Demonstration of Antigenic and Genotypic Variation in <i>Orientia tsutsugamushi</i> Which Were Isolated in Japan, and Their Classification into Type and Subtype

Ohashi, Norio; Koyama, Yoko; Urakami, Hiroshi; Fukuhara, Masahiro; Tamura, Akira; Kawamori, Fumihiko; Yamamoto, Seigo; Kasuya, Shiro; Yoshimura, Kazuya

doi:10.1111/j.1348-0421.1996.tb01120.x

Cited by 71 publications

(109 citation statements)

References 31 publications

(54 reference statements)

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“…These strains are antigenically different but could not be differentiated by our method. 18,19 Only the Boryong strain, and not the Kuroki strain, is mentioned in this study, because it is a long-term predominant strain and there has been no evidence of divergence. The term Kanda/Kawasaki is used for the 14 cases of Kanda or Kawasaki strains.…”

Section: Genotypes Of O Tsutsugamushimentioning

confidence: 99%

Antigenic Drift of Orientia tsutsugamushi in South Korea as Identified by the Sequence Analysis of a 56-kDa Protein-Encoding Gene

Park¹,

Lee²,

Kwak³

et al. 2010

The American Journal of Tropical Medicine and Hygiene

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Abstract. This study was performed to determine the nationwide antigenic diversity of Orientia tsutsugamushi in South Korea. Sequence analysis was performed around variable domains I and II of a 56-kDa protein-encoding gene. We used eschar to overcome the disadvantages of conventional serotyping. The serological passive hemagglutination assay (PHA) was assessed based on the genotyping results. We analyzed 153 isolates from scrub typhus patients in major endemic areas and found that Boryong was the major strain (68.6%). New strains were also identified: Taguchi (19.6%), Kanda/Kawasaki (9.2%), and UAP7 (1.3%). PHA yielded significantly fewer positive results among Kawasaki strains ( P < 0.001), which are not included in the PHA antigen panel. In South Korea, Boryong was still the predominant strain, but the sequence analysis identified new changes in minor strains (30.1%). This antigenic drift had a negative effect on the PHA results. Periodic surveillance of the contemporary strains using sequence analysis is needed.

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Section: Genotypes Of O Tsutsugamushimentioning

confidence: 99%

Antigenic Drift of Orientia tsutsugamushi in South Korea as Identified by the Sequence Analysis of a 56-kDa Protein-Encoding Gene

Park¹,

Lee²,

Kwak³

et al. 2010

The American Journal of Tropical Medicine and Hygiene

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“…This has been accomplished by restriction fragment length polymorphism (RFLP) or sequence analysis of the 56-kDa TSA gene or gene fragment PCR amplicons (17,29). In contrast to serotyping, molecular methods (8,18) can be used to determine evolutionary relationships among the different genotypes.…”

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confidence: 99%

Genotype Diversity and Distribution of Orientia tsutsugamushi Causing Scrub Typhus in Thailand

et al. 2011

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Scrub typhus, caused by antigenically disparate isolates of Orientia tsutsugamushi, is a widely distributed mite-borne human disease in the Asia Pacific region. Information regarding the heterogeneity of the immunodominant 56-kDa type-specific antigen (TSA) gene is crucial for the design and evaluation of scrub typhusspecific diagnostic assays and vaccines. Using indirect immunofluorescence assays (IFA) and PCR assays, O. tsutsugamushi was detected samples from rodents and patients with fever of unknown origin obtained from six provinces of Thailand during 2004 to 2007. Sequences were determined for a fragment of the 56-kDa TSA gene, and the relationship between these sequences and those previously determined were assessed. The phylogenetic analyses of partial 56-kDa TSA gene sequences demonstrated wide diversity and distribution of O. tsutsugamushi genotypes in Thailand. Furthermore, the genetic diversity grouped the scrub typhus agents into two commonly and five infrequently found genotypes within six provinces of Thailand. The two most commonly found genotypes of O. tsutsugamushi described in this study do not associate with the prototype strains that are widely used for the design and evaluation of diagnostic assays and vaccine candidates. Thus, these new genotypes should be considered for future scrub typhus assay and vaccine development.

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“…Furthermore, different genotypes associated with different Orientia serotypes can be identified by analysis of variable regions of this gene without isolation of the organism (10,13,14,16,17,25,34). However, gene amplification requires a sophisticated instrument and labile reagents which are generally not available in most rural medical facilities.…”

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confidence: 99%

Early Diagnosis of Scrub Typhus with a Rapid Flow Assay Using Recombinant Major Outer Membrane Protein Antigen (r56) of Orientia tsutsugamushi

Ching

Rowland²,

Zhang

et al. 2001

Clin Diagn Lab Immunol

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The variable 56-kDa major outer membrane protein of Orientia tsutsugamushi is the immunodominant antigen in human scrub typhus infections. We developed a rapid immunochromatographic flow assay (RFA) for the detection of immunoglobulin M (IgM) and IgG antibodies to O. tsutsugamushi. The RFA employs a truncated recombinant 56-kDa protein from the Karp strain as the antigen. The performance of the RFA was evaluated with a panel of 321 sera (serial bleedings of 85 individuals suspected of scrub typhus) which were collected in the Pescadore Islands, Taiwan, from 1976 to 1977. Among these 85 individuals, IgM tests were negative for 7 cases by both RFA and indirect fluorescence assay (IFA) using Karp whole-cell antigen. In 29 cases specific responses were detected by the RFA earlier than by IFA, 44 cases had the same detection time, and 5 cases were detected earlier by IFA than by RFA. For IgG responses, 4 individuals were negative with both methods, 37 cases exhibited earlier detection by RFA than IFA, 42 cases were detected at the same time, and 2 cases were detected earlier by IFA than by RFA. The sensitivities of RFA detection of antibody in sera from confirmed cases were 74 and 86% for IgM and IgG, respectively. When IgM and IgG results were combined, the sensitivity was 89%. A panel of 78 individual sera collected from patients with no evidence of scrub typhus was used to evaluate the specificity of the RFA. The specificities of the RFA were 99% for IgM and 97% for IgG. The sensitivities of IFA were 53 and 73% for IgM and IgG, respectively, and were 78% when the results of IgM and IgG were combined. The RFA test was significantly better than the IFA test for the early detection of antibody to scrub typhus in primary infections, while both tests were equally sensitive with reinfected individuals.

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Demonstration of Antigenic and Genotypic Variation in Orientia tsutsugamushi Which Were Isolated in Japan, and Their Classification into Type and Subtype

Cited by 71 publications

References 31 publications

Antigenic Drift of Orientia tsutsugamushi in South Korea as Identified by the Sequence Analysis of a 56-kDa Protein-Encoding Gene

Antigenic Drift of Orientia tsutsugamushi in South Korea as Identified by the Sequence Analysis of a 56-kDa Protein-Encoding Gene

Genotype Diversity and Distribution of Orientia tsutsugamushi Causing Scrub Typhus in Thailand

Early Diagnosis of Scrub Typhus with a Rapid Flow Assay Using Recombinant Major Outer Membrane Protein Antigen (r56) of Orientia tsutsugamushi

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