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

OBJECTIVETo investigate rodents' natural infection of Orientia tsutsugamushi (Ot) in some areas of Inner Mongolia and Xinjiang, China.

METHODSDNAs were extracted from spleens of the captured mice and nested-polymerase chain reaction (nPCR) technique was used to detect the Ot-Sta56 gene. Six positive samples were sequenced and analyzed by Clustal X (5.0) and DNA Club software.

RESULTSA total of 90 rodents were captured in Inner Mongolia, and the overall prevalence of Ot was 6.67%. There was no significant difference in infection rates among the positive rodents species. 20 rodents were captured in Xinjiang, and the prevalence of Ot was 5.00%. The geographical difference in infection rates was not statistically significant between Inner Mongolia and Xinjiang. 9 rodents were captured in farmlands of Inner Mongolia and Xinjiang but there was no positive samples found. 101 rodents were captured in grasslands, and the prevalence of Ot was 6.93%. The Sta56 gene nucleotide sequence homology to Karp strain of N59 (from Microtus maximowiczii), N69 (from Cricetulus barabensis) and X33(from Cricetus cricetus) was 99%. The sequence homology to Taitung-2 strain and TW461 strain of N65 (from C. barabensis) was 94%, and the sequence homology to Taitung-2 strain and TW461 strain of N88(from Apodemus agrarius) was also 94%. The sequence homology to Oishi strain of N90 (from A. agrarius) was 96.00%.

CONCLUSIONOur findings indicated that infections of Ot did exist in rodents captured from Inner Mongolia and Xinjiang. The genotypes of Ot in Inner Mongolia and Xinjiang were quite complex, with some of them belonged to Karp type, and the others belonged to Taitung-2, TW461 and Oishi types which providing evidence for further investigation on the scrub typhus fuci in the two areas.

Animals ; China ; Geography ; Orientia tsutsugamushi ; genetics ; isolation & purification ; Polymerase Chain Reaction ; Rodentia ; microbiology ; Scrub Typhus

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

BACKGROUND/AIMS: Orientia -tsutsugamushi infection is an acute febrile disease due to the accidental transmission through human skin of forest dwelling vector Leptotrombidium larva. The authors observed liver dysfunctions in patients diagnosed with tsutsugamushi disease (Scrub typhus) in the past 3 years and report the data in the hope of bringing attention to this disease in the differential diagnosis of autumn-season hepatitis, especially of non-A, non-B and non-C hepatitis. METHODS: Medical records of 22 patients diagnosed with tsutsugamushi disease by the hemagglutinin method between October 2000 and November 2002 were reviewed. RESULTS: Female gender was dominant in the ratio of 3.4:1. Mean age was 56.4 +/- 2.6. Admission was between 23rd September and 15th November with the peak between mid October and early November. Fever, being the most common symptom, was observed in 21 cases, myalgia in 13, arthralgia in 12, chills in 6, and skin rash in 6. An incubation period of 7-9 days was most common (10 cases), 13-15 days (4), 10-12 days (3), within 3 days (3), and 4-6 days (2). Average ALT, AST and GGTP were increased to 93.2 +/- 17.3 IU/L (18 +/- 345 IU/L), 92.5 +/- 11.7 IU/L (34-255 IU/L) and 132.2 +/- 14.5 IU/L (19-251 IU/L), respectively, but total bilirubin was normal. All the patients improved with doxycycline therapy. CONCLUSIONS: Since it usually shows liver dysfunction, it is important to take Orientia tsutsugamushi into consideration in differential diagnosis of autumn-season, febrile hepatic disease.
Adult ; Aged ; Diagnosis, Differential ; *Disease Outbreaks ; Hepatitis/*diagnosis/microbiology ; Humans ; Korea/epidemiology ; Male ; Middle Aged ; Scrub Typhus/complications/*diagnosis/epidemiology

No abstract available.
Animal ; Antibodies, Bacterial/blood ; Antigens, Bacterial/blood ; Human ; Mites/microbiology ; Orientia tsutsugamushi/classification/immunology ; Scrub Typhus/diagnosis/*epidemiology/immunology

OBJECTIVETo study the increasing incidence and the characteristics of Tsutsugamushi disease in the areas of Nan Peng Lie islands, Nan Ao island, Wan Shan archipelago, Nao Zhou island and Lei Zhou peninsula, located in the southern part of China and to develop strategies for preventive measures.

METHODSBoth epidemiological investigation, isolation and gene identification of Orientia tsutsugamushi, as well as pilot preventive measures were carried out.

RESULTSThese islands belonged to the epidemic area of south subtropical zone of Tsutsugamushi disease. The main host was Rattus norvegicu and the overall rates of infection on Orientia tsutsugamushi were 22.78%-33.75%. The main biological vector was Leptotrombidium (Leptotrombidium) deliens and the rates of infection on Orientia tsutsugamushi were 40.00%-75.00%. 25 strains of Orientia tsutsugamushi had been isolated from Rattus norvegicu and Leptotrombidium (Leptotrombidium) deliens. Results showed that the isolated strains of Orientia tsutsugamushi were 15 Karp, 8 Kato, 2 Yonchon. Results from serological studies showed that the positive rate of anti-Orientia tsutsugamushi antibodies was high, in both residents and soldiers stationed in these islands. On these islands, rats and biological vectors were killed. Results showed that these measures had positive impact in reducing the incidence.

CONCLUSIONIslands from the southern part of the country belonged to the epidemic area of Tsutsugamushi disease. People visiting this areas should be under protection.

Animals ; Antibodies, Bacterial ; blood ; Bacterial Typing Techniques ; China ; epidemiology ; Disease Outbreaks ; Disease Reservoirs ; microbiology ; Geography ; Humans ; Incidence ; Orientia tsutsugamushi ; genetics ; isolation & purification ; Rats ; Scrub Typhus ; epidemiology ; Trombiculidae ; 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

Orientia tsutsugamushi, a causative pathogen of Scrub typhus, is a gram-negative intracellular bacterium. Outer membrane vesicles (OMVs) are produced from the membrane of bacteria and play many roles related to the survival of the pathogen. However, there have been no reports confirming whether O. tsutsugamushi indeed produce OMVs. O. tsutsugamushi boryong was cultured in ECV-304 cells for the purification of OMVs. Western blot analysis and immunoenrichment using anti-O. tsutsugamushi monoclonal antibody and electron microscopy were employed for identification and characterization of OMVs. We confirm the presence of OMVs derived from O. tsutsugamushi, and also found that those OMVs contain a major surface antigen of 56-kDa protein and variant immunogenic antigens.
Antibodies, Monoclonal/*immunology ; Antigens, Bacterial/*immunology ; Antigens, Surface/*immunology ; Cell Line ; Cell Membrane/immunology ; Humans ; Microscopy, Electron ; Orientia tsutsugamushi/*immunology/metabolism ; Scrub Typhus/diagnosis/microbiology ; Secretory Vesicles/*immunology

PURPOSE: Previous studies and our own clinical experience suggest that concurrent corticosteroid treatment for severe rickettsial disease with multiorgan failure may improve the clinical course or reduce mortality. However, the use of corticosteroids as adjunctive treatment for rickettsial diseases is controversial. We attempted to determine the influences of corticosteroid on the growth of Orientia tsutsugamushi in vitro to justify and evaluate the clinical applicability of corticosteroid in rickettsial disease. MATERIALS AND METHODS: L929 cells were infected with Orientia tsutsugamushi Gilliam. Dexamethasone was added to the cells at final concentrations of 10(1) and 10(7) pg/mL. Cultures were incubated at 35degrees C and processed for flow cytometry on the 6th day after addition of dexamethasone. RESULTS: Observation on the 6th day after treatment with dexamethasone in infected cultures revealed that there was no difference in fluorescence intensity among the treatment wells. Treatment of the cells with dexamethasone at concentrations of 10(1) and 10(7) pg/mL showed no influence on the growth of Orientia tsutsugamushi. CONCLUSION: Our results to show that isolated corticosteroid does not enhance the replication of Orientia tsutsugamushi in vitro. Concurrent use of anti-inflammatory or immunosuppressive doses of corticosteroids in conjunction with antibiotics may not have detrimental effects on the course of scrub typhus.
Animals ; Cell Line ; Cell Proliferation/drug effects ; Dexamethasone/*pharmacology ; Flow Cytometry ; Interferon-gamma/pharmacology ; Mice ; Orientia tsutsugamushi/*drug effects/growth & development ; Scrub Typhus/drug therapy/microbiology