{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,4]],"date-time":"2026-02-04T16:21:33Z","timestamp":1770222093222,"version":"3.49.0"},"reference-count":25,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,2]],"date-time":"2026-02-02T00:00:00Z","timestamp":1769990400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Hainan Provincial Natural Science Foundation of China","award":["825RC880"],"award-info":[{"award-number":["825RC880"]}]},{"name":"Key Research and Development Plan of Hainan Province","award":["ZDYF2022SHFZ098"],"award-info":[{"award-number":["ZDYF2022SHFZ098"]}]},{"name":"Hainan Provincial International Science and Technology Cooperation Research and Development Project","award":["GHYF2024021"],"award-info":[{"award-number":["GHYF2024021"]}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"crossref","award":["82560403"],"award-info":[{"award-number":["82560403"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Guangzhou National Laboratory","award":["GZNL2023A01001"],"award-info":[{"award-number":["GZNL2023A01001"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Scrub typhus, caused by Orientia tsutsugamushi, remains a neglected cause of acute febrile illness. Molecular testing of blood supports early diagnosis, yet once doxycycline is started, blood qPCR positivity can drop rapidly, complicating short-term follow-up and relapse surveillance. We compared detection across multiple clinical specimens and evaluated nasopharyngeal swabs (NPSs) as noninvasive supplementary specimens during treatment initiation. In a prospective single-center cohort from Hainan, China, we enrolled 20 patients with scrub typhus. Blood, NPS, urine, and stool were collected before doxycycline administration 24 h after the first dose and on day 5. qPCR was performed for the analysis of Orientia tsutsugamushi. qPCR-positive specimens were subjected to nested PCR targeting TSA56, and nested PCR-positive amplicons were Sanger sequenced for genotyping. Before treatment, O. tsutsugamushi DNA was detected in 15\/20 blood samples (75.00%) and 5\/20 NPS samples (25.00%), but 0\/20 urine samples (0%) and 0\/20 stool samples (0%). At 24 h after treatment, detection in blood was 0\/20 (0%) while NPS samples were positive in 3\/20 (15.00%). All specimens were negative by day 5 after treatment. Across sequenced NPS positives (n = 3), Karp 2\/3 (66.77%) and Gilliam 1\/3 (33.33%) predominated. In paired blood\u2013NPS positives, inter-specimen homology was high (percentage nucleotide identity 100% for Karp and 100% for Gilliam). NPS is not sensitive enough for primary diagnosis; however, within the first 24 h after doxycycline it offers a practical, noninvasive supplementary specimen to support short-term follow-up and community-based sampling when venipuncture or transport are constrained. Larger, multi-center studies are warranted to refine sampling windows and diagnostic performance.<\/jats:p>","DOI":"10.3390\/pathogens15020158","type":"journal-article","created":{"date-parts":[[2026,2,2]],"date-time":"2026-02-02T09:48:08Z","timestamp":1770025688000},"page":"158","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Nasopharyngeal Swabs for Orientia tsutsugamushi Detection in Doxycycline Treatment: A Prospective Cohort Study in Hainan, China"],"prefix":"10.3390","volume":"15","author":[{"given":"Yuanze","family":"Chen","sequence":"first","affiliation":[{"name":"Department of Infectious Diseases, The Second Affiliated Hospital, Hainan Medical University, Haikou 570311, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-7114-3164","authenticated-orcid":false,"given":"Siqi","family":"Chen","sequence":"additional","affiliation":[{"name":"The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases\u2014Hainan Medical University, Key Laboratory of Tropical Translational Medicine of Ministry of Education, Academician Workstation of Hainan Province, School of Basic Medicine and Life Sciences, Hainan Medical University, Haikou 571199, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jiajia","family":"An","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, The Second Affiliated Hospital, Hainan Medical University, Haikou 570311, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xiaojing","family":"Zheng","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, The Second Affiliated Hospital, Hainan Medical University, Haikou 570311, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Qi","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, The Second Affiliated Hospital, Hainan Medical University, Haikou 570311, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuyan","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, The Second Affiliated Hospital, Hainan Medical University, Haikou 570311, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wenjing","family":"Fu","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, The Second Affiliated Hospital, Hainan Medical University, Haikou 570311, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Biao","family":"Wu","sequence":"additional","affiliation":[{"name":"Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou 570100, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yongguo","family":"Du","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, The Second Affiliated Hospital, Hainan Medical University, Haikou 570311, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Feifei","family":"Yin","sequence":"additional","affiliation":[{"name":"The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases\u2014Hainan Medical University, Key Laboratory of Tropical Translational Medicine of Ministry of Education, Academician Workstation of Hainan Province, School of Basic Medicine and Life Sciences, Hainan Medical University, Haikou 571199, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7032-6757","authenticated-orcid":false,"given":"Liyuan","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, The Second Affiliated Hospital, Hainan Medical University, Haikou 570311, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Taylor, A.J., Paris, D.H., and Newton, P.N. 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