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

We investigated the persistence of viable Orientia tsutsugamushi in patients who had recovered from scrub typhus. Blood specimens were available from six patients with scrub typhus who were at 1 to 18 months after the onset of the illness. The EDTA-treated blood specimens were inoculated into ECV304 cells, and cultures were maintained for 7 months. Sequencing of the 56-kDa type-specific antigen gene of O. tsutsugamushi was performed to ascertain the homology of isolates. O. tsutsugamushi was isolated from all six patients, and nucleotide sequences of isolates serially collected from each patient were identical in all five patients in whom nucleotide sequences were compared. One patient relapsed 2 days after completion of antibiotic therapy; two patients complained of weakness for 1 to 2.5 months after the illness; one patient underwent coronary angioplasty 6 months later; and one patient suffered from a transient ischemic attack 8 months later. This finding suggests that O. tsutsugamushi causes chronic latent infection, which may be associated with certain clinical illnesses, preceded by scrub typhus. Antibiotic therapy abates the symptoms of scrub typhus, but does not eradicate O. tsutsugamushi from the human body.
Adult ; Aged ; Aged, 80 and over ; Antigens, Bacterial/genetics ; Bacterial Proteins/genetics ; Base Sequence ; Case-Control Studies ; Chronic Disease ; Coronary Artery Disease/etiology ; DNA, Bacterial/genetics/isolation & purification ; Female ; Genes, Bacterial ; Humans ; Ischemic Attack, Transient/etiology ; Male ; Membrane Proteins/genetics ; Middle Aged ; Muscle Weakness/etiology ; Orientia tsutsugamushi/genetics/immunology/*isolation & purification ; Recurrence ; Scrub Typhus/complications/drug therapy/*microbiology ; Time Factors

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

No abstract available.
Anti-Bacterial Agents/therapeutic use ; Doxycycline/therapeutic use ; Face ; Humans ; Male ; Middle Aged ; Orientia tsutsugamushi/isolation & purification ; Scrub Typhus/drug therapy/microbiology/*pathology ; Skin/drug effects/*pathology ; Treatment Outcome

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

A survey to determine the geographical distribution and relative abundance of potential vectors of scrub typhus was conducted from October to November 2006 at 13 localities throughout the Republic of Korea. Apodemus agrarius accounted for 97.6% (80/82) of all rodents, while only 2 Myodes regulus (2/82) were collected. A total of 10,860 chiggers were collected from A. agrarius belonging to 4 genera and 8 species, while only Walchia fragilis (40) was collected from Myodes regulus. Leptotrombidium pallidum (8,137; 74.9%), a vector of scrub typhus, was the predominant species collected from A. agrarius followed by Leptotrombidium scutellare (2,057, 18.9%), Leptotrombidium palpale (279; 2.7%), Leptotrombidium orientale (232; 2.1%), and Leptotrombidium zetum (79; 0.7%), Neotrombicula tamiyai (58; 0.5%), Euschoengastica koreaensis (16; 0.1%), and Cheladonta ikaoensis (2; < 0.1%). L. pallidum was the predominant chigger collected at collection sites in Gangwon (100%), Gyeonggi (87.2%), Chungnam (100%), Chungbuk (100%), Jeonbuk (73.9%), Jeonnam (77.0%), and Gyeongbuk (66.1%) provinces, whereas L. scutellare was the predominant chigger collected in Gyeongnam province (77.9%) and Jeju Island (62.3%). Data suggest a correlation between chigger population abundance and human cases of scrub typhus in Korea.
Animals ; Arvicolinae/*parasitology ; *Disease Vectors ; Geography ; Mites/*microbiology ; Murinae/*parasitology ; Orientia tsutsugamushi/*isolation & purification ; Republic of Korea ; Scrub Typhus/transmission

OBJECTIVEScrub typhus is an infectious disease due to Orientia tsutsugamushi transmitted by infected chigger mites. Scrub typhus has long been recognized to occur in southern areas of China, but has recently been increasingly often reported from the north since the first case was reported in Mengyin County, Shandong Province in 1986. The key objectives of the present study were to investigate the clinical manifestations and epidemic factors of scrub typhus in children from the northern new natural foci.

METHODSThe case records of 56 children with scrub typhus who were admitted to the 5 hospitals of Fei County from September 1993 to January 2004 were reviewed. Orientia tsutsugamushi (Ot) was isolated from the cases. Based on ecological observations on the composition, seasonal fluctuation of animal hosts and chigger mites, Ot was isolated from rodents and chiggers. IgG antibodies to Ot was detected by IFA. Genotypes of the Ot isolates were also identified by nested PCR.

RESULTSAmong 56 children scrub typhus cases, 46 were male, 10 were female; 96% exhibited typical eschars or ulcers, 100% cases had high fever, skin rashes were observed in 55 cases (98%), and regional lymphadenopathy occurred in 48 cases (86%). All cases came from countryside, and all had histories of exposure to the crop field. fifty-one serum samples of suspected patients with scrub typhus were collected, 48 were positive for antibodies to Ot. The serotypes were Gilliam types. The cases only appeared in September to December with the peak at mid and late October. Leptotrombidium (L.) scutellare was the most important vector causing scrub typhus in the foci. Apodemus (A.) agrarius was the main host animals of Ot in the crop field. Totally 26 strains were isolated from patients, rodents, and chigger mites. The serotypes of 24 out of the 26 isolates were Gilliam types, while the genotypes of these isolates were Kawasaki types. The serotypes of the other 2 isolates were identical and both were Karp types.

CONCLUSIONChildren scrub typhus patients were frequently seen in the new natural foci of Shandong province. Exposure history, typical eschars or ulcers, and presence of IgG antibody were the important indexes to diagnose the disease.

Adolescent ; Animals ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Mice ; parasitology ; Orientia tsutsugamushi ; isolation & purification ; Scrub Typhus ; epidemiology ; Seasons ; Trombiculidae ; 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

OBJECTIVETo investigate whether HV and Ot can coexist in their host (Leptotrombidium scutellare).

METHODSCollecting the separate Leptotrombidium scutellare and the ones from mice in epidemic area. The cells of mites at larva, nymph, and adult stages were cultured and made into smear. In situ RT-PCR and PCR were used to detect and locate HV RNA and Ot DNA in the primary cultured cells.

RESULTSPositive signals of HV RNA and Ot DNA distributed mostly in epithelial cells of digestive system and ovary cells of larva and nymph. The positive rate increased by the generation of passages.

CONCLUSIONCoinfection of HV and Ot did exist in wild Leptotrombidium scutellare.

Animals ; Cells, Cultured ; DNA, Bacterial ; analysis ; Female ; Hantavirus ; isolation & purification ; Mice ; Mites ; microbiology ; virology ; Orientia tsutsugamushi ; isolation & purification ; RNA, Viral ; analysis ; Reverse Transcriptase Polymerase Chain Reaction