Neodiplostomum seoulense (Digenea: Neodiplostomidae)
was described first from the small intestine of house
rats (Seo et al., 1964a) and later in a total of 26 docu-
mented human infections (Seo et al., 1982; Hong et al.,
1984, 1986). Several species of frogs and tadpoles were
found to be the second intermediate hosts, and
snakes, Rhabdophis tigrina, take the role of a paratenic
host and the source of human infections (Hong, 1982;
Seo et al., 1988). A species of freshwater snail,
Hippeutis cantori, is known to be the first intermediate
host (Seo et al., 1988; Chai and Lee, 2002).
With regard to the natural definitive host for N.
seoulense, limited information is available. Several sur-
veys on intestinal parasites of rodents in the Republic
of Korea (South Korea) suggested that N. seoulense
was a species having one natural definitive host, R.
norvegicus (Seo et al., 1964a, b, 1981; Yong et al., 1991),
� Brief Communication �
Apodemus agrarius as a new definitive host for
Jong-Yil CHAI1)*, Jae-Hwan PARK1), Sang-Mee GUK1), Jae-Lip KIM1), Hyo-Jin KIM1), Won-Hee KIM1),
Eun-Hee SHIN1), Terry A. KLEIN2), Heung-Chul KIM3), Sung-Tae CHONG3),
Jin-Won SONG4)and Luck-Ju BAEK4)
1)Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, and
Institute of Endemic Diseases, Seoul National University Medical Research Center, Seoul 110-799,
2)Regional Emerging Infectious Disease Consultant, 18thMedical Command, APO AP 96205-5281,
3)5thMedical Detachment, 168thMedical Battalion (AS), 18thMedical Command, APO AP 96205-5247,
4)Department of Microbiology, College of Medicine, Korea University, Seoul 136-701, Korea
Abstract: A total of 1,496 rodents and insectivores were live-trapped at Yeoncheon-gun (n = 351), Paju-shi (804),
and Pocheon-gun (343), Gyeonggi-do (Province), and examined for intestinal helminths, including Neodiplostomum
seoulense, seasonally from December 2004 to September 2005. Six species of rodents, including Apodemus agrarius
(1,366), Mus musculus (32), Micronytus fortis (28), Eothenomys regulus (9), Micronys minutus (6), and Cricetulus tri-
ton (3), and 1 species of insectivores Crocidura lasiura (54) were collected. A total of 321 adult N. seoulense were
collected from 19 (1.4%) A. agrarius. The worm burden ranged from 1 to 101 per A. agrarius (mean; 16.9). No N.
seoulense was observed in other rodent or insectivore species examined. The infection rate during autumn (4.5%)
was higher than those during spring (0.8%), summer (0.8%), and winter (0.5%). The average number of N. seoulense
in infected A. agrarius was the highest in spring (66.0 specimens), followed by autumn (15.2), winter (4.5), and sum-
mer (3.3). This study first confirms that A. agrarius is a natural definitive host for N. seoulense, and demonstrates that
the infection rates and intensities vary seasonally and geographically.
Key words: Neodiplostomum seoulense, wild rodent, Apodemus agrarius, prevalence, worm burden, Gyeonggi-do
Korean Journal of Parasitology
Vol. 45, No. 2: 157-161, June 2007
�Received 23 January 2007, accepted after revision 16
�Funding for portions of this work was provided by the
U.S. Department of Defense, Global Emerging Infections
Surveillance and Response System, Silver Spring, Maryland,
and the Armed Forces Medical Intelligence Center, Ft.
Detrick, Maryland, USA.
*Corresponding author (e-mail: firstname.lastname@example.org)