Identification of Theileria infections in living salivary glands of ticks

Abstract

SUMMARYIt was found that interference contrast microscopy gave good morphological differentiation of the living and intact salivary glands from adult ixodid ticks, Rhipicephalus appendiculatus and Amblyomrna variegatum, removed by dissection. In many cases the individual cell types of the acini could be recognized. When the salivary glands of infected adult ticks were examined Theileria parasites were detected. Theileria parva, T. taurotragi and T. mutans could be detected in the salivary glands after they reached the mature secondary sporoblast stage achieved even in unfed ticks. Parasites were detected only in type III acini. The morphology of tertiary sporoblasts and sporozoites of these Theileria spp. was clearly recognized in feeding ticks. Sporozoites of T. parva proved to be infective to cattle and to peripheral blood leucocytes of cattle in vitro after interference contrast examination. Interference contrast examination of living salivary glands was used for selection of salivary glands with high infections of T. parva sporozoites and the sporozoites could be separated in large numbers from these salivary glands. Using this technique it appeared possible to clone Theileria parasites from salivary glands with 1 infected acinus.