Genotyping Plasmodium vivax isolates from the 2011 outbreak in Greece

Area of Science:

• Molecular Epidemiology
• Infectious Disease Dynamics
• Parasitology

Background:

• Greece was declared malaria-free in 1974, but imported Plasmodium vivax malaria cases increased post-2000.
• A significant rise in autochthonous (locally acquired) malaria cases occurred in 2011, primarily in Laconia, Southern Peloponnese.
• This resurgence prompted an investigation into the genetic diversity of P. vivax strains to understand disease origin and spread.

Purpose of the Study:

• To describe the genotypic complexity of Plasmodium vivax infections during the 2011 outbreak in Greece.
• To elucidate the potential origin and transmission patterns of P. vivax malaria in the affected regions.
• To assess the utility of molecular epidemiology in classifying malaria cases.

Main Methods:

• Genotyping of P. vivax isolates using three polymorphic markers: Pvmsp-3α, and microsatellites m1501 and m3502.
• Analysis of 39 P. vivax isolates, including 20 autochthonous and 19 imported cases, predominantly from the Evrotas municipality in Laconia.
• Comparison of haplotypes between autochthonous and imported cases across different regions of Greece.

Main Results:

• Seven distinct P. vivax haplotypes were identified in the Evrotas samples.
• Two dominant haplotypes (A10-128-151 and A10-121-142) were prevalent in both autochthonous and imported cases in Evrotas, suggesting continuous local transmission.
• Autochthonous cases outside Evrotas exhibited mostly unique haplotypes, indicating limited transmission in those areas.

Conclusions:

• The study identified multiple imported P. vivax strains contributing to malaria risk in Greece.
• Ongoing transmission was confirmed in the Evrotas region, necessitating enhanced malaria control strategies in Southern Europe.
• Molecular epidemiology tools are valuable for accurate case classification, especially when clinical or travel histories are incomplete.