Staining characteristics of colonies of Anaplasma marginale Theiler in Dermacentor andersoni Stiles.

Colonies of Anaplasma marginale Theiler were studied in midgut epithelial cells of adult Dermacentor andersoni Stiles that were infected as nymphs. The colonies were demonstrated in plastic sections (1 micrometer) and frozen sections (6 micrometer) with Mallory's stain. Colonies were also demonstrated in frozen sections, using direct fluorescent antibody technique. Colonies were not observed in plastic or frozen sections stained by the Giménez method. In all preparations, the colonies were usually found near the basement membrane of the midgut tissue.