{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T05:29:35Z","timestamp":1782365375531,"version":"3.54.5"},"reference-count":41,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,8,29]],"date-time":"2025-08-29T00:00:00Z","timestamp":1756425600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Microbiol."],"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p>Scrub typhus (ST), is a vector borne zoonotic disease, transmitted by the larva of the trombiculid mites. The enzootic cycle of the pathogen involves rodents\/shrews as the animal reservoirs and humans are the accidental dead-end host. A transposon-like activity in its major antigen 56\u202fkDa, has led to the evolution of several serotypes\/strains, and more than 40 serotypes are reported globally. Puducherry, India, is endemic to scrub, but limited data exist on local serotype distribution across hosts and vectors.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methodology<\/jats:title><jats:p>A longitudinal molecular surveillance was conducted in Puducherry to investigate the genetic diversity of <jats:italic>Orientia tsutsugamushi<\/jats:italic> among humans, animal reservoirs, and vectors. Samples from febrile patients, trapped rodents\/shrews, and their infesting mites were screened using real-time and nested PCR. Serotype analysis was performed by partial amplification and sequencing of the 56\u202fkDa gene, followed by phylogenetic, pairwise genetic distance and amino acid analysis.<\/jats:p><\/jats:sec><jats:sec><jats:title>Result<\/jats:title><jats:p>ST infection was detected in 4.37% (95% CI: 3.05\u20135.71%) of human, 11.52% (95% CI: 8.6\u201314.4%) of rodent\/shrew, and 2.36% (95% CI: 0.95\u20134.87%) of mite samples. Karp-like (51.72%) and Gilliam-like (41.38%) strains were predominant in both humans and animal hosts, with pairwise genetic distance (&amp;lt;0.1) and amino acid identity (&amp;gt;85%) analysis revealing a close relationship between the strains identified across the region. Notably, the only mite pool that tested positive for the 56\u202fkDa gene, along with a shrew, was identified to belong to the TA678-like serotype (6.90%), which has not been previously reported from Puducherry.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>This study provides molecular evidence of the enzootic maintenance and active human transmission of <jats:italic>O. tsutsugamushi<\/jats:italic> in Puducherry, with multiple co-circulating serotypes. The first detection of the TA678-like strain in the region suggests the possible introduction of new strains and underscores the need to monitor for strain-specific clinical manifestations in future studies.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fmicb.2025.1634394","type":"journal-article","created":{"date-parts":[[2025,8,29]],"date-time":"2025-08-29T05:43:39Z","timestamp":1756446219000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":3,"title":["A longitudinal molecular surveillance of genetic heterogeneity of Orientia tsutsugamushi in humans, reservoir animals, and vectors in Puducherry, India"],"prefix":"10.3389","volume":"16","author":[{"given":"Krishan Kumar","family":"Sihag","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Waseema","family":"Arif","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Srikanth","family":"Srirama","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anand Kumar","family":"Chandrasekaran","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vinod","family":"Raveendran","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Asayas Bosco","family":"Chandrakumar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anand","family":"Kasirajan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sivagamy Alias Punitha","family":"Thavaraj","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lakshmy","family":"Srinivasan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anoop C.","family":"Choolayil","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mathivanan","family":"Ashokkumar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amala","family":"Ramasamy","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nanda Kumar","family":"Yellapu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Panneer","family":"Devaraju","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2025,8,29]]},"reference":[{"key":"ref1","volume-title":"Taxonomic studies on Indian Muridae and Hystricidae (Mammalia: Rodentia)","author":"Agrawal","year":"2000"},{"key":"ref2","doi-asserted-by":"publisher","DOI":"10.4172\/2472-4998.1000124","article-title":"Occurrence of Orientia tsutsugamushi genotypes in areas of union territory of Puducherry and Tamil Nadu state, India","volume":"2","author":"Anitha","year":"2017","journal-title":"J. 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