A family’s collection of antique microscope slides became a trove of genetic information about the eradicated European malaria pathogen. These slides of stained blood droplets date to the 1940s and contain strains of the malaria parasite that are now extinct (image).
Lalueza-Fox and his colleagues were left with the first genetic material of extinct European Plasmodium species ever studied. They recovered DNA from both P. falciparum, the predominant species in Africa and the species responsible for the majority of today’s malaria deaths, and P. vivax, a less virulent species found widely across the globe. Scientists have long debated how P. vivax arrived in the Americas, with one theory suggesting colonial Europeans brought the pathogen over, while another posits entry from the other direction, when early humans crossed the Bering Land Bridge from Asia. The two theories, notes Jane Carlton, a malaria researcher at New York University who was not involved in the study, are not necessarily mutually exclusive.
The extinct European P. vivax genome more closely resembled strains found today in South America than those found in East Asia, lending credibility to the theory of a more recent introduction by European colonists. The European P. falciparum genome, however, was starkly divergent from the modern South American subtype, supporting the theory that this more-deadly species came to South America directly from Africa during the slave trade.
Missing Link in Malaria Evolution Discovered in Historical Specimens
Source: The Scientist Magazine®
Image: Charles Aranda