Genetic analysis reveals unique characteristics of Plasmodium falciparum parasite populations in Haiti

Rachel F Daniels,Dyann F Wirth,Eric Rogier,Michelle A Chang,Jacques Boncy,Camelia Herman,Venkatachalam Udhayakumar,Baby Pierre,Jean Frantz Lemoine,Naomi Lucchi,Sarah K Volkman,Stella Chenet

doi:10.1186/s12936-020-03439-7

Abstract

BackgroundWith increasing interest in eliminating malaria from the Caribbean region, Haiti is one of the two countries on the island of Hispaniola with continued malaria transmission. While the Haitian population remains at risk for malaria, there are a limited number of cases annually, making conventional epidemiological measures such as case incidence and prevalence of potentially limited value for fine-scale resolution of transmission patterns and trends. In this context, genetic signatures may be useful for the identification and characterization of the Plasmodium falciparum parasite population in order to identify foci of transmission, detect outbreaks, and track parasite movement to potentially inform malaria control and elimination strategies.MethodsThis study evaluated the genetic signals based on analysis of 21 single-nucleotide polymorphisms (SNPs) from 462 monogenomic (single-genome) P. falciparum DNA samples extracted from dried blood spots collected from malaria-positive patients reporting to health facilities in three southwestern Haitian departments (Nippes, Grand’Anse, and Sud) in 2016.ResultsAssessment of the parasite genetic relatedness revealed evidence of clonal expansion within Nippes and the exchange of parasite lineages between Nippes, Sud, and Grand'Anse. Furthermore, 437 of the 462 samples shared high levels of genetic similarity–at least 20 of 21 SNPS–with at least one other sample in the dataset.ConclusionsThese results revealed patterns of relatedness suggestive of the repeated recombination of a limited number of founding parasite types without significant outcrossing. These genetic signals offer clues to the underlying relatedness of parasite populations and may be useful for the identification of the foci of transmission and tracking of parasite movement in Haiti for malaria elimination.

Highlights

With increasing interest in eliminating malaria from the Caribbean region, Haiti is one of the two countries on the island of Hispaniola with continued malaria transmission
Individuals of all ages seeking treatment at clinics located at the sentinel sites with symptoms of malaria who tested positive for malaria by either microscopy or rapid diagnostic test (RDT) from March 2016 to December 2017 were considered eligible to participate
The use of the population genetic approaches relies on the routine collection of parasite genetic data since the discriminatory power of the genotyping method depends on the local epidemiology and transmission setting

Summary

Introduction

With increasing interest in eliminating malaria from the Caribbean region, Haiti is one of the two countries on the island of Hispaniola with continued malaria transmission. While the Haitian population remains at risk for malaria, there are a limited number of cases annually, making conventional epidemiological measures such as case incidence and prevalence of potentially limited value for fine-scale resolution of transmission patterns and trends. In this context, genetic signatures may be useful for the identification and characterization of the Plasmodium falciparum parasite population in order to identify foci of transmission, detect outbreaks, and track parasite movement to potentially inform malaria control and elimination strategies. As part of ongoing malaria elimination efforts, surveys have been carried out to understand the overall prevalence and transmission foci of the disease in Haiti

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