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Studies on scrib typhus; tsutsugamushi disease; heterogenicity of strains of R. tsutsugamushi as demonstrated by cross-vaccination studies.

Antigenic differences among strains of R. tsutsugamushi are sufficiently great that vaccines prepared from certain strains fail to induce resistance in mice to infection with other strains. Although the results of cross-vaccination tests indicate varying degrees of relationship between a number of the strains, there is no correlation between source of the rickettsia and antigenic pattern of the agent.

Transformation and allelic exchange in Orientia tsutsugamushi.

Orientia tsutsugamushi is a mite-transmitted obligate intracellular bacterium that causes the potentially deadly zoonosis, scrub typhus. The absence of genetic tools for Orientia have limited studies of the microbe-host interactions that underlie scrub typhus. To address this gap, we developed a protocol for transforming and achieving allelic exchange in O. tsutsugamushi str. Ikeda. From evaluating multiple cell lines and antibiotics, we found that contact-inhibited EA.hy926 human endothelial-like cells best supported Orientia replication and that chloramphenicol was an effective selection mar…

Designing a potent multivalent epitope vaccine candidate against Orientia tsutsugamushi via reverse vaccinology technique - bioinformatics and immunoinformatic approach.

Scrub typhus is a life-threatening, undifferentiated febrile illness caused by a gram-negative bacterium, Orientia tsutsugamushi. The bacterial strain is a global health concern that should be considered. Despite several years of effort for the development of an effective immunogenic vaccine, no successful licensed vaccine is available. The aim of the study is to construct an epitope response using a reverse vaccinology approach. The TSA56 and ScaA proteins combined can be the most promising subunit vaccine candidates against O. tsutsugamushi. B-cell, CTL, and HTL epitopes were predicted, and …

Изоляция цецугамуши в культуре из Веллоре, Южная Индия.

Фон: Orientia tsutsugamushi, причинно-следственный агент скруба тифа — внутриклеточный паразит. Мы представляем информацию об изоляции этого патогена в центре третичного ухода в Веллоре, Южная Индия. Материалы и методы: PBMC (периферальные моноядерные клетки крови), собранные у предполагаемых пациентов скруба тифа, были привиты в линии Vero и L929 клеток и инкубированы при 37°C с 5% СО2 в течение 30 дней. Они были обследованы на предмет присутствия "Ористиа цуцугамуши" 10, 15, 20 дней после интоксикации и ежедневно в течение максимум 30 дней после вакцинации. Скраски были подвергнуты пятнам Gi

Совпадение в аннотации оригинала
Background: Orientia tsutsugamushi, causative agent of scrub typhus is an obligate intracellular parasite. We present information on isolation of this pathogen at a tertiary care centre in Vellore, Southern India. Materials & Methods: PBMCs (peripheral blood mononuclear cells) collected from suspected scrub typhus patients were inoculated into Vero and L929 …

Molecular characterization and evolutionary analysis of Orientia tsutsugamushi in eastern Indian population.

Scrub typhus is a bacterial zoonotic acute febrile illness (AFI) caused by the obligate intracellular bacterium Orientia tsutsugamushi, which is an antigenically diverse strain frequently observed in the tropical region of Southeast Asian countries. The recent investigation was conducted to delineate the genotype identification of Orientia tsutsugamushi predominating in the eastern zone of India such as Odisha to decipher its strain type, and evaluate its diversity as well as evolutionary pattern based on the nucleotide analysis of the immune dominant 56 KDa gene. During this study, we have in…

CCR7/dendritic cell axis mediates early bacterial dissemination in Orientia tsutsugamushi-infected mice.

Scrub typhus is a life-threatening zoonosis caused by the obligate intracellular bacterium Orientia tsutsugamushi (Ot) that is transmitted by the infected larvae of trombiculid mites. However, the mechanism by which Ot disseminates from the bite site to visceral organs remains unclear; host innate immunity against bacterial dissemination and replication during early infection is poorly understood. In this study, by using an intradermal infection mouse model and fluorescent probe-labeled Ot, we assessed the dynamic pattern of innate immune cell responses at the inoculation site. We found that n…

Comparative pan-genomic analyses of Orientia tsutsugamushi reveal an exceptional model of bacterial evolution driving genomic diversity.

Orientia tsutsugamushi, formerly Rickettsia tsutsugamushi, is an obligate intracellular pathogen that causes scrub typhus, an underdiagnosed acute febrile disease with high morbidity. Scrub typhus is transmitted by the larval stage (chigger) of Leptotrombidium mites and is irregularly distributed across endemic regions of Asia, Australia and islands of the western Pacific Ocean. Previous work to understand population genetics in O. tsutsugamushi has been based on sub-genomic sampling methods and whole-genome characterization of two genomes. In this study, we compared 40 genomes from geographic…

Molecular epidemiology of Orientia tsutsugamushi in Cambodia and Central Vietnam reveals a broad region-wide genetic diversity.

Scrub typhus is an acute infectious disease caused by an obligate intracellular bacterium Orientia tsutsugamushi following the bite of infected trombiculid mites of the genus Leptotrombidium. This zoonotic disease is a major cause of febrile illness in the Asia-Pacific region, with a large spectrum of clinical manifestations from unapparent or mild disease to fatal disease. O. tsutsugamushi is characterized by a very high genomic plasticity and a large number of antigenic variants amongst strains. The 56-kDa type specific antigen (TSA) gene, encoding the major antigenic protein, was used as re…

Acute kidney injury in tropical acute febrile illness in a tertiary care centre--RIFLE criteria validation.

BACKGROUND: Acute febrile illnesses are a common cause of tropical acute kidney injury (AKI). The incidence and severity of AKI in tropical … : The 367 patients (mean age 39.7±16.9 years; 60% males) with tropical acute febrile illness due to scrub typhus (51.2%), falciparum malaria (10.4%), enteric fever (8.7%), dengue (7.6%), mixed malaria (6.5%), leptospirosis (3.3%), undifferentiated acute febrile illness (8.4%) and others (3.8%) (spotted fever, vivax malaria and Hantaan virus infection) had an o …

Acute undifferentiated febrile illness in adult hospitalized patients: the disease spectrum and diagnostic predictors - an experience from a tertiary care hospital in South India.

Local prevalences of individual diseases influence the prioritization of the differential diagnoses of a clinical syndrome of acute undiffer … were made between each disease and the other AFIs. A total of 398 AFI patients were diagnosed with: scrub typhus (47.5%); malaria (17.1%); enteric fever (8.0%); dengue (7.0%); leptospirosis (3.0%); spotted fever rickettsiosis (1.8%); Hantavirus (0.3%); alternate diagnosis (7.3%); and unclear diagnoses (8.0%). Leucocytosis, acute respiratory distress syndrome, …

Murine T-cell response to native and recombinant protein antigens of Rickettsia tsutsugamushi.

A polyclonal T-cell line with TH1 characteristics was used to assess the murine cellular immune response to native and recombinant Rickettsia tsutsugamushi antigens. Proliferation of this T-cell line was observed in response to numerous native antigen fractions, which indicates that the murine T-helper-cell response is directed at multiple scrub typhus antigens with no apparent antigenic immunodominance. Subsequent analysis of recombinant R. tsutsugamushi antigens made it possible to identify a 47-kDa scrub typhus antigen (Sta47) that was stimulatory for the polyclonal T-cell line. Recombinant…

Chemoprophylaxis of Tropical Infectious Diseases.

Travelers to tropical countries are at risk for a variety of infectious diseases. In some cases effective vaccinations are available, but for other infections chemoprophylaxis can be offered. Malaria prevention has become increasingly complex as Plasmodium species become resistant to available drugs. In certain high risk settings, antibiotics can be used to prevent leptospirosis, scrub typhus and other infections. Post-exposure prophylaxis is appropriate for selected virulent infections. In this article the evidence for chemoprophylaxis will be reviewed.

Arthropod borne disease: the leading cause of fever in pregnancy on the Thai-Burmese border.

BACKGROUND: Fever in pregnancy is dangerous for both mother and foetus. In the 1980's malaria was the leading cause of death in pregnant women in refugee camps on the Thai-Burmese border. Artemisinin combination therapy has significantly reduced the incidence of malaria in the population. The remaining causes of fever in pregnancy are not well documented. METHODOLOGY: Pregnant women attending antenatal care, where weekly screening for malaria is routine, were invited to have a comprehensive clinical and laboratory screen if they had fever. Women were admitted to hospital, treated and followed

The role of gut microbiota and the gut-lung axis in sepsis: A case study of a pregnant woman with severe rickettsial pneumonia and septic shock complicated by MODS.

KEY CLINICAL MESSAGE: In this case report, we describe the successful management of severe scrub typhus with pneumonia, sepsis, and multiple organ dysfunction in a pregnant woman. Despite initial challenges, the patient responded favorably to fecal microbiota transplantation and oral fecal microbiota capsule therapy. ABSTRACT: Scrub typhus, caused by Orientia tsutsugamushi, can lead to severe multiorgan dysfunction and carries a mortality rate of up to 70% if not treated properly. In this report, we present the case of a 27-year-old pregnant woman at 18 + 6 weeks gestation whose symptoms wors…