Round to oval with scattered brown pigment Parasitised red cell larger than normal May almost fill the RBC Chromatic mass is eccentric and red Cytoplasm homogeneous, without vacuoles; blue (macrogametocyte) or light blue to pink (microgametocyte) Pigment is scattered

Mature schizonts contain 8-24 merozoites Usually fills about 2/3 of the infected RBC Dark pigment, clumped in one mass Schizonts are rarely seen in peripheral blood of P. falciparum infections, except in severe cases  

Irregular shaped cytoplasm – amoeboid in shape Cytoplasm more denser and vacuole become smaller 01 nucleus Few coarse grains of pigment in cytoplasm (Maurer’s dots) may be visible  P. falciparum trophozoites are rarely seen in peripheral blood smears

Crescent or sausage shaped Chromatin is in a single mass (macrogamete) or diffused (microgamete) Cytoplasm is blue to violet (macrogamete) or more reddish (microgamete) Pigment concentrated round chromatin  

Ring-like with delicate cytoplasm and small vacuole 1 – 2 small chromatin dots Infected RBC are not enlarged Often multiple rings per cell Often multiple infection per RBC

Found in various sites throughout host body – common in brain, and, skeletal & cardiac muscles Morphological Features Size: 5-50 µm in diameter Shape: usually spherical in the brain; more elongated in cardiac and skeletal muscles 

Found in blood and various other body fluids of infected host Morphological Features Size: 4-8 µm long by 2-3 µm wide Shape: Tapered anterior end, a blunt posterior end Large nucleus 

Disease: Toxoplasmosis Definitive host: Cats Human is the intermediate host; also rats, pigs, cattle, sheep, and birds Location of tissue cysts in human: Various tissues – common in brain and skeletal and cardiac muscles Infective stage to human: Mature oocyst Diagnosis of infection in human: Mainly via immunological assays to detect antibodies; Stained biopsy tissues […]

Disease: Cryptosporidiosis Habitat in human: Intestinal tract; occasionally in lungs if infected through inhalation Diagnosis of infection: Microscopic examination of faeces to detect oocysts Morphological Features of Oocyst Size: 3-6 µm (usual range: 4-5 µm) Shape: Spherical or oval Thick wall Nonmotile

Disease: Leishmaniasis Habitat in human: Blood – in macrophages, monocytes and neutrophils Diagnosis of infection: Microscopic examination of blood to detect amastigotes Morphological Features of Amastigote Size: 2 – 4 mm Shape: Small, round to oval Large nucleus and a prominent rod shaped kinetoplast Undulating membrane is absent Flagellum is embedded in cytoplasm as a […]