Evidence of strain structure in Plasmodium falciparum var gene repertoires in children from Gabon, West Africa

Karen P. Day, Yael Artzy-Randrup, Kathryn E. Tiedje, Virginie Rougeron, Donald S. Chen, Thomas S. Rask, Mary M. Rorick, Florence Migot-Nabias, Philippe Deloron, Adrian J.F. Luty, Mercedes Pascual

Research output: Contribution to journalArticlepeer-review


Existing theory on competition for hosts between pathogen strains has proposed that immune selection can lead to the maintenance of strain structure consisting of discrete, weakly overlapping antigenic repertoires. This prediction of strain theory has conceptual overlap with fundamental ideas in ecology on niche partitioning and limiting similarity between coexisting species in an ecosystem, which oppose the hypothesis of neutral coexistence. For Plasmodium falciparum, strain theory has been specifically proposed in relation to the major surface antigen of the blood stage, known as PfEMP1 and encoded by the multicopy multigene family known as the var genes. Deep sampling of the DBLα domain of var genes in the local population of Bakoumba, West Africa, was completed to define whether patterns of repertoire overlap support a role of immune selection under the opposing force of high outcrossing, a characteristic of areas of intense malaria transmission. Using a 454 high-throughput sequencing protocol, we report extremely high diversity of the DBLα domain and a large parasite population with DBLα repertoires structured into nonrandom patterns of overlap. Such population structure, significant for the high diversity of var genes that compose it at a local level, supports the existence of 'strains' characterized by distinct var gene repertoires. Nonneutral, frequency-dependent competition would be at play and could underlie these patterns. With a computational experiment that simulates an intervention similar to mass drug administration, we argue that the observed repertoire structure matters for the antigenic var diversity of the parasite population remaining after intervention.

Original languageEnglish (US)
Pages (from-to)E4103-E4111
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number20
StatePublished - May 16 2017


  • Gabon
  • Parasite diversity
  • Plasmodium falciparum
  • Strain structure
  • Var genes

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Evidence of strain structure in Plasmodium falciparum var gene repertoires in children from Gabon, West Africa'. Together they form a unique fingerprint.

Cite this