Infectivity of microsporidian spores exposed to temperature extremes and chemical disinfectants.

MICROSPORIDIA in the genus Encephalitozoon are obligate intracellular parasites transmitted by spores via the fecal– oral route. Encephalitozoon intestinalis, E. hellem, and E. cuniculi infect humans and wild and domesticated animals. Relevant reservoirs and the routes of spread of these species infecting humans remain largely unknown. However, detection of spores in groundwater, water used for drinking, and in an outbreak thought to be waterborne strongly suggest the potential and importance of waterborne transmission (Cotte et al. 1999; Dowd, Gerba, and Pepper 1998; Fournier et al. 2000). Rendering spores non-infectious is extremely important for food and water protection and for safe facility management but data on inactivation and disinfection of spores are sparse. The present studies were designed to investigate the effects of ethanol, chlorine, heating and freezing on infectivity of E. intestinalis, E. hellem, and E. cuniculi spores using cell culture as a bioassay.