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

No abstract available.
Aged ; Early Diagnosis ; Female ; Humans ; *Immunochromatography ; Male ; Middle Aged ; Orientia tsutsugamushi/*immunology ; Predictive Value of Tests ; Prognosis ; Republic of Korea/epidemiology ; Scrub Typhus/*diagnosis/epidemiology/immunology

Diagnosis of scrub typhus is difficult because its symptoms are very similar to other acute febrile illnesses, such as leptospirosis, murine typhus, and other viral hemorrhagic fevers. To differentiate scrub typhus from other acute febrile diseases, a rapid and reliable serological diagnosis is important. We have developed a chimeric recombinant antigen cr56 and two other recombinant antigens, r21 and kr56, from various serotypes of Orientia tsutsugamushi. They were tested for the detection of antibodies against O. tsutsugamushi in the patient's serum samples using enzyme-linked immunosorbent assay (ELISA) and dot-blot analyses. As of conventional immunofluorescence assay (IFA), when the mixture of these three recombinant antigens was used, both sensitivity and specificity of the recombinant antigens were increased up to 98% in IgM and IgG at ELISA and dot blotting. Additionally, both sensitivity and specificity by detection of IgM and IgG antibodies at rapid diagnostic test (RDT), using the mixture of three antigens and gold conjugated antibodies, were 99%. Our results suggest the use of mixture of these recombinant antigen proteins in ELISA or RDT is suitable as a diagnostic test for scrub typhus.
Antibodies, Bacterial/blood/chemistry/immunology ; Antigens, Bacterial/diagnostic use/genetics/metabolism ; Enzyme-Linked Immunosorbent Assay ; Fluorescent Antibody Technique, Indirect ; Gold/chemistry ; Humans ; Immunoassay ; Immunoglobulin G/blood ; Immunoglobulin M/blood ; Orientia tsutsugamushi/immunology/*metabolism ; Recombinant Proteins/biosynthesis/diagnostic use/genetics ; Scrub Typhus/*diagnosis ; Sensitivity and Specificity ; Serotyping

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

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

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

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

BACKGROUND: Korea is an endemic area of scrub typhus and it is a common seasonal febrile illness. Although, various humoral immune responses to scrub typhus have been documented, no association between gammopathy and scrub typhus has ever been reported. We analyzed the incidences and types of monoclonal and biclonal gammopathies in scrub typhus for better coping with those gammopathies in scrub typhus. METHODS: Anti-Orientia tsutsugamushi antibody-positive sera identified by indirect immunofluorescence assay were acquired from 40 patients with confirmed scrub typhus. Monoclonal and biclonal gammopathies were screened by protein electrophoresis and were confirmed using immunofixation electrophoresis (IFE). Laboratory findings on admission of the patients with monoclonal or biclonal gammopathy were investigated retrospectively to characterize the gammopathies. RESULTS: Monoclonal or biclonal gammopathies were detected in 30% (12/40) of patients with scrub typhus (IgG-lambda, 40%; IgG-kappa, 30%; IgM-kappa, 10%; IgM-lambda, 10%; IgA-kappa, 5%; IgA-lambda, 5%). Concentrations of clonal immunoglobulin were less than 3 g/dL in all gammopathies, and hypercalcemia was not detected in any of the patients. CONCLUSIONS: Our results suggest possible association between gammopathies and scrub typhus. Further studies in larger series will be needed for exact incidence and clinical course of gammopathies in scrub typhus.
Adult ; Aged ; Humans ; Immunoglobulin A/blood ; Immunoglobulin G/blood ; Immunoglobulin Heavy Chains/blood ; Immunoglobulin Light Chains/blood ; Immunoglobulin M/blood ; Incidence ; Middle Aged ; Orientia tsutsugamushi/immunology ; Paraproteinemias/complications/*diagnosis/epidemiology/immunology ; Retrospective Studies ; Scrub Typhus/complications/*diagnosis/immunology

BACKGROUNDHuman rickettsioses are worldwide zoonoses and it is not easy to differentiate them from other infectious diseases because of their atypical manifestation. In recent years the number of patients with fever of unknown causes from Hongta District CDC, Yuxi city of Yunnan Province has been increasing significantly in the summer. Diagnosis of scrub typhus was made by local clinicians. In order to ascertain the disease, we undertook a laboratory investigation for such patients from August 18 to 26, 2005.

METHODSActive surveillance was conducted by Hongta District CDC Yuxi city of Yunnan Province from 2002 to 2004 and basic data were obtained from cases confirmed according to clinical definitions. Average incidences and town-level incidences were calculated during the study periods. Blood samples were analyzed by PCR and serological test. Based on the groEL gene sequences a paired general outer primers (Gro-1 and Gro-2) targeting typhus, spotted fever as well as scrub typhus and two paired inner primers (SF1, SR2 and TF1, TR2) for typhus together with spotted fever and scrub typhus, respectively, were designed to perform a multiplex-nested PCR. Serological assay was carried out by indirect immunofluorescence assay with 7 different rickettsial antigens, i.e., R.mossori, R.sibirica, R.conorii, O.tsutsugamushi, B.quintana, B.henselae and Coxilella burnetii phase II Ag.

RESULTSEpidemiological surveillance showed that from 2002 to 2004, the average incidences of the scrub typhus or scrub typhus with murine typhus were 222.1/10(5), 204.3/10(5) and 109.6/10(5), respectively. Of 13 blood samples taken during acute stage of illness, 6 showed the amplified products for scrub typhus and the sequenced products showed 100%, 99%, 99%, 99%, 99%, 99% similarity to O.tsutsugamushi Karp but they shared the same deduced amino acid sequences, which indicated 100% identity with the heat shock protein of the O.tsutsugamushi Karp strain. Five yielded PCR products for murine typhus and their corresponding nucleotide sequences exhibited 100%, 100%, 99%, 99% and 99% similarity to R. mossori Wilmington and the analyses of predicted amino acid sequences indicated 100%, 100%, 98%, 98% and 98% identity with the heat shock protein of R. mossori Wilmington strain. Of the 8 PCR positive patients, 3 showed a co-infection of scrub typhus with murine typhus. All the 13 serum samples from febrile patients were positive against O. tsutsugamushi and 8 of them were positive against R. mossori. All of the 8 paired specimens had four-fold elevation of antibody against O. tsutsugamushi, and seroconversion for typhus was demonstrated in 3 paired serum samples. Another finding in the study was that a high seropositive prevalence (76.9%) of Q fever was detected.

CONCLUSIONIt's confirmed that co-prevalence of scrub typhus with murine typhus are occurring in Yuxi city of Yunnan province, China. Other rickettsial diseases also need to be investigated in these areas.

Adolescent ; Adult ; Aged ; Antibodies, Bacterial ; blood ; China ; epidemiology ; Female ; Humans ; Male ; Middle Aged ; Orientia tsutsugamushi ; genetics ; immunology ; Polymerase Chain Reaction ; Prevalence ; Scrub Typhus ; diagnosis ; epidemiology ; Typhus, Endemic Flea-Borne ; diagnosis ; epidemiology