Fig. 1. Scanning electron micrograph of a microsporidian spore with an extruded polar tubule inserted into a larger eukaryotic host cell. Reprinted from the Parasite Image Library of the Centers for Disease Control and Prevention Website on Laboratory Identification of Parasites of Public Health Concern (DPDx). (Available at http://www.dpd.cdc.gov/dpdx/HTML/ImageLibrary/Microsporidiosis_il.htm accessed February 17, 2005.)