1940s blood samples reveal historical spread of malaria

DNA from 75-year old eradicated European malaria parasites uncovers the historical spread of one of the two most common forms of the disease, Plasmodium vivax, from Europe to the Americas during the colonial period, finds a new study co-led by UCL. The research published in Molecular Biology and Evolution reports the genome sequence of a malaria parasite sourced from blood-stained medical microscope slides used in 1944 in Spain, one of the last footholds of malaria in Europe. Malaria was a major disease throughout Europe since antiquity and was only eradicated in the region in the 20th century. The international team, led by UCL, the Institute of Evolutionary Biology (IBE), Barcelona, and the University of Copenhagen, analysed microscopy slides from the 1940s that were obtained with permission from the medical collection of Dr Ildefonso Canicio, a Spanish malaria researcher from the early 1900s. The slides were used to diagnose patients suffering from malaria in Spain's Ebro Delta, where malaria was common until the 1960s. By comparing the genetic data from the slides to a global dataset of modern P. vivax genomes, the researchers found that the eradicated European malaria parasites were genetically most similar to tertian ( P. vivax ) malaria strains currently found in the Americas, including Mexico, Brazil and Peru. "Being able to obtain a full genome of extinct European Plasmodium vivax from these decades old slides allowed us to ask questions as to how malaria may have been affecting us centuries ago," said co-lead author Dr Lucy van Dorp (UCL Genetics Institute).