Parasitic Protozoa of the blood of rodents. V. Plasmodium vinckei brucechwatti subsp. nov. A malaria parasite of the thicket rat, Thamnomys rutilans, in Nigeria.

A description is given of the blood stages of a new subspecies of Plasmodium vinckei in the blood of naturally infected thicket rats (Thamnomys rutilans) from Nigeria and experimentally infected mice. Sporogony was obtained at 25 degrees C in Anopheles stephensi A. quadrimaculatus and A.l. atroparvus, but sporozoites in the salivary glands of the mosquitoes were never infective. The new parasite is differentiated from 7 other species of malaria parasites of African rodents principally on the morphology of the erythrocytic stages. It is designated as a subspecies of P. vinckei (P.v. brucechwatti subsp. nov.) because of the (i) zoogeography, (ii) morphology of sporogonic stages and (iii) forms isoenzymes of blood stages.