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Genetic typing of the 56-kDa type-specific antigen gene of contemporary Orientia tsutsugamushi isolates causing human scrub typhus at two sites in north-eastern and western Thailand.

Orientia tsutsugamushi is the causative agent of scrub typhus, a major cause of febrile illness in the rural areas of Southeast Asia. Twenty-three strains of O. tsutsugamushi were isolated from patients with scrub typhus in north-east (Udorn Thani province) and western Thailand (Tak province) between 2003 and 2005. The isolates were characterized by sequencing the entire ORF of the 56-kDa-type-specific antigen gene, followed by phylogenetic analysis. The majority (15/23) of isolates clustered with the Karp-type strain, six with a Gilliam-type strain and one each with the TA716- and TA763-type …

Occurrence of Orientia tsutsugamushi, the Etiological Agent of Scrub Typhus in Animal Hosts and Mite Vectors in Areas Reporting Human Cases of Acute Encephalitis Syndrome in the Gorakhpur Region of Uttar Pradesh, India.

Outbreaks of acute encephalitis syndrome (AES) with high fatality and disability, are reported every year in the Gorakhpur region of Uttar Pradesh, India, with the etiology of >60% of the cases being attributed to scrub typhus. In the present study, the prevalence of Orientia tsutsugamushi, the etiological agent of scrub typhus, was investigated among animal hosts and their ectoparasitic trombiculid mites prevalent in AES-reported areas of Gorakhpur. A total of 154 rodents/shrews were collected using 777 Sherman traps set in 12 study villages, and the overall trap rate was 19.8%. In total, 272…

Prospective evaluation of commercial antibody-based rapid tests in combination with a loop-mediated isothermal amplification PCR assay for detection of Orientia tsutsugamushi during the acute phase of scrub typhus infection.

Samples from 160 prospectively recruited febrile patients with typhus-like illness in an area of Thailand (Chiang Rai, northern Thailand) where scrub typhus is endemic were used to evaluate the diagnostic capabilities of four rapid immunochromatographic tests (ICTs) for the detection of Orientia tsutsugamushi IgM and total antibodies during acute scrub typhus infection. Of the 160 cases, 54 (34%) had been confirmed to have scrub typhus using the reference scrub typhus infection criteria (STIC), i.e., positive cell culture isolation, an admission IgM antibody titer of ≥1:12,800, a 4-fold rising…

Development of a New Genus-Specific Quantitative Real-Time PCR Assay for the Diagnosis of Scrub Typhus in South America.

Scrub typhus is a potentially severe rickettsiosis, caused by Orientia tsutsugamushi in the Asia-Pacific region. Recently, however, two distinct pathogens, "Candidatus Orientia chuto" and "Candidatus Orientia chiloensis", have been discovered in the Middle East and South America, respectively. Since the novel pathogens differ significantly from O. tsutsugamushi, many established diagnostic methods are unreliable. This work describes the development and validation of a new quantitative real-time PCR (qPCR) assay (Orien16S) for the detection of all known Orientia species. Based on a 94 bp sequen…

Gaps and inconsistencies in the current knowledge and implementation of biosafety and biosecurity practices for rickettsial pathogens.

INTRODUCTION: Rickettsia spp. and Orientia spp. are the causes of neglected infections that can lead to severe febrile and systemic illnesses in humans. Implementing proper biosafety practices when handling these pathogens is crucial to ensure a safe and sustainable work environment. It is essential to assess the current knowledge and identify any potential gaps to develop effective measures that minimise the risk of exposure to these pathogens. By doing so, we can establish a comprehensive framework that promotes safety, mitigates hazards, and safeguards the well-being of personnel and the su…

Comparison of immune response against Orientia tsutsugamushi, a causative agent of scrub typhus, in 4-week-old and 10-week-old scrub typhus-infected laboratory mice using enzyme-linked immunosorbent assay technique.

Using the indirect enzyme-linked immunosorbent assay (ELISA) technique, we compared the immune response of specific antibodies (IgM and IgG) in serum samples of scrub typhus-infected and non-infected mice against Orientia sutsugamushi (a causative agent of scrub typhus). Two different age groups (4-week-old and 10-week-old) of ICR laboratory mice were infected with O. tsutsugamushi by the animal passage procedure. Serum samples were detected for scrub typhus-specific antibodies using ELISA technique. Results from determining the presence of IgM and IgG in the serum samples obtained from scrub …

[Study on the characteristics of Tsutsugamushi disease in the epidemic areas of south islands in China].

OBJECTIVE: To 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. METHODS: Both epidemiological investigation, isolation and gene identification of Orientia tsutsugamushi, as well as pilot preventive measures were carried out. RESULTS: These islands belonged to the epidemic area of south subtropical zone of Tsutsugamushi disease. The main host was Rattus norvegicu…

Scrub typhus (Orientia tsutsugamushi), spotted fever (Rickettsia australis) and dengue fever as possible causes of mysterious deaths in the Strickland Gorge area of Southern Highlands and West Sepik Provinces of Papua New Guinea.

A medical investigation was carried out in April 2001 into an outbreak of a mysterious haemorrhagic disease and deaths in the remote picture … litis (JE) (6%) were identified. Surprisingly, a number of the sera were positive for scrub typhus (Orientia tsutsugamushi) (28%) and spotted fever (Rickettsia australis) (11%). The last reported cases of scrub typhus in PNG were during World War Two among the allied troops. This is the first time spotted fever (R. australis) has been reported in PNG. Thes …

[The recognition of the epidemic area of tsutsugamushi disease on Nan Peng Lie Island in China and the strategy of prevention].

OBJECTIVE: To investigate the region for the epidemic area of tsutsugamushi disease. METHODS: Epidemiological studies, Orientia tsutsugamushi isolation, and preventive measures were used. RESULTS: The region belonged to epidemic area of south subtropical zone. The main host was found Rattus norvegicu. The main biological vector was Leptotrombidium deliens. The seasonal trends of the quantity of Rattus norvegicu and Leptotrombidium deliens were consistent with the incidence change of the disease in the region. Orientia tsutsugamushi has been isolated from Rattus norvegicu and Leptotrombidium …

Metagenomics as New Tool for Diagnosis of Scrub Typhus: Two Case Reports.

Scrub typhus is a vector-borne infectious disease caused by Orientia tsutsugamushi. Accurate and timely diagnosis at the early infection stage could save the patients' lives. Traditional technologies were limited to rapidly and successfully detecting Orientia tsutsugamushi due to poor specificity, especially in the condition of atypical symptoms. The technology of Metagenomic next-generation sequencing (mNGS) is amenable to finding the real pathogen because it holds potential as a diagnostic platform for unbiased pathogen identification and precision medicine. Herein, we reported two clinical …

Comprehensive Laboratory Analysis of a Scrub Typhus and H1N1 Influenza Co-Infection: A Case Report from Hainan, China.

Co-infection of Orientia tsutsugamushi and influenza A virus complicates diagnosis and treatment in endemic regions because of overlapping clinical features and potential synergistic inflammation. We describe a 68-year-old woman from Hainan, China, who presented with five days of high fever (39.2 °C), nonproductive cough, eschar formation, lymphadenopathy, cytopenias, elevated liver enzymes, and raised inflammatory markers. On the day of admission, influenza A was confirmed by rapid antigen test and Orientia tsutsugamushi IgM/IgG was detected via colloidal-gold immunochromatography, prompting …

Эндемическая болезнь, похожая на тиф, Чили.

Сообщаем, что 54-летний мужчина, который был укушен несколькими наземными пиявками во время поездки на остров Чилоэ в южной части Чили в 2006 году, был укушен тифом. Молекулярный образец, идентифицированный как относящийся к цутсугамуши на основе последовательности гена 16S rRNA, был получен из биопсии эшара на ноге пациента. Серологический анализ показал, что иммуноглобулин G преобразуется в антиген целой клетки О. цутсугамуши. Этот случай и связанные с ним молекулярные анализы свидетельствуют о том, что в Западном полушарии присутствует агент, похожий на Ориентию, который может вызывать боле

Совпадение в аннотации оригинала
We report a case of scrub typhus in a 54-year-old man who was bitten by several terrestrial leeches during a trip to Chiloé Island in southern Chile in 2006. A molecular sample, identified as related to Orientia tsutsugamushi based on the sequence of the16S rRNA gene, was obtained from a biopsy specimen of the eschar on the patient's leg. Serologic analysis …

Clinical, Molecular, and Immunological Characteristics of Scrub Typhus in Nepal.

In a serologically diagnosed Nepalese scrub typhus cohort (n = 77), gastrointestinal symptoms were common. We assessed Orientia tsutsugamushi DNA in serum and performed TSA56 genotyping. Orientia DNA was detected in 10 of 77 samples (12%). TSA56 sequencing identified 4 genotypes. Polymerase chain reaction positivity was associated with diarrhea, groin lymphadenopathy, and stronger Th1-type cytokine responses.

Tick-borne pathogens isolated from ticks, rodents, and a shrew in Gangwon and Gyeonggi provinces in the Republic of Korea.

The prevalence of tick-borne pathogens (TBP), Orientia tsutsugamushi, Rickettsia and Borrelia spp. in wild small animals, namely wild rodents, is now widely investigated. This study is to present the prevalence and distribution of O. tsutsugamushi, Rickettsia and Borrelia spp. in wild small animals and ticks collected from Gyeonggi and Gangwon provinces, Republic of Korea (ROK) in 2014. A total of 131 wild small animals, rodents and shrews, and 2,954 ticks were collected from Gyeonggi and Gangwon provinces from May to November 2014. The wild small animals (KR1-9) and ticks (K1-17) were grouped…

Leptotrombidium imphalum Chiggers as Vector for Scrub Typhus in Human Settlements, India, 2022-2023.

Scrub typhus is a common bacterial infection in many parts of Asia. The causative agent, Orientia tsutsugamushi, is transmitted by trombiculid mite (chigger) larvae that require small mammals as maintaining hosts. We studied the prevalence of O. tsutsugamushi infection in mites and small mammals in villages and land surrounding them in South India to determine high-risk settings. We identified 12,431 mite larvae on 883 small mammals, 32% of which were bandicoot rats, 31% black rats, and 31% Asian house shrews. Leptotrombidium imphalum was the most common mite species and the only species assoc…

[An outbreak of endemic typhus in Baoshan city, Yunnan province].

OBJECTIVE: To understand the epidemiologic characteristics of endemic typhus in Baoshan city. METHODS: Epidemiological data were collected and characteristics were analyzed. IgG antibody (Ab) of Rickettsia mooseri and Orientia tsutsugamushi in serum of patients were tested using both Weil-Felix and IFA method. The Rickettsia mooseri gltA gene, Rickettsia prowazekii gltA gene, Orientia tsutsugamushi 56 kDa protein gene, SFGR ompA gene, Ehrlichia sp. 16S rRNA gene and Anaplasma sp. 16S rRNA gene in spleen of mice were examined by PCR. RESULTS: Fifty-eight endemic typhus cases were found in Lon…

Scrub Typhus: No Longer Restricted to the Tsutsugamushi Triangle.

Scrub typhus is the most important rickettsial disease in the world. Its previous endemic region was considered to be in Asia, Australia and islands in the Indian and Pacific Oceans; this area was referred to as the Tsutsugamushi Triangle. Accumulation of serological, molecular, genetic, and culture data have shown that not only is scrub typhus not limited to the Tsutsugamushi Triangle, but can be caused by orientiae other than Orientia tsutsugamushi. This review describes evidence currently available that will be instrumental to researchers, healthcare providers and medical leaders in develop…

Approach for classification and taxonomy within family Rickettsiaceae based on the Formal Order Analysis.

Genome sequences of 36 Rickettsia and Orientia were analyzed using Formal Order Analysis (FOA). This approach takes into account arrangement of nucleotides in each sequence. A numerical characteristic, the average distance (remoteness) - "g" was used to compare of genomes. Our results corroborated previous separation of three groups within the genus Rickettsia, including typhus group, classic spotted fever group, and the ancestral group and Orientia as a separate genus. Rickettsia felis URRWXCal2 and R. akari Hartford were not in the same group based on FOA, therefore designation of a so-calle…

Scrub typhus associated with reactive arthritis: A case report and literature review.

Scrub typhus (tsutsugamushi disease) is an acute febrile illness caused by Orientia tsutsugamushi, often found in Asia and Oceania. The presence of an eschar, characterized by a crust, is a key diagnostic finding. Many symptoms of this disease are already known, however reactive arthritis following scrub typhus is very rare. Here, we present a case of 79-year-old man who was referred to our hospital because of continuous fever and left shoulder pain. We found 4-fold rise in Orientia tsutugamushi-specific IgG titer using paired serum samples and Orientia sp. genes by real-time PCR from a crust …

Strategies for detecting rickettsiae and diagnosing rickettsial diseases.

Rickettsial diseases and scrub typhus constitute a group of the oldest known vector-borne diseases. The cosmopolitan distribution of the vectors that transmit rickettsiae and orientiae leads to a worldwide prevalence of these diseases. Despite their significant historical status, detection and diagnosis of these diseases are still evolving today. Serological methods remain among the most prevalent techniques used for the detection/diagnosis of rickettsial diseases and scrub typhus. Molecular techniques have been instrumental in increasing the sensitivity/specificity of diagnosis, identifying n…