Population Genomics of Plasmodium vivax in Papua New Guinea

Understanding of the biology of P.vivax is lagging far behind that of the higher profile Plasmodium falciparum.

In the laboratory, this is largely due to the absence of an in vitro culture model for P.vivax, and in the field it is undoubtedly due to under-recognition of the problem it presents.

If malaria is to be controlled globally then P.vivax must be controlled; and if P.vivax is to be controlled, then we must focus efforts on understanding the factors underlying the dynamics of transmission and the acquisition of immunity to it.

This will underpin the development of evidence based interventions and support the development of new therapeutics, such as vaccines.

2011-2014

One of the fundamental factors governing transmission and immunity is parasite diversity.

Understanding the way in which natural parasite populations structure genetically gives us real insight into the pattern of transmission, and therefore the possible impact of intervention, and the spread of traits such as drug resistance.

Studying the population structure of genes under immune selection also allows us to explore the dynamic interplay between transmission and immunity.

This is also important in predicting the impact of potential vaccines, possibly even driving the empirical design of vaccines with optimal coverage.

In this study we aim to investigate the population genetics of P.vivax in Papua New Guinea, taking advantage of valuable sample sets collected by the CIs from cross-sectional surveys with distinct geographic separation, at both a local and regional level, which were repeated after a 2 year interval.

After using microsatellite typing to perform traditional population genetics, we will concentrate on analysing a series of genes under immune selection, all of which are potential vaccine candidates.

While adding to the understanding of the population structure, this will also have practical application in ranking these candidates in terms of immune pressure, diversity and breadth of potential coverage.

In the final part of the study we explore the use of the population genetic data to produce reagents that can be applied in monitoring the acquisition of P.vivax immunity relative to exposure to the strains circulating in the community.