Diagnosis of scrub typhus is challenging due to its more than twenty serotypes and the similar clinical symptoms with other acute febrile illnesses including leptospirosis, murine typhus and hemorrhagic fever with renal syndrome. Accuracy and rapidity of a diagnostic test to Orientia tsutsugamushi is an important step to diagnose this disease. To discriminate scrub typhus from other diseases, the improved ImmuneMed Scrub Typhus Rapid Diagnostic Test (RDT) was evaluated in Korea and Sri Lanka. The sensitivity at the base of each IgM and IgG indirect immunofluorescent assay (IFA) in Korean patients was 98.6% and 97.1%, and the specificity was 98.2% and 97.7% respectively. The sensitivity and specificity for retrospective diagnosis at the base of IFA in Sri Lanka was 92.1% and 96.1%. ImmuneMed RDT was not reactive to any serum from seventeen diseases including hemorrhagic fever with renal syndrome (n = 48), leptospirosis (n = 23), and murine typhus (n = 48). ImmuneMed RDT shows superior sensitivity (98.6% and 97.1%) compared with SD Bioline RDT (84.4% at IgM and 83.3% at IgG) in Korea. The retrospective diagnosis of ImmuneMed RDT exhibits 94.0% identity with enzyme-linked Immunosorbent assay (ELISA) using South India patient serum samples. These results suggest that this RDT can replace other diagnostic tests and is applicable for global diagnosis of scrub typhus. This rapid and accurate diagnosis will be beneficial for diagnosing and managing scrub typhus.
Antibodies, Bacterial/blood ; Enzyme-Linked Immunosorbent Assay ; Fluorescent Antibody Technique, Indirect ; Humans ; Immunoglobulin G/blood ; Immunoglobulin M/blood ; Orientia tsutsugamushi/immunology ; Reagent Kits, Diagnostic ; Retrospective Studies ; Scrub Typhus/*diagnosis/microbiology ; Sensitivity and Specificity

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

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

Nephrotic syndrome associated with Tsutsugamushi disease has not been previously reported. We are describing a case of Tsutsugamuchi disease presenting with nephrotic syndrome. A 72-year-old woman presented with fever and generalized edema. Laboratory studies revealed a leukocytosis, hypoalbuminemia, and hypercholesterolemia. Her urine protein excretion was 5.4 g/day. The anti-Tsutsugamushi antibody test was strongly positive (1:2,560). A renal biopsy was performed, and pathologic findings revealed membranous glomerulonephritis. The patient's clinical symptoms improved markedly after treatment with doxycycline.
Aged ; Anti-Bacterial Agents/therapeutic use ; Antibodies, Bacterial/blood ; Biopsy ; Doxycycline/therapeutic use ; Female ; Glomerulonephritis, Membranous/diagnosis/*etiology ; Humans ; Nephrotic Syndrome/diagnosis/*etiology ; Orientia tsutsugamushi/immunology ; Scrub Typhus/*complications/diagnosis/drug therapy/microbiology ; Treatment Outcome

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

Monthly surveys were conducted to investigate the occurrence of chigger mites and seroprevalence of scrub typhus among small mammals in Jeollanam-do, the southwestern part of Korea, from November 2006 through October 2007. Fifty-eight small mammals, including 57 Apodemus agrarius (98.3%) and 1 Crocidura lasiura (1.7%), were captured, and a total of 4,675 chigger mites representing 4 genera and 8 species were collected from them. The chigger infestation rate among small mammals was 69.0%. The most predominant species in A. agrarius was Leptotrombidium scutellare (54.0%), followed by Leptotrombidium pallidum (39.4%), Leptotrombidium orientale (4.4%), Leptotrombidium palpale (1.1%), Neotrombicula tamiyai (0.6%), Eushoengastia koreaensis (0.3%), Neotrombicula gardellai (0.3%), and Cheladonta ikaoensis (<0.1%). The chigger index of A. agrarius was the highest in October (740.0), followed by November (242.0), September (134.6), March (98.3), February (38.2), January (35.3), December (34.5), April (30.8), and May (1.7). The average antibody positive rate of scrub typhus in wild rodents was 50.0%. The seropositive rates were high in October (100.0%) and November (83.3%), whereas those in other months were relatively low (28.6-57.1%). The chigger index of L. scutellare rapidly increased in September to form an acuminate peak in October, followed by a gradual decline. These results suggest that the outbreak of scrub typhus in the southwestern part of Korean peninsula is mostly due to L. scutellare.
Animals ; Antibodies, Bacterial/blood ; Antibody Specificity ; Arachnid Vectors/*microbiology ; *Disease Reservoirs ; Humans ; Murinae/parasitology ; Orientia tsutsugamushi/*immunology ; Population Dynamics ; Public Health Surveillance ; Republic of Korea/epidemiology ; Rodent Diseases/parasitology/transmission ; Scrub Typhus/epidemiology/*transmission ; Seasons ; Seroepidemiologic Studies ; Shrews/parasitology ; Species Specificity ; Trombiculiasis/parasitology/veterinary ; Trombiculidae/*microbiology

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

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