Clinical malaria incidence following an outbreak in Ecuador was predominantly associated withPlasmodium falciparumwith recombinant variant antigen gene repertoires Journal Article uri icon

Overview

abstract

  • AbstractTo better understand the factors underlying the continued incidence of clinical episodes of falciparum malaria in E-2020 countries targeting elimination, we have characterisedPlasmodium falciparumdisease transmission dynamics after a clonal outbreak on the northwest coast of Ecuador over a period of two years. We apply a novel, high-resolution genotyping method, the “varcode” based on a single PCR to fingerprint the DBLα region of the 40-60 members of the variant surface antigen-encodingvarmultigene family.Vargenes are highly polymorphic within and between genomes, withvarrepertoires rapidly evolving by outcrossing during the obligatory sexual phase ofP. falciparumin the mosquito. The continued incidence of clinical malaria after the outbreak in Ecuador provided a unique opportunity to usevarcodes to document parasite microevolution and explore signatures of local disease transmission on the time scale of months to two years post-outbreak. We identified nine geneticvarcodes circulating locally with spatiotemporal parasite genetic relatedness networks revealing that diversification of the clonal outbreak parasites by sexual recombination was associated with increased incidence of clinical episodes of malaria. Whether this was due to chance, immune selection or sexual recombination per se is discussed. Comparative analyses to other South American parasite populations whereP. falciparumtransmission remains endemic elucidated the possible origins of Ecuadorianvarcodes. This analysis demonstrated that the majority of clinical cases were due to local transmission and not importation. Nonetheless, some of thevarcodes that were unrelated to the outbreakvarcode were found to be genetically related to other South American parasites. Our findings demonstrate the utility of thevarcode as a high-resolution surveillance tool to spatiotemporally track disease outbreaks using variant surface antigen genes and resolve signatures of recombination in an E-2020 setting nearing elimination.

publication date

  • April 15, 2021

has restriction

  • green

Date in CU Experts

  • April 18, 2021 6:30 AM

Full Author List

  • Ruybal-Pesántez S; Sáenz FE; Deed S; Johnson EK; Larremore DB; Vera-Arias CA; Tiedje KE; Day KP

author count

  • 8

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