Chlamydiae are obligate intracellular bacteria that form inclusions within the cytoplasm of epithelial cells. The developmental cycle of chlamydiae involves an alternation between the intracellular reticulate body and the extracellular elementary body, which is the infectious form of the organism. Chlamydiae infect the mucosa of a variety of anatomic sites, including the gastrointestinal tract, reproductive tract, and conjunctiva. Although some infection may be localized, animals are typically infected systemically, resulting in potential pathology and chlamydial shedding at various anatomic sites.