Ultrastructural visualization of Orientia tsutsugamushi in biopsied eschars and monocytes from scrub typhus patients in South Korea

AbstractOrientia tsutsugamushi, an obligate intracellular organism, is the causative agent of scrub typhus, which is endemic in the Asia-Pacific region. No comparative studies on the genotypic properties of O. tsutsugamushi have been performed using multilocus sequence typing (MLST) in South Korea. Here, we characterized 51 clinical isolates from Jeonju, in southwestern Korea, and we compared them to isolates from Thailand, Laos, and Japan. We also identified 10 new alleles and six novel sequence types. Overall, our results suggest that the relative genetic stability and the clonal populations of O. tsutsugamushi strains in South Korea have remained mostly conserved.Author summaryScrub typhus is a life-threatening disease, caused by infection with O. tsutsugamushi, a Gram-negative intracellular bacterium. Approximately one million people are infected globally every year, especially in the Asia-Pacific region. Strains of O. tsutsugamushi are typically distinguished serologically on the basis of sequences of the highly polymorphic 56-kDa outer membrane protein. Multilocus sequence typing (MLST) is a generic typing method that provides a unified bacterial isolate characterization approach that can be used for evolutionary and population studies of bacteria. In this study, we describe the development and application of a MLST scheme that was applied to 51 O. tsutsugamushi isolates. We found 10 new alleles and six new STs, which yielded a total of seven O. tsutsugamushi STs in South Korea. Among seven different STs (ST 48, 93-98), ST 48 account for the largest proportion (49.0%) of O. tsutsugamushi STs in South Korea. With the exception of the appearance of six novel STs, the clonal populations have remained conserved but further study of population structure and evolutionary trends is warranted.

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Faculty Opinions recommendation of Urbanization of scrub typhus disease in South Korea.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.725510185.793508102 ◽

2015 ◽

Author(s):

Daniel Paris ◽

Thomas Althaus

Keyword(s):

South Korea ◽

Scrub Typhus

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Scrub typhus (Orientia tsutsugamushi), A rapidly spreading epidemic in Chennai - A standalone lab experience

International Journal of Bioassays ◽

10.21746/ijbio.2016.09.0021 ◽

2016 ◽

Vol 5 (09) ◽

pp. 4896

Author(s):

Sripriya C.S.* ◽

Shanthi B. ◽

Arockia Doss S. ◽

Antonie Raj I. ◽

Mohana Priya

Keyword(s):

Scrub Typhus ◽

Clinical Symptoms ◽

Clinical Manifestations ◽

Febrile Illness ◽

Orientia Tsutsugamushi ◽

The Past ◽

Igm Elisa ◽

The Mean ◽

Specific Symptoms ◽

Symptoms And Signs

Scrub typhus (Orientia tsutsugamushi), is a strict intracellular bacterium which is reported to be a recent threat to parts of southern India. There is re-emergence of scrub typhus during the past few years in Chennai. Scrub typhus is an acute febrile illness which generally causes non-specific symptoms and signs. The clinical manifestations of this disease range from sub-clinical disease to organ failure to fatal disease. This study documents our laboratory experience in diagnosis of scrub typhus in patients with fever and suspected clinical symptoms of scrub typhus infection for a period of two years from April 2014 to April 2016 using immunochromatography and IgM ELISA methods. The study was conducted on 648 patients out of whom 188 patients were found to be positive for scrub typhus. Results also showed that pediatric (0 -12 years) and young adults (20 – 39 years) were more exposed to scrub typhus infection and female patients were more infected compared to male. The study also showed that the rate of infection was higher between September to February which also suggested that the infection rate is proportional to the climatic condition. Statistical analysis showed that the mean age of the patients in this study was 37.6, standard deviation was 18.97, CV % was 50.45.

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Scrub Typhus and Molecular Characterization of Orientia tsutsugamushi from Central Nepal

Pathogens ◽

10.3390/pathogens10040422 ◽

2021 ◽

Vol 10 (4) ◽

pp. 422

Author(s):

Rajendra Gautam ◽

Keshab Parajuli ◽

Mythili Tadepalli ◽

Stephen Graves ◽

John Stenos ◽

...

Keyword(s):

Genetic Diversity ◽

Scrub Typhus ◽

Febrile Illness ◽

Acute Febrile Illness ◽

Limited Information ◽

Orientia Tsutsugamushi ◽

Health Measures ◽

Central Nepal ◽

Vector Borne

Scrub typhus is a vector-borne, acute febrile illness caused by Orientia tsutsugamushi. Scrub typhus continues to be an important but neglected tropical disease in Nepal. Information on this pathogen in Nepal is limited to serological surveys with little information available on molecular methods to detect O. tsutsugamushi. Limited information exists on the genetic diversity of this pathogen. A total of 282 blood samples were obtained from patients with suspected scrub typhus from central Nepal and 84 (30%) were positive for O. tsutsugamushi by 16S rRNA qPCR. Positive samples were further subjected to 56 kDa and 47 kDa molecular typing and molecularly compared to other O. tsutsugamushi strains. Phylogenetic analysis revealed that Nepalese O. tsutsugamushi strains largely cluster together and cluster away from other O. tsutsugamushi strains from Asia and elsewhere. One exception was the sample of Nepal_1, with its partial 56 kDa sequence clustering more closely with non-Nepalese O. tsutsugamushi 56 kDa sequences, potentially indicating that homologous recombination may influence the genetic diversity of strains in this region. Knowledge on the circulating strains in Nepal is important to the development of diagnostic tests and vaccines to support public health measures to control scrub typhus in this country.

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