P. billbrayi is phylogenetically very close to Plasmodium gaboni,[1] with both sharing a recent common ancestor.

[2] The parasite is named in honour of the distinguished malariologist “Bill” Robert Stow Bray (1923–2008).

[2] Plasmodium billbrayi was first described along with Plasmodium billcollinsi by Krief et al. in February 2010, by sequencing the whole Plasmodium mitochondrial genome in chimpanzees.

[1] This species is found in East Africa.

[1] Plasmodium billbrayi infects common chimpanzees (Pan troglodytes) and Eastern chimpanzees (Pan troglodytes schweinfurthii).