Comparative ultrastructural features of the sporozoite of Lankesterella minima (Apicomplexa) in its anuran host and leech vector

Abstract

The ultrastructural features of sporozoites of Lankesterella minima (Apicomplexa) from erythrocytes of the bullfrog (Rana catesbeiana) and from the salivary cells of the leech vector (Batracobdella picta) were compared. Two notable differences were observed. Firstly, the intraerythrocytic sporozoites were more regular in outline and usually assumed a slightly flexed position within a closely applied parasitophorous vacuole. Sporozoites in the salivary cells were more irregular in shape and were often reflexed sharply in their mid or posterior region. Secondly, although the sporozoites in both hosts contained pre- and post-nuclear dense bodies, these were more numerous and approximately twice the diameter in parasites from the leech. These morphological differences may reflect the maturation and attainment of infectivity of the sporozoites in the tissues of the leech vector.