Tick-borne rickettsial pathogens in ticks and small mammals in Korea.
In order to investigate the prevalence of tick-borne infectious agents among ticks, ticks comprising five species from two genera (Hemaphysalis spp. and Ixodes spp.) were screened using molecular techniques. Ticks (3,135) were collected from small wild-caught mammals or by dragging/flagging in the Republic of Korea (ROK) and were pooled into a total of 1,638 samples (1 to 27 ticks per pool). From the 1,638 tick samples, species-specific fragments of Anaplasma phagocytophilum (1 sample), Anaplasma platys (52 samples), Ehrlichia chaffeensis (29 samples), Ehrlichia ewingii (2 samples), Ehrlichia canis (18 samples), and Rickettsia rickettsii (28 samples) were amplified by PCR assay. Twenty-one pooled and individual tick samples had mixed infections of two (15 samples) or three (6 samples) pathogens. In addition, 424 spleen samples from small captured mammals (389 rodents, 33 insectivores, and 2 weasels) were screened for selected zoonotic pathogens. Species-specific DNA fragments of A. phagocytophilum (110 samples), A. platys (68 samples), E. chaffeensis (8 samples), E. ewingii (26 samples), E. canis (51 samples), and Rickettsia sp. (22 samples) were amplified by PCR assay. One hundred thirty small mammals had single infections, while 4, 14, and 21 striped field mice (Apodemus agrarius) had mixed infections of four, three, and two pathogens, respectively. Phylogenetic analysis based on nucleotide sequence comparison also revealed that Korean strains of E. chaffeensis clustered closely with those from China and the United States, while the Rickettsia (rOmpA) sequences clustered within a clade together with a Chinese strain. These results suggest that these agents should be considered in differential diagnosis while examining cases of acute febrile illnesses in humans as well as animals in the ROK.
Kim
Chul-Min
CM
Bio-Safety Research Institute and College of Veterinary Medicine, Chonbuk National University, Jeonju 561-756, Korea.
Yi
Ying-Hua
YH
Yu
Do-Hyeon
DH
Lee
Mi-Jin
MJ
Cho
Mae-Rim
MR
Desai
Atul R
AR
Shringi
Smriti
S
Klein
Terry A
TA
Kim
Heung-Chul
HC
Song
Jin-Won
JW
Baek
Luck-Ju
LJ
Chong
Sung-Tae
ST
O'guinn
Monica L
ML
Lee
John S
JS
Lee
In-Yong
IY
Park
Jin-Ho
JH
Foley
Janet
J
Chae
Joon-Seok
JS
D000709:Anaplasma / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004536:Ehrlichia / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D006801:Humans; D018884:Ixodes / Q000382:microbiology; D007723:Korea; D008322:Mammals / Q000382:microbiology*; D051189:Murinae / Q000382:microbiology; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012281:Rickettsia / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D017282:Tick-Borne Diseases / Q000175:diagnosis / Q000382:microbiology; D013987:Ticks / Q000382:microbiology*
D017931:DNA Primers; D004269:DNA, Bacterial