Simultaneous detection of 7 important Rickettsiales pathogens by TaqMan-probe quantitative real-time PCR / 中华流行病学杂志

Objective: To establish and optimize a TaqMan-probe quantitative real-time PCR (qPCR) assay for the detection of 7 important Rickettsiales pathogens and simultaneous identification of the infection types. Methods: Based on the ompB gene of Rickettsia prowazekii, Rickettsia mooseri and spotted fever group rickettsiae, the groEL gene of Orientia tsutsugamushi, the 16S rRNA of Ehrlichia chaffeensis, the gltA gene of Anaplasma phagocytophilum and the com1 gene of Coxiella burnetii, we synthesized primers and TaqMan-probes and optimized the reaction system and reaction process to same solution. The sensitivity, specificity and reproducibility of this assay were evaluated and the assay was used for the detection of simulated and actual samples. Results: The Ct value of the standard curves of the 7 pathogens showed a good linear relationship with the number of DNA copies (all R2 >0.990 0), the minimum detection limit was 10 copies/μl, showing good specificity. In the 96 tick nucleic acid extracts, Coxiella burnetii was detected in 1 sampleand spotted fever group Rickettsiae was detected in 3 samples. In the 80 blood samples from patients with undefined febrile illness, Orientia tsutsugamushi was detected in 1 sample and spotted fever group rickettsiae was detected in 2 samples. Conclusions: In this study, based on the established TaqMan-probe qPCR assay, the reaction system and reaction condition of the 7 important pathogens of Rickettsiales were optimized to the same solution. This method overcomes the shortcomings of using different reaction systems and reaction conditions for different pathogens, which can precisely identify the species of 7 important pathogens of Rickettsiales in clinical sample detections and is important for the infection type identification and laboratory detection time reduction to facilitate precise treatment of the patients.

Annual Fluctuation in Chigger Mite Populations and Orientia Tsutsugamushi Infections in Scrub Typhus Endemic Regions of South Korea

OBJECTIVES: Chigger mites are vectors for scrub typhus. This study evaluated the annual fluctuations in chigger mite populations and Orientia tsutsugamushi infections in South Korea.METHODS: During 2006 and 2007, chigger mites were collected monthly from wild rodents in 4 scrub typhus endemic regions of South Korea. The chigger mites were classified based on morphological characteristics, and analyzed using nested PCR for the detection of Orientia tsutsugamushi.RESULTS: During the surveillance period, the overall trapping rate for wild rodents was 10.8%. In total, 17,457 chigger mites (representing 5 genera and 15 species) were collected, and the average chigger index (representing the number of chigger mites per rodent), was 31.7. The monthly chigger index was consistently high (> 30) in Spring (March to April) and Autumn (October to November). The mite species included Leptotrombidium pallidum (43.5%), L. orientale (18.9%), L. scutellare (18.1%), L. palpale (10.6%), and L. zetum (3.6%). L. scutellare and L. palpale populations, were relatively higher in Autumn. Monthly O. tsutsugamushi infection rates in wild rodents (average: 4.8%) and chigger mites (average: 0.7%) peaked in Spring and Autumn.CONCLUSION: The findings demonstrated a bimodal pattern of the incidence of O. tsutsugamushi infections. Higher infection rates were observed in both wild rodents and chigger mites, in Spring and Autumn. However, this did not reflect the unimodal incidence of scrub typhus in Autumn. Further studies are needed to identify factors, such as human behavior and harvesting in Autumn that may explain this discordance.

Survey of Rickettsia spp. and Orientia tsutsugamushi Pathogens Found in Animal Vectors (Ticks, Fleas, Chiggers) in Bangkaew District, Phatthalung Province, Thailand

Rickettsial infections (Rickettsioses) are the causes of acute fever found in Thailand. It is classified as acute febrile illnesses transmitted by bloodsucking arthropod vectors (tick, flea, and chigger). This research investigated pathogens of scrub typhus in vectors from Bangkaew District, Phatthalung Province. A total of 303 pools of vector samples were ticks (Rhipicephalus sanguineus, R. microplus, and Haemaphysalis sp.), fleas (Ctenocephalides felis orientis, C. f. felis, and C. canis), and chiggers (Leptotrombidium deliense, Aschoschoengastia indica, Blankaartia acuscutellaris and Walchia disparunguis pingue) collected from reservoir hosts (dogs and rodents). The 17 and 56 kDa gene of Rickettsia causing scrub typhus were found in 29% of ticks and 98% of flea. DNA sequence analysis reveeled the detected strains were R. asembonensis and Rickettsia sp. cf1 and 5.The chiggers, 1%, were infected with Rickettsia strain TA763, a pathogen of scrub typhus.

A Case of Scrub Typhus complicated with a Splenic Infarction

We present a patient with scrub typhus complicated with a splenic infarction. A 40-year-old man visited the emergency medical center complaining of fever for the previous week. He had no past medical history, but reported engaging in outdoor activities. Examination revealed a maculopapular rash on his trunk and an eschar on his epigastrium. Abdominal computed tomography was performed to examine the cause of the tenderness on the left upper quadrant of his abdomen, which revealed a splenic infarct. The patient was diagnosed with scrub typhus based on the results of blood polymerase chain reaction testing, and genetic sequencing confirmed the presence of Orientia tsutsugamushi Boryong. His symptoms improved following doxycycline treatment.

A Case of Scrub Typhus complicated with a Splenic Infarction

We present a patient with scrub typhus complicated with a splenic infarction. A 40-year-old man visited the emergency medical center complaining of fever for the previous week. He had no past medical history, but reported engaging in outdoor activities. Examination revealed a maculopapular rash on his trunk and an eschar on his epigastrium. Abdominal computed tomography was performed to examine the cause of the tenderness on the left upper quadrant of his abdomen, which revealed a splenic infarct. The patient was diagnosed with scrub typhus based on the results of blood polymerase chain reaction testing, and genetic sequencing confirmed the presence of Orientia tsutsugamushi Boryong. His symptoms improved following doxycycline treatment.

Tifus de los matorrales, una enfermedad emergente en Chile / Scrub typhus, an emerging infectious disease in Chile

Resumen El tifus de los matorrales, causado por Orientia tsutsugamushi y transmitido por larvas de ácaros trombicúlideos de roedores silvestres es una rickettsiosis endémica en el Asia Pacífico. Luego del primer caso identificado en Chile en el año 2006, nuestro grupo ha identificado más de 30 casos a partir del año 2015. Los casos se han presentado con un marcado predominio en meses de verano, y su presentación clínica incluye fiebre, exantema y una mancha negra en el sitio de inoculación. Otros hallazgos frecuentes han sido cefalea intensa, sudoración nocturna, aumento de PCR, VHS y transaminasas hepáticas. La gran mayoría de los pacientes se han diagnosticado en el sur de Chile (principalmente la isla de Chiloé), pero recientemente también se han presentado casos en la Región Metropolitana, en personas volviendo de viajes al sur de Chile. Los médicos clínicos deben estar informados de esta enfermedad emergente en el país, de modo de sospecharla e iniciar terapia empírica con doxiciclina. La confirmación de estos casos con los métodos diagnósticos disponibles en Chile contribuirá a una mejor comprensión del rango epidemiológico y la relevancia clínica de esta infección nueva en el país.

Scrub typhus, caused by Orientia tsutsugamushi and transmitted by larvae of trombiculid mites, is an endemic rickettsiosis in the Asia Pacific region. After the first identification of a case in Chile in 2006, more than 30 cases have been diagnosed by our group since 2015. Cases were detected predominantly during the Chilean summer months. Patients presented with fever, rash, and a typical eschar at the inoculation site; other frequent findings were intense headache, night sweats, increased laboratory markers of inflammation and transaminases. The vast majority of cases have been diagnosed in southern Chile (mainly Chiloé Island), although recently some cases were also identified in the central Metropolitan Region in patients returning from trips to southern Chile. Physicians attending Chilean patients should be aware of this emerging infection to be able to initiate empirical therapy with doxycycline. The confirmation of cases by the diagnostic methods available in Chile will contribute to a better understanding of the epidemiological and clinical relevance of this emerging infection in South America.

Survey and Phylogenetic Analysis of Rodents and Important Rodent-Borne Zoonotic Pathogens in Gedu, Bhutan

Rodents are well-known reservoirs and vectors of many emerging and re-emerging infectious diseases, but little is known about their role in zoonotic disease transmission in Bhutan. In this study, a cross-sectional investigation of zoonotic disease pathogens in rodents was performed in Chukha district, Bhutan, where a high incidence of scrub typhus and cases of acute undifferentiated febrile illness had been reported in people during the preceding 4–6 months. Twelve rodents were trapped alive using wire-mesh traps. Following euthanasia, liver and kidney tissues were removed and tested using PCR for Orientia tsutsugamushi and other bacterial and rickettsial pathogens causing bartonellosis, borreliosis, human monocytic ehrlichiosis, human granulocytic anaplasmosis, leptospirosis, and rickettsiosis. A phylogenetic analysis was performed on all rodent species captured and pathogens detected. Four out of the 12 rodents (33.3%) tested positive by PCR for zoonotic pathogens. Anaplasma phagocytophilum, Bartonella grahamii, and B. queenslandensis were identified for the first time in Bhutan. Leptospira interrogans was also detected for the first time from rodents in Bhutan. The findings demonstrate the presence of these zoonotic pathogens in rodents in Bhutan, which may pose a risk of disease transmission to humans.

Respuesta a la carta de Faccini et al / Reply to Faccini et al

Sr. Editor, Agradecemos los aportes en relación con nuestra publicación. El objetivo del artículo "Enfoque clínico del síndrome febril agudo en Colombia" fue el de considerar los posibles diagnósticos etiológicos que se enmarquen dentro de la definición de la duración de la fiebre en el tiempo, definiendo como aguda aquella que tiene una duración de hasta 7 días. Sin embargo, el cuadro de Chagas agudo incluye en su definición de caso probable "Fiebre continua o prolongada mayor de 7 días, acompañado o no de alguno de los siguientes síntomas. . .". Este criterio ha sido utilizado en los estudios de brotes referenciados en Colombia. Por esta razón, no fue incluido como parte de la revisión

Mr. Editor, We appreciate the contributions in relation to our publication. The aim of the article "Clinical approach to acute febrile syndrome in Colombia" was to consider the possible etiological diagnoses that fall within the definition of the duration of fever over time, defining as acute that which has a duration of up to 7 days. However, acute Chagas disease includes in its probable case definition "Continuous or prolonged fever greater than 7 days, accompanied or not by any of the following symptoms . . .". This criterion has been used in outbreak studies referenced in Colombia. For this reason, it was not included as part of the review.

Opsoclonus-Myoclonus Syndrome Associated with Scrub Typhus / 대한평형의학회지

Scrub typhus is an infective acute febrile disorder caused by the intracellular parasite Orientia tsutsugamushi. Neurological manifestations of scrub typhus are meningoencephalitis, cerebellitis, transverse myelitis, papilledema, and cranial nerve palsy. However, opsoclonus-myoclonus syndrome associated with scrub typhus has been rarely reported. A 59-year-old man developed vertigo, nausea, vomiting, and imbalance following scrub typhus infection for eight days. Examination showed eschar at the axilla, decreased mentality, and opsoclonus-myoclonus syndrome. Video-oculography disclosed opsoclonus with an amplitude of 15°–20° and a frequency of 6–8 Hz. The serum antibody titers to Orientia tsutsugamushi were 1:5,120, and cerebrospinal fluid analysis revealed pleocytosis. Brain magnetic resonance imaging was normal. Neurological symptoms and signs completely improved by systemic steroid and antibiotics treatment. Various mechanisms including direct disseminating inflammation or indirect immune modulation may give rise to neurological complications following scrub typhus.

Severe Scrub Typhus with Hemophagocytic Lymphohistiocytosis Occurring in Summer / 대한내과학회지

In Korea, scrub typhus usually occurs in October and November. Hemophagocytic lymphohistiocytosis (HLH) is a distinct clinical entity characterized by a high fever, pancytopenia, hepatosplenomegaly, histiocyte proliferation, and hemophagocytosis. We encountered a summertime case of severe scrub typhus presenting as HLH. A 49-year-old female complained of abdominal pain and fever 3 days in duration. On hospital day 3 she was transferred to the intensive care unit because of clinical deterioration accompanied by severe sepsis. As an eschar was evident on the right shoulder, we commenced doxycycline. Her condition improved dramatically and she was discharged on day 14. Although the indirect immunofluorescence antibody test (IFA) for Orientia tsutsugamushi was negative on admission, a repeat IFA test was positive; the antibody titer was 1:5,120 on hospital day 10. Scrub typhus should be considered during differential diagnosis in a patient with severe sepsis in any season except the fall.

Isolation and Genetic Characterization of Orientia tsutsugamushi from Scrub Typhus Patients in Gyeongsangnam-do, Korea

Orientia tsutsugamushi (O. tsutsugamushi), which is endemic to an Asia-Pacific region, has increased its incidence and caused annually around 10 thousand patients infected with scrub typhus in Korea in the past several years. In the present study, we isolated 44 O. tsutsugamushi from the patients with febrile illness accompanied with or without an eschar in Gyeongsangnam-do, Korea. These isolates were characterized by genetic analysis of the major outer membrane protein, the 56-kDa type-specific antigen (tsa56), which is unique to O. tsutsugamushi. Two types of sequences of tsa56, designated by JJ1 and JJ2, were determined from 37 and 7 isolates of the 44 isolates, respectively. JJ1 and JJ2 showed 74.7~90.8% identity in nucleotide sequence and 66.1~90.5% identity in amino acid sequence with 33 reference strains except for Boryong and Kuroki. JJ1 and JJ2 had 100 and 99.9% nucleotide identity to Boryong strain, and 99.9 and 99.8% to Kuroki, which has been known to be similar to Boryong, respectively. In addition, they showed 77.9~ 81.4% nucleotide identity with the cluster of Gilliam-related genotypes, whereas they showed higher nucleotide identity (89.6~90.8%) with the cluster of Karp-related genotypes. To our knowledge, this is the first report to isolate O. tsutsugamushi and characterize their genotype as the Boryong in Jinju and West Gyeongsangnam-do, Korea, even though it has been reported that the Boryong was the predominant genotype in isolates from chiggers, domestic rodents, and patients in the southern part of Korea. Furthermore, our isolates could be useful source to study on the pathophysiology and epidemiology of scrub typhus in Korea.

Acute Fulminant Myocarditis Recovered from Electro-Mechanical Dissociation in Scrub Typhus / 이화의대지

Scrub typhus, caused by Orientia tsutsugamushi, is an acute febrile illness. Characteristics of tsutsugamushi disease are fever, rash and eschar. However, severe complications might rarely occur, such as acute fulminant myocarditis caused by scrub typhus. Thus, there are few reports of recovery from seriously complicated cases. We report on an adult male with scrub typhus complicated with acute fulminant myocarditis with no previous comorbid illness who recovered successfully with proper treatment including antibiotics, ventilator support, percutaneous cardiopulmonary support, and continuous renal replacement therapy.

Clinical Evaluation of Rapid Diagnostic Test Kit for Scrub Typhus with Improved Performance

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.

Seroepidemiological Survey of Zoonotic Diseases in Small Mammals with PCR Detection of Orientia tsutsugamushi in Chiggers, Gwangju, Korea

Serosurveillance for zoonotic diseases in small mammals and detection of chiggers, the vector of Orientia tsutsugamushi, were conducted from September 2014 to August 2015 in Gwangju Metropolitan Area. Apodemus agrarius was the most commonly collected small mammals (158; 91.8%), followed by Myodes regulus (8; 4.6%), and Crocidura lasiura (6; 3.5%). The highest seroprevalence of small mammals for O. tsutsugamushi (41; 26.3%) was followed by hantaviruses (24; 15.4%), Rickettsia spp. (22; 14.1%), and Leptospira (2; 1.3%). A total of 3,194 chiggers were collected from small mammals, and 1,236 of 3,194 chiggers were identified with 7 species of 3 genera: Leptotrombidium scutellare was the most commonly collected species (585; 47.3%), followed by L. orientale (422; 34.1%), Euchoengastia koreaensis (99; 8.0%), L. palpale (58; 4.7%), L. pallidum (36; 2.9%), Neotrombicula gardellai (28; 2.3%), and L. zetum (8; 0.6%). L. scutellare was the predominant species. Three of 1,236 chigger mites were positive for O. tsutsugamushi by PCR. As a result of phylogenetic analysis, the O. tsutsugamushi strain of chigger mites had sequence homology of 90.1-98.2% with Boryong. This study provides baseline data on the distribution of zoonotic diseases and potential vectors for the development of prevention strategies of vector borne diseases in Gwangju metropolitan area.

In Vitro Activity of Tigecycline Against Orientia tsutsugamushi

Scrub typhus is a zoonosis caused by Orientia tsutsugamushi (O. tsutsugamushi) occurring mainly in autumn in Korea. The need of new antibiotics has arisen with a report on strains resistant to antibiotics and chronic infection. This study aims to identify susceptibility of tigecycline in-vitro as a new therapeutic option for O. tsutsugamushi. Antibacterial activity of tigecycline against the O. tsutsugamushi was compared with doxycycline using flow cytometry assay. The inhibitory concentration 50 (IC50) was 3.59×10(-3) µg/mL in doxycycline-treated group. Whereas in 0.71×10(-3) µg/mL tigecycline-treated group. These findings indicate that tigecycline may be a therapeutic option for the treatment of scrub typhus.

Leukocytoclastic Vasculitis Associated with Orientia tsutsugamushi Infection: A Report of Two Cases / 대한피부과학회지

No abstract available.

Pulmonary Embolism Associated with Scrub Typhus / 대한내과학회지

Acute pulmonary embolism is a cardiovascular emergency and is a major cause of morbidity and mortality. Endothelial damage secondary to invasion by Orientia tsutsugamushi can lead to focal occlusive endangiitis, causing microinfarcts in various tissues. This localized process can also cause venous thrombosis and peripheral gangrene. However, pulmonary embolism associated with scrub typhus has not been reported in Korea. Here, we report a patient diagnosed with pulmonary embolism associated with scrub typhus, the first report of its kind. The patient had an eschar with detection of anti-tsutsugamushi antibody, fever, dyspnea, and a maculopapular rash over the entire body. He was treated with doxycycline and anticoagulation therapy.

Scrub typhus associated hepatic dysfunction and abdominal CT findings

This retrospective study investigated abnormal hepatic dysfunction and abdominal computed tomography [CT] findings in scrub typhus. Three hundred forty nine adult patients were diagnosed with scrub typhus. Ninety four underwent abdominal CT. The CT images were reviewed by the attending radiologist. Patient data of history, symptoms, signs, and results of laboratory tests were collected from the electronic medical records. In 349 patients with scrub typhus, elevation of aspartate aminotransferase [78.5%] and alanine aminotransferase [63.0%] were dominant compared to alkaline phosphatase [27.2%] and total bilirubin [16.1%]. Abdominal CT findings of 94 patients were, in descending order of frequency, enlarged lymph node [53.2%], inhomogeneous enhancement of liver [47.9%], splenomegaly [46.8%], ascites [28.7%], low attenuation of periportal areas [27.7%], gallbladder wall thickening [17.0%], and splenic infarct [6.4%]. Also, the level of aspartate aminotransferase tended to be elevated according to the number of CT findings [P= 0.028] We found that abdominal CT manifestations of scrub typhus with elevated aminotransferases were varied and not specific. However, knowledge of these findings may evoke the recognition of scrub typhus by clinicians in endemic areas

Extracorporeal Membrane Oxygenation for Complicated Scrub Typhus / 대한중환자의학회지

Scrub typhus is a mite-borne infectious disease caused by Orientia tsutsugamushi . Although early diagnosis and appropriate antibiotic therapy improve the prognosis for the majority of patients, life-threatening complications are not uncommon. Here, we present a case of successful veno-veno-type extracorporeal membrane oxygenation for scrub typhus-induced complications, including acute respiratory distress syndrome, myocarditis and multi-organ dysfunction. To our knowledge, this is the first case report of successful extracorporeal membrane oxygenation in complicated scrub typhus in Korea.

Identification of Outer Membrane Vesicles Derived from Orientia tsutsugamushi

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.