Abstract:
Colonies of Cowdria ruminantium were studied in midgut epithelial cells and salivary gland acini of
nymphal Amblyomma hebraeum that were infected experimentally as larvae. Colonies were found in both tissues
and studied with light and electron microscopy. Colonies observed within gut cells frequently contained 2 types
of the organism : electron-dense and reticulated forms. The morphology of colonies from salivary glands, as seen
with light microscopy, varied from compact, densely-staining, small colonies to larger ones in which individual
organisms were apparent. With electron microscopy, most organisms in salivary glands were reticulated and
appeared to be dividing by binary fission. In both types of host cells, colonies often contained a dense inclusion
to which reticulated organisms were adhered.
