Old Plasmodium DNA from Spain hints at parasite origins

After the certification of eradication of malaria in Spain in 1964, and in southern Europe in the mid-20th century, several studies focused on the capacity of the former malaria vector Anopheles atroparvus, still present in the region, to transmit different malaria parasites, mainly Plasmodium vivax and Plasmodium falciparum. A strain of An. atroparvus from Ebro delta in Tarragona was isolated and maintained and tests were carried out to determine its sensibility to P. falciparum, showing no infectivity. In 2015, a set of slides with blood stains of malaria-affected people from the Ebro delta, dated between 1942-1944, were recovered in a local medical collection. DNA was extracted from the slides, a subset stained with Giemsa and another consisting of dried blood spots; data was generated using Illumina sequencing. P. vivax and P. falciparum mitochondrial genome sequences were subsequently reconstructed from the resulting data. Phylogenetic analysis of the eradicated European P. vivax mtDNA genome indicates that the European isolate is closely related to the most common present-day American haplotype and likely entered the American continent post-Columbian contact. Furthermore, the European P. falciparum mtDNA indicates a link with current Indian strains that is in agreement with historical accounts. Present and future results will give light on the interaction vector parasite and supports that present Plasmodium distribution is a result of a series of human mediated dispersals involving transport between different continents. (Texte integral