Case 206. Malaria falciparum (60 y-o M)
    Japanese photographer who traveled in Kenya, menifesting high fever, jaundice and consciouness disturbance (Refer to case 129, the same case)    
Key words : Plasmodium falciparum, malaria
More than half of erythrocytes are infected by the ring form of Plasmodium falciparum. Not rarely, two or more ring forms are seen in one red cell. The banana-shaped "crescentic gametocyte" is characteristic of P. falciparum (Giemsa).   At autopsy, the spleen is soft, swollen and black in color (gross findings). Histologically, the red pulp is filled with erythrocytes having concentrated malaria pigments. The cause of death was coma due to cerebral malaria.
Stamp smear preparation of the spleen discloses trophozoites (ameboid form) and schizonts in the red cells. Macrophages phagocytize the infected red cells to contain coarse malaria pigment in the cytoplasm (Giemsa).   Another view of the stamp preparation of the spleen, showing numerous schizonts and schizont-phagocytizing macrophages (Giemsa).
The liver tissue at autopsy exhibits stasis of red cells containing coarse malaria pigment in the sinusoid, and activation of Kupffer cells, phagocytizing the infected red cells (Giemsa). In case of falciparum malaria, the red cells infected by trophozoites and schizonts are trapped to the endothelial cells via CD36 and ICAM-I, so that these cells are not seen in the peripheral blood.   Reference case 206A
Thick smear preparation from a Kenyan child with falciparum malaria. This method is suitable for malaria screening in the field work. Morphologic preservation is poor, and red cells hemolysed. A few ring forms and a gametocyte are observed. The post-meiotic gamatocytes of both sexes unite to oocysts ("gametogony") in the gut wall of the mosquito Anopheles.
Reference case 206B
Blood smear from a febrile Kenyan 25 y-o woman runner, who completed to run the next day as a member of Ekiden relay in Yokohama (Giemsa, pH 7.2). At neutral pH 7.2, the red cells are stained bluish-tinted, so that ring forms and Schuffner's spots are more easily identified than the conventional Giemsa solution, pH 6.4.
  Reference case 206B
Blood smear from the same Ekiden runner (Giemsa, pH 6.4). Compare orange-tinted red cells with the previous panel (pH 7.2). This Kenyan lady is regarded as a carrier of falciparum malaria.
Reference case 206C
In tertian malaria caused by Plasmodium vivax, the infected red cells are much less in number than falciparum malaria (Giemsa). Malaria in Asia is mostly tertian in type. . The red cells with a large ring form parasite are swollen, in association with fine eosinophilic dots (Schuffner's dots) in the cytoplasm. A large gametocyte with fine malaria pigment is also seen.
  Reference case 206D
In quartan malaria caused by Plasmodium malariae, the trophozoites are seen as a band form (Giemsa). Infected red cells are not swollen. Quartan malaria is seen worldwide, but is relatively infrequent. Most of the lethal children's cases suffer from falciparum (malignant) malaria.
Reference case 206E
In oval malaria caused by Plasmodium ovale, the red cells infected by oval-shaped trophozoites reveal Schuffner's spots. The red cells with ring form become oval in shape. Oval malaria is seen only in the subsaharan Africa. It is well known that patients with sickle cell anemia or thalassemia are resistant to malaria.