الفهرس 
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Abstract
Microsporidia constitute a diverse group of obligate intracellular pathogens that infect a wide range of vertebrate and invertebrate hosts. Microsporidia have been originally recognized as opportunistic pathogens of immunocompromised patients. Recently, cases of microsporidiosis in immunocompetent persons are increasingly reported. The most commonly reported symptom associated with microsporidiosis in humans is diarrhea that resolves after a few weeks in immunocompetent individuals but persists in immune deficient cases. Two species of microsporidia; E. bieneusi and E. intestinalis, are known to infect mainly the gastrointestinal tract of humans.
Diagnosis of microsporidiosis relies essentially on microscopic detection of spores in stool using modified trichrome stain. Alternatively, immunofluorescence tests have been successfully used for the diagnosis and species differentiation of microsporidia.
The present study was conducted to compare between microscopical staining technique and immunofluorescent assay for the diagnosis of intestinal microsporidiosis in patients with diarrhea. Differentiation of species was done subsequently using IFA utilizing monoclonal antibodies.
This study was based on the examination of stool samples collected from 100 diarrheic patients attending the Parasitology Department laboratory in the Medical Research Institute and from different private laboratories in Alexandria. Freshly collected stool specimens were examined by formalin ethyl-acetate concentration technique, MTS (Kokoskin hot method) and IFA-MAbs.
The overall percentage of intestinal parasites as diagnosed by formalin ethyl-acetate was 38%. G. lamblia showed the highest percentage of infection (19%), while only one case of S. mansoni was detected (1%).
Using MTS, microsporidial spores were detected in 36% of the stool samples examined. The stained spores appeared as small refractile ovoid or rounded pink bodies with polar bodies at one end and a vacuole at the other. Using IFA-MAbs, out of the 100 fecal specimens tested, 60 samples were positive. Microsporidial spores appeared as bright apple green oval halos, with an orange to brownish yellow background. As for the different species of microsporidia as diagnosed by IFA-MAbs, 67% were E. intestinalis, 6% were E. bieneusi and mixed infections in 27%.
Regarding the conjunction of microsporidia with other parasites detected by formalin ethyl-acetate concentration, among the 36 cases of microsporidia diagnosed by MTS, 29 cases had single infection, 5 cases had an associated B. hominis infection and 2 cases combined with G. lamblia. By using IFA, microsporidia spores were detected in 60 samples. Microsporidia spores were coupled with B. hominis in 7 cases, with G. lamblia in 4 cases, and associated with only one case of E.coli, E. histolytica and A. lumbricoides.
As for age, sex, and residence, the majority of positive cases fell in the age group 21-40, with values equal to 52.8% and 50% by MTS and IFA respectively. Females showed the majority of positive cases by both techniques. Concerning residence, higher rates of microsporidia were detected among those who reside in urban communities (67%) than rural ones (33%). Statistical significant associations between residence and both MTS and IFA were found.
The agreement between MTS and IFA-MAbs in diagnosing microsporidal infections was moderate. MTS failed to detect 26 cases tested positive by IFA, while IFA missed two MTS positive cases.
In conclusion, microsporidia spores were detected in a substantial proportion of diarrheic patients. With well-trained laboratory staff, both MTS and IFA complement each other for the diagnosis of microsporidiosis.