[Should the microsporidian spores be treated as dormant stages?].

Spores of bacteria, fungi, microsporidia and other protists are traditionally treated as dormant stages, intended to the long-term survival in the environment and to activation of parasitic forms during the infestation of a new host. However, in the process of examination of insect microsporidia at the molecular cellular levels and also at the level of organisms and populations, we came to a conclusion that spores are very active developmental stages with the entire potential directed to the rapid and successful infestation of new hosts during contact with the later. The work summarizes the original data demonstrating (1) the necessity of the rapid activation of microsporidian spores during host contact, (2) hopelessness of the long retaining of viability by spores of many microsporidia in the environment after leaving host organism; and (3) specific accumulation of metabolic ferments in "dormant" spores, but not in actively proliferating prespore developmental stages. On the basis of these data we conclude that microsporidian spores tend to shorten the period when they stay outside host organism to the maximal degree. The probability of host infestation within the limited time period increases due to diverse modes of transmission of pathogens, accumulation of maximally possible volume of infective spores, and the rapid mobilization of the extrusion apparatus.