Genotyping Plasmodium vivax isolates from the 2011 outbreak in Greece

Abstract

BackgroundPlasmodium vivax malaria was common in Greece until the 1950s with epidemics involving thousands of cases every year. Greece was declared free of malaria by the World Health Organization in 1974. From 1974 to 2010, an average of 39 cases per year were reported, which were mainly imported. However, in 2009 and 2010 six and one autochthonous cases were reported culminating with a total of 40 autochthonous cases reported in 2011, of which 34 originated from a single region: Laconia of Southern Peloponnese. In this study the genotypic complexity of the P. vivax infections from the outbreak in Greece during 2011 is described, to elucidate the possible origin and spread of the disease.MethodsThree polymorphic markers of P. vivax were used; Pvmsp-3α and the microsatellites m1501 and m3502 on P. vivax isolates sampled from individuals diagnosed in Greece. Thirty-nine isolates were available for this study (20 autochthonous and 19 imported), mostly from Evrotas municipality in Laconia region, in southern Greece, (n = 29), with the remaining representing sporadic cases originating from other areas of Greece.ResultsGenotyping the Evrotas samples revealed seven different haplotypes where the majority of the P. vivax infections expressed two particular Pvmsp-3α-m1501-m3502 haplotypes, A10-128-151 (n = 14) and A10-121-142 (n = 7). These haplotypes appeared throughout the period in autochthonous and imported cases, indicating continuous transmission. In contrast, the P. vivax autochthonous cases from other parts of Greece were largely comprised of unique haplotypes, indicating limited transmission in these other areas.ConclusionsThe results indicate that several P. vivax strains were imported into various areas of Greece in 2011, thereby increasing the risk of re-introduction of malaria. In the region of Evrotas ongoing transmission occurred exemplifying that further control measures are urgently needed in this region of southern Europe. In circumstances where medical or travel history is scarce, methods of molecular epidemiology may prove highly useful for the correct classification of the cases.

Genetic Spatiotemporal Anatomy ofPlasmodium vivaxMalaria Episodes in Greece, 2009–2013

“…We pooled data available from a previous study for a subset of the samples (genotyped for a subset of markers) with the data we obtained using additional samples and microsatellite markers ( 13 ). We performed genotyping for PvMSP-3α and microsatellite loci m1501 and m3502 as previously described ( 13 ) and for microsatellite loci MS1, MS5, MS7, MS8, MS12, and MS20 as previously described ( 14 ).…”

“…We pooled data available from a previous study for a subset of the samples (genotyped for a subset of markers) with the data we obtained using additional samples and microsatellite markers ( 13 ). We performed genotyping for PvMSP-3α and microsatellite loci m1501 and m3502 as previously described ( 13 ) and for microsatellite loci MS1, MS5, MS7, MS8, MS12, and MS20 as previously described ( 14 ). For a subset of samples (n = 54) that yielded similar or closely related haplotypes, we performed genotyping for 4 additional polymorphic markers (3 microsatellite loci MS10, MS16, and Pv3.27, and the polymorphic F3 domain of PvMSP1 ), which are hereafter referred to as additional markers, as previously described ( 15 ).…”

“…The availability of archived blood samples from a substantial proportion of all the P. vivax malaria cases recorded in Greece during 2009–2013, including those from Laconia, provided the opportunity to investigate in detail the spatiotemporal distribution of P. vivax introduction during this period through a molecular description of select parasite polymorphic genetic markers ( 13 ). Here we report on the spatiotemporal genotypic data from these cases and discuss the insights the data provide on the potential for P. vivax to establish sustained transmission in vulnerable receptive areas.…”

Uncovering the transmission dynamics ofPlasmodium vivaxusing population genetics

“…Genotyping analyses conducted on a broad scale using informative markers could generate a database of population-specific genotypes or 'geographic markers', to identify the origin of imported cases. 50,85,86 Primarily, control programmes will need adequate surveillance to rapidly identify cases for investigation and the capacity to mount a response. In addition, the length of time and the advanced skills needed to conduct genetic analyses is a barrier that needs to be overcome before their implementation in a public health setting.…”

Population Genetics and Molecular Epidemiology of Eukaryotes

“…As the incidence fell, diversity returned to pre-outbreak levels (12). By contrast, during a resurgence of vivax malaria in Greece (109) and Sri Lanka (45) high parasite diversity indicated contribution from multiple strains consistent with rapid expansion of the local population. In the context of declining prevalence, this suggested multiple introductions, rather than clonal expansion.…”