Morphology & Degeneration of Exoerythrocytic Forms of Plasmodium y. yoelii & Reactions of Host Cells in Rats & Mice / 第三军医大学学报

ABSTRACT

The exoerythrocytic forms (EEF) of Plasmodium yoelii yoelii BY265 in the liver of rats and mice are morphologically similar, however, the size of the matured EEF in the former is far much larger than that in the latter. In the sections of the liver of both the animals, which are sliced 48-65 hours after the inoculation of sporozoites, certain degenerated EEF can be found. The degenerated EEF fall into two types(1) Degenerated EEF without WBC infiltration, These EEF usually remain intact in their outline with many vacuoles of the size 1-6?m in diameter in the cytoplasm. The nuclei of the host hepatic cells parasitized are usually swollen and appear blank after staining. No WBC infiltration can be found.(2) Degenerated EEF with WBC infiltration The outline of these degenerated EEF is no more intact. They are usually infiltrated and/or surrounded by WBC.Degeneration occurs in 6.6% of the EEF in rats and 5.8% in mice. Once the normally developed parasites become matured and ruptured, large amoants of WBC are attracted and accumlated to form local foci of WBC infiltration of the size 35-90?m in diameter. In some of the foci, remnants of the parasites can be seen, while in some others, no remnants can be found and they most likely are also formed by the degenerated EEF or ruptured matured parasites.