Molecular Detection of Multiple Genotypes of <i>Orientia tsutsugamushi</i> Causing Scrub Typhus in Febrile Patients from Theni District, South India
Scrub typhus (St) is a re-emerging mite-transmitted public health problem in Southeast Asia with escalating case incidences in the endemic areas. Though, more than 40 genotypes of the causative agent <i>Orientia tsutsugamushi</i> (<i>Ot</i>) have been documented, the informat...
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MDPI AG
2023-03-01
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| Series: | Tropical Medicine and Infectious Disease |
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| Online Access: | https://www.mdpi.com/2414-6366/8/3/174 |
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| author | Krishnamoorthy Nallan Gopinathan Rajan Lallitha Sivathanu Panneer Devaraju Balaji Thiruppathi Ashwani Kumar Paramasivan Rajaiah |
| author_facet | Krishnamoorthy Nallan Gopinathan Rajan Lallitha Sivathanu Panneer Devaraju Balaji Thiruppathi Ashwani Kumar Paramasivan Rajaiah |
| author_sort | Krishnamoorthy Nallan |
| collection | DOAJ |
| description | Scrub typhus (St) is a re-emerging mite-transmitted public health problem in Southeast Asia with escalating case incidences in the endemic areas. Though, more than 40 genotypes of the causative agent <i>Orientia tsutsugamushi</i> (<i>Ot</i>) have been documented, the information on the circulating genotypes in India is scanty. A hospital-based retrospective screening was undertaken to map the circulating molecular subtypes of the etiological agent in serologically confirmed scrub typhus (St) human cases, by targeting the GroEL gene of <i>O. tsutsugamushi</i> using the nested polymerase chain reaction method. Nine out of 34 samples (26%) yielded positive results and DNA sequencing analysis of six positive samples out of nine revealed that the sequences were related to three major genotypes, such as Karp (HSB1, FAR1), Kato (Wuj/2014, UT76), and Kawasaki (Kuroki, Boryong, Gilliam, and Hwasung). Additionally, the St-positive samples exhibited 100% and 99.45%; 97.53% and 97.81%; 96.99% nucleotide identity with the closely related Karp, Kato, and Kawasaki-related sequences, respectively. Overall, 94% of the nucleotides were conserved, and the variable site was 20/365 (5.5%). The prevalence of multiple genotypes among human cases further stresses the need to conduct in-depth studies to map the genotypes and their clinical relevance, and the contributing risk factors for the emergence of St cases in this area. |
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| series | Tropical Medicine and Infectious Disease |
| spelling | doaj.art-a5de9e9d105a44f388168c93990477cf2023-11-17T14:15:28ZengMDPI AGTropical Medicine and Infectious Disease2414-63662023-03-018317410.3390/tropicalmed8030174Molecular Detection of Multiple Genotypes of <i>Orientia tsutsugamushi</i> Causing Scrub Typhus in Febrile Patients from Theni District, South IndiaKrishnamoorthy Nallan0Gopinathan Rajan1Lallitha Sivathanu2Panneer Devaraju3Balaji Thiruppathi4Ashwani Kumar5Paramasivan Rajaiah6ICMR-Vector Control Research Centre, Field Unit, Madurai 625 002, IndiaDepartment of Microbiology, Government Medical College and Hospital, Theni 625 512, IndiaDepartment of Microbiology, Government Medical College and Hospital, Theni 625 512, IndiaICMR-Vector Control Research Centre, Puducherry 605 006, IndiaICMR-Vector Control Research Centre, Field Unit, Madurai 625 002, IndiaICMR-Vector Control Research Centre, Puducherry 605 006, IndiaICMR-Vector Control Research Centre, Field Unit, Madurai 625 002, IndiaScrub typhus (St) is a re-emerging mite-transmitted public health problem in Southeast Asia with escalating case incidences in the endemic areas. Though, more than 40 genotypes of the causative agent <i>Orientia tsutsugamushi</i> (<i>Ot</i>) have been documented, the information on the circulating genotypes in India is scanty. A hospital-based retrospective screening was undertaken to map the circulating molecular subtypes of the etiological agent in serologically confirmed scrub typhus (St) human cases, by targeting the GroEL gene of <i>O. tsutsugamushi</i> using the nested polymerase chain reaction method. Nine out of 34 samples (26%) yielded positive results and DNA sequencing analysis of six positive samples out of nine revealed that the sequences were related to three major genotypes, such as Karp (HSB1, FAR1), Kato (Wuj/2014, UT76), and Kawasaki (Kuroki, Boryong, Gilliam, and Hwasung). Additionally, the St-positive samples exhibited 100% and 99.45%; 97.53% and 97.81%; 96.99% nucleotide identity with the closely related Karp, Kato, and Kawasaki-related sequences, respectively. Overall, 94% of the nucleotides were conserved, and the variable site was 20/365 (5.5%). The prevalence of multiple genotypes among human cases further stresses the need to conduct in-depth studies to map the genotypes and their clinical relevance, and the contributing risk factors for the emergence of St cases in this area.https://www.mdpi.com/2414-6366/8/3/174scrub typhus<i>Orientia tsutsugamushi</i>antigenic variantschiggerKarpKato |
| spellingShingle | Krishnamoorthy Nallan Gopinathan Rajan Lallitha Sivathanu Panneer Devaraju Balaji Thiruppathi Ashwani Kumar Paramasivan Rajaiah Molecular Detection of Multiple Genotypes of <i>Orientia tsutsugamushi</i> Causing Scrub Typhus in Febrile Patients from Theni District, South India Tropical Medicine and Infectious Disease scrub typhus <i>Orientia tsutsugamushi</i> antigenic variants chigger Karp Kato |
| title | Molecular Detection of Multiple Genotypes of <i>Orientia tsutsugamushi</i> Causing Scrub Typhus in Febrile Patients from Theni District, South India |
| title_full | Molecular Detection of Multiple Genotypes of <i>Orientia tsutsugamushi</i> Causing Scrub Typhus in Febrile Patients from Theni District, South India |
| title_fullStr | Molecular Detection of Multiple Genotypes of <i>Orientia tsutsugamushi</i> Causing Scrub Typhus in Febrile Patients from Theni District, South India |
| title_full_unstemmed | Molecular Detection of Multiple Genotypes of <i>Orientia tsutsugamushi</i> Causing Scrub Typhus in Febrile Patients from Theni District, South India |
| title_short | Molecular Detection of Multiple Genotypes of <i>Orientia tsutsugamushi</i> Causing Scrub Typhus in Febrile Patients from Theni District, South India |
| title_sort | molecular detection of multiple genotypes of i orientia tsutsugamushi i causing scrub typhus in febrile patients from theni district south india |
| topic | scrub typhus <i>Orientia tsutsugamushi</i> antigenic variants chigger Karp Kato |
| url | https://www.mdpi.com/2414-6366/8/3/174 |
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