MICROSPORIDIA (cont.)

direct inoculation of infectious spores from the environment. Infection occurs with the introduction of infective sporoplasm through the polar tubule into the host cell. Microsporidia multiply extensively with the host cell cytoplasm; the life cycle includes repeated divisions by binary fission (merogony) or multiple fission (schizogony) and spore production (sporogony). During sporogony, a thick spore wall is formed, providing environmental protection for this infectious stage of the parasite.