Light and electron microscope study of a Lankesterella petiti n. sp., (Apicomplexa: Lankesterellidae) infecting Bufo marinus (Amphibia: Anura) in Pará, North Brazil

摘要

Captive toads, Bufo marinus, were either inoculated with blood or fed with blood and liver from two other toads which were showing sporozoites of a Lankesterella sp., in their erythrocytes. Stages ranging from late zygotes to sporulated oocysts were encountered in various tissues of two of the experimental animals. Development of the parasite was shown to be in the endothelium of the blood vessels, which explains distribution of resulting sporozoites in a wide range of different tissues. Ultrastructure studies revealed wall-forming-like organelles in the late zygote which are seemingly involved in the deposition of the thick wall of the sporulating oocyst. This wall is perforated in several places, allowing extensions of the parasite, with contained mitochondria, to extend out to the limits of the parasitophorous vacuole. These features, together with the presence of one to several refractile bodies bounded by a coat of electron-dense droplets, appear to be unique to Lankesterella.