polyclonal antibodies are used, and PCR has recently been employed for E. bieneusi (CDC). Life cycle The infective form of E. bieneusi is the resistant spore and it can survive for a long time in the environment. The spore extends its polar tubule and infects the host cell. The spore injects the infective sporoplasm into the eukaryotic host cell through the polar tubule. Inside the cell, the sporoplasm undergoes extensive multiplication either by merogony (binary fission) or schizogony (multiple fission). This development occurs in direct contact with the host cell cytoplasm. In the cytoplasm, microsporidia develop by sporogony to mature spores. During sporogony, a thick wall is formed around the spore, which provides resistance to adverse environmental conditions. When the spores increase in number and completely fill the host cell cytoplasm, the cell membrane is disrupted and releases the spores to the surroundings. These free mature spores can infect new cells thus continuing the cycle (Desportes 1985). Transmission mode Enerocytozoon bieneusi is transported through environment resistant spores. Common environmental sources of E. bieneusi include ditch and other surface waters, and several species of microsporidia can be isolated from such sources indicating that the disease may be waterborne. The different modes of transmission that may be possible include the fecal-oral or oral-oral route, inhalation of aerosols, or ingestion of food contaminated with fecal material (Mathis et al. 2005). Furthermore, there seem to be a close relationship between E. bieneusi strains from humans and pigs, suggesting the absence of transmission barrier between pigs and humans for this parasite (Rinder et al. 2000). Animals, particularly pigs, may play a role of zoonotic reservoir in transmitting the disease to other organisms (Abreu-Acosta et al. 2005), (Lores et al. 2002). Both vertical and horizontal transmissions are possible. Hosts Hosts include pigs, fish, birds, cattle, human (including H. neanderthalensis), and other mammals, such as monkeys. Effects on hosts Enterocytozoon bieneusi is a common parasite in pigs and it causes diarrhea, from self-limited to severe forms. This is documented by the lack of intestinal lesions in pigs experimentally infected with E. bieneusi (Mathis et al. 2005). The pigs that were infected with this disease excreted more spores. Treatment Inhibitors of chitin synthase enzymes seem to be effective against this pathogen. Fumagillin and albendazole treatments seem promising in swine (Mathis et al. 2005). Prevalence It is very common in pigs and seems to be a natural pathogen in