Figure 1. Comparison of morphology and tinctorial properties of Feulgen stained, intact tick salivary glands infected by three of the deer tick pathogen guild. Spirochetes only transiently migrate through salivary tissues, and thus would not be visualized by this technique. (A) Ehrlichia microti. Polyhedral clusters of rickettsiae (arrows) within hypertrophied salivary acinus. (B) Babesia microti, dense stippling of sporoblasts (arrows). Each minute dot represents the nucleus of a sporozoite. (C) Deer tick virus. Hypotrophied salivary acinus filled with amorphous masses of pinkstaining (=Feulgen positive) material (arrows). Scale bar = 10 µm.