title: Latent microsporidial infection in immunocompetent individuals - a longitudinal study.
abstract: BACKGROUND
  Microsporidia (Fungi) have been repeatedly identified as the cause of opportunistic infections predominantly in immunodeficient individuals such as AIDS patients. However, the global epidemiology of human microsporidiosis is poorly understood and the ability of microsporidia to survive and multiply in immunocompetent hosts remains unsolved.
  
  
  OBJECTIVE
  To determine the presence of latent microsporidia infections in apparently healthy humans in the Czech Republic, the authors tested sera, urine and stool originating from fifteen persons within a three month period examined on a weekly basis.
  
  
  METHODS
  Sera, stool and urine samples originating from fifteen HIV-negative people at risk with occupational exposure to animals, aged 22-56 years, living in the Czech Republic were tested by indirect immunofluorescence assay (IFA) for the presence of specific anti-microsporidial antibodies, standard Calcofluor M2R staining for the detection of microsporidian spores in all urine sediments and stool smears and molecular methods for the microsporidial species determination.
  
  
  RESULTS
  Specific anti-microsporidial antibodies were detected in fourteen individuals, asymptomatic Encephalitozoon spp. infection was found in thirteen and E. bieneusi infection was detected in seven of those examined. While E. hellem 1A and E. cuniculi II were the major causative agents identified, seven different genotypes of E. bieneusi were recorded.
  
  
  CONCLUSIONS
  These findings clearly show that exposure to microsporidia is common and chronic microsporidiosis is not linked to any clinical manifestation in healthy population. Moreover, our results indicate much higher incidence of microsporidial infections among an apparently healthy population than previously reported. These results open the question about the potential risk of reactivation of latent microsporidiosis in cases of immunosupression causing life-threatening disease.
authors.affiliation: Biology Centre of the Academy of Sciences of the Czech Republic, v.v.i., Institute of Parasitology, České Budějovice, Czech Republic.
authors.forename: Bohumil
authors.initials: B
authors.lastname: Sak
authors.forename: Martin
authors.initials: M
authors.lastname: Kváč
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Kučerová
authors.forename: Dana
authors.initials: D
authors.lastname: Květoňová
authors.forename: Kamila
authors.initials: K
authors.lastname: Saková
mesh_terms: D000328:Adult; D000818:Animals; D000908:Antibodies, Fungal / Q000097:blood; D058070:Asymptomatic Diseases / Q000453:epidemiology*; D018153:Czech Republic / Q000453:epidemiology; D016819:Encephalitozoon / Q000166:cytology / Q000276:immunology / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008853:Microscopy; D016881:Microsporidiosis / Q000175:diagnosis* / Q000453:epidemiology* / Q000382:microbiology; D008875:Middle Aged; D009172:Mycology / Q000379:methods; D044967:Serum / Q000382:microbiology; D013172:Spores, Fungal / Q000166:cytology / Q000302:isolation & purification; D013194:Staining and Labeling / Q000379:methods; D014556:Urine / Q000382:microbiology
chemical_list: D000908:Antibodies, Fungal