Microsporidiosis is a recent and important disease related particularly specially with problems of immunosuppression as is the case in AIDS. The authors mention several studies related with this parasitosis, especially the presentation, for the first time in Costa Rica and probably in Central America, of Enterocytozoon bieneusi or Nosema infestation in human. Some data dealing with the history of this parasitosis are mentioned, and the morphology of the known genera and species is briefly described. Notes on the epidemiology and transmissión of these organisms, as well as the pathology produced by microsporidial infection are also presented. The more relevant and useful diagnostic methods, and the known treatment and prevention measures are indicated.

Microsporidia; microsporidiosis