{"id":523,"date":"2025-11-06T20:35:55","date_gmt":"2025-11-06T22:35:55","guid":{"rendered":"https:\/\/sites.usp.br\/lambs\/?p=523"},"modified":"2025-11-06T20:35:55","modified_gmt":"2025-11-06T22:35:55","slug":"paper-how-duffy-blood-group-fy-polymorphism-and-age-modulate-vivax-malaria-risk-at-the-community-level-a-population-based-retrospective-cohort-study-in-the-amazon","status":"publish","type":"post","link":"https:\/\/sites.usp.br\/lambs\/paper-how-duffy-blood-group-fy-polymorphism-and-age-modulate-vivax-malaria-risk-at-the-community-level-a-population-based-retrospective-cohort-study-in-the-amazon\/","title":{"rendered":"Paper: How Duffy blood group (FY) polymorphism and age modulate vivax malaria risk at the community level: a population-based retrospective cohort study in the Amazon"},"content":{"rendered":"<p style=\"font-weight: 400;\"><strong><em>Background. <\/em><\/strong>A promoter variant commonly found in sub-Saharan Africans and their descendants disrupts Duffy antigen (Fy) expression on erythrocytes, leading to the Fy-negative phenotype, and confers partial resistance to blood-stage <em>Plasmodium vivax<\/em>infection. In addition, the 125G-&gt;A substitution, rare in Africans, defines the Fy<sup>a<\/sup>\/Fy<sup>b<\/sup> polymorphism that can modulate vivax malaria risk in Amazonians. The combined effect of these <em>FY <\/em>polymorphisms on <em>P. vivax<\/em> infection risk remains little explored at the population level.<\/p>\n<p style=\"font-weight: 400;\"><strong><em>Methods. <\/em><\/strong>We studied a household-based random sample of 1,737 Amazonians, with a well-balanced distribution of <em>FY<\/em> alleles, who were exposed to <em>P. vivax<\/em> transmission and contributed 7,878.9 person-years of follow-up. We fitted a multivariable zero-inflated negative binomial model to incidence data, assuming that zero counts could arise from individuals at risk who remained uninfected over 5 years of follow-up (\u201csampling zeroes\u201d) or from not-at-risk individuals (\u201cstructural zeroes\u201d).<\/p>\n<p style=\"font-weight: 400;\"><strong><em>Results<\/em><\/strong>. <em>Plasmodium vivax<\/em> infections were heterogeneously distributed in the population, with 0 to 11 cases per person (average incidence, 25.8 cases\/100 person-years at risk). We show that Fy-negativity remains a major malaria resistance trait in Amazonians and contributes significantly to the \u201cstructural zeroes\u201d observed in <em>P. vivax<\/em> incidence data. Moreover, the differences in <em>P. vivax<\/em>infection risk associated with the Fy<sup>a<\/sup>\/Fy<sup>b<\/sup> polymorphism observed among young participants were attenuated with increasing age, most likely because more susceptible Fy(b+) individuals develop clinical immunity faster than less susceptible Fy(a+) individuals.<\/p>\n<p style=\"font-weight: 400;\"><strong><em>Conclusions. <\/em><\/strong><em>FY<\/em> polymorphism appears to modulate the rate at which immunity to <em>P. vivax<\/em> develops in Amazonians, with clear clinical and public health implications.<\/p>\n<p>Check it out: <a href=\"https:\/\/doi.org\/10.1093\/infdis\/jiaf562\">https:\/\/doi.org\/10.1093\/infdis\/jiaf562<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Background. A promoter variant commonly found in sub-Saharan Africans and their descendants disrupts Duffy antigen (Fy) expression on erythrocytes, leading to the Fy-negative phenotype, and confers partial resistance to blood-stage Plasmodium vivaxinfection. In addition, the 125G-&gt;A substitution, rare in Africans, defines the Fya\/Fyb polymorphism that can modulate vivax malaria risk in Amazonians. The combined effect [&hellip;]<\/p>\n","protected":false},"author":23934,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[1],"tags":[],"class_list":["post-523","post","type-post","status-publish","format-standard","hentry","category-posts"],"_links":{"self":[{"href":"https:\/\/sites.usp.br\/lambs\/wp-json\/wp\/v2\/posts\/523","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.usp.br\/lambs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sites.usp.br\/lambs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sites.usp.br\/lambs\/wp-json\/wp\/v2\/users\/23934"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.usp.br\/lambs\/wp-json\/wp\/v2\/comments?post=523"}],"version-history":[{"count":2,"href":"https:\/\/sites.usp.br\/lambs\/wp-json\/wp\/v2\/posts\/523\/revisions"}],"predecessor-version":[{"id":550,"href":"https:\/\/sites.usp.br\/lambs\/wp-json\/wp\/v2\/posts\/523\/revisions\/550"}],"wp:attachment":[{"href":"https:\/\/sites.usp.br\/lambs\/wp-json\/wp\/v2\/media?parent=523"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sites.usp.br\/lambs\/wp-json\/wp\/v2\/categories?post=523"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sites.usp.br\/lambs\/wp-json\/wp\/v2\/tags?post=523"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}