What Is Microsporidiosis?

• The main risk factor associated with acquiring microsporidiosis is immunodeficiency. The vast majority of cases of microsporidiosis occur in individuals with a compromised immune system, primarily in people withHIV/AIDS-related immunosuppression.
• It can also affect immunocompromised individuals such as organ-transplant recipients, people withdiabetes,cancerpatients, and those who are chronically on steroids. Rarely, microsporidiosis can occur in healthy people with a normal immune system.

Though the route of spread is poorly understood, studies have suggested that humans may possibly contract microsporidia via sexual transmission with an infected individual. Transmission from human to human may also possibly occur via the fecal-oral route or through direct contact withocularsecretions from infected individuals.

确切的潜伏期microsporidiosis我n humans has not been definitively established for all species.

• Microsporidia spores are released from the凳子, respiratory secretions, and urine of infected animals. A number of animals, including insects, birds, and mammals, can serve as reservoirs of infection for microsporidia.
• Transmission of these spores is thought to occur primarily via ingestion orinhalationby humans, though the process is not perfectly understood. Studies have also suggested that water-borne and food-borne transmission may be possible.
• Once within a cell, the microsporidia develop and multiply, producing more spores. The infective spores are then released when the cell expands and bursts.

• Although microsporidiosis can occur in people with normal immune systems, it is very uncommon. The symptoms of microsporidiosis primarily occur in people with immune-system deficiency, such asHIV-infected individuals and organ-transplant recipients. Microsporidiosis can cause intestinal, lung, kidney, brain, sinus, muscle, or eye disease.
• Intestinal symptoms that are caused by microsporidia infection include chronicdiarrhea, wasting, malabsorption, andgallbladder disease. In patients withAIDS, the chronicdiarrheamay be extremely debilitating and carries a significant mortality (death) risk. The majority of cases of intestinal microsporidiosis inAIDSpatients are caused byEnterocytozoon bieneusi.
• Lung symptoms may include acoughand difficult, laboredbreathing. Achest X-raymay show signs of inflammation, fluid, orcavitiesin thelungs.
• Microsporidiosis can cause infection in the urinary tract,kidney failure, bladder inflammation, and bowel perforation. Microsporidia can also spread throughout the body (disseminate) to cause inflammation in the brain, pancreas, sinuses, and muscle tissue.
• Eye infection with microsporidia can cause inflammation of thecorneaandconjunctiva(keratoconjunctivitis). Symptoms of ocular microsporidiosis may includeeye pain,eye redness, or blurry vision.

• There are several tests available to diagnose microsporidia infection. Microscopic examination of stained samples of body fluids, primarily fecal samples, allows for rapid diagnosis, although the exact species of microsporidia may not be identified. Urine samples can also be used to detect spores when the kidney and/or bladder are involved.
• A powerful microscope, called a transmission electron microscope, is needed to identify the exact species of microsporidia. However, this form of testing is expensive, and it is not available for routine use in all laboratories.
• Other methods, such as immunofluorescence assays andpolymerase chain reaction(PCR) testing, can also identify microsporidia infection in the research-laboratory setting.
• Finally, blood tests and imaging studies can also assist in detecting microsporidiosis.

Microsporidiosis is generally treated primarily by an infectious-disease specialist. Other specialists may be consulted depending on the site of infection, such as an ophthalmologist for eye involvement.

• The treatment of microsporidiosis is generally achieved with medications and supportive care. Depending on the site of infection and the microsporidia species involved, different medications are utilized. The most commonly used medications for microsporidiosis includealbendazole(Albenza) and fumagillin.
• For patients withdiarrheaanddehydration, intravenous fluid administration andelectrolyterepletion may be necessary. Dietary and nutritional regimens may also assist with chronic diarrhea.
• Finally, improvement of immune system function with antiretroviral therapy inHIV-infected individuals may also lead to improvement of symptoms.

In general, the prognosis of microsporidiosis in healthy individuals with a normal immune system is good. However, immunocompromised individuals who develop microsporidiosis have a more guarded prognosis, with the outcome determined by the site of infection, the severity of infection, and the time elapsed to seek prompt medical treatment. Microsporidiosis in these individuals can sometimes be fatal.

For patients with HIV infection, microsporidiosis may be prevented by maintaining an intact immune system through the use of antiretroviral medications. Frequent hand washing and limiting exposure to potential sources of infection are also recommended. Because of the possibility of sexual transmission, safe sexual practices are an important preventive step. At this time, there is novaccineavailable to prevent microsporidiosis.