[Microsporidiosis: current state of a new parasitosis].

Protozoa of the order Microsporida have become regarded as causes of several pathologies in patients with severe immunodeficiencies. Apparently they are transmitted to the human through fecalism, but also the respiratory route has been considered. People most affected are young males infected with the human immunodeficiency virus. The most important genera are: Enterocytozoon, Encephalitozoon, Septata, Nosema and Pleistophora. There are discrepancies about the biology of these parasites and little is known of their behavior in the human host. It is concluded that with the advent of AIDS, many nosological entities by opportunistic organisms, that were not previously considered as human infections are appearing. This work is a review of the literature published from 1959 to 1995, related to epidemiological, clinical, diagnostic and therapeutic aspects.