Morphology of Malaria Parasites

Comparative Morphology of Malaria Parasites

Author:MBLOGSTU

P. falciparum P. vivax P. malariae P. ovale

Summary Comparison

Feature	P. falciparum	P. vivax	P. malariae	P. ovale
RBC Size	Not enlarged	Enlarged	Not enlarged (occasionally smaller)	Enlarged (similar to vivax)
Infection per RBC	Multiple infections common	Single infection	Single infection	Single infection
Stippling/Supplementary Dots	Maurer’s dots not clearly visible	Schuffner’s dots clearly visible	Ziemann’s stippling not clearly visible	James dots (larger/darker than vivax) present
Trophozoite Form	Small rings with sometimes double chromatin dots	Large, coarse rings (often amoeboid)	Small, compact rings or band forms	Ring forms larger and maintained throughout
Schizont Merozoites	16–32 (compact cluster)	12–24 (irregular cluster)	6–12 (rosette formation or irregular cluster)	8–12 (rosettes or irregular clusters)
Gametocyte Shape	Banana-shaped/rounded	Round and large	Round, compact, with coarse pigments	Fimbriated edges, slightly smaller

P. falciparum

Trophozoite Stage

• Small, regular with fine to fleshy cytoplasm.
• Infected RBCs are not enlarged; multiple infections are common.
• Forms appear as rings, comma, marginal, or accole shapes; often with double chromatin dots.
• Maurer’s dots are not clearly visible.

Schizont Stage

• Small schizonts rarely fill the RBC.
• Contain 16–32 (or more) merozoites in a compact cluster.
• Usually associated with many young ring forms.

Gametocyte Stage

• Gametocytes are banana shaped or rounded.
• Macrogametocyte: small, compact with a central chromatin dot and closely adherent pigment.
• Microgametocyte: broader and shorter (sausage shaped) with loosely scattered chromatin and golden brown pigments.

P. vivax

Trophozoite Stage

• Infected RBCs are usually enlarged.
• Cytoplasm appears irregular or fragmented (amoeboid); mature ring forms tend to be large and coarse.
• Schuffner’s dots (stippling) are frequently visible.

Schizont Stage

• Schizonts are large, often covering almost the entire enlarged RBC.
• Contain 12–24 merozoites in an irregular cluster with yellowish-brown loose pigment.

Gametocyte Stage

• Gametocytes are round and large, typically with a compact, peripheral nucleus and deep red or magenta chromatin.

P. malariae

Trophozoite Stage

• Trophozoites are small and few, appearing as ring or rounded forms (with or without vacuolation) and may show distinctive band forms.
• Pigments are dark and scattered; Ziemann's stippling is not clearly visible.
• Infected RBCs do not enlarge.

Gametocyte Stage

• Gametocytes are round, compact, and typically smaller than those seen in P. vivax; pigments are scattered and coarse.
• Eroded forms (with only chromatin and pigment remaining) may also be seen.

Schizont Stage

• Schizonts are small, compact, and dark, usually few in number.
• They contain 6–12 merozoites arranged in a rosette formation (or sometimes in irregular clusters) with concentrated pigments.

P. ovale

Trophozoite Stage

• Early ring forms display James dots that may be larger and darker than in P. vivax.
• The rings are larger than those seen in P. vivax and maintain their distinctive shape until late in development.

Schizont Stage

• Schizonts are stippled; about ¾ of the cell is occupied by 8–12 merozoites in rosettes or irregular clusters with clustered pigment.

Gametocyte Stage

• Gametocytes exhibit fimbriated (fringed) edges and are smaller than those seen in P. vivax.