isolates showed high variation. The variation rate of patientisolates was about one-half when compared with that of rodentisolates. On the basis of phylogenetic analysis Hantaan viruses isolated were divided into two genogroups. These results indicate that Hantaan virus is highly dominant serotype in Korea and the virologic property and genogroup are not correlated.

• The Journal of Korean Society of Virology
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• v.28 no.2
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• pp.147-155
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• 1998

Hantavirus is a genus of the Bunyaviridae family consisting following serotype groups: Hantaan, Seoul, Puumala, Prospect Hill, Thailand, Belgrade, Thotta palayam, Sin Nombre. Most of Hantavirus group have been associated with many clinically similar disease known collectively as hemorrhagic fever with renal syndrome (HFRS). Hantaan virus is the prototype of the genus hantavirus, originally isolated from Apodemus agrarius. Bat was found as a natural host for Hantaan virus in Lee's lab for the first time. Then, Hantaan-like virus was isolated Hantaan-like virus from bat. To identify hantaviruses that are present in Korea among bats, bats were collected from Jeong-Sun, Won-Joo, Chung-Ju and Hwa-Cheon area, RNA was isolated from lung and serum. RT-PCR was performed with a universal primer from M segment. Nested RT-PCR was carried out to differentiate Hantaan, Seoul and Puumala virus using serotype specific primers. As we expected, Hantaan viruses were detected in bats and Seoul virus was not detected. Interestingly, Puumala viruses were also detected in bats from Won-Ju, but not in other areas. Puumala virus is originally isolated from Clethrinomys glareolus, and cause light HFRS. Recently, Paradoxomis webbiana, a wild bird turn out to be a reservoir for Puumala virus in Korea. These data indicate that bat is a new natural reservoir of Puumala virus.

• Animal Systematics, Evolution and Diversity
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• v.30 no.3
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• pp.159-175
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• 2014

A taxonomic study of small mammals (Erinaceomorpha, Soricomorpha and Rodentia) was conducted in order to find out the scientific names which have been used in Korea. The synonymy of each species and taxonomical research was reviewed and confirmed in this study. The species names are rearranged based on recent studies. Among the various confused names, available names were adopted such as follows: C. shantungensis shantungensis known as Crocidura suaveolens; C. shantungensis quelpartis known as C. dsinezumi; Rattus tanezumi known as R. rattus, called black rat, roof rat and ship rat, respectively. Apodemus sylvaticus (Muridae, wood mouse) is excluded in the checklist based on indistinct previous records and ambiguous habitation on the Korean Peninsula, and neighbors. In addition, we provide a new Korean vernacular name for Myocastor coypus, called the "Nutria" in Korea. We reflect that several species are repositioned to other genera. A checklist of Korean small mammals and synonym list for each species is provided to avoid confusion of scientific names in Korea. In this study, the list of small mammals in Korea is arranged to 33 species, 20 genera, 8 families, and 3 orders.

• Animal cells and systems
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• v.1 no.1
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• pp.53-61
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• 1997

Seasonal variation of the population structure and the reproductive pattern of the Korean striped field mouse, Apodemus agrarius, were investigated. High capture ratios in juveniles, young adult, and old adult mice were found during the period from October to November, from November to March, and from May to September, respectively, and extremely low capture ratios of old adults during the period from November to February were characteristic. It seemed that the young adults that survived during the winter might become older by summer and have been counted as the old adults. The breeding in the mice began earlier in males (from mid February or early March to late October) than in females (from mid March to late October), having a peak in August and September, and both the male and female mice weighing more than 20 g generally reached sexual maturation in general. In the breeding season, both young and old adult males had large testes with enlarged seminiferous tubules filled with numerous germ and Sertoli cells, and expanded caudal epididymides with a vast number of spermatozoa; the females had many Graafian follicles and corpora lutea in large ovaries, and developed uterine glands in the thick endometria. The lower ratios of the testis weight to the body weight in July and August in 1994 compared to 1995 seemed due to the extreme drought and considerably higher temperature in 1994, but the decrease in the ratio in mid-summer, only in the old mice, in both years might be explained partially by aging.

• The Korean Journal of Ecology
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• v.11 no.1
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• pp.17-28
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• 1988

Five hundrad and eight rats were caught in Shiheung-dong and Mt. Kwan-ak from 1986 to 1987 in this survey. Ectoparasites were got from these rats and classified. The results were as follows: 9,191 mites (16 genera, 30 species), 408 fleas (4 genera, 4 species), and 521 lice (3 genera, 5 species) were observed in this survey. In the residential area, Rattus norvesicus(71.74%) was dominant species and in Mt. Kwan-ak Apodemus agrarius(93.62%). In these areas, the mites belonging to suborder Mesostigmata were dominant (Laelaps nuttli, 52.61%; Ornithonyssus bacoti, 36.05%). In Mt. Kwan-ak, family Frombiculidae belonging to suborder Prostigmata were dominant (Leptotromibidium orientalis, 31.04%; Leptotrombidium palpalis, 30.00%). In this way, it was discovered that the difference between the two regions in dominant species was noticeable. As for the hosts parasitized by mites, L. nuttalli in R. norvegicus (54.85%), L. nuttalli in R. rattus (32.90%), and L. orientalis in A. agrarius (31.27%) were dominant species, respectively. In the mites parasitizing on A. agrarius in each altitude, the species were more varied as the region was lower and the dominant species were more concentrated as it was higher.

• The Korean Journal of Zoology
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• v.1 no.1
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• pp.1-6
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• 1958

A rat-fleas survey was carried out in Ducksonm and Kwangnaru areas of Seoul city from Janurary to December 1955 . In this survey, 1,204 redents were trapped alive and 740 of which being Rattus norvegicus, 457 Apodemus agrarius, 5 Eutamiias asiaticus and 2 shrewes ((crocidura rusila). On these rodents 270 fleas were collected and identified thus : Ceratopylidae : Monopsyllus anisus (Rothschild 1908) ···200 Leptosylla segnis(Schonherr, 1832)···1 Hystrichopsyllidae : Ctenophthalmus congener, Rothschild ···43 Neopsylla bidentiformis (Wagner, 1893)···11 Stenoponia sidimi Marikovsky, 1936···9 Pulcidae : Xenopsylla cheopis (Rothschild, 1903)···6 On the average 8.5% of the rodents were infestated with fleas. The infestation rate showed a marked varying degree in a year and three high incidence peaks in Spring (10.3%), Summer (11.4%-11.8%) and Winter (13.7%). The average number of fleas per rat (flea-index) was 0.22 for the whole year with a maximum of 0.41 in December and a minimum of 0.03 in February. Of all, the most prevalent species are Monopsyllus anisus (74.1%) and secondly Ctenophthalmus congener (15.9%). both species occupied 90% of all. Xenopsylla cheopis, a known vector of plague, was found very rare in our survey and only appeared in Winter. The striking lower incidence of flea-index compared with previous data (6.6 by Nagahana, 1931-1936) appears to be due to the nationwide application of DDT and BHC insecticides since 1945.

• Parasites, Hosts and Diseases
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• v.58 no.5
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• pp.559-564
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• 2020

A survey of rodents and chiggers associated with Orientia tsutsugamushi was conducted in a rural region of the Republic of Korea (Korea) between 2014 and 2018. Overall Apodemus agrarius 15.2% had the highest seropisitive for O. tsutsugamushi, followed by Myodes regulus 11.4%. Monthly risk factors using logistic regression analysis were not associated with O. tsutsugamushi infections in rodents. The overall prevalence rate of O. tsutsugamushi among chiggers was 0.3%. The chigger (Leptotrombidium scutellare) and monthly (October) risk factors were associated with O. tsutsugamushi human infections (P<0.05). Orientia tsutsugamushi infections are endemic in rodents in Korea and people, for example, soldiers who are active outdoors, must employ preventive measures, especially during October (P<0.05). When there are many reports of O. tsutsugamushi infections in Korea. The Boryong strain 85.7% (2/14) was the most common strain detected in chiggers, followed by the Shimokoshi 7.1% (1/14) and Karp 7.1% strains.

• Parasites, Hosts and Diseases
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• v.59 no.3
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• pp.319-324
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• 2021

Incidence of tsutsugamushi disease (scrub typhus) caused by Orientia tsutsugamushi, is steadily increasing. It is a mite-borne disease transmitted by chigger mites. In this study, the chigger mites were collected from field small mammals in Hwaseong-si (city), Gyeonggi-do (province), Korea, 2019 and 2020. The field small mammals captured were 56 Apodemus agrarius (94.9%) and 3 Crocidura lasiura (5.1%). A total of 7,531 chigger mites were collected from the captured small mammals. Using PCR test, 153 chigger mite pools were examined and 17 pools were reported positive for O. tsutsugamushi. The O. tsutsugamushi were identified to 5 strains; Jecheon strain was most prevalent, followed by Boryong strain. The other strains were OI011, Taguchi, and Shimokoshi. Collectively, these results provide essential regional information on mite-borne tsutsugamushi disease in the Hwaseong-si, and further contribute to bring awareness and rapid diagnosis for the tsutsugamushi disease.

• Parasites, Hosts and Diseases
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• v.52 no.2
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• pp.225-229
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• 2014

A total of 9,281 larval chigger mites were collected from small mammals captured at Hwaseong-gun, Gyeonggi-do (Province) (2,754 mites from 30 small mammals), Asan city, Chungcheongnam-do (3,358 mites from 48 mammals), and Jangseong-gun, Jeollanam-do (3,169 for 62 mammals) from April-November 2009 in the Republic of Korea (= Korea) and were identified to species. Leptotrombidium pallidum was the predominant species in Hwaseong (95.8%) and Asan (61.2%), while Leptotrombidium scutellare was the predominant species collected from Jangseong (80.1%). Overall, larval chigger mite indices decreased from April (27.3) to June (4.9), then increased in September (95.2) and to a high level in November (169.3). These data suggest that L. pallidum and L. scutellare are the primary vectors of scrub typhus throughout their range in Korea. While other species of larval chigger mites were also collected with some implications in the transmission of Orientia tsutsugamushi, they only accounted for 11.2% of all larval chigger mites collected from small mammals.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.242-246
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• 2016

The distribution and population density of rodents and chigger mites were investigated between April 2013 and November 2013 in the Gokseong-gun of Jeollanam-do, Korea. A total of 79 rodents were collected using Sherman collapsible traps, and among them, 73 were Apodemus agrarius (92.4%), 4 were Crocidura lasiura (5.0%), and 2 were Microtus fortis (2.5%). Sixty-eight out of the 79 rodents were parasitized by chiggers, showing an infestation rate of 86.0% and a chigger index of 74.5; the chigger index of A. agrarius was 75.4. From the trapped field rodents, 5,063 chigger mites were collected and identified with 6 species of 2 genera. Leptotrombidium scutellare was the dominant species with 3,535 chiggers (69.8%), followed by L. pallidum with 777 chiggers (15.3%). This results showed that the distribution of chigger mites differ in dominant species according to seasons. L. pallidum was the predominant chigger collected in April (34.3%), May (70.0%), and June (55.1%); whereas L. scutellare was the predominant chigger collected in September (75.5%), October (71.8%), and November (74.2%).