Parasites of Plasmodium ovale are usually found in enlarged and stippled red cells (James's dots) , similar to those found in Plasmodium vivax infections. Host cells show an oval shape, particularly those containing younger stages of the parasites and the host cell may also show "spiking" or fimbriation.

 Trophozoites

Young trophozoites are found as compact rings in cells containing James's dots. The trophozoite rings remain compact as they developand show little of the amoeboid features common in Plasmodium vivax. Small scattered pigment granules can be seen in developing trophozoites which disperse as the trophozoite matures. Late trophozoites are round and consolidated with an increase in cytoplasm, they are very similar to P. vivax at this stage.

An early Trophozoite of Plasmodium ovale

A trophozoite of Plasmodium ovale, the red cell exhibiting an oval shape.

 Gametocytes

The mature gametocytes are round, filling two thirds of the red cell. The red cell is slightly enlarged and and stippled and contains pigment which has a distinct arrangement of concentric rodlets, mostly at the periphery.

A gametocyte of Plasmodium ovale

A gametocyte of Plasmodium ovale, the oval red cell exhubiting fimbriation

 Schizonts

The parasite is smaller than red cell and contains 6-12 merozoites, usually 8 in a single ring. The pigmentis a brown/greenish central clump. The red cell slightly enlarged, stippled, frequently oval and fimbriated.

A schizont of Plasmodium ovale, the oval red cell exhibiting fimbriation.