African clade The species infecting Old World monkeys (subgenus Plasmodium) seem to form a clade. P. ovale is more closely related to P. malariae than to P. vivax. Plasmodium ovale has recently been shown to consist of two cocirculating species - Plasmodium ovale curtisi and Plasmodium ovale wallikeri. These two species can only be distinguished by genetic means and they separated between and . A second estimate has placed the separation of these species at (95% confidence interval 0.7-7.7 Mya) P. ovale, based on an analysis of the apicoplast genome, appears to be related to the rodent species suggesting an ancestral host switch. The relationship between the P. ovale species and those with rodent hosts has been confirmed by sequencing the genomes of both P. ovale species.<ref name=Rutledge2017>{{cite journal | last1 = Rutledge | first1 = GG | last2 = Böhme | first2 = U | last3 = Sanders | first3 = M | last4 = Reid | first4 = AJ | last5 = Cotton | first5 = JA | last6 = Maiga-Ascofare | first6 = O | last7 = Djimdé | first7 = AA | last8 = Apinjoh | first8 = TO | last9 = Amenga-Etego | first9 = L | last10 = Manske | first10 = M | last11 = Barnwell | first11 = JW | last12 = Renaud | first12 = F | last13 = Ollomo | first13 = B | last14 = Prugnolle | first14 = F | last15 = Anstey | first15 = NM | last16 = Auburn | first16 = S | last17 = Price | first17 = RN | last18 = McCarthy | first18 = JS | last19 = Kwiatkowski | first19 = DP | last20 = Newbold | first20 = CI | last21 = Berriman | first21 = M | last22 = Otto | first22 = TD | year = 2017 | title = Plasmodium malariae and P. ovale genomes provide insights into malaria parasite evolution | journal = Nature | volume = 542 | issue = 7639| pages = 101–104 | doi=10.1038/nature21038 | pmid = 28117441 | pmc = 5326575 | bibcode = 2017Natur.542..101R}}</ref> One paper has reported a strain of malaria in a chimpanzee with a mitochondrial sequence identical to that of P. ovale and a second closely related to it. It seems likely as has been proposed earlier that P. ovale may have an animal reservoir. Two unnamed potential