{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,28]],"date-time":"2026-01-28T18:50:29Z","timestamp":1769626229888,"version":"3.49.0"},"reference-count":46,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,1,28]],"date-time":"2026-01-28T00:00:00Z","timestamp":1769558400000},"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. Cell. Infect. Microbiol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>\n                      Malaria remains a persistent health challenge in southern Saudi Arabia, particularly along the border with Yemen. Understanding the genetic diversity and population structure of\n                      <jats:italic>Plasmodium falciparum<\/jats:italic>\n                      antigens is essential for tracking transmission dynamics and informing vaccine design. This study characterises population genetics of the Cell-Traversal Protein for Ookinetes and Sporozoites (\n                      <jats:italic>CelTOS<\/jats:italic>\n                      ) gene in Jazan Province, a region of active transmission and frequent cross-border movement.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      We analysed 202 high-quality\n                      <jats:italic>P. falciparum CelTOS<\/jats:italic>\n                      coding sequences from 201 patients in Jazan. Diversity indices and neutrality tests were estimated in DnaSP, and demographic history was assessed using mismatch-distribution models (SSD, raggedness). Gene-wide dN\/dS (\u03c9) was derived from MEGA pairwise distances, and recombination was evaluated using PHI and GARD. Recombination-aware codon-based models (SLAC, FEL, MEME, and FUBAR) were implemented via Datamonkey. Population structure was examined using pairwise F\n                      <jats:sub>ST<\/jats:sub>\n                      , AMOVA, principal coordinate analysis (PCoA), and PERMANOVA. Haplotype networks were stratified by nationality, parasite density, region, and season, and parasitaemia correlates were explored using multivariable regression.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      The 726-bp\n                      <jats:italic>CelTOS<\/jats:italic>\n                      alignment contained 18 segregating sites and 27 haplotypes (Hd = 0.921; \u03c0 = 0.0059). Gene-wide \u03c9 was \u22480.36, consistent with predominant purifying selection, with only a few codons showing episodic diversifying selection. The mismatch distribution was unimodal (SSD = 0.029; raggedness = 0.0487), and recombination tests indicated low-level intragenic recombination (PHI p = 1.44 \u00d7 10\n                      <jats:sup>\u22125<\/jats:sup>\n                      ; Rm = 4). Pairwise F\n                      <jats:sub>ST<\/jats:sub>\n                      values were essentially zero, and PERMANOVA showed a weak, non-significant regional structure. Dominant\n                      <jats:italic>CelTOS<\/jats:italic>\n                      haplotypes were shared across nationality, density, and regional and seasonal strata. In the main logistic model (PD4 vs. PD1\u2013PD3), age (OR 1.03; 95% CI 1.00\u20131.06) and non-Saudi nationality (OR 2.21; 95% CI 1.02\u20134.81) showed modest associations with very high parasitaemia.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>\n                      <jats:italic>CelTOS<\/jats:italic>\n                      diversity in Jazan is characterised by high haplotype but low nucleotide diversity within a largely panmictic, recombining parasite population. Extensive haplotype sharing across demographic and ecological gradients underscores strong gene flow, supporting cross-border, year-round control strategies and highlighting\n                      <jats:italic>CelTOS<\/jats:italic>\n                      as a relevant marker for vaccine development and molecular surveillance in this elimination setting.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fcimb.2025.1660506","type":"journal-article","created":{"date-parts":[[2026,1,28]],"date-time":"2026-01-28T06:44:23Z","timestamp":1769582663000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Genetic diversity and haplotype structure of the CelTOS gene in Plasmodium falciparum from Jazan Province, Saudi Arabia: implications for vaccine development and malaria elimination"],"prefix":"10.3389","volume":"15","author":[{"given":"Hani","family":"Alothaid","sequence":"first","affiliation":[{"name":"Department of Basic Medical Sciences, Faculty of Applied Medical Sciences, Al-Baha University","place":["Al\u2212Baha, Saudi Arabia"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fatimah","family":"Alghnnam","sequence":"additional","affiliation":[{"name":"Department of Infection and Immunity, Research Centre, King Faisal Specialist Hospital and Research Centre","place":["Riyadh, Saudi Arabia"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Arwa A.","family":"Al-Qahtani","sequence":"additional","affiliation":[{"name":"Department of Family Medicine, College of Medicine, Imam Mohammad Ibn Saud Islamic University (IMSIU)","place":["Riyadh, Saudi Arabia"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Abdullah","family":"Al Marzan","sequence":"additional","affiliation":[{"name":"Department of Data Science, Toxicology Society of Bangladesh","place":["Dhaka, Bangladesh"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mashael","family":"Abu Alola","sequence":"additional","affiliation":[{"name":"Department of Infection and Immunity, Research Centre, King Faisal Specialist Hospital and Research Centre","place":["Riyadh, Saudi Arabia"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marie Fe F.","family":"Bohol","sequence":"additional","affiliation":[{"name":"Department of Infection and Immunity, Research Centre, King Faisal Specialist Hospital and Research Centre","place":["Riyadh, Saudi Arabia"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fatimah","family":"Alhamlan","sequence":"additional","affiliation":[{"name":"Department of Infection and Immunity, Research Centre, King Faisal Specialist Hospital and Research Centre","place":["Riyadh, Saudi Arabia"]},{"name":"Department of Microbiology and Immunology, School of Medicine, Alfaisal University","place":["Riyadh, Saudi Arabia"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mohammed I.","family":"Shafeai","sequence":"additional","affiliation":[{"name":"Sabya General Hospital","place":["Sabya, Saudi Arabia"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fuad H.","family":"Rudiny","sequence":"additional","affiliation":[{"name":"Sabya General Hospital","place":["Sabya, Saudi Arabia"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ali M.","family":"Motaen","sequence":"additional","affiliation":[{"name":"Sabya General Hospital","place":["Sabya, Saudi Arabia"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ahmed A.","family":"Al-Qahtani","sequence":"additional","affiliation":[{"name":"Department of Infection and Immunity, Research Centre, King Faisal Specialist Hospital and Research Centre","place":["Riyadh, Saudi Arabia"]},{"name":"Department of Microbiology and Immunology, School of Medicine, Alfaisal University","place":["Riyadh, Saudi Arabia"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,1,28]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"25","DOI":"10.1016\/j.meegid.2014.06.015","article-title":"The prospect of malaria elimination in the Arabian Peninsula: a population genetic approach","volume":"27","author":"Al-Hamidhi","year":"2014","journal-title":"Infect Genet. 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