Microsporidia

Microsporidia the tiny unicellular eukaryotes are intracellular parasites of almost all animals. The diverged and specialized nature of these organisms, show some similarity to fungi. They cause opportunistic infections in animals and humans ranging between asymptomatic and severe life-threatening infections in immunocompromised individuals. Transmission occurs mainly by oral route, but other methods of transmission include inhalation, sexual contact, ocular mucosa, wounds, and insect bites. Food and water are relevant vehicles of infection. Animals act as reservoirs as they harbor most of the species that can also infect man and might contaminate water and environment with spores expelled in feces and/or urine. Clinical presentation is mainly intestinal with chronic diarrhea, mal-absorption, and loss of weight in immunocompromised persons, and self-limiting diarrhea in the immunocompetent individuals. Dissemination to other organs, may threaten the life of patients. Clinical picture of disseminated infection includes fever, cerebral manifestations or some other unexplained symptoms. Diagnosis of spores in feces, urine, CSF, sputum and in tissue is difficult and necessitates the use of special stains. Other methods of laboratory diagnosis include immunofluorescence, Electron Microscopy, and DNA detection. Treatment with Albendazole is effective for intestinal and other deep infections of various species of microsporidia except E. bieneusi, where fumagillin, can be considered. This drug is also used as topical treatment for eye infections by E. hellem and other species. Trials to produce vaccine against microsporidia are still under study. The increasing awareness will lead to a better understanding of the epidemiology, clinical relevance and control of microsporidiosis in humans and animals.

Keywords: AIDS, Dissemination, Encephalitozoon, Enterocytozoon, HIV, Microsporidia, Microsporidiosis, Parasitophorous vacuole, Protista, Polar tubule, Septata, Spores.