Brief SummaryRead full entry The species-rich phylum
Microsporidia includes obligate intracellular parasites that
infect a wide range of vertebrate and invertebrate hosts.
Microsporidians have evolved an elaborate mechanism for invading
animal host cells, but have otherwise greatly reduced biological
complexity. The smallest known autonomous nuclear genome is that
of a microsporidian, Encephalitozoon intestinalis (Keeling and
Corradi 2011). Although the taxonomic affiliation of the
Microsporidia has long been controversial, they are now known to
either fall within the Fungi or to be extremely closely related
to the Fungi. Microsporidians produce resistant spores and
possess a unique organelle, the polar tubule, or polar filament,
which is coiled inside the spore (see below). The spores of
microsporidians known to infect humans range from 1 to 4 microns
in diameter. At least 14 microsporidian species have been
identified as human pathogens (see Table from U.S. CDC):
Brachiola algerae, B. connori, B. vesicularu