Publisher Summary This chapter describes Leucocytozoon. It discusses the prevalence, taxonomy, life cycles, ultrastructure, pathogenesis, and pathology of these avian blood parasites, together with treatment in terms of prevention and control, immunity and cultivation. Progress has been made in the knowledge of these parasites, but there is uncertainty about some of the many “species” and difficulties concerning life cycles, the experimental study of which demands satisfactory methods of maintaining hosts and vectors. Genetics is unexplored and cytological observations are reported on only one species. Intriguing epizootiological problems requiring ecological investigations of avian and insect hosts in different parts of the world await attention. These parasites can be used as models for research pertaining to the biology of cells. Information should be, especially relevant to an understanding of the related coccidian and malaria parasites. Current interest in several places leads to the expectation of interesting discoveries during the next decade.

A virus disease of the malaria parasite

On species of leucocytozoon.

SYNOPSIS

Cytoplasmic vacuoles seen in methanol-fixed, Giemsa's-stained ookinetes of Leucocytozoon simondi, Parahaemoproteus fringillae and Plasmodium gallinaceum, when studied with the electron microscope, were found to correspond with crystalloid inclusions of similar structure, particle size, and arrangement. Cytochemical examination of these “crystalloids” revealed their lipid-protein nature. Morphologically similar inclusions were found also in ookinetes of Leucocytozoon ziemanni and Parahaemoproteus velans. In L. simondi, crystalloid is formed rapidly after fertilization, from amorphous electron dense material seen in mature macrogametocytes. The arrangement and distribution of crystalloids in the zygote, ookinete, oocyst, and sporozoite are described. On the basis of differences in structure and particle size, it is proposed that the crystalloid inclusions in Haemosporina be divided into 2 types. Type I—lipid-protein in nature, characterized by electron dense irregularly spherical particles, 25–40 nm in diameter, with individual particles not invested by membrane. Type II—probably virus, characterized by electron dense, irregularly spherical, membrane-bounded particles, with a diameter usually greater than 40 nm.

Crystalloid inclusions in species of Leucocytozoon, Parahaemoproteus, and Plasmodium.

http://academic.oup.com/milmed/article-pdf/134/9/916/24650008/milmed-134-9-916.pdf

A virus disease of the malaria parasite

Citations

On species of leucocytozoon.

Crystalloid inclusions in species of Leucocytozoon, Parahaemoproteus, and Plasmodium.

References

A protozoan virus.

Liver infections with Plasmodium v. vinckei in hosts refractory to blood infection.

A possible virus disease of the malaria parasite

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