Use of rapid diagnostic tests for the detection of ancient malaria infections in dental pulp from the sixth century in Versailles, France

BACKGROUND: Paleomicrobiological data have clarified that Plasmodium spp. was circulating in the past in southern European populations, which are now devoid of malaria. The aim of this study was to evaluate the efficacy of immunodetection and, more particularly, rapid diagnostic tests (RDT), in order to further assess Plasmodium infections in ancient northern European populations. METHODS: A commercially available RDT, PALUTOP(®) + 4 OPTIMA, which is routinely used to detect malaria, was used to detect Plasmodium antigens from proteins recovered from ancient specimens extracted from 39 dental pulp samples. These samples were collected from 39 individuals who were buried in the sixth century, near the site of the current Palace of Versailles in France. Positive and negative controls were also used. Antigens detected were quantified using chemiluminescence imaging system analysis. RESULTS: Plasmodium antigens were detected in 14/39 (35.9%) individuals, including Plasmodium vivax antigens in 11 individuals and Plasmodium falciparum antigens co-detected in two individuals, while Pan-Plasmodium antigens were detected in three individuals. Controls all yielded expected results. CONCLUSIONS: The data reported here showed that RDTs are a suitable tool for detecting Plasmodium spp. antigens in ancient dental pulp samples, and demonstrated the existence of malaria in Versailles, France, in the sixth century. Plasmodium vivax, which is regarded as being responsible for an attenuated form of malaria and less deadly forms, was the most prevalent species. This illustrates, for the first time in ancient populations, co-infection with P. falciparum, bringing into question the climate-driven ecosystems prevailing at that time in the Versailles area.