Guidelines for the Prevention and Treatment of Opportunistic Infections in HIV-Exposed and HIV-Infected Children

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Microsporidiosis

Last Updated: December 15, 2016; Last Reviewed: December 15, 2016

Panel's Recommendations for Microsporidiosis
Panel's Recommendations
  1. In children with HIV infection, what are the best interventions (compared with no intervention) to treat microsporidiosis?
    • Effective antiretroviral therapy (ART) is the primary initial treatment for microsporidiosis in HIV-infected children (strong, very low).
    • Supportive care with hydration, correction of electrolyte abnormalities, and nutritional supplementation should be provided (expert opinion).
    • Albendazole, in addition to ART, is also recommended for initial therapy of microsporidiosis caused by microsporidia other than Enterocytozoon bieneusi and Vittaforma corneae (strong, low).<.LI>
    • Systemic fumagillin (where available), in addition to ART, is recommended for microsporidiosis caused by E. bieneusi and V. corneae (strong, moderate).
    • Topical therapy with fumagillin eye drops, in addition to ART, is recommended in HIV-infected children with keratoconjunctivitis caused by microsporidia (strong, very low)
    • Oral albendazole can be considered in addition to topical therapy for keratoconjunctivitis due to microsporidia other than E. bieneusi and V. corneae (expert opinion).
  2. In HIV-infected children who have been treated for microsporidiosis, when can treatment (secondary prophylaxis) be safely discontinued?
    Clinicians may consider continuing treatment for microsporidiosis until improvement in severe immunosuppression is sustained (more than 6 months at Centers for Disease Control and Prevention immunologic category 1 or 2) and clinical signs and symptoms of infection are resolved (weak, very low).
Rating System 
Strength of Recommendation: Strong; Weak
Quality of Evidence: High; Moderate; Low; or Very Low

Introduction/Overview

Epidemiology

Microsporidia are obligate, intracellular, spore-forming organisms that primarily cause moderate to severe diarrhea. They are ubiquitous and infect most animal species. They are classified as fungi and defined by their unique single polar tube that coils around the interior of the spore.1 Many microsporidia have been reported as pathogens in humans, but Enterocytozoon bieneusi and Encephalitozoon intestinalis are the most common microsporidia that cause infection in HIV-infected patients. Other microsporidia, such as Encephalitozoon cuniculi, Encephalitozoon hellem, Trachipleistophora hominis, Trachipleistophora anthropophthera, Pleistophora spp., Pleistophora ronneeafiei, Vittaforma (Nosema) corneae, Mycobacterium africanum, Mycobacterium ceylonensis, Nosema ocularum, Tubulinosema acridophagus, Anncaliia (syns Brachiola/Nosema) connori, Anncaliia (syn Brachiola) vesicularum, and Anncaliia (syns Brachiola/Nosema) algerae also have been implicated in human infections. The organisms develop in enterocytes and are excreted in feces. They are transmitted by the fecal-oral route, including through ingestion of contaminated food or water, and, possibly, through contact with infected animals.2,3 Vertical transmission from an infected mother to her child has not been demonstrated in humans but it does occur in animals.

Prior to the era of antiretroviral therapy (ART), prevalence rates for microsporidiosis were reported to be as high as 70% in HIV-infected adults with diarrhea.1,4-6 The role of microsporidiosis in chronic diarrhea was questioned early in the HIV epidemic but is now believed to be causal.7,8 The incidence of microsporidiosis has declined with the widespread use of effective ART, but it is still observed in HIV-infected individuals who are not receiving effective ART.9 Among HIV-uninfected individuals, microsporidiosis is increasingly recognized in children, travelers, organ transplant recipients, contact lens wearers, and the elderly.10

Clinical Manifestations

The most common manifestation of microsporidiosis is gastrointestinal (GI) tract infection. Microsporidia-associated diarrhea is intermittent, copious, watery, and non-bloody. It may be accompanied by crampy abdominal pain; fever is uncommon. Chronic severe diarrhea can result in dehydration, malnutrition, and failure to thrive. Microsporidia species have been found to cause disease in multiple other organs besides the GI tract, as well as disseminated disease.4,11 Different infecting species may result in different clinical manifestations. E. bieneusi is associated with malabsorption, diarrhea, pulmonary disease, and cholangitis. E. cuniculi is associated with hepatitis, encephalitis, peritonitis, keratoconjunctivitis, sinusitis, osteomyelitis, pulmonary disease, and disseminated disease. Encephalitozoon (syn Septata) intestinalis is associated with diarrhea, cholangitis, dermatitis, disseminated infection, and superficial keratoconjunctivitis. E. hellem is associated with superficial keratoconjunctivitis, sinusitis, respiratory disease, prostatic abscesses, nephritis, urethritis, cystitis, and disseminated infection. Nosema, Vittaforma, and Microsporidium spp. are associated with stromal keratitis following trauma in immunocompetent hosts. Pleistophora, Anncaliia, and Trachipleistophora spp. are associated with myositis. Trachipleistophora spp. are also associated with encephalitis, cardiac disease, and disseminated disease.

Diagnosis

To diagnose microsporidia GI infection, thin smears of unconcentrated stool-formalin suspension or duodenal aspirates can be stained with modified trichrome stain. Microsporidia spores are small (1–5 µm diameter) and ovoid; they stain pink to red with modified trichrome stain and contain a distinctive equatorial belt-like stripe. They can also be visualized with hematoxylin-eosin, Giemsa, and acid-fast staining but are often overlooked because of their small size. Chemofluorescence agents such as chromotrope 2R, calcofluor-white (a fluorescent brightener), or Uvitex 2B are useful as selective stains for microsporidia in stool and other body fluids. 

Urine sediment examination by light microscopy can be used to identify microsporidia spores causing disseminated disease (such as Encephalitozoonidae or Trachipleistophora). Transmission electron microscopy, staining with species-specific antibodies, or polymerase chain reaction (PCR) (using specific primers) is needed for speciation.
 
Endoscopic biopsy should be considered for all patients with chronic diarrhea of longer than 2 months duration and negative stool examinations. Touch preparations are useful for rapid diagnosis (i.e., within 24 hours). The organisms can be visualized with Giemsa, tissue Gram stain, calcofluor-white or Uvitex 2B, Warthin-Starry silver staining, or chromotrope 2R.12 Immunofluorescent antibody assays using monoclonal and/or polyclonal antibodies are also available. Sensitive assays using PCR amplification of DNA sequences extracted from stool or biopsy specimens have been developed for E. bieneusi, E. intestinalis, E. hellem, and E. cuniculi13,14 and can be performed at the Centers for Disease Control and Prevention (CDC).

Primary Prevention

Preventing Exposure

Because microsporidia are most likely transferred from contaminated water, food, or contact with an infected individual or animal, direct contact should be avoided. Untreated water sources (drinking water that has not been chemically treated, filtered, or boiled to eliminate infectious agents) should also be avoided. Fresh fruit and vegetables should be thoroughly washed or peeled prior to eating. This recommendation is especially important for individuals with severe immunosuppression. Hand-washing after exposure to potentially contaminated material or contact with infected individuals or animals also is recommended. 

In a hospital, standard precautions (e.g., use of gloves and hand-washing after removal of gloves) should be sufficient to prevent transmission from an infected patient to a susceptible HIV-infected individual. However, contact precautions should be used in the case of a diapered or incontinent child.

Preventing Disease

No chemoprophylactic regimens are known to be effective in preventing microsporidiosis. 

Discontinuing Primary Prophylaxis

Not applicable.

Treatment Recommendations

Treating Disease

Immune reconstitution resulting from ART often results in clearance of microsporidia infections. Effective ART is the primary initial treatment for these infections in HIV-infected children and adults.15 Interestingly, some protease inhibitors, but not others, may have direct inhibitory activity against microsporidia.16 Supportive care with hydration, correction of electrolyte abnormalities, and nutritional supplementation should be provided. Albendazole has activity against many species of microsporidia,17-19 but it is not effective against Enterocytozoon infections or V. corneae.20,21 Albendazole, in addition to ART, is recommended for initial therapy of microsporidiosis caused by microsporidia other than E. bieneusi and V. corneae

Fumagillin (Sanofi-Synthelabo Laboratories, Gentilly, France) (a water-insoluble antibiotic made by Aspergillus fumigatus) and its synthetic analog, TNP-470,22 have both been used to treat microsporidiosis in animals and humans. In a placebo-controlled study of immunocompromised adults (10 of 12 of whom were HIV-infected adults) with E. bieneusi microsporidiosis, fumagillin (20 mg/dose orally 3 times daily for 2 weeks) was associated with decreased diarrhea and clearance of microsporidia spores, which was not observed in placebo recipients.23 Placebo recipients received fumagillin at the conclusion of the trial and all 6 demonstrated clearance of microsporidia. Thrombocytopenia occurred in 2 of the 6 patients randomized to receive fumagillin. No data are available on use of fumagillin or TNP-470 in HIV-infected children, and neither drug is available for systemic use in the United States. Despite the lack of experience using these agents in children, fumagillin and TNP-470 (where available), in addition to ART, are recommended based on demonstration of efficacy in adults. Consultation with an expert is recommended.
 
Keratoconjunctivitis caused by microsporidia in HIV-infected adults responds to topical therapy with investigational fumagillin eye drops prepared from Fumidil B® (fumagillin bicyclohexylammonium, a commercial product used to control a microsporidia disease of honeybees) in saline to achieve a concentration of 70 µg/mL of fumagillin.24-27 Topical therapy with investigational fumagillin eye drops, in addition to ART, is recommended for HIV-infected children with keratoconjunctivitis caused by microsporidia. The addition of oral albendazole to topical fumagillin can be considered for keratoconjunctivitis due to microsporidia other than infections with Enterocytozoon or V. corneae, because microsporidia may persist systemically despite clearance from the eye with topical therapy alone.28,29 Children with suspected keratoconjunctivitis that is unresponsive to antibacterial or antiviral therapy should be referred to a pediatric ophthalmologist for evaluation for possible microsporidiosis.
 
Other agents, including nitazoxanide, atovaquone, metronidazole, and fluoroquinolones, have been reported to reduce diarrhea associated with microsporidia infection. However, metronidazole and atovaquone are not active in vitro or in animal models and should not be used to treat microsporidiosis. The role of alternative agents or the use of combination regimens for initial therapy is unknown; albendazole remains the preferred therapy for GI tract and disseminated infection caused by microsporidia other than E. bieneusi and V. corneae.21,30,31

Monitoring and Adverse Events (Including IRIS)

Patients with diarrhea should be closely monitored for signs and symptoms of volume depletion, electrolyte and weight loss, and malnutrition. In severely ill patients, total parenteral nutrition may be indicated.

Albendazole side effects are rare, but hypersensitivity (e.g., rash, pruritus, fever), neutropenia (reversible), central nervous system effects (e.g., dizziness, headache), GI disturbances (e.g., abdominal pain, diarrhea, nausea, vomiting), hair loss (reversible), and elevated hepatic enzymes (reversible) have been reported. Dose-related bone marrow toxicity is the principal adverse effect of systemic fumagillin, with reversible thrombocytopenia and neutropenia being the most frequent adverse events; topical fumagillin has not been associated with substantial side effects.

There has been one report of immune reconstitution inflammatory syndrome (IRIS) following initiation of ART in a patient with E. bieneusi infection,32 but IRIS has not been described in association with treatment for non-E. bieneusi microsporidiosis. Concern for IRIS should not delay institution of ART in the presence of microsporidia infection.

Managing Treatment Failure

The only feasible approaches to managing treatment failure are supportive treatment and optimization of ART to achieve full virologic suppression. The roles of alternative and combination therapy are unknown.

Secondary Prevention

No pharmacologic interventions are known to be effective in preventing recurrence of microsporidiosis. However, the use of ART alone in patients with microsporidiosis has resulted in clearance of infection and symptoms,15 suggesting that improvements in the immune system after successful ART are critical to recovery and may prevent recurrence. Continued albendazole therapy after treatment for an acute episode of GI or disseminated infection caused by microsporidia other than E. bieneusi and V. corneae may be considered in those with severe immunosuppression (CDC immunologic category 3) until immune recovery is observed (longer than 6 months at CDC immunologic category 1 or 2). 

For keratoconjunctivitis, discontinuation of fumagillin and albendazole treatment may be considered after resolution of infection in patients and immune recovery is observed (longer than 6 months at CDC immunologic category 1 or 2). Therapy should be continued indefinitely if severe immunosuppression (CDC immunologic category 3) persists because recurrence or relapse may follow treatment discontinuation.

Discontinuing Secondary Prophylaxis

Discontinuation of secondary prophylaxis can be considered when immune recovery is observed (longer than 6 months at CDC immunologic category 1 or 2).

Recommendations

Treatment

  1. In children with HIV infection, what are the best interventions (compared with no intervention) to treat microsporidiosis?

    • Effective ART is the primary initial treatment for microsporidiosis in HIV-infected children. (strong, very low)

      An observational study of four adults with documented E. bieneusi infection followed stool samples and duodenal biopsy pre-ART, then 1–3 and 6 months post-ART.15 Results demonstrated that if the patient responded to ART, symptoms related to microsporidiosis improved within 1 month and evidence of eradication of the organism occurred at 6 months. Unfortunately, there are no comparable data for children.

    • Supportive care with hydration, correction of electrolyte abnormalities, and nutritional supplementation should be provided (expert opinion)

      There are no studies that address this specific management issue in microsporidiosis. However, recognition and management of hydration status and electrolyte imbalance are key to management of infectious diarrhea. 

    • Albendazole, in addition to ART, is also recommended for initial therapy of microsporidiosis caused by microsporidia other than E. bieneusi and V. corneae (strong, low)

      Albendazole has activity against many species of microsporidia but it is not effective against E. bieneusi or V. corneae. Small observational cohort studies in adults have demonstrated improvement in symptoms and resolution of diarrhea as well as clearance of the organism in some patients following albendazole treatment.17,18 A large randomized, open-label study in immunocompetent children in Costa Rica demonstrated clinical improvement in 95% of children receiving albendazole within 48 hours of initiation of therapy compared with only 30% who received supportive care only.19 Case reports suggest that albendazole therapy is not effective in cases of infection with E. bieneusi and V. corneae.20 In these cases, systemic fumagillin therapy, where available, is recommended. 

    • Systemic fumagillin (where available) in addition to ART is recommended for microsporidiosis caused by E.bieneusi and V. corneae (strong, moderate)

      In a placebo-controlled study of immunocompromised adults (10 of 12 of whom were HIV-infected adults) with E. bieneusi microsporidiosis, fumagillin (20 mg/dose orally 3 times daily for 2 weeks) was associated with decreased diarrhea and clearance of microsporidia spores, which was not observed in placebo recipients.23 Placebo recipients received fumagillin at the conclusion of the trial and all 6 demonstrated clearance of microsporidia. 

    • Topical therapy with fumagillin eye drops, in addition to ART, is recommended in HIV-infected children with keratoconjunctivitis caused by microsporidia (strong, very low).

      Improvements have been demonstrated in a small number of reported cases of topical fumagillin treatment of microsporidial keratoconjunctivitis. Treatment with this agent is complicated by lack of a licensed preparation in the United States.24-27 

    • Oral albendazole can be considered in addition to topical therapy for keratoconjunctivitis caused by microsporidia other than E. bieneusi and V. corneae (expert opinion)

      The addition of oral albendazole to topical fumagillin can be considered for keratoconjunctivitis caused by microsporidia other than E. bieneusi or V. corneae because microsporidia may persist systemically despite clearance from the eye with topical therapy alone.28,29

Secondary Prevention

II. In HIV-infected children who have been treated for microsporidiosis, when can treatment (secondary prophylaxis) be safely discontinued?
Clinicians may consider continuing treatment for microsporidiosis until improvement in severe immunosuppression is sustained (more than 6 months at CDC immunologic category 1 or 2) and clinical signs and symptoms of infection are resolved (weak, very low)

Recurrence of microsporidiosis has been documented following discontinuation of treatment in severely immunosuppressed patients.24 However, discontinuation of therapy following immune restoration resulting from initiation of ART was successful in a small number of patients.15

References

  1.  Mathis A. Microsporidia: emerging advances in understanding the basic biology of these unique organisms. Int J Parasitol. 2000;30(7):795-804. Available at http://www.ncbi.nlm.nih.gov/pubmed/10899524.
  2. Hutin YJ, Sombardier MN, Liguory O, et al. Risk factors for intestinal microsporidiosis in patients with human immunodeficiency virus infection: a case-control study. J Infect Dis. 1998;178(3):904-907. Available at http://www.ncbi.nlm.nih.gov/pubmed/9728570.
  3. Didier ES, Stovall ME, Green LC, Brindley PJ, Sestak K, Didier PJ. Epidemiology of microsporidiosis: sources and modes of transmission. Vet Parasitol. 2004;126(1-2):145-166. Available at http://www.ncbi.nlm.nih.gov/pubmed/15567583.
  4. Kotler DP, Orenstein JM. Clinical syndromes associated with microsporidiosis. Advances in Parasitology. 1998;40:321-349. Available at http://www.ncbi.nlm.nih.gov/pubmed/9554078.
  5. Wittner M, Weiss L. The Microsporidia and Microsporidiosis. Washington DC: ASM Press; 1999.
  6. Deplazes P, Mathis A, Weber R. Epidemiology and zoonotic aspects of microsporidia of mammals and birds. Contributions to Microbiology. 2000;6:236-260. Available at http://www.ncbi.nlm.nih.gov/pubmed/10943515.
  7. Eeftinck Schattenkerk JK, van Gool T, van Ketel RJ, et al. Clinical significance of small-intestinal microsporidiosis in HIV-1-infected individuals. Lancet. 1991;337(8746):895-898. Available at http://www.ncbi.nlm.nih.gov/pubmed/1672978.
  8. Molina JM, Sarfati C, Beauvais B, et al. Intestinal microsporidiosis in human immunodeficiency virus-infected patients with chronic unexplained diarrhea: prevalence and clinical and biologic features. J Infect Dis. 1993;167(1):217-221. Available at http://www.ncbi.nlm.nih.gov/pubmed/8418171.
  9. Stark D, Barratt JL, van Hal S, Marriott D, Harkness J, Ellis JT. Clinical significance of enteric protozoa in the immunosuppressed human population. Clin Microbiol Rev. 2009;22(4):634-650. Available at http://www.ncbi.nlm.nih.gov/pubmed/19822892.
  10. Didier ES, Weiss LM. Microsporidiosis: not just in AIDS patients. Curr Opin Infect Dis. 2011;24(5):490-495. Available at http://www.ncbi.nlm.nih.gov/pubmed/21844802.
  11. Didier ES, Weiss LM. Microsporidiosis: current status. Curr Opin Infect Dis. 2006;19(5):485-492. Available at http://www.ncbi.nlm.nih.gov/pubmed/16940873.
  12. Weiss LM, Vossbrinck CR. Microsporidiosis: molecular and diagnostic aspects. Advances in Parasitology. 1998;40:351-395. Available at http://www.ncbi.nlm.nih.gov/pubmed/9554079.
  13. McLauchlin J, Amar CF, Pedraza-Diaz S, Mieli-Vergani G, Hadzic N, Davies EG. Polymerase chain reaction-based diagnosis of infection with Cryptosporidium in children with primary immunodeficiencies. Pediatr Infect Dis J. 2003;22(4):329-335. Available at http://www.ncbi.nlm.nih.gov/pubmed/12690272.
  14. Menotti J, Cassinat B, Porcher R, Sarfati C, Derouin F, Molina JM. Development of a real-time polymerase-chain-reaction assay for quantitative detection of Enterocytozoon bieneusi DNA in stool specimens from immunocompromised patients with intestinal microsporidiosis. J Infect Dis. 2003;187(9):1469-1474. Available at http://www.ncbi.nlm.nih.gov/pubmed/12717629.
  15. Miao YM, Awad-El-Kariem FM, Franzen C, et al. Eradication of cryptosporidia and microsporidia following successful antiretroviral therapy. J Acquir Immune Defic Syndr. 2000;25(2):124-129. Available at http://www.ncbi.nlm.nih.gov/pubmed/11103042.
  16. Menotti J, Santillana-Hayat M, Cassinat B, Sarfati C, Derouin F, Molina JM. Inhibitory activity of human immunodeficiency virus aspartyl protease inhibitors against Encephalitozoon intestinalis evaluated by cell culture-quantitative PCR assay. Antimicrob Agents Chemother. 2005;49(6):2362-2366. Available at http://www.ncbi.nlm.nih.gov/pubmed/15917534.
  17. Dore GJ, Marriott DJ, Hing MC, Harkness JL, Field AS. Disseminated microsporidiosis due to Septata intestinalis in nine patients infected with the human immunodeficiency virus: response to therapy with albendazole. Clin Infect Dis. 1995;21(1):70-76. Available at http://www.ncbi.nlm.nih.gov/pubmed/7578763.
  18. Leder K, Ryan N, Spelman D, Crowe SM. Microsporidial disease in HIV-infected patients: a report of 42 patients and review of the literature. Scand J Infect Dis. 1998;30(4):331-338. Available at http://www.ncbi.nlm.nih.gov/pubmed/9817510.
  19. Tremoulet AH, Avila-Aguero ML, Paris MM, Canas-Coto A, Ulloa-Gutierrez R, Faingezicht I. Albendazole therapy for Microsporidium diarrhea in immunocompetent Costa Rican children. Pediatr Infect Dis J. 2004;23(10):915-918. Available at http://www.ncbi.nlm.nih.gov/pubmed/15602190.
  20. Weber R, Sauer B, Luthy R, Nadal D. Intestinal coinfection with Enterocytozoon bieneusi and Cryptosporidium in a human immunodeficiency virus-infected child with chronic diarrhea. Clin Infect Dis. 1993;17(3):480-483. Available at http://www.ncbi.nlm.nih.gov/pubmed/8218693.
  21. Molina JM, Chastang C, Goguel J, et al. Albendazole for treatment and prophylaxis of microsporidiosis due to Encephalitozoon intestinalis in patients with AIDS: a randomized double-blind controlled trial. J Infect Dis. 1998;177(5):1373-1377. Available at http://www.ncbi.nlm.nih.gov/pubmed/9593027.
  22. Didier PJ, Phillips JN, Kuebler DJ, et al. Antimicrosporidial activities of fumagillin, TNP-470, ovalicin, and ovalicin derivatives in vitro and in vivo. Antimicrob Agents Chemother. 2006;50(6):2146-2155. Available at http://www.ncbi.nlm.nih.gov/pubmed/16723577.
  23. Molina JM, Tourneur M, Sarfati C, et al. Fumagillin treatment of intestinal microsporidiosis. N Engl J Med. 2002;346(25):1963-1969. Available at http://www.ncbi.nlm.nih.gov/pubmed/12075057.
  24. Diesenhouse MC, Wilson LA, Corrent GF, Visvesvara GS, Grossniklaus HE, Bryan RT. Treatment of microsporidial keratoconjunctivitis with topical fumagillin. Am J Ophthalmol. 1993;115(3):293-298. Available at http://www.ncbi.nlm.nih.gov/pubmed/8117342.
  25. Lowder CY, McMahon JT, Meisler DM, et al. Microsporidial keratoconjunctivitis caused by Septata intestinalis in a patient with acquired immunodeficiency syndrome. Am J Ophthalmol. 1996;121(6):715-717. Available at http://www.ncbi.nlm.nih.gov/pubmed/8644819.
  26. Garvey MJ, Ambrose PG, Ulmer JL. Topical fumagillin in the treatment of microsporidial keratoconjunctivitis in AIDS. The Annals of Pharmacotherapy. 1995;29(9):872-874. Available at http://www.ncbi.nlm.nih.gov/pubmed/8547736.
  27. Rosberger DF, Serdarevic ON, Erlandson RA, et al. Successful treatment of microsporidial keratoconjunctivitis with topical fumagillin in a patient with AIDS. Cornea. 1993;12(3):261-265. Available at http://www.ncbi.nlm.nih.gov/pubmed/8500340.
  28. Tham AC, Sanjay S. Clinical spectrum of microsporidial keratoconjunctivitis. Clin Experiment Ophthalmol. 2012;40(5):512-518. Available at http://www.ncbi.nlm.nih.gov/pubmed/22003887.
  29. Didier ES. Effects of albendazole, fumagillin, and TNP-470 on microsporidial replication in vitro. Antimicrob Agents Chemother. 1997;41(7):1541-1546. Available at http://www.ncbi.nlm.nih.gov/pubmed/9210681.
  30. Hicks P, Zwiener RJ, Squires J, Savell V. Azithromycin therapy for Cryptosporidium parvum infection in four children infected with human immunodeficiency virus. J Pediatr. 1996;129(2):297-300. Available at http://www.ncbi.nlm.nih.gov/pubmed/8765631.
  31. Bicart-See A, Massip P, Linas MD, Datry A. Successful treatment with nitazoxanide of Enterocytozoon bieneusi microsporidiosis in a patient with AIDS. Antimicrob Agents Chemother. 2000;44(1):167-168. Available at http://www.ncbi.nlm.nih.gov/pubmed/10602740.
  32. Sriaroon C, Mayer CA, Chen L, Accurso C, Greene JN, Vincent AL. Diffuse intra-abdominal granulomatous seeding as a manifestation of immune reconstitution inflammatory syndrome associated with microsporidiosis in a patient with HIV. AIDS Patient Care STDS. 2008;22(8):611-612. Available at http://www.ncbi.nlm.nih.gov/pubmed/18627278.

Dosing Recommendations for Preventing and Treating Microsporidiosis
Preventative Regimen 
Indication First Choice Alternative Comments/Special Issues
Primary Prophylaxis
N/A
N/A
Not recommended
Secondary Prophylaxis
Disseminated, Non-Ocular Infection or GI Infection Caused by Microsporidia Other Than E. Bieneusi or V. Corneae:
  • Albendazole 7.5 mg/kg body weight (maximum 400 mg/dose) by mouth twice daily 
Ocular Infection:
  • Topical fumagillin bicyclohexylammonium (Fumidil B) 3 mg/mL in saline (fumagillin 70 μg/mL) eye drops: 2 drops every 2 hours for 4 days, then 2 drops QID (investigational use only in United States) plus, for infection attributed to microsporidia other than E. bieneusi or V. corneae, albendazole 7.5 mg/kg body weight (maximum 400 mg/dose) by mouth twice daily for management of systemic infection
N/A
Criteria for Discontinuing Secondary Prophylaxis
  • After initiation of ART, resolution of signs and symptoms and sustained immune reconstitution (more than 6 months at CDC immunologic category 1 or 2)  
Treatment Effective ART Therapy
  • Immune reconstitution may lead to microbiologic and clinical response. 
For Disseminated (Not Ocular) and Intestinal Infection Attributed to Microsporidia Other Than E. bieneusi or V. corneae:
  • Albendazole 7.5 mg/kg body weight (maximum 400 mg/dose) by mouth twice daily (in addition to ART)
Treatment Duration: 
  • Continue until sustained immune reconstitution (longer than 6 months at CDC immunologic category 1 or 2) after initiation of ART and resolution of signs and symptoms 
For E. bieneusi or V. corneae Infections:
  • Fumagillin (where available) adult dose 20 mg by mouth 3 times daily, or
  • TNP-470 (a synthetic analogue of fumagillin; where available) recommended for treatment of infections caused by E. bieneusi in HIV-infected adults (in addition to ART)
For Ocular Infection:
  • Topical fumagillin bicyclohexylammonium (Fumidil B) 3 mg/mL in saline (fumagillin 70 µg/mL) eye drops: 2 drops every 2 hours for 4 days, then 2 drops QID (investigational use only in United States) plus, for microsporidial infection other than E. bieneusi and V. corneae, albendazole 7.5 mg/kg body weight (maximum 400 mg/dose) by mouth twice daily for management of systemic infection (in addition to ART)
Treatment Duration: 
  • Continue until sustained immune reconstitution (longer than 6 months at CDC immunologic category 1 or 2) after initiation of ART and resolution of signs and symptoms.  
N/A
  • Supportive care (e.g., hydration, correction of electrolyte abnormalities, nutritional support)
  • Fumagillin for systemic use is unavailable in the United States and data on dosing in children are unavailable. Consultation with an expert is recommended. 
     
Key to Acronyms: ART = antiretroviral therapy; CDC = Centers for Disease Control and Prevention; GI = gastrointestinal; QID = 4 times a day

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