{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T16:13:28Z","timestamp":1780330408941,"version":"3.54.1"},"reference-count":28,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,4,7]],"date-time":"2026-04-07T00:00:00Z","timestamp":1775520000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100015691","name":"Division of Microbiology and Infectious Diseases","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100015691","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Parasitol."],"abstract":"<jats:p>\n                    Malaria remains a major public health concern in Cameroon, with\n                    <jats:italic>Plasmodium falciparum<\/jats:italic>\n                    responsible for most morbidity and mortality, particularly among children under five. In response to rising cases, Cameroon began implementing the RTS,S\/AS01 malaria vaccine in early 2024. Given the vaccine\u2019s strain-specific efficacy, understanding haplotypic diversity is critical for evaluating long-term impact. We analyzed 100\u00a0\n                    <jats:italic>P. falciparum<\/jats:italic>\n                    -positive dried blood spots collected in Mapoussere, Kaele Health District (2022\u20132023). Using the 4CAST amplicon sequencing assay, we targeted four genes:\n                    <jats:italic>csp<\/jats:italic>\n                    (circumsporozoite protein),\n                    <jats:italic>ama1<\/jats:italic>\n                    (apical membrane antigen 1),\n                    <jats:italic>sera2<\/jats:italic>\n                    (serine repeat antigen 2), and\n                    <jats:italic>trap<\/jats:italic>\n                    (thrombospondin-related anonymous protein). Haplotypes were identified using SeekDeep, and diversity metrics including heterozygosity (He), nucleotide diversity (\u03c0), and selection statistics (Tajima\u2019s\n                    <jats:italic>D<\/jats:italic>\n                    , Fu and Li\u2019s\n                    <jats:italic>D*<\/jats:italic>\n                    ,\n                    <jats:italic>F*<\/jats:italic>\n                    ) were computed. We successfully genotyped\n                    <jats:italic>csp<\/jats:italic>\n                    in 35% of samples, identifying 22 haplotypes (He = 0.908; \u03c0 = 0.021). The vaccine-matched haplotype was present in 20% of genotyped infections. The T cell TH2 and TH3 epitopes of\n                    <jats:italic>csp<\/jats:italic>\n                    showed signs consistent with balancing selection. Both\n                    <jats:italic>ama1<\/jats:italic>\n                    and\n                    <jats:italic>sera2<\/jats:italic>\n                    exhibited higher genotyping success and diversity, with\n                    <jats:italic>ama<\/jats:italic>\n                    showing significant Tajima\u2019s\n                    <jats:italic>D<\/jats:italic>\n                    values. Within-participant haplotype counts were highest for\n                    <jats:italic>ama1<\/jats:italic>\n                    (mean = 2.8), followed by\n                    <jats:italic>sera2<\/jats:italic>\n                    (2.1),\n                    <jats:italic>csp<\/jats:italic>\n                    (1.3), and\n                    <jats:italic>trap<\/jats:italic>\n                    (1.2). This study provides a baseline of\n                    <jats:italic>P. falciparum<\/jats:italic>\n                    haplotype diversity in a vaccine-targeted region. The presence of vaccine-matched strains and high diversity in TH2\/TH3 epitopes in\n                    <jats:italic>csp<\/jats:italic>\n                    may influence vaccine efficacy. Continued molecular surveillance is essential to monitor antigenic shifts and guide future strategies.\n                  <\/jats:p>","DOI":"10.3389\/fpara.2026.1749169","type":"journal-article","created":{"date-parts":[[2026,4,7]],"date-time":"2026-04-07T11:17:48Z","timestamp":1775560668000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["Haplotype diversity of Plasmodium falciparum circumsporozoite protein prior to malaria vaccine implementation in Kael\u00e9 Health District, Cameroon, 2022\u20132023"],"prefix":"10.3389","volume":"5","author":[{"given":"Innocent M.","family":"Ali","sequence":"first","affiliation":[{"name":"Department of Biochemistry, Faculty of Science, Universit\u00e9 de Dschang","place":["Dschang, Cameroon"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brenda","family":"Vasquez Martinez","sequence":"additional","affiliation":[{"name":"Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill","place":["Chapel Hill, NC, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Valery P. K.","family":"Tchuenkam","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, Faculty of Science, Universit\u00e9 de Dschang","place":["Dschang, Cameroon"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jacob M.","family":"Sadler","sequence":"additional","affiliation":[{"name":"Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill","place":["Chapel Hill, NC, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Catherine C.","family":"Gorman","sequence":"additional","affiliation":[{"name":"Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill","place":["Chapel Hill, NC, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sandrine E.","family":"Nsango","sequence":"additional","affiliation":[{"name":"Centre Pasteur du Cameroun","place":["Yaound\u00e9, Cameroon"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Voundi Voundi","family":"Junior","sequence":"additional","affiliation":[{"name":"National Malaria Control Program, Ministry of Public Health","place":["Yaounde, Cameroon"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joel Marcellin","family":"Ateba","sequence":"additional","affiliation":[{"name":"National Malaria Control Program, Ministry of Public Health","place":["Yaounde, Cameroon"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Grace Yimga","family":"Wanda","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, Faculty of Science, Universit\u00e9 de Dschang","place":["Dschang, Cameroon"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jeffrey A.","family":"Bailey","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, Brown University","place":["Providence, RI, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rhoel R.","family":"Dinglasan","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Immunology and the Emerging Pathogens Institute, College of Veterinary Medicine, University of Florida","place":["Gainesville, FL, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jessica T.","family":"Lin","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, Faculty of Science, Universit\u00e9 de Dschang","place":["Dschang, Cameroon"]},{"name":"Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill","place":["Chapel Hill, NC, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jonathan J.","family":"Juliano","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, Faculty of Science, Universit\u00e9 de Dschang","place":["Dschang, Cameroon"]},{"name":"Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill","place":["Chapel Hill, NC, United States"]},{"name":"Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill","place":["Chapel Hill, NC, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,4,7]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"1863","DOI":"10.1056\/NEJMoa1102287","article-title":"First results of phase 3 trial of RTS,S\/AS01 malaria vaccine in African children","volume":"365","author":"Agnandji","year":"2011","journal-title":"N. 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