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.
Animals ; Arachnid Vectors ; Larva/*microbiology ; Orientia tsutsugamushi/*isolation & purification ; Republic of Korea ; Rodentia ; Scrub Typhus/*microbiology ; Trombiculidae/*classification/*microbiology

Comprehensive quarterly serosurveillance on scrub typhus in small mammals collected from military training sites located near the Demilitarized Zone (DMZ), northern Gyeonggi-do (Province), ROK was conducted to determine the potential rodent-borne and associated ectoparasite disease risks to military personnel. A total of 1,196 rodents and insectivores representing 8 species, Apodemus agrarius (87.3%, n = 1,044), Mus musculus (5.4%, n = 65), Crocidura lasiura (3.3%, n = 40), Microtus fortis (2.6%, n = 31), Micromys minutus (0.3%, n = 4), Tscherskia triton (0.3%, n = 4), Rattus norvegicus (0.3%, n = 4), and Myodes regulus (0.3%, n = 4) were assayed for the presence of antibodies to Orientia tsutsugamushi. O. tsutsugamushi antibodies were detected in 6 of 8 species and seroprevalence determined; A. agrarius (45.6%), M. musculus (23.1%), M. fortis (48.4%), M. minutus (50.0%), T. triton (50.0%), and R. norvegicus (25.0%). A total of 31,184 chigger mites collected from 508 rodents and insectivores were slide-mounted and 10 species belonging to 4 genera were identified. Leptotrombidium pallidum (53.4%) was the most frequently collected, followed by L. palpale (15.7%), Neotrombicula tamiyai (14.3%), L. orientale (10.7%), L. zetum (3.1%), Walchia fragilis (2.1%), and L. gemiticulum (0.8%), while the remaining 3 species, L. subintermedium, N. gardellai, and Euschoengastia koreaensis were rarely observed (prevalence < 10%). In contrast to previous surveys, higher chigger indices of the primary scrub typhus vectors, L. pallidum (165.4), L. orientale (45.0), and L. palpale (21.4), were observed during the spring season.
Animals ; Antibodies, Bacterial/immunology ; Arachnid Vectors/classification/*microbiology ; Disease Reservoirs/classification/microbiology/*parasitology ; Humans ; Military Facilities ; Orientia tsutsugamushi/*immunology/isolation & purification ; Republic of Korea ; Rodentia/classification/*immunology/microbiology/*parasitology ; Scrub Typhus/microbiology/*transmission/*veterinary ; Seroepidemiologic Studies ; Trombiculidae/classification/*microbiology

OBJECTIVETo understand the epidemic status of Rickettsia in Xinyang areas of Henan province.

METHODSSamples including liver, spleen, kidney from mouse and chigger mites from Xinyang areas and serum samples were detected by nested-polymerase chain reaction (PCR) and indirect immunofluorescence assay (IFA).

RESULTSIn 62 viscus samples from mice organs, the positive rates were 16.13%, 8.06% and 6.45% for Orientia tsutsugamushi, R. typhii and Spotted fever group rickettsiae respectively. In blood clots samples from mice, the positive rates were 8.06%, 6.45% and 1.61 % for O. tsutsugamushi, R. typhii and Spotted fever group rickettsiae respectively. Three out of 26 mouse serum samples were positive for the predicted fluorexcent intensity O. tsutsugamushi.

CONCLUSIONUsing nested-PCR and IFA methods, O. tsutsugamushi, R. typhii and Spotted fever group rickettsiae were detected in the captured mice living in Xinyang areas of Henan province. Results showed that there were intensive natural reserviors of Rickettsia in Henan province, suggesting that the risk of outbreak of Rickettsia in these areas was high.

Animals ; China ; Fluorescent Antibody Technique, Indirect ; Humans ; Kidney ; microbiology ; Liver ; microbiology ; Mice ; Orientia tsutsugamushi ; classification ; genetics ; isolation & purification ; pathogenicity ; Phylogeny ; Polymerase Chain Reaction ; Rickettsia ; classification ; genetics ; isolation & purification ; pathogenicity ; Scrub Typhus ; epidemiology ; microbiology ; Spleen ; microbiology

There are several antigenic variants of Orientia tsutsugamushi. The 56-kDa type-specific antigen (TSA) is responsible for the antigenic variation. Nucleotide sequences of the 56-kDa TSA obtained from 44 eschar samples of Korean scrub typhus patients and from 40 representative strains retrieved from the GenBank database were analyzed phylogenetically. Clinical patient data were assessed based on the genotyping results. Of the 44 nucleotide sequences, 32 (72.7%) clustered with the Boryong genotype, which is the major genotype in Korea. Eleven nucleotide sequences (25%) clustered with the Kawasaki genotype, not identified in Korea until 2010. One nucleotide sequence was consistent with the Karp genotype. The clinical course of the patients infected with each genotype showed no differences. Diagnostic performance of the immunofluorescence assay (IFA) using the 56-kDa TSA from Gilliam, Karp and Boryong as test antigens were not different for the Boryong and Kawasaki genotypes. Although Boryong is still the predominant genotype, the results suggest that Kawasaki genotype is quite prevalent in Chungbuk province of Korea.
Aged ; Bacterial Proteins/*genetics/metabolism ; Base Sequence ; DNA, Bacterial/analysis ; Databases, Genetic ; Female ; Genotype ; Humans ; Male ; Middle Aged ; Open Reading Frames ; Orientia tsutsugamushi/*classification/isolation & purification ; Phylogeny ; Republic of Korea ; Scrub Typhus/diagnosis/metabolism/*microbiology ; Sequence Analysis, DNA

There are several antigenic variants of Orientia tsutsugamushi. The 56-kDa type-specific antigen (TSA) is responsible for the antigenic variation. Nucleotide sequences of the 56-kDa TSA obtained from 44 eschar samples of Korean scrub typhus patients and from 40 representative strains retrieved from the GenBank database were analyzed phylogenetically. Clinical patient data were assessed based on the genotyping results. Of the 44 nucleotide sequences, 32 (72.7%) clustered with the Boryong genotype, which is the major genotype in Korea. Eleven nucleotide sequences (25%) clustered with the Kawasaki genotype, not identified in Korea until 2010. One nucleotide sequence was consistent with the Karp genotype. The clinical course of the patients infected with each genotype showed no differences. Diagnostic performance of the immunofluorescence assay (IFA) using the 56-kDa TSA from Gilliam, Karp and Boryong as test antigens were not different for the Boryong and Kawasaki genotypes. Although Boryong is still the predominant genotype, the results suggest that Kawasaki genotype is quite prevalent in Chungbuk province of Korea.
Aged ; Bacterial Proteins/*genetics/metabolism ; Base Sequence ; DNA, Bacterial/analysis ; Databases, Genetic ; Female ; Genotype ; Humans ; Male ; Middle Aged ; Open Reading Frames ; Orientia tsutsugamushi/*classification/isolation & purification ; Phylogeny ; Republic of Korea ; Scrub Typhus/diagnosis/metabolism/*microbiology ; Sequence Analysis, DNA

OBJECTIVETo analyze the genetic differences of Orientia tsutsugamushi (Ot) Sta56 gene between Shandong isolates and other strains deposited in GenBank.

METHODSPCR and restriction fragment length polymorphism (RFLP) were used to amplify the complete sequence of Ot-Sta56 gene. RFLP profiles of Ot were predicted by a computer program according to their complete sequences of Ot-Sta56 gene. PCR amplicon from XDM2 strain was sequenced and analyzed by Clustal X (1.8) and PHYLIP software.

RESULTSThe complete sequences (about 1.6 kbp) of Ot-Sta56 gene were amplified from B16 strain (isolated from patients), FXS2 strain (isolated from A. agrarius) and XDM2 strain. Four species of restriction endonucleases (Hha I, Hinf I, Hae III, Pst I) were used to digest the PCR amplicons from the 3 isolates. When comparing with the RFLP profiles of prototype Ot, the RFLP profiles of PCR amplicons from the 3 isolates were similar to those of Japan Kawasaki strain, but were quite different from the international reference strains Gilliam, Karp, Kato. Results from DNA sequence analysis showed that the complete sequence of Ot-Sta56 gene homology to Japan Kawasaki strain of XDM2 strain was 97%, and deduced amino acid sequence was 92%.

CONCLUSIONData from the complete sequence of Sta56 gene indicated that the genotypes of Ot isolates in Shandong province were similar, but with distinction from the Kawasaki strain.

Amplified Fragment Length Polymorphism Analysis ; Antigens, Bacterial ; genetics ; Bacterial Proteins ; genetics ; Bacterial Typing Techniques ; classification ; DNA, Bacterial ; genetics ; Genes, Bacterial ; Membrane Proteins ; genetics ; Orientia tsutsugamushi ; genetics ; isolation & purification ; Polymorphism, Restriction Fragment Length ; Sequence Analysis, DNA