Microsporidia infection in patients with autoimmune diseases

Purpose

Microsporidium is a spore-forming intracellular parasite that affects a wide range of hosts including humans. The tumor necrosis factor alpha (TNF-α) plays a key role in the immunity to infection with microsporidia. Recently, the TNF-α antagonists have proven successful in treating variable autoimmune diseases. In the current study, we aimed to investigate the impact of using TNF-α antagonists as a therapeutic regimen in the prevalence of infections with microsporidia.

Materials and Methods

Diarrheal patients with distinct autoimmune diseases (n = 100) were assigned to the study. Patients taking anti-TNF-α medications (n = 60) were allocated to Group 1A and those undergoing non-TNF-α inhibitor treatment (n = 40) to Group 1B. Furthermore, patients with diarrhea without autoimmune disorders (n = 20) were allocated as controls. Stool specimens, 3 per patient, were collected and microscopically examined for microsporidia spores. A microsporidia-specific stool polymerase chain reaction was used to confirm the microscopic findings.

Results

Microsporidia infection was identified in 28.3% (17/60), 10% (4/40), and in 5% (1/20) of patients in Group 1A, Group 1B, and in the control group, respectively. Overall, infection was significantly high in cases compared to the controls and in patients receiving TNF-α antagonists compared to patients not given TNF-α inhibitors (P < 0.05). Finally, infection was significantly higher in cases treated with TNF-α antagonists for ≥2 months compared to cases treated for <2 months of duration (P < 0.05).

Conclusion

There was a significant increase in microsporidia infection in autoimmune disease patients undergoing treatment with TNF-α antagonists, and the duration of treatment is one of the risk factors. The study highlights the importance of microsporidia testing in immunocompromised patients, particularly those undergoing treatment with anti-TNF-α drugs and emphasises the need for awareness among clinicians regarding this opportunistic parasite.

Dual infection of urinary tract with Enterocytozoon bieneusi and Encephalitozoon cuniculi in HIV/AIDS patients

Microsporidia are emerging pathogens which cause an opportunistic infections in immunocompromised patients, especially those with AIDS. Intestinal microsporidiosis is the most recognized infection, whereas urinary tract infections caused by microsporidia are rarely paid attention to either due to their subclinical course or diagnostic difficulties. In this report dual microsporidial infection of urinary tract, caused by Enterocytozoon bieneusi and Encephalitozoon cuniculi was described in HIV/AIDS patients under cART therapy. Since microsporidiosis can cause severe complications or even death in immunosuppressed patients, our results suggest that microsporidial infection should be included in routine investigation of HIV-positive patients, even asymptomatic.

[On the use of FTA technology for collection, archieving, and molecular analysis of microsporidia dna from clinical stool samples]

The FTA technology was applied for sampling, archiving, and molecular analysis of the DNA isolated from stool samples to diagnose and identify microsporidia, the intracellular opportunistic parasites which induce malabsortion syndrome in immunosuppressed humans, particularly in patients with AIDS. Microsporidia DNA was successfully amplified in 6 of 50 stool samples of HIV-positive patients of the S. P. Botkin Memorial Infectious Disease Hospital (St. Petersburg) applied to FTA cards (FTA-Cars, Whatman Inc. Florham Park, NJ, USA). Amplicons (the fragments of rDNA) were directly sequenced, and microsporidia species--Encephalitozoon intestinalis, E. cuniculi, E. hellem, and Enterocytozoon bieneusi--were identified in Genbank by NCBI BLAST program. The FTA method of DNA immobilization is especially promising for epidemiological and field population studies which involve genotyping of microsporidia species and isolates.

[Investigation of microsporidia in patients with acute and chronic urticaria]

Microsporidia species are one of the major causes of severe diarrhea especially in immunocompromised patients, however they also cause infections in immunocompetent subjects. Urticaria, which is a common dermatologic disease may be triggered by drugs, infections, foods or food additives, psychogenic factors and autoimmune, metabolic and malignant diseases. While the etiologic grounds of acute urticaria are generally identified, the etiology remains unknown in most of the chronic urticaria cases. The studies on the roles of parasitic infections in the etiology of urticaria have indicated that the most responsible protozoa are Giardia intestinalis and Blastocystis hominis. However, no data have been found in the literature concerning the relationship between Microsporidia and urticaria. The aim of this study was to investigate the presence of Microsporidia spores in the stool samples of patients diagnosed as acute or chronic urticaria in dermatology clinics and to determine the rates of positivity. All of the samples stained with modified trichrome and calcofluor staining methods were examined microscopically. The samples were accepted as positive when the spores of Microsporidia were detected by both of the staining methods. Microsporidia were detected in 26 (19.7%) of the patients and in 1 (2.8%) of the control subjects. Thus the total rate of positivity was 16% (27/168). In cases with acute/chronic urticaria, microsporidia positivity rate was found significantly higher than the control group (p= 0.028; p< 0.05). No statistically significant difference was detected between Microsporidia positivity and age or gender (p= 0.27 and p= 0.99, respectively; p> 0.05). In conclusion, Microsporidia should be taken into consideration in patients with unknown origin of urticaria. However, advanced studies are needed for supporting the relation between Microsporidia and acute/chronic urticaria.

High prevalence of Microsporidium infection in HIV-infected patients

Sixty-four patients infected with human immunodeficiency virus (HIV) participated in a study to determine opportunistic enteric pathogens and compare them with the patients' clinical status. The most frequently found pathogens were microsporidium (81.2%), Cryptosporidium parvum (20.3%), Candida albicans (12.5%) and Blastocystis hominis (10.9%). Less frequently found pathogens were Giardia intestinalis (6.2%), Cyclospora (4.7%), Opishorchis viverrini ova (3.1%), Strongyloides stercoralis larvae (3.1%) and hookworm ova (1.6%). The presence of enteric pathogens was not significantly associated with sex, length of HIV seropositivity and diarrheal symptoms. A high prevalence of microsporidium, based on microscopic examination, was found in Thai HIV-infected patients. This confirms the importance of microsporidium in HIV-infected/AIDS patients and the necessity for stool evaluation in all HIV-infected patients.

Correlation between CD4 counts of HIV patients and enteric protozoan in different seasons - an experience of a tertiary care hospital in Varanasi (India)

BACKGROUND

Protozoan infections are the most serious among all the superimposed infections in HIV patients and claim a number of lives every year. The line of treatment being different for diverse parasites necessitates a definitive diagnosis of the etiological agents to avoid empirical treatment. Thus, the present study has been aimed to elucidate the associations between diarrhoea and CD4 counts and to study the effect of HAART along with management of diarrhoea in HIV positive patients. This study is the first of its kind in this area where an attempt was made to correlate seasonal variation and intestinal protozoan infestations.

METHODS

The study period was from January 2006 to October 2007 wherein stool samples were collected from 366 HIV positive patients with diarrhea attending the ART centre, inpatient department and ICTC of S.S. hospital, I.M.S., B.H.U., Varanasi. Simultaneously, CD4 counts were recorded to assess the status of HIV infection vis-à-vis parasitic infection. The identification of pathogens was done on the basis of direct microscopy and different staining techniques.

RESULTS

Of the 366 patients, 112 had acute and 254 had chronic diarrhea. The percentages of intestinal protozoa detected were 78.5% in acute and 50.7% in chronic cases respectively. Immune restoration was observed in 36.6% patients after treatment on the basis of clinical observation and CD4 counts. In 39.8% of HIV positive cases Cryptosporidium spp. was detected followed by Microsporidia spp. (26.7%). The highest incidence of intestinal infection was in the rainy season. However, infection with Cyclospora spp. was at its peak in the summer. Patients with chronic diarrhea had lower CD4 cell counts. The maximum parasitic isolation was in the patients whose CD4 cell counts were below 200 cells/microl.

CONCLUSION

There was an inverse relation between the CD4 counts and duration of diarrhea. Cryptosporidium spp. was isolated maximum among all the parasites in the HIV patients. The highest incidence of infection was seen in the rainy season.

A case of bilateral microsporidial keratitis from Bangladesh – infection by an insect parasite from the genus Nosema

An HIV-negative patient from Bangladesh with bilateral keratitis was found to be infected with a microsporidian parasite belonging to the genus Nosema. Significantly, the patient had bathed in a rural pond 7 days prior to the development of ocular symptoms. Nosema parasites are common insect parasites and the source of this microsporidial infection was possibly from mosquito larvae developing in the pond in which the patient bathed. The reduced temperature of the human eye and its immune status may have allowed a poikilothermic insect parasite to establish infection in the cornea of a homeothermic human host. This case highlights the opportunistic potential of insect microsporidial parasites to infect immunocompetent humans as well as those who are immunodeficient.

HIV enteropathy: crypt stem and transit cell hyperproliferation induces villous atrophy in HIV/Microsporidia-infected jejunal mucosa

OBJECTIVES

The study aim was to analyse the kinetics of stem and transit cells in the crypts of jejunal mucosa infected with HIV and Microsporidia.

DESIGN

The size of villi, depth of crypts and proliferative activity of transit and stem cells in jejunal mucosa were measured using morphometric techniques.

METHODS

The surface area/volume ratio (S/V) of jejunal biopsies was estimated under light microscopy using a Weibel graticule. Crypt length was measured by counting enterocytes along the crypt side from the base to the villus junction, and the mean crypt length was calculated. The S/V and crypt lengths of the jejunal mucosa of 21 HIV and Microsporidia-infected test cases were compared with 14 control cases. The labelling index in relation to the crypt cell position of 10 of the test cases was analysed compared with 13 control cases.

RESULTS

Differences were found in the S/V and crypt length, and there was a negative correlation between S/V and crypt length in test and control cases combined. Cell labelling indices fell into low and high proliferation groups. There were significant differences in labelling indices between low proliferation test cases and controls, between high proliferation test cases and controls, and between high and low proliferation test cases.

CONCLUSION

Villous atrophy induced by HIV and Microsporidia is attributed to crypt cell hyperplasia and the encroachment of crypt cells onto villi. These infections induce crypt hypertrophy by stimulating cell mitosis predominantly in transit cells but also in stem cells. Increased stem cell proliferation occurs only in high proliferation cases.

Microsporidiosis in a Brazilian University Hospital: case report

This is the report on a patient with chronic diarrhea caused by microsporidia. He is married, infected with HIV and has low CD4 cell count. The diagnosis was established through stool parasite search using concentration methods and Gram - chromotrope staining technique. Ileum biopsy was also performed in this case. The etiological diagnosis may be established in a clinical laboratory, by chromotrope staining technique in routine microscopic examination of stool specimens.

Identification of genotypes of Enterocytozoon bieneusi from stool samples from human immunodeficiency virus-infected patients in Thailand

We identified genotypes of Enterocytozoon bieneusi from 33 stool samples of Thai human immunodeficiency virus (HIV)-infected adult patients. Genotype D was identified at the highest frequency (36.4%), while genotype E was the second most common (15.1%). Genotypes O and PigEBITS 7, previously found only in pigs, were observed in Thai HIV-infected patients. Phylogenetic analysis supported a zoonotic nature for E. bieneusi.

Prevalence of intestinal parasites including microsporidia in human immunodeficiency virus-infected adults in Cameroon: a cross-sectional study

To assess the prevalence of intestinal parasites in a cohort of human immunodeficiency virus (HIV)-infected adults in Cameroon, a cross-sectional study was conducted. Detection of parasites was performed in 181 stool samples from 154 HIV-infected patients with a mean CD4 cell count of 238 cells/mm(3). Only 35 patients (22%) were receiving antiretroviral therapy at the time of stool sampling, and 46 (29%) had diarrhea. Opportunistic protozoa were found in 15 patients (9.7%), 8 of whom (53%) had diarrhea. Enterocytozoon bieneusi was found in eight patients, C. parvum in six patients, and Isospora belli in three patients. All E. bieneusi isolates tested belonged to the same genotype. The prevalence of opportunistic protozoa among patients with CD4 cell counts less than 50/mm(3) was 32%.

In vitro cultivation and electron microscopy characterization of Trachipleistophora anthropophthera isolated from the cornea of an AIDS patient

We describe an in vitro culture technique for a microsporidian isolated from the corneal biopsy of an HIV-infected patient. The corneal biopsy was inoculated into a monolayer culture of fibroblasts derived from newborn mouse brain and incubated at 37 degrees C in an atmosphere of 5% CO2. Minimum essential medium supplemented with 2% fetal bovine serum appeared to be an optimum medium for growth and maintenance of the parasite and for production of large numbers of spores. This microsporidian was identified as Trachipleistophora anthropophthera based on ultrastructural features. It forms two types of sporophorous vesicles and two types of spores simultaneously: polysporous vesicle type I with eight or more oval spores, 3.7-4.0 microm by 2.0-2.3 microm, and bisporous vesicle type II with two round spores, 1.7-2.2 microm by 1.6-2.0 microm in size.

Cryptosporidiosis and microsporidiosis in ugandan children with persistent diarrhea with and without concurrent infection with the human immunodeficiency virus

Cryptosporidium spp. and Enterocytozoon bieneusi are enteric pathogens that have emerged as significant causes of persistent diarrhea (PD) in immunologically compromised individuals particularly in association with HIV/AIDS. We conducted a cross-sectional study on the clinical epidemiology of E. bieneusi and Cryptosporidium in children with PD, with and without HIV/AIDS, attending Uganda's Mulago National Referral Hospital. Two hundred forty-three children aged < 60 months, admitted between November 2002 and May 2003 with PD (> 14 days), were analyzed for HIV status and CD4 lymphocyte counts, and stools were screened for the presence of E. bieneusi and Cryptosporidium by microscopy and positive samples genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Eighty (32.9%) of the children were excreting E. bieneusi, and 76 (31.3%) were excreting Cryptosporidium. Ninety-one of the 243 children had HIV, of who 70 (76.9%) had E. bieneusi, versus 10 (6.6%) of the 152 without (odds ratio = 47.33; 95% CI = 19.88 to 115.97), while 67 (73.6%) had Cryptosporidium, versus 9 (5.9%) without (odds ratio = 44.36; 95% CI = 18.39 to 110.40). Children with counts < 25% CD4 cells were more likely to have either E. bieneusi (odds ratio = 7.42; 95% CI = 3.77 to 14.69) or Cryptosporidium (odds ratio = 6.45; 95% CI = 3.28 to 12.76) than those with higher CD4 percentages. However, only HIV status was independently associated with either Cryptosporidium or E. bieneusi. Among the 243 children with PD, 67 (27.8%) were infected with both enteric pathogens, with HIV being the only independent predictor of coinfection. Finally, some 81% of HIV-infected children with PD excreted one or both organisms, compared with only 10% of children with PD testing negative for HIV. Seventy-four percent of isolates were C. hominis, the anthroponotic species, 17% were C. parvum, the zoonotic species, and 8% were a mixture of the two or others.

Detection of intestinal microsporidiosis in diarrhoeal patients infected with the human immunideficiency virus (HIV-1) using PCR and Uvitex-2B stain

A total of 105 single fresh stool samples were collected from diarrhoeal patients with (80 HIV-positive and 25 HIV-negative) from the Army and the Police hospitals, Addis Ababa. The stool samples were processed by water-ether sedimentation method; they were stained with Uvitex-2B technique for microscopic detection of intestinal microsporidium. A portion of all samples were preserved in 200microl PBS containing 2% PVPP ((Polyvinylpolypyrolidone) for confirmation with PCR. 18/105(17.2%) of the cases were positive for intestinal microsporidial infection by at least one method. 8/105 (7.6%) positive both by microscopy and PCR and 10/105 (9.5%) were positive only by PCR. All microsporidia positive cases were also HIV positive. Based on PCR analysis, 15 Enterocytozoon bieneusi and 3 Encephalitozoon intestinalis were identified. This study has shown that intestinal microsporidiosis is a common cause of chronic diarrhoea in advanced AIDS patients and this is mainly attributed to Enterocytozoon bieneusi. To the best of our knowledge, this is the first report of intestinal microsporidiosis in Ethiopia. It has an important implication for the understanding of the aetiology of diarrhoea in HIV/AIDS patients in the country.

Trachipleistophora hominis infection in the myocardium and skeletal muscle of a patient with AIDS

OBJECTIVES

To review the literature relevant to microsporidial infection of muscle and to describe a case of human microsporidial infection involving both skeletal and cardiac muscle.

METHODS

Samples from an AIDS patient with myositis have been examined by light and electron microscopy.

RESULTS

We describe the findings at autopsy of a 47 year old Australian male with late stage AIDS, who had skeletal and cardiac muscle involvement with the microsporidian Trachipleistophora hominis. This is the third definitively identified case of human T. hominis infection and the first to describe infection of the myocardium.

CONCLUSIONS

Microsporidial infection of muscle is rare in humans, but more work is needed to elucidate both the organisms and routes of transmission of this group of parasitic protozoa.

Albendazole therapy for Microsporidium diarrhea in immunocompetent Costa Rican children

BACKGROUND

Microsporidia comprise a large group of obligate intracellular parasites. Although several species have emerged as opportunistic agents in immunocompromised patients, cases have also been reported in immunocompetent patients.

METHODS

During 21 months, we conducted a randomized, open label study in 200 children hospitalized with Microsporidium subacute diarrhea. Patients had prolonged, nonbloody, nonmucoid diarrhea, with > or =10 bowel movements/day for >10 days. Patients had negative rotavirus tests, bacterial stool cultures and sugar reductive tests in feces. Stool examinations to rule out Giardia intestinalis and intestinal nematodes were performed. Microsporidium was identified by light microscopy in stool specimens stained with Giemsa and Weber techniques. One hundred patients received oral albendazole (15 mg/kg/day twice a day for 7 days) and 100 patients received only supportive therapy.

RESULTS

Both groups were comparable regarding gender, age, clinical evolution and weight. Median (range) age was 24 (6-36) months. All children had abdominal pain, nausea, vomiting and anorexia. The primary endpoint, defined as clinical improvement within 48 h of initial therapy, occurred in 95 and 30% of the albendazole-treated and untreated patients, respectively (P < 0.05). There was a significant decrease in stool frequency, reduction of clinical findings and decrease in Microsporidium parasites in stool specimens of children treated with albendazole compared with the untreated group. Median (range) duration of diarrhea was 5 (3-7) days in albendazole-treated patients versus 10 (8-15) days in untreated patients (P < 0.05).

CONCLUSION

Albendazole therapy was effective in improving the clinical manifestations and decreasing the duration of the illness of children with diarrhea caused by Microsporidium.

[Prevalence of microsporidia and other intestinal parasites in patients with HIV infection, Bogota, 2001]

Opportunistic intestinal parasites are a common cause of diarrhea in HIV-infected patients. To determine the prevalence of microsporidia and other opportunistic parasites infecting HIV patients in Bogotá, Colombia, 115 patients were examined for these infections during the year 2001. The institution and the sample percent from each are as follows: Santa Clara Hospital, 33.0%; San Pedro Claver, 20.0%; Simón Bolívar Hospital, 14.8%; San José Hospital, 13.9%; Central de la Policía Hospital, 6.1%; Compensar, 5.2%; Colombian League against AIDS, 2.6%; San Ignacio Hospital, 2.6%, and the Military Hospital, 1.7%. The average patient age was 36 years, with a range from 18 to 71 years. Patients with complaint of gastrointestinal symptoms were asked to provide two consecutive stool samples. The samples were concentrated in formalin-ether and examined microscopically for intestinal coccidian parasites by direct wet slide mounts. The prevalence of intestinal opportunistic parasites was 10.4% for Cryptosporidium sp. Initially, 29% of the samples were found to be positive for microsporidian spores using a modified Ziehl Neelsen chromotrope stain, but only 3.5% of them were confirmed as positive when a calcofluor/Gram chromotrope stain was used. The general prevalence of intestinal parasites was 59.1%. The most frequently found pathogens were Blastocystis hominis, 25.2%, and Entamoeba histolytica, 13%. In other studies with HIV patients in Colombia, lower prevalences of Cryptosporidium sp. infection were observed.

Quantitative evaluation of Enterocytozoon bieneusi infection in simian immunodeficiency virus-infected rhesus monkeys

The association of the microsporidia Enterocytozoon bieneusi with chronic diarrhea and wasting in individuals with acquired immunodeficiency syndrome (AIDS) has been demonstrated. The disease caused by E. bieneusi has been linked to decreased levels of circulating CD4+ T lymphocytes. In this study, we investigated the relationship between the extent of excretion of E. bieneusi in feces of simian immunodeficiency virus (SIV)-infected juvenile macaques and the CD4+ T lymphocyte counts in the peripheral blood. Twelve juvenile rhesus monkeys (Macaca mulatta) were intravenously inoculated with the pathogenic molecular clone SIVmac239. Numbers of CD4+ T lymphocytes were assessed by three-color flow cytometry. The presence of E. bieneusi DNA in feces was assessed by nested PCR. In addition, selected samples of feces were examined by competitive quantitative PCR to assess the level of E. bieneusi infection. Low (n = 5) to undetectable (n = 7) quantities of E. bieneusi were present in feces of the twelve animals in prior to inoculation with SIV. After SIV inoculation the number of animals shedding E. bieneusi increased (n = 10) as did the quantity of E. bieneusi shedding in the feces. Of the twelve juvenile animals, five animals died within 8 months post-SIV inoculation with symptoms of AIDS. Four of the five deceased animals showed shedding of E. bieneusi DNA in feces (> or =100 spores/g) for at least three consecutive months. Increased number of E. bieneusi in feces was accompanied by decreased counts of circulating CD4+ T lymphocytes and increased SIV plasma viral load.

Evaluation of chronic diarrhea in patients with human immunodeficiency virus infection

Chronic diarrhea is a common problem for patients with human immunodeficiency virus infection, especially those with advanced disease. The extent of evaluation and whether to do flexible sigmoidoscopy, colonoscopy, and/or upper endoscopy have been areas of significant debate. Based upon the marked improvement in long-term survival since the introduction of highly active antiretroviral therapy, a comprehensive evaluation is currently justified. A stepwise approach to the evaluation of chronic diarrhea appears to be the best approach. The first step is a history, with a focus on any association between the onset of diarrhea and the institution of protease inhibitor therapy, which is associated with significant diarrhea in many patients. If there is no temporal association with antiretroviral therapy, the next step is examination of stool for bacterial and protozoal pathogens. If the stool studies are negative, the next step is to proceed to colonoscopy. Flexible sigmoidoscopy alone has been noted to miss up to 39% of cases of cytomegalovirus colitis. The inclusion of ileoscopy and biopsy of the terminal ileum during colonoscopy has a significant yield for microsporidiosis, which may obviate the need for upper endoscopy. The highest yield can be expected in patients with fever, weight loss, and a CD4 count of under 200 cells/mm3, especially those with a CD4 count less than 50 cells/mm3.

A case of pulmonary Microsporidiasis in an acute myeloblastic leukemia (AML) - M3 patient

Reported here is a case of microsporidiasis that occurred in an acute myeloblastic leukemia (AML)-M3 patient who underwent chemotherapy. Fever, cough, expectorate and dyspnea were observed during the therapy. Since this case was considered as adult respiratory distress syndrome due to the chest X-ray and arterial blood gas findings, the male patient was bounded to a mechanical ventilator. As coagulation tests showed compatible findings with disseminate intravascular coagulation (DIC), it was thought to be a case of sepsis originating from the lungs and DIC. Pseudomonas aeruginosa and Staphylococcus aureus were found in the sputum of the patient. Although he was given combined antibiotic therapy, there was no reduction in the fever. A bronchoalveolar lavage (BAL) sample was taken and Microsporidia sp. was found upon staining with Giemsa. The patient died due to sepsis and DIC just before receiving therapy for microsporidiasis. Pulmonary infection with Microsporidia, although classically occurring in patients with HIV infection, may occur rarely in leukemia patients, especially if previously treated with systemic immune suppression. This case reinforces the need to consider Microsporidia as a possible pathogen in immunocompromised patients with pulmonary infections.

Intestinal microsporidiosis in HIV-infected children with diarrhea

Intestinal microsporidiosis is a common opportunistic disease associated with diarrhea in adult AIDS patients in Thailand; the data regarding this infection in children are scarce. The present study was designed to investigate the prevalence and clinical features of intestinal microsporidiosis in hospitalized HIV-infected and uninfected (free of HIV) children with diarrhea. Of the 95 HIV-infected children and 87 uninfected children, 24 (25.3%) and 13 (14.9%) respectively were diagnosed with intestinal microsporidiosis. Species identification of microsporidia spores, by transmission electron microscopy, demonstrated Enterocytozoon bieneusi in 5 cases. Cryptosporidium parvum was a common coinfective parasite; pneumonia was the most frequent concurrent disease found in children with intestinal microsporidiosis. Malnutrition was commoner in the HIV-infected group (79.2% vs 23.1%; p = 0.003). This study indicates that intestinal microsporidiosis is an important disease in both HIV-infected and uninfected Thai children with diarrhea.

Intestinal microsporidiosis: a current infection in HIV-seropositive patients in Portugal

Intestinal microsporidiosis is recognised as an important cause of opportunistic infections in immunocompromised patients, especially those with AIDS. Two species are implicated in diarrhoea and other gastrointestinal disease in HIV-infected patients: Enterocytozoon bieneusi and Encephalitozoon intestinalis. Diagnosis of gastrointestinal microsporidiosis was made by detecting spores of the parasite in stool specimens with Weber's modified trichrome stain and with some optical brightening agents such as UVITEX 2B or calcofluor white M2R. The identification of microsporidiosis at the species level was made using appropriate primers with PCR. The diagnosis of intestinal microsporidiosis is currently performed in the parasitology laboratory. In a study of 215 HIV-infected patients, conducted from 1996 to 1999 (approximately n = 60/year), we found a prevalence of spores of microsporidia of 51.5% (n = 31) in 1996, 14.0% (n = 5) in 1997 and 12.5% (n = 8) in 1998 and 42.8% (n = 25) in 1999. Using PCR we found that E. intestinalis was the only species responsible for the gastrointestinal symptoms in 49 patients with microsporidian spores (71%) and E. bieneusi in 29% (n = 20).

Intestinal parasites in HIV-2 associated AIDS cases with chronic diarrhoea in Guinea-Bissau

Previous studies from African countries where HIV-1 infection is prevalent have shown that infections with Cryptosporidium parvum, Isospora belli and microsporidia are frequently associated with chronic diarrhoea in AIDS patients. The information about the occurrence of these parasites in HIV-2 associated AIDS cases with chronic diarrhoea is limited. We have performed a study of stool parasites in patients from Guinea-Bissau, the country with the highest prevalence of HIV-2 in the world. Stool specimens from 52 adult patients with chronic diarrhoea of which 37 were HIV-positive and fulfilling the clinical criteria of AIDS (five HIV-1, 28 HIV-2 and four dually infected with HIV-1 and HIV-2) were screened for parasitic infections. Twenty five percent of the HIV-2 positive patients were infected with C. parvum, 11% with I. belli and 11% with microsporidia, all three parasites were seen only in HIV-positive patients. The three patients with microsporidiosis, all HIV-2 infected, are to our knowledge the first cases reported from Guinea-Bissau. Other stool parasites such as Blastocystis hominis, hookworm and Strongyloides stercoralis were observed both among HIV-positive and HIV-negative patients.

Parasitic diseases and immunodeficiencies

In the last two decades, major immunodeficiency syndromes have strongly influenced medical parasitology. Some animal parasitoses, once unknown in human medicine, have become zoonotic and sometimes anthroponotic. In other cases, the clinical evolution of human parasitoses has been severely aggravated and/or modified in immunodeficient patients especially in toxoplasmosis, cryptosporidiosis, leishmaniasis, strongyloidiasis and scabies. The parasites implicated are varied (protozoa, helminths and even Acaridae) but have in common the capacity to reproduce in or on the human host. These immunodeficiency syndromes are often related to AIDS but other major immunodepressions, such as post-therapeutically in organ transplantation, may also be responsible and raise difficult problems for prevention. The munological mechanisms involved are not always well understood. In addition, genetic predisposition factors, gradually becoming better-understood in parasites and man, complete and complicate our understanding of the immunological mechanisms.

Dual microsporidial infection with Encephalitozoon cuniculi and Enterocytozoon bieneusi in an HIV-positive patient

This report describes the first dual microsporidial infection with Encephalitozoon cuniculi and Enterocytozoon bieneusi in an HIV-positive patient. In view of clinical and epidemiological findings, our E. cuniculi isolate was deduced to be of the dog strain. The patient's occupational involvement with dogs indicates that canines should be considered as a reservoir of human infections for both microsporidial species. Furthermore, our report provides detailed clinical and radiological information on a rare case of a symptomatic pulmonary infection by E. cuniculi and its improvement after treatment with albendazole.

Serological differentiation of microsporidia with special reference to Trachipleistophora hominis

Myositis is a common clinical syndrome in advanced stages of AIDS. Trachipleistophora hominis (phylum Microspora) has been detected in several cases of painful, immobilising myositis in AIDS patients. Enzyme linked immunosorbent assays (ELISAs) and Western blotting of protein profiles separated by SDS PAGE were used to determine whether this species could be detected and differentiated by serology. Sixteen microsporidia, including several species known to infect man and species infecting fish, crustaceans and a mosquito, were used as antigen. Each species had a unique profile of SDS PAGE-separated proteins. In Western blots, mouse antiserum, raised to T. hominis and selected for its high ELISA specificity, bound to antigens ranging from less than 25 kDa to greater than 250 kDa with major bands at 39-44 kDa and 98-150 kDa on T. hominis protein profiles. The serum also recognised some high molecular weight antigens in the profiles of Vavraia culicis, Heterosporis anguillarum, and three species of Pleistophora but none in the remaining genera examined. It was concluded that ELISA and Western blotting could be used to detect and differentiate T. hominis in muscle biopsy tissue from patients with myositis. However, sera from T. hominis-infected patients in the terminal stages of AIDS would not be useful for detection of infections because of a sharp decline in antibody level.

[Human microsporidiosis]

This review shows the Microsporidia as unicellular protozoa strictly intracellular eukaryotic parasites of animals and humans. These study concerns life cycles, cytology, host-parasite relationships in animal models experimentally infected with microsporidia from human feces, demonstrating the host-inespecificity and visceral dissemination with histopathological studies in digestive, tract, kidney, liver, spleen, brain, heart, pancreas, thyroid, suprarenal glands. It is presented the microsporidiosis in Venezuela in immunocompetent patients and immunodeficients HIV+, with diarrheic syndromes with keratoconjuntivitis microsporidial punctata diffuse and with disseminated microsporidia in urine, tracheobronchial sputum, nasal and pharyngeal exudates. Also we have found the microsporidia in river and lake waters and in animals relationed with the man: dogs, cats, pigs, monkeys, donkeys, guts. The patients are treated specially with Albendazole and also with Trimethoprim-Sulphametoxazol for the children until two years of age. We use as laboratory diagnosis the technique of Kinyoun stain, in support of the acid resistance property of these parasites, and also the Chromotrope staining. Our recommendations for a proper identification of the Microspora species, should be done with Electron Microscopy and the TCR reaction.

Intestinal microsporidiosis in HIV-infected children with acute and chronic diarrhea

A prospective study of intestinal microsporidiosis in HIV-positive children was conducted at the Queen Sirikit National Institute of Child Health and Phramongkutklao Hospital, Bangkok, Thailand. Hospitalized HIV-positive children with and without diarrhea were enrolled in this study. Microsporidial spores identified by calcofluor fluorescent and gram-chromotrope stain were confirmed by electron microscopy. As well as Cryptosporidium parvum, Microsporidia was the most common protozoa found in the present study, each was 7.1%. Microsporidia was significantly more common in those who had diarrhea. Intestinal microsporidiosis was found in HIV-positive children with both acute and chronic diarrhea. This study emphasizes the importance of Microsporidia in HIV-infected children. Early detection of microsporidia could be of benefit for the patients, since the infection is treatable.

Chronic diarrhea as a result of intestinal microsposidiosis in a liver transplant recipient

BACKGROUND

Microsporidia are common pathogens among patients infected with human immunodeficiency virus. They account for a substantial proportion of chronic diarrhea and malabsorption in acquired immune deficiency syndrome, but their appearance after solid organ transplantation has only rarely been reported. Methods. We report what we believe is the first case of documented Enterocytozoon bieneusi infection in a liver transplant recipient. Results. Our patient presented with chronic diarrhea and colicky abdominal pain. Although symptoms were severe, only mild microscopical mucosal changes were found in the intestinal tract. A modified trichrome stain of stool specimens revealed microsporidial spores, and species differentiation by restriction fragment length polymorphism polymerase chain reaction identified Enterocytozoon bieneusi. Albendazole therapy brought symptomatic relief but no microbiological clearance.

CONCLUSIONS

Enterocytozoon bieneusi may cause chronic diarrhea not only in immunosuppression as a result of human immunodeficiency virus infection but also among patients with therapeutic immunosuppression after organ transplantation. Therefore, microsporidial infection should be considered in immunosuppressed patients with otherwise unexplained diarrhea.

Clinical and diagnostic aspects of intestinal microsporidiosis in HIV-infected patients with chronic diarrhea in Rio de Janeiro, Brazil

The objectives of this study were to determine both the prevalence of microsporidial intestinal infection and the clinical outcome of the disease in a cohort of 40 HIV-infected patients presenting with chronic diarrhea in Rio de Janeiro, Brazil. Each patient, after clinical evaluation, had stools and intestinal fragments examined for viral, bacterial and parasitic pathogens. Microsporidia were found in 11 patients (27.5%) either in stools or in duodenal or ileal biopsies. Microsporidial spores were found more frequently in stools than in biopsy fragments. Samples examined using transmission electron microscopy (n=3) or polymerase chain reaction (n=6) confirmed Enterocytozoon bieneusi as the causative agent. Microsporidia were the only potential enteric pathogens found in 5 of the 11 patients. Other pathogens were also detected in the intestinal tract of 21 patients, but diarrhea remained unexplained in 8. We concluded that microsporidial infection is frequently found in HIV infected persons in Rio de Janeiro, and it seems to be a marker of advanced stage of AIDS.

Eradication of cryptosporidia and microsporidia following successful antiretroviral therapy

OBJECTIVES

Incidence of opportunistic protozoal infections causing diarrheal illnesses in patients with HIV has decreased since the introduction of highly active antiretroviral therapy (HAART). The objective of this study was to determine whether the parasites, cryptosporidia, and microsporidia were effectively eradicated or only suppressed following treatment.

DESIGN

Six HIV-positive patients with diarrheal symptoms caused by cryptosporidia or microsporidia were prospectively followed up with stool samples and duodenal biopsies. Samples were taken before HAART, between 1 to 3 months, and 6 months post-HAART.

METHODS

Duodenal samples were analyzed using routine histology and transmission electron microscopy. Stool samples were analyzed by both light microscopy and polymerase chain reaction (PCR) techniques.

RESULTS

Patients who responded successfully to HAART eradicated both cryptosporidial and microsporidial organisms. Symptoms improved within 1 month of therapy but complete eradication of the organisms was only observed after 6 months of treatment.

CONCLUSIONS

AIDs-related cryptosporidiosis and microsporidiosis can be cured following successful antiretroviral therapy.

[Identification of Enterocytozoon bieneusi in a patient with sclerosing cholangitis and AIDS]

Enterocytozoon bieneusi is the most common microsporidian parasite found in patients with AIDS. We report the clinical features of a patient with chronic diarrhea, pancreatitis, and AIDS-related sclerosing cholangitis. Ultrasonography and endoscopic retrograde cholangiopancreatography disclosed intrahepatic and extrahepatic bile duct changes identical to those seen in sclerosing cholangitis. Enterocytozoon bieneusi was found in duodenum and peripapillary duodenum by means of light microscopy, and confirmed by PCR amplification of paraffin-embedded tissues with species-specific primers. Microsporidian infection should be suspected in patients with advanced immunodeficiency and AIDS-related sclerosing cholangitis in our country.

Trial of oral fumagillin for the treatment of intestinal microsporidiosis in patients with HIV infection. ANRS 054 Study Group. Agence Nationale de Recherche sur le SIDA

OBJECTIVE

Intestinal microsporidiosis caused by Enterocytozoon bieneusi is a cause of chronic diarrhoea in patients with HIV infection for which there is no current therapy. This study was designed to assess the safety and efficacy of oral fumagillin in this infection.

DESIGN

A dose-escalation trial.

METHODS

Twenty-nine HIV-infected patients with E. bieneusi infection were consecutively enrolled in the trial. Oral doses of fumagillin were given to four groups of patients for 14 days: 10 mg/day (group 1), 20 mg/day (group 2), 40 mg/day (group 3), and 60 mg/day (group 4). Patients were seen at weeks 1, 2, 4 and 6 to assess safety and efficacy. Efficacy was assessed primarily by the clearance of microsporidia from stools and follow-up duodenal biopsies.

RESULTS

Thirteen patients complained of abdominal cramps, vomiting or diarrhoea during the study, and three patients had fumagillin withdrawn because of adverse events. Thrombocytopenia, neutropenia and hyperlipasaemia were the most frequent biological adverse events. Twenty-one out of 29 patients transiently cleared microsporidia from their stools during the study. By week 6, however, all patients in groups 1, 2 and 3 had parasitic relapse. Interestingly, eight out of 11 (72%) patients treated with 60 mg/day (group 4) apparently cleared microsporidia from their gastrointestinal tract and gained weight. No parasitic relapse was documented in these eight patients during a mean follow-up of 11.5 months.

CONCLUSION

Treatment with fumagillin at 60 mg/day for 14 days has promise as an effective oral treatment for E. bieneusi infections.

Microsporidia: emerging advances in understanding the basic biology of these unique organisms

Microsporidia are long-known parasites of a wide variety of invertebrate and vertebrate hosts. The emergence of these obligate intracellular organisms as important opportunistic pathogens during the AIDS pandemic and the discovery of new species in humans renewed interest in this unique group of organisms. This review summarises recent advances in the field of molecular biology of microsporidia which (i) contributed to the understanding of the natural origin of human-infecting microsporidia, (ii) revealed unique genetic features of their dramatically reduced genome and (iii) resulted in the correction of their phylogenetic placement among eukaryotes from primitive protozoans to highly evolved organisms related to fungi. Microsporidia might serve as new intracellular model organisms in the future given that gene transfer systems will be developed.

Waterborne outbreak of intestinal microsporidiosis in persons with and without human immunodeficiency virus infection

Among 1454 persons whose stool samples (n=5692) were submitted to a reference laboratory for microsporidia assessment from 1993 to 1996, microsporidia were identified in 338 persons: 261 persons infected with human immunodeficiency virus (HIV), 16 transplant patients, and 61 others. Intestinal microsporidiosis appears to be an endemic disease in HIV-positive persons (prevalence, 0.1%) and a sporadic disease in HIV-negative persons (prevalence, <1/1 million). A waterborne outbreak in 200 persons (attack rate, 1% in HIV-positive patients/month) occurred in the 1995 summer, without evidence of fecal contamination of water. No explanation was found before the outbreak ended, several months before the antiprotease era. Factors associated with microsporidiosis diagnosis were HIV infection, male homosexuality, low CD4 cell counts, and diarrhea. The major factor associated with a diagnosis of microsporidiosis during the outbreak was living in an area corresponding to one of the three water distribution subsystems of the town. Lake contamination was suspected.

[Role of cryptosporidia and microsporidia in diarrhea in immunocompromised patients]

Cryptosporidium and Microsporidian play an important part in the diarrhoeic pathology of the immunocompromised patients. The study of 35 cases of cryptosporidiosis and 4 cases of intestinal microsporidiosis diagnosed in the parasitology laboratory of Rabta hospital of Tunis shows that cryptosporidiosis prevalence is 17.24% for AIDS patients, 3.45% for immunocompromised patients VIH (-), and microsporidiosis prevalence is 5.7% for patients with acquired immunodeficiency syndrome. Common points for these two parasitosis are: Clinical syndromes dominated by an acute diarrhea A diagnosis based on specific techniques showing the significance of the clinical orientation. Lack of an effective specific therapy.

Natural history of intestinal microsporidiosis among patients infected with human immunodeficiency virus

A chart review of 73 human immunodeficiency virus (HIV)-infected patients with enteric microsporidiosis was conducted to define the natural history of microsporidiosis. A substantial proportion of patients remained symptomatic after 6 months (54.8% with persistent diarrhea and 51.2% with weight loss). Predictors for persistent diarrhea included high HIV RNA viral load and no initiation of protease inhibitor therapy.

Molecular techniques for detection, species differentiation, and phylogenetic analysis of microsporidia

Microsporidia are obligate intracellular protozoan parasites that infect a broad range of vertebrates and invertebrates. These parasites are now recognized as one of the most common pathogens in human immunodeficiency virus-infected patients. For most patients with infectious diseases, microbiological isolation and identification techniques offer the most rapid and specific determination of the etiologic agent. This is not a suitable procedure for microsporidia, which are obligate intracellular parasites requiring cell culture systems for growth. Therefore, the diagnosis of microsporidiosis currently depends on morphological demonstration of the organisms themselves. Although the diagnosis of microsporidiosis and identification of microsporidia by light microscopy have greatly improved during the last few years, species differentiation by these techniques is usually impossible and transmission electron microscopy may be necessary. Immunfluorescent-staining techniques have been developed for species differentiation of microsporidia, but the antibodies used in these procedures are available only at research laboratories at present. During the last 10 years, the detection of infectious disease agents has begun to include the use of nucleic acid-based technologies. Diagnosis of infection caused by parasitic organisms is the last field of clinical microbiology to incorporate these techniques and molecular techniques (e.g., PCR and hybridization assays) have recently been developed for the detection, species differentiation, and phylogenetic analysis of microsporidia. In this paper we review human microsporidial infections and describe and discuss these newly developed molecular techniques.

Declining CD4+ T-lymphocyte counts are associated with increased risk of enteric parasitosis and chronic diarrhea: results of a 3-year longitudinal study

From January 1991 through September 1994, we observed people who were infected with HIV to assess the impact of enteric parasite-associated diarrhea. Respondents answered comprehensive questionnaires covering clinical and epidemiologic information and provided stool specimens monthly, which were examined unstained as well as stained with trichrome, chromotrope 2R, and with Kinyoun carbol-fuchsin, and with indirect immunofluorescence for Cryptosporidium. In all, 602 participants, who were interviewed, provided stool specimens at 3254 monthly visits. Parasites were associated with 50 of 354 (14.1%) acute diarrheal episodes (lasting < or = 28 days) and with 97 of 279 (34.8%) chronic episodes (lasting > 28 days). A parasite was associated with 31 of 222 (14.0%) episodes that occurred when CD4+ counts were > or = 200 cells/microl and with 150 of 566 (26.5%) episodes that occurred when CD4+ counts were < 200 cells/microl. The most commonly identified parasite was C. parvum, which was associated with 18 of 354 (5.1%) acute episodes and 36 (12.9%) of the 279 chronic episodes of diarrhea. In this patient population, enteric protozoan parasites were commonly associated with illness, particularly as immunosuppression worsened, and were more likely to be associated with chronic rather than acute diarrhea.

Microsporidial disease in HIV-infected patients: a report of 42 patients and review of the literature

Microsporidiosis is recognized as an increasingly important infection, particularly in patients with human immunodeficiency virus (HIV) infection. In this retrospective study we have reviewed the clinical features, laboratory findings and management of 42 HIV positive patients co-infected with microsporidia. All patients had spores identified in faeces stained with a modified trichome blue stain. Patients were all markedly immunosuppressed (median CD4 20 cells/microl). Common symptoms included weight loss, diarrhoea, abdominal pain, anorexia and nausea. 29 patients were diagnosed with Enterocytozoon bieneusi infection; 13 were infected with Encephalitozoon intestinalis, and disseminated disease was confirmed in 8. Albendazole therapy in patients with E. intestinalis (but not E. bieneusi) resulted in good clinical response.

Factors of weight loss in patients with HIV and chronic diarrhea

Weight loss is significant in patients with HIV and chronic diarrhea. The aim of our study was to test for the links between weight loss, the level of food intake, and the severity of diarrhea and nutrient malabsorption. One hundred and sixteen patients with HIV and chronic diarrhea underwent a standardized gastrointestinal and nutritional evaluation, which included a questionnaire on diarrhea, a prospective estimation of food intake, a measurement of blood parameters and fecal lipid and nitrogen outputs, a stool examination for bacteria and parasites, and upper and lower digestive tract endoscopy. Diarrhea resulted from an infection by Cryptosporidia, Microsporida, or other pathogens in 22%, 20%, and 13% of the patients, respectively. Diarrhea appeared idiopathic in 45% of the patients. A significant negative correlation existed between the severity of weight loss and the levels of nutrient intake (p < .005), and a significant positive correlation between the severity of weight loss and stool frequency (p < .01). Multiple linear regression identified low caloric intake and high stool frequency as predictive of weight loss. No significant correlation was found between weight loss and the parameters of malabsorption, either by bivariate study or multiple regression. These results suggest that, in patients with HIV and chronic diarrhea, the degree of wasting is significantly related to the levels of dietary intake and the clinical severity of diarrhea, but not to the extent of nutrient malabsorption.

Localization of persistent Enterocytozoon bieneusi infection in normal rhesus macaques (Macaca mulatta) to the hepatobiliary tree

Enterocytozoon bieneusi is the most common microsporidian parasite recognized in human patients with AIDS. Recently, we identified a virtually identical organism causing a spontaneous infection associated with hepatobiliary and intestinal disease in simian immunodeficiency virus (SIV)-infected macaques. To examine the natural history of the infection, we examined captive rhesus macaques for E. bieneusi by PCR, in situ hybridization, and cytochemical techniques. PCR performed on fecal DNA detected enterocytozoon infection in 22 (16.7%) of 131 normal rhesus macaques (Macaca mulatta), compared to 18 (33.8%) of 53 rhesus macaques experimentally inoculated with SIV. In normal rhesus macaques, persistence of infection was demonstrated for up to 262 days and was usually not associated with clinical signs. In six of seven normal rhesus animals, E. bieneusi was detected by PCR in bile obtained through percutaneous cholecystocentesis but not by in situ hybridization performed on endoscopic biopsies of duodenum and proximal jejunum.

Ultrastructure of atypical (teratoid) sporogonial stages of Enterocytozoon bieneusi (Microsporidia) in naturally infected rhesus monkeys (Macacca mulatta)

OBJECTIVE

To demonstrate the ultrastructural features of normal and atypical (teratoid) developmental stages of Enterocytozoon bieneusi in naturally infected rhesus monkeys (Macacca mulatta).

DESIGN AND METHODS

Two rhesus monkeys with chronic simian immunodeficiency virus infection developed naturally acquired microsporidian infections. The gallbladder had a high parasite burden and was evaluated by transmission electron microscopy. The microsporidian agent was confirmed as E bieneusi by polymerase chain reaction.

RESULTS

In addition to normal sporogonial plasmodia and spores of E bieneusi, abnormal teratoid structures were noted. These structures were greatly enlarged (up to 10 microm) and were surrounded by an electron-dense exospore and electron-lucent endospore typical of mature spores. Unlike mature spores, the abnormal structures contained multiple nuclei and polar tubes in varying proportions, which were reminiscent of sporogonial plasmodia.

CONCLUSIONS

These teratoid structures represent aberrant sporogonial stages, a result of defective maturation in which abnormal cytokinetic replication of organelles occurs, and normal development into uninucleate sporoblasts and spores is inhibited. This leads to the development of teratoid stages having mature spore walls, but containing multiple sets of nuclei and polar tubes, unusual polyribosomal arrays and vacuoles, or persistent cleavage. The biological significance of these atypical spores is unknown, but it is evident that they develop in the absence of antimicrosporidian drugs in extraintestinal tissues from nonhuman primates. Teratoid spores of E bieneusi should not be misinterpreted as another microsporidian species or confused with other pathogenic protozoa, nor should their presence be misconstrued as evidence of antimicrosporidian drug efficacy or toxicity.

Microsporidia in duodenal biopsies from 72 HIV-infected patients with abdominal complaints

In order to evaluate the capacity of routine histological examination to detect microsporidiosis, a retrospective study was performed on 72 duodenal biopsies from 72 HIV-infected patients with upper abdominal symptoms of unknown cause. Two light microscopic cytological staining techniques, modified trichrome stain and the fluorochrome Calcofluor, were used. Two cases of microsporidiosis were detected among the 20 patients with prolonged diarrhoea of unknown origin in whom no etiological agent had been demonstrated by stool examination, mycobacterial and cytomegalovirus culture of biopsies, and histological routine staining of duodenal biopsies. The calculated confidence interval of 3-30% corresponds to the prevalence of intestinal microsporidiosis in HIV patients with prolonged diarrhoea in various parts of the world. The findings motivate attempts to identify microsporidia using special cytological staining methods. Improved methods of species identification are needed to aid in the choice of chemotherapy.

Potential efficacy of fumagillin in intestinal microsporidiosis due to Enterocytozoon bieneusi in patients with HIV infection: results of a drug screening study. The French Microsporidiosis Study Group

OBJECTIVE

Intestinal microsporidiosis due to Enterocytozoon bieneusi is a frequent cause of chronic diarrhoea in patients with HIV infection for which there is no available therapy. This study was designed to search for a drug with activity against this organism.

DESIGN

Prospective open-labelled Phase II multicentre study.

SETTING

University hospitals.

PATIENTS

Sixty HIV-infected men with intestinal E. bieneusi infection.

INTERVENTIONS

Ten drug regimens were consecutively tested orally for 3 weeks: albendazole plus metronidazole, sulphadiazine plus pyrimethamine, atovaquone, doxycycline plus nifuroxazide, itraconazole, flubendazole, chloroquine, paromomycin, sparfloxacin and fumagillin. Nine evaluable patients per regimen were required, but each patient could be enrolled up to three times in the study.

OUTCOME MEASURE

Efficacy was assessed primarily by the clearance of E. bieneusi from stools and intestinal biopsies. The safety of each regimen was also assessed.

RESULTS

Only purified fumagillin was able to clear E. bieneusi from stools as well as intestinal biopsies, whereas all other regimens failed to show antiparasitic efficacy. However, only four patients received fumagillin because of drug-induced thrombocytopenia. The four patients who received fumagillin remained free of E. bieneusi infection after a mean follow-up of 10 months.

CONCLUSION

Eradication of E. bieneusi from the intestinal tract of patients with HIV infection and persistent immunosuppression is an achievable goal. Our study allowed the identification of oral fumagillin as a potential treatment for intestinal microsporidiosis due to E. bieneusi.