Microsporidiosis - Definition, Causes, Symptoms and Treatment

Microsporidiosis Definition

Microsporidiosis is an infection by a microorganism that normally does not cause disease but becomes pathogenic when the body's immune system is impaired and unable to fight off infection. An infection in a person with an impaired immune system caused by an organism that does not usually cause disease in people with healthy immune systems.

Microsporidia has small simple single-celled (protozoan) parasites that form spores. These parasites must live within other cells and are found in the intestine, liver, kidney, cornea, brain, nerves, and muscles. These spores spread to other cells or are eliminated in the stool or urine.

Microsporidiosis Causes

Microsporidiosis is a devastating, life threatening infection in people with AIDS. It can cause disease all over the body (lungs, eyes, etc), but it most often infects the gut and causes diarrhea. The microsporidia spores are released from the gastrointestinal and urinary tracts of infected animals. The spores are then consumed by people. Within the bowels, a spore unfolds a long, thin, coiled tube that is used to penetrate a cell. Once within the cell, the microsporidia develop and multiply. Microsporidia have even been seen in muscle tissue.

Microsporidia are small, sporeforming, obligate intracellular protozoan parasites that are found in the intestine, liver, kidney, cornea, and brain. Two types of microsporidial eye infection occur in patients with AIDS. The first type is infection of the cornea following an eye injury, which may result in corneal perforation and blindness. The second type involves inflammation of the cornea and the conjunctiva of the eye in patients with AIDS.

Microsporidiosis Symptoms

Although microsporidia can infect people with normal immune systems, they typically do not develop symptoms. Symptoms of microsporidiosis generally occur in people with immune deficiency. The symptoms appear to be intermittent, and may have been coming and going for some months before the individual seeks medical advice.

The symptoms of the microsporidiosis may be included:

• Nausea
• Abdominal pain
• Weight loss
• Loss of appetite
• Dehydration
• passing gas (flatulence)
• Cramping stomach pains
• Wind bowel movements
• Irregular bowel movements

Microsporidiosis Treatments

There is no standard treatment. Albendazole is commonly used. Albendazole is an inhibitor of tublin polymerization and is chemically related to metronidazole.

At a dose of 100 mg/day, thalidomide, an inhibitor of TNF-alpha, may be useful in the symptomatic therapy of Enterocytozoon bieneusi diarrhea that does not respond to albendazole.

No anti-parasitic drugs have been approved for the treatment of microsporidiosis but several have shown efficacy in clinical trials.

Other treatments for microsporidiosis includine metronidazole, itraconazole, atovaquone, and nitazanoxide.