Note on the Origin of the Madagascar Strain of Plasmodium vivax

Recent studies have established the potential for strains of Plasmodium vivax in Madagascar to infect Duffy-negative populations, and polymerase chain reaction (PCR)-based screening suggests a previously unrecognized burden of this parasite in sub-Saharan Africa. There is a dearth of data concerning any P. vivax parasites from Africa; however, one of the most widely studied strains used during the malariotherapy era was the Madagascar strain, used at the Horton Hospital research site in the UK from 1923 to ca. 1970. This isolate has been the subject of extensive studies, but there has been considerable debate about the geographic origin of this strain, and two recent papers specifically suggest the origin may well be elsewhere. However, further detail is provided in the work of Percy G. Shute, the clinician and malariologist who personally interviewed and treated the index patient for this strain. In his comprehensive report (which is not readily available) related to this clinical isolate, he states: