Genetic profiling of Plasmodium ovale wallikeri relapses with microsatellite markers and whole-genome sequencing.

Like Plasmodium vivax, both Plasmodium ovale curtisi and Plasmodium ovale wallikeri have the ability to cause relapse in humans, defined as recurring asexual parasitaemia originating from liver dormant forms subsequent to a primary infection. Here, we investigated relapse patterns in P. ovale wallikeri infections from a cohort of travelers who were exposed to the parasite in Sub-Saharan Africa and then experienced relapses after their return to France. Using a novel set of eight highly polymorphic microsatellite markers, we genotyped 15 P. ovale wallikeri relapses. For most relapses, the paired primary and relapse infections were highly genetically related (with 12 being homologous), an observation that was confirmed by whole-genome sequencing for the four relapses we further studied. This is, to our knowledge, the first genetic evidence of relapses in P. ovale spp.