AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Background

Microsporidia are obligately intracellular, spore-forming parasites belonging to the phylum Microspora and the order Microsporida. They are eukaryotic organisms containing 70S ribosomes but lacking mitochondria, peroxisomes, Golgi membranes, and other typically eukaryotic organelles. The phylum Microspora contains over 1000 species. They are ubiquitous organisms with an extensive host range, including honeybees, fish, mosquitoes, ticks, grasshoppers, rodents, rabbits, and other fur-bearing mammals. Species identified as causing disease in humans include the following:

• Enterocytozoon bieneusi
• Encephalitozoon hellem
• Encephalitozoon intestinalis (previously Septata intestinalis)
• Encephalitozoon cuniculi
• Pleistophora species
• Trachipleistophora hominis
• Trachipleistophora anthropophthera
• Nosema connori (see Image 1)
• Nosema ocularum
• Brachiola vesicularum
• Vittaforma corneae (previously Nosema corneum)
• Microsporidium ceylonensis
• Microsporidium africanum
• Brachiola algerae

Currently, most cases of human microsporidiosis are associated with HIV infection or other forms of immunosuppression, particularly in organ transplant recipients; however, cases have been reported in immunocompetent individuals.

Pathophysiology

Humans acquire infection through ingestion or inhalation of spores. Studies isolating Encephalitozoon species in the urinary tract in those with disseminated infections suggest that sexual transmission is possible. The spore is the infective form. Spores are environmentally resistant and are surrounded by an outer electron-dense glycoprotein layer and an electron-lucent endospore layer composed primarily of chitin. The spore extrudes its polar tubule and injects the infective sporoplasm into the host cell. Once inside the cell, it multiplies by binary fission or schizogony. Development can occur directly inside the host cell cytoplasm or inside parasitophorous vacuoles. As mature spores develop and accumulate, the cell expands and eventually ruptures, releasing the spores.

Frequency

United States

Currently, most cases of microsporidiosis are reported in adults with immunosuppression, especially HIV-related immunosuppression. According to studies, infection of small intestinal enterocytes with E bieneusi is detected among 15-34% of patients with AIDS with chronic diarrhea and no other identified causes.

Renal transplant recipients with chronic weight loss and diarrhea have also been found to have E bieneusi infection. A case of fatal myositis due to B algerae has been documented in a woman with diabetes and rheumatoid arthritis who had been prescribed infliximab (Coyle, 2004).

International

Microsporidia have a worldwide distribution. Cases are reported in developed and developing countries among individuals who are immunosuppressed and individuals who are immunocompetent. Human cases are reported from the Americas, Asia, Europe, and Africa.

Mortality/Morbidity

Clinical symptoms and disease associated with microsporidiosis vary with the species that causes the infection and the host's immune status. Microsporidial keratoconjunctivitis has been identified in healthy nonimmunocompromised individuals, and the use of topical steroids could have been the initial predisposing factor in one case series (Chan, 2003). The individuals in this case series exhibited unilateral punctate epithelial involvement of the cornea. V corneae was identified as a cause of unilateral stromal keratitis in a case report by Font et al, and topical steroid use had also preceded the diagnosis.

• Bilateral punctate epithelial involvement of the cornea is the typical manifestation of ocular microsporidiosis in immunocompromised individuals.
• Most cases of intestinal and disseminated microsporidiosis in patients infected with HIV are reported in patients who are severely immunocompromised (CD4 <100/mm³); in these patients, morbidity can be significant. E bieneusi infections often result in protracted debilitating illness with diarrhea, which may last several months. The mortality rates in patients with E bieneusi are reported as high as 56%. In addition to chronic diarrhea, malabsorption and wasting can occur in persons with AIDS. E bieneusi causes more than 90% of intestinal microsporidiosis cases in this population; E intestinalis causes the remainder.
• Reports of E bieneusi infections are increasing among travelers and residents of tropical countries (ie, people who are HIV negative). E intestinalis infection associated with chronic diarrhea is reported in travelers who are immunocompetent.
• E bieneusi usually is found only in enterocytes. E intestinalis is more invasive and produces disseminated disease involving the small and large intestines, gallbladder, urinary tract epithelium, and respiratory tract epithelium. Biliary tract involvement leading to cholangitis and cholecystitis is common in patients infected with E bieneusi and AIDS.

Race

Race has no known influence on infection.

Sex

Gender has no known influence on infection.

Age

Age has no known influence on infection.

CLINICAL

Section 3 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

History

• Intestinal or biliary disease
• • Chronic diarrhea (loose, watery, nonbloody)
  • Weight loss
  • Abdominal pain
  • Nausea
  • Vomiting
• Disseminated infection
• • Symptoms of cholecystitis, renal failure, and respiratory infections occur.
  • Patients with respiratory tract involvement may present with persistent cough, dyspnea, and wheezing.
  • Headache, nasal congestion or discharge, ocular pain, and loss of taste may indicate sinus involvement.
  • Patients with urinary tract involvement frequently are asymptomatic.
• Ocular disease
• • Foreign body sensation, eye pain, or both
  • Light sensitivity
  • Ocular redness
  • Excessive tearing
  • Blurred or decreased vision
• Musculoskeletal: Myalgia, generalized muscle weakness, and fever are common in patients with myositis and severe cellular immunodeficiency.
• Dermatologic: A microsporidian is associated with a nodular cutaneous lesion in patients with HIV infection.
• Central nervous system: Seizures and headache may be present in those with infection involving the brain.

Physical

• Head, eyes, ears, nose, and throat (HEENT) examination
• • Patients with ocular involvement due to Encephalitozoon species can have conjunctival hyperemia. A slit lamp examination can reveal keratoconjunctivitis, which is characterized by diffuse, superficial, punctate keratopathy. Infection frequently is bilateral in immunosuppressed individuals.
  • Corneal ulceration is rare in patients with AIDS. Retinal involvement is not reported.
  • Those with sinus involvement may have nasal crusting or purulence, polypoid tissue, or thickened and granular-appearing mucosa.
• Abdominal examination
• • Patients with intestinal or biliary involvement may have abdominal tenderness.
  • Clinical jaundice is rare.
  • Severe wasting and signs of malnourishment usually are observed in cases with prolonged, severe diarrhea.
• Musculoskeletal examination: Muscle tenderness and generalized weakness may be noted in patients with myositis.
• Skin examination: A skin examination may reveal nodules or necrotic lesions.

Causes

• Microsporidiosis is believed to be a zoonosis. Evidence suggests that they may be water-borne pathogens and may be transmitted from human to human.
• Most cases in patients with HIV infection occur with severe immunodeficiency.
• Cases are reported in individuals who are HIV negative and who are immunocompromised secondary to transplant surgery or prolonged steroid use.
• Travelers who are immunocompetent are reported to develop self-limited diarrhea due to microsporidia, and waterborne transmission may play a role.

DIFFERENTIALS

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Other Problems to be Considered

AIDS enteropathy
Cyclosporiasis

WORKUP

Section 5 of 11  

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• Medication
• Follow-up
• Miscellaneous
• Multimedia
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Lab Studies

• Body fluid specimens
• • Microscopic examination of stained stool samples allows the most rapid diagnosis of microsporidial infection, but it does not allow identification to the species level.
  • Examine stools for other parasites (ova and parasite exam) and bacteria. Fecal white blood cells usually are absent.
  • The modified trichrome stain (chromotrope 2R) commonly is used to detect microsporidia in urine, stool, or mucus. The microsporidia appear as ovoid, refractile spores with bright red walls. Some spores may have an equatorial beltlike stripe.
  • The rapid Gram chromotrope method can be performed more quickly (about 11 min) and combines the chromotrope method with a Gram-staining step. The spores stain dark violet, and the equatorial stripe is enhanced. E bieneusi spores measure about 0.9 x 1.5 µm, and Encephalitozoon species measure about 1.5 x 3.0 µm.
  • Cytologic and histologic examinations are quite useful in diagnosis. A conjunctival scraping or swab frequently can reveal the organism after a Gram stain (organisms usually stain gram-positive) or chromotrope stain. Microsporidial spores can be identified in tissue specimens obtained by biopsy or at autopsy. Stains that are used to detect microsporidia include the Brown Brenn Gram stain, Warthin-Starry silver stain, Giemsa, and trichrome blue.
  • Fluorochrome stains, including calcofluor white and uvitex 2B, have a high affinity for chitin. They can be used to detect microsporidia in urine, stool, mucus, and tissue sections.
  • Microsporidia stain poorly with hematoxylin-eosin.
• Transmission electron microscopy is the gold standard and allows species identification based on ultrastructure, but it is too costly and time consuming for routine use.
• Polymerase chain reaction is available in some research laboratories and can be used to diagnose the following 3 Encephalitozoon species: (1) E bieneusi, (2) V corneae, and (3) Nosema species.
• Immunofluorescence assays using monoclonal or polyclonal antibodies are available in some research laboratories and can be performed on most specimens, including formalin-fixed tissues. It allows visualization of spores and extruded polar tubules.
• Urinalysis: Routinely examine the urine for spores because E intestinalis and E hellem frequently involve the kidney in disseminated disease.
• Liver function tests
• • Elevations usually are observed in alkaline phosphatase, gamma-glutamyltransferase, and aspartate and alanine aminotransferases.
  • Bilirubin level is usually normal.
• Creatine phosphokinase and aldolase may be elevated in those with myositis.
• CD4: Patients with disseminated microsporidiosis usually are severely immunocompromised, and CD4 generally is less than 100/mm³.
• D-xylose test and qualitative fecal fat: Patients with prolonged diarrhea can develop malabsorption of fats, vitamins, and other nutrients; therefore, stool studies are required to assess for malabsorption in patients with microsporidiosis of the gastrointestinal tract.

Imaging Studies

• Computed tomography scan
• • Conduct a CT scan of the sinuses in patients with sinus complaints to search for evidence of sinusitis and middle ear involvement.
  • Obtain a CT scan of the brain in patients with a headache to determine if any ring-enhancing lesions are present.
  • Abdominal CT scan is used in patients with signs of hepatic involvement to assess for intrahepatic and extrahepatic ductal dilatation, gallbladder abnormalities, and liver parenchymal abnormalities.
• Conduct an abdominal ultrasound with elevated liver function tests to evaluate for cholelithiasis or other abnormalities in the biliary system.
• Perform chest radiograph on patients with respiratory complaints to look for pneumonia.

Other Tests

• Micronutrients
• • Micronutrient deficiency can develop secondary to diarrhea. Vitamin B-12 is the micronutrient that is most commonly deficient in HIV infection, and deficiency is associated with cognitive dysfunction and anemia.
  • Depending upon symptoms, pay special attention to the levels of micronutrients, especially when a particular deficiency syndrome is detected.
  • Other assays to consider include vitamin B-6 and other B vitamins, fat-soluble vitamins, zinc, and selenium.

Procedures

• Small bowel endoscopy: Parasite burden is greatest in the proximal jejunum. Obtain biopsies here whenever possible. Spores often can be found in duodenal fluid obtained at this time.
• Slit lamp examination: Keratoconjunctivitis is characterized by diffuse, superficial, punctate keratopathy.
• Punch biopsy of skin: Use Gram stain or other staining methods to identify microsporidia.

Histologic Findings

Histologic sections from the small bowel tend to reveal a mild inflammatory infiltrate (primarily lymphocytic) and a patchy distribution of infected enterocytes; therefore, a high index of suspicion is needed and the request for a Gram stain on intestinal biopsy specimens of patients suspected of having microsporidiosis is important. Villous atrophy and fusion, crypt elongation, and goblet cell depletion are frequent in affected mucosa.

E intestinalis is more invasive than E bieneusi. It can infect enterocytes and cells in the lamina propria, fibroblasts, and macrophages.

Granulomatous lesions are found in the kidneys and liver related to Encephalitozoon species.

Foamy histiocytes were observed in the lower dermis of a patient reported to have nodular skin lesions.

TREATMENT

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Medical Care

• Pay attention to volume replacement and electrolyte repletion in patients with severe diarrhea.
• Evaluate the patient by assessing dentition and addressing difficulty of chewing or swallowing. Then, focus on providing adequate nutritional support with the aid of a dietitian.
• Consider enteral feeding for those patients who are too ill to obtain adequate nutrition by mouth. Substitution of medium-chain for long-chain triglycerides can lessen fat malabsorption. Parenteral nutrition is reserved for situations in which the small intestine is nonfunctional.

Consultations

• Gastroenterologist for colonoscopy and small bowel endoscopy
• Ophthalmologist for a slit lamp examination in patients who are symptomatic

Diet

One study (Wanke, 1996) has indicated that individuals infected with HIV and who have microsporidium-related diarrhea had less diarrhea and malabsorption on a medium-chain triglyceride diet as opposed to a long-chain triglyceride diet.

MEDICATION

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Albendazole is the drug of choice for ocular, intestinal, and disseminated microsporidiosis. When used to treat infections due to E intestinalis, it is associated with abatement of gastrointestinal symptoms, histopathologic evidence of clearance in the intestine, and weight gain. No consistently effective therapies exist for E bieneusi. Albendazole is reported to reduce frequency and volume of diarrhea and stabilize the weight of patients with E bieneusi infection in some studies, but this is not associated with clearance of the organism on stool specimens or duodenal biopsy specimens. Metronidazole was associated with a good clinical response in patients with AIDS and with E bieneusi enteritis in a few reports, but the parasite was not eradicated. Most studies have not found metronidazole to be efficacious.

Topical fumagillin is used for microsporidial keratoconjunctivitis. Clinical response can be observed after 1 week of topical therapy, but long-term use usually is required to prevent recurrence. Oral fumagillin is useful in the treatment of E bieneusi but is associated with thrombocytopenia.

In one study (Sharpstone, 1997), thalidomide decreased stool frequency and improved weight in patients who are HIV infected (patients were treated q1mo), but it was not associated with significant decreases in fecal tumor necrosis factor alpha (TNF-alpha). Due to its significant toxicity, consider it only in those patients who have failed other treatments. Thalidomide has no known direct antimicrobial action but has been demonstrated to selectively inhibit TNF-alpha in a monocytic cell line.

Improved immune function in response to antiretroviral therapy seems to lead to normalization of intestinal architecture, clearance of parasites in the stool, and clinical improvement.

Drug Category: Anthelmintics

Parasite biochemical pathways are sufficiently different from the human host to allow selective interference by chemotherapeutic agents in relatively small doses.

Drug Category: Antibiotics

Therapy should cover all likely organisms in the context of the clinical setting.

Drug Category: Immunomodulators

Modulate key factors of the immune system.

Drug Category: Antiprotozoals

Used for symptomatic patients with diarrhea.

FOLLOW-UP

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• Follow-up
• Miscellaneous
• Multimedia
• References

Further Inpatient Care

• For patients with severe fluid loss due to diarrhea, replace volume with intravenous fluids.
• Monitor electrolytes frequently and replace as necessary.

Further Outpatient Care

• Follow-up visit: In patients with persistent diarrhea, obtain stool samples to assess response to therapy and evaluate for other etiologies. Also, consider repeating small bowel endoscopy.
• Nutritional assessment: Question patients regarding dietary habits at each routine clinic visit. Dietary referral may be needed to assist in obtaining a dietary history and calorie count. Immediately address complaints regarding loss of appetite and weight loss to determine if an opportunistic infection is the underlying cause. Bioimpedance analysis (BIA) is a rapid, noninvasive technique that uses a portable analyzer to help assess lean body mass. When BIA is performed on subsequent visits, the information obtained can be used to determine the need for intervention, such as anabolic steroids.

In/Out Patient Meds

• Postantibiotic treatment: After an adequate course of antibiotic treatment, patients with significant weight loss or appetite loss will need further assessment regarding whether nutritional supplements, drugs, or both are indicated to reverse these effects (eg, anabolic steroids such as testosterone or oxandrolone, appetite stimulant such as megestrol acetate).

Deterrence/Prevention

• Counsel patients with immunosuppression on the importance of frequent handwashing, thorough cooking of meat, and limiting exposure to animals suspected of being infected with microsporidia.
• Inform patients that their disease may be transmitted sexually and to consider screening of sexual partners.

Prognosis

• Most patients who develop intestinal microsporidiosis usually are severely immunosuppressed, and, therefore, the prognosis usually is poor.
• Immunocompetent patients generally have a spontaneous resolution of diarrhea.

Patient Education

• Counsel patients regarding meticulous handwashing to help decrease the risk of opportunistic infection.

MISCELLANEOUS

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• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

• Ocular infection occurs in 1-2% of HIV-infected persons with advanced illness; therefore, ophthalmological examination is indicated in this group of patients.
• Persons with AIDS may have relapse of microsporidiosis if the antiretroviral regimen fails.
• Suspect ocular microsporidiosis in HIV-negative individuals with unilateral eye symptoms, especially if topical steroids have been used.
• The author would like to thank Deidrea Parker, BS, and the Medical College of Georgia Department of Pharmacy for assistance in the literature review of the drug therapy for microsporidiosis.

MULTIMEDIA

Section 10 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  Electron micrograph (X30,000) of Nosema connori in diaphragm showing a coiled polar filament (arrow). Courtesy of the Armed Forces Institute of Pathology (AFIP 71-11521-4).
	View Full Size Image
Media type:  Photo

REFERENCES

Section 11 of 11

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• Introduction
• Clinical
• Differentials
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• Miscellaneous
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• Bach AC, Babayan VK. Medium-chain triglycerides: an update. Am J Clin Nutr. Nov 1982;36(5):950-62. [Medline].
• Bartlett JG, Belitsos PC, Sears CL. AIDS enteropathy. Clin Infect Dis. Oct 1992;15(4):726-35. [Medline].
• Carr A, Marriott D, Field A. Treatment of HIV-1-associated microsporidiosis and cryptosporidiosis with combination antiretroviral therapy. Lancet. Jan 24 1998;351(9098):256-61. [Medline].
• Chan CM, Theng JT, Li L, Tan DT. Microsporidial keratoconjunctivitis in healthy individuals: a case series. Ophthalmology. Jul 2003;110(7):1420-5. [Medline].
• Conteas CN, Berlin OG, Ash LR, Pruthi JS. Therapy for human gastrointestinal microsporidiosis. Am J Trop Med Hyg. Sep-Oct 2000;63(3-4):121-7.
• Coyle CM, Weiss LM, Rhodes LV, et al. Fatal myositis due to the microsporidian Brachiola algerae, a mosquito pathogen. N Engl J Med. Jul 1 2004;351(1):42-7. [Medline].
• Cunningham E. Ocular Complications of HIV Infection. In: The Medical Management of AIDS. Philadelphia, Pa: WB Saunders, Co;. 1999:171-84.
• DeGirolami PC, Ezratty CR, Desai G, et al. Diagnosis of intestinal microsporidiosis by examination of stool and duodenal aspirate with Weber''s modified trichrome and Uvitex 2B strains. J Clin Microbiol. Apr 1995;33(4):805-10. [Medline].
• Didier ES. Microsporidiosis. Clin Infect Dis. Jul 1998;27(1):1-7; quiz 8. [Medline].
• Didier ES. Microsporidiosis: an emerging and opportunistic infection in humans and animals. Acta Trop. Apr 2005;94(1):61-76. [Medline].
• Diesenhouse MC, Wilson LA, Corrent GF, et al. Treatment of microsporidial keratoconjunctivitis with topical fumagillin. Am J Ophthalmol. Mar 15 1993;115(3):293-8. [Medline].
• Dore GJ, Marriott DJ, Hing MC, et al. Disseminated microsporidiosis due to Septata intestinalis in nine patients infected with the human immunodeficiency virus: response to therapy with albendazole. Clin Infect Dis. Jul 1995;21(1):70-6. [Medline].
• Dunand VA, Hammer SM, Rossi R, et al. Parasitic sinusitis and otitis in patients infected with human immunodeficiency virus: report of five cases and review. Clin Infect Dis. Aug 1997;25(2):267-72. [Medline].
• Dunn JP, Holland GN. Human immunodeficiency virus and opportunistic ocular infections. Infect Dis Clin North Am. Dec 1992;6(4):909-23. [Medline].
• Eeftinck Schattenkerk JK, van Gool T, van Ketel RJ, et al. Clinical significance of small-intestinal microsporidiosis in HIV-1-infected individuals. Lancet. Apr 13 1991;337(8746):895-8. [Medline].
• Font RL, Su GW, Matoba AY. Microsporidial stromal keratitis. Arch Ophthalmol. Jul 2003;121(7):1045-7. [Medline].
• Garcia L, Bruckner D. Intestinal Protozoa (Coccidia, Microsporidia) and Algae. In: Diagnostic Medical Parasitology. 3rd ed. Washington, DC: ASM Press;. 1997:54-89.
• Gunnarsson G, Hurlbut D, DeGirolami PC, et al. Multiorgan microsporidiosis: report of five cases and review. Clin Infect Dis. Jul 1995;21(1):37-44. [Medline].
• Infectious Diseases Society of America. 1999 USPHS/IDSA guidelines for the prevention of opportunistic infections in persons infected with Human Immunodeficiency Virus. USPHS/IDSA Prevention of Opportunistic Infections Working Group. Infectious Diseases Society of American. Ann Intern Med. Dec 7 1999;131(11):873-908. [Medline].
• Kartalija M, Sande MA. Diarrhea and AIDS in the era of highly active antiretroviral therapy. Clin Infect Dis. Apr 1999;28(4):701-5; quiz 706-7. [Medline].
• Kester KE, Turiansky GW, McEvoy PL. Nodular cutaneous microsporidiosis in a patient with AIDS and successful treatment with long-term oral clindamycin therapy. Ann Intern Med. Jun 1 1998;128(11):911-4. [Medline].
• Kotler DP. Malnutrition in HIV infection and AIDS. AIDS. 1989;3 Suppl 1:S175-80. [Medline].
• Kotler DP. Nutrition and Wasting in HIV Infection. MEDSCAPE HIV Clinical Management Series. 1999;8:1-33. [Full Text].
• Lew EA, Poles MA, Dieterich DT. Diarrheal diseases associated with HIV infection. Gastroenterol Clin North Am. Jun 1997;26(2):259-90. [Medline].
• Lowder CY, McMahon JT, Meisler DM, et al. Microsporidial keratoconjunctivitis caused by Septata intestinalis in a patient with acquired immunodeficiency syndrome. Am J Ophthalmol. Jun 1996;121(6):715-7. [Medline].
• MICROMEDEX. Albendazole. Available at: http://www.micromedex.com. 2000. [Full Text].
• MICROMEDEX. Fumagillin. Available at: http://www.micromedex.com. 2000. [Full Text].
• Markell E. Lumen-Dwelling Protozoa. In: Markell and Voge's Medical Parasitology. 8th ed. Philadelphia, Pa: WB Saunders, Co;. 1999:24-89.
• Medical letter on drugs and therapeutics. Drugs for parasitic infections. Med Lett Drugs Ther. Jan 2 1998;40(1017):1-12. [Medline].
• Molina JM, Tourneur M, Sarfati C, et al. Fumagillin treatment of intestinal microsporidiosis. N Engl J Med. Jun 20 2002;346(25):1963-9. [Medline].
• Moon TD, Oberhelman RA. Antiparasitic therapy in children. Pediatr Clin North Am. Jun 2005;52(3):917-48, viii. [Medline].
• Ott M, Fischer H, Polat H, et al. Bioelectrical impedance analysis as a predictor of survival in patients with human immunodeficiency virus infection. J Acquir Immune Defic Syndr Hum Retrovirol. May 1 1995;9(1):20-5. [Medline].
• PDR. Physicians' Desk Reference. Montvale, NJ: Medical Economics Company, Inc;. 2000.
• Patel R. Infections in recipients of kidney transplants. Infect Dis Clin North Am. Sep 2001;15(3):901-52, xi. [Medline].
• Raynaud L, Delbac F, Broussolle V, et al. Identification of Encephalitozoon intestinalis in travelers with chronic diarrhea by specific PCR amplification. J Clin Microbiol. Jan 1998;36(1):37-40. [Medline].
• Rosenblatt JE. Antiparasitic agents. Mayo Clin Proc. Nov 1999;74(11):1161-75. [Medline].
• Sandfort J, Hannemann A, Gelderblom H, et al. Enterocytozoon bieneusi infection in an immunocompetent patient who had acute diarrhea and who was not infected with the human immunodeficiency virus. Clin Infect Dis. Sep 1994;19(3):514-6. [Medline].
• Schwartz DA, Visvesvara GS, Diesenhouse MC, et al. Pathologic features and immunofluorescent antibody demonstration of ocular microsporidiosis (Encephalitozoon hellem) in seven patients with acquired immunodeficiency syndrome. Am J Ophthalmol. Mar 15 1993;115(3):285-92. [Medline].
• Sharpstone D, Rowbottom A, Francis N, et al. Thalidomide: a novel therapy for microsporidiosis. Gastroenterology. Jun 1997;112(6):1823-9. [Medline].
• Strano A, Cali A, Neafie R. Microsporidiosis. In: Pathology of Tropical and Extraordinary Diseases. Vol 1. Washington, DC: Armed Forces Institute of Pathology;. 1976:336-9.
• Talal A, Dieterich D. Gastrointestinal and Hepatic Manifestations of HIV Infection. In: The Medical Management of AIDS. 6th ed. Philadelphia, Pa: WB Saunders, Co;. 1999:195-216.
• Thomson MICROMEDEX. Albendazole. MICROMEDEX Healthcare Series. 2007;131.
• Wanke CA, Pleskow D, Degirolami PC, et al. A medium chain triglyceride-based diet in patients with HIV and chronic diarrhea reduces diarrhea and malabsorption: a prospective, controlled trial. Nutrition. Nov-Dec 1996;12(11-12):766-71. [Medline].
• Weber R, Schwartz D, Bryan R. Microsporidia. In: Mandell, Douglas, and Bennett's Principles and Practice of Infectious Disease. Philadelphia, Pa: Churchill Livingstone;. 2000:2920-29.
• Weber R, Bryan RT. Microsporidial infections in immunodeficient and immunocompetent patients. Clin Infect Dis. Sep 1994;19(3):517-21. [Medline].
• Weiss L. Microsporidiosis. Mandell, Bennett, and Dolin's Principles and Practice of Infectious Diseases. 2005;2:3237-54.
• Wittner M, Tanowitz HB, Weiss LM. Parasitic infections in AIDS patients. Cryptosporidiosis, isosporiasis, microsporidiosis, cyclosporiasis. Infect Dis Clin North Am. Sep 1993;7(3):569-86. [Medline].

Article Last Updated: Feb 5, 2007