Microsporidia cause opportunistic infections in AIDS patients and commonly infect laboratory animals, as well. Euthymie C57B1/6 mice experimentally infected with intraperitoneal injections of lxlO6 Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923, Encephalitozoon hellem Didier et al., 1991, or Nosema comeum Shadduck et al., 1990 displayed no clinical signs of disease. Athymic mice, however, developed ascites and died 8-16 days after inoculation with N. comeum, 21-25 days after inoculation with E. cuniculi, and 34-37 days after inoculation with E. hellem. All athymic mice displayed hepatomegaly, dilated intestine and accumulation of ascites fluid. Granulomatous lesions were primarily located in the liver, lung, pancreas, spleen, and on serosal surfaces of abdominal organs.
Three strains of mice, BALB/c, IL-12 knock-out (KO) and INF-γ knock-out, were chosen as an experimental model for the study of intestinal immunity induction against Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 infection. Mice were infected perorally with 107 spores and re-infected with the same dose 70 days after the first infection. The anti-E. cuniculi IgA, IgG and IgM responses in sera and extracts of stool samples were determined by ELISA. Results have shown specific antibody production in the sera and intestinal secretions of all three strains of mice induced orally by E. cuniculi spores. BALB/c mice developed a stronger humoral immune response than IL-12 KO mice. The lowest antibody response developed in INF-γ KO mice that succumbed to the infection within 28 days post infection.
Microsporidiosis is an increasingly important opportunistic infection in HIV-positive patients. Five species of microsporidia {Enterocytozoon bieneusi, Encephalitozoon hellem and E. cunieuli, Seplata intestinalis, and Pleistophora sp.) have been reported to occur in AIDS, with each agent producing a different clinicopathologic spectrum of disease. This communication reviews routine and specialized methods for diagnosis of these important pathogenic protozoa, including biopsy, cytology, ultrastructural and immunologic examination, and tissue culture, and describes the current knowledge of organ distribution for microsporidia in persons with AIDS.
The phylum Microsporidia is a large group of parasitic unicellular eukaryotes that infect a wide range of invertebrate and vertebrate taxa. These organisms are significant human and veterinary pathogens with impacts on medicine, agriculture and aquaculture. Scientists working on these pathogens represent diverse disciplines that have had limited opportunities for detailed interactions. A NATO Advanced Research Workshop 'Emergent Pathogens in the 21st Century: First United Workshop on Microsporidia from Invertebrate and Vertebrate Hosts' was held July 12-15, 2004 at the Institute of Parasitology of the Academy of Sciences of the Czech Republic to bring together experts in insect, fish, veterinary and human microsporidiosis for the exchange of information on these pathogens. At this meeting, discussions were held on issues related to taxonomy and phylogeny. It was recognized that microsporidia are related to fungi, but the strong opinion of the participants was that the International Code of Zoological Nomenclature should continue to be applied for taxonomic descriptions of the Microsporidia and that they be treated as an independent group emerging from a paraphyletic fungi. There continues to be exponential growth in the pace and volume of research on these ubiquitous intracellular protists. The small genomes of these organisms and the reduction in the size of many of their genes are of interest to many disciplines. Many microsporidia are dimorphic and the mechanisms underlying these morphologic changes remain to be elucidated. Epidemiologic studies to clarify the source of human microsporidiosis and ecologic studies to understand the multifaceted relationship of the Microsporidia and their hosts are important avenues of investigation. Studies on the Microsporidia should prove useful to many fields of biologic investigation.
This paper summarizes work done in this laboratory over the last two years on the cloning of microsporidian rRNA by homology PCR and its subsequent use in diagnostic tests and phylogenetic studies. Using highly conserved primers in the 16S or small subunit rRNA (SSU-rRNA) these genes were cloned from human intestinal biopsies with transmission electron microscopy proven Enterocytozoon bieneusi and Septata intestinalis. The SSU-rRNA genes were then used to design and test several primer pairs for the diagnosis of microsporidian infection. Utilizing the polymerase chain reaction and primers V1 and EB45Ü Ent. bieneusi infected duodenal aspirates or intestinal biopsies could be detected. Using V I and SI500 infection with S. intestinalis could be detected. In addition to diagnostic tests, phylogenetic relationships were examined using sequence data from the fragment amplified by PCR by primer 530f in the SSU-rRNA and primer 580r in the large subunit rRNA. This data supported the placement of S. intestinalis in the family Encephalitozoonidae. In addition, it confirmed that Encephalitozoon cuniculi, E. hellem and S. intestinalis are distinct organisms. These techniques have broad applications to the study of other microsporidia and the development of a molecular phylogeny.
Contamination of Enterocytozoon bieneusi Desportes, Charpentier, Galian, Bernard, Cochand-Priollet, Laverne, Ravisse, et Modigliani, 1985 in water sources may cause outbreaks of microsporidiosis. To examine the occurrence of E. bieneusi, 108 raw wastewater samples were collected from three wastewater treated plants in Zhengzhou, China. In total, 46 samples were PCR positive for E. bieneusi. A total of 15 ITS genotypes was identified, including ten known genotypes (D, BEB6, I, J, PigEbIX, PigEBITS5, EbpA, Peru6, Peru8, Type IV) and five novel genotypes (HNWW1, HNWW2, HNWW3, HNWW4, HNWW5). Nine genotypes belonged to a known zoonotic group (group 1) and the other genotypes belonged to potential zoonotic group (group 2). Most of the genotypes had been identified in wildlife or domestic animals in former reports in Zhengzhou. The occurrence of E. bieneusi in wastewater was probably related to the rainfall day before sampling. Of 36 sampling days, 20 days had rainfall on the previous day and 16 days had none. As many as 43 of 60 samples were found to be E. bieneusi-positive in the 20 days which had rainfall on the previous day. Only three of 48 samples were found to be E. bieneusi-positive in the 16 days without rainfall the day before. The significant difference of the occurrence of E. bieneusi was observed between wet days and dry days by t-test (43/60 vs 3/48, p < 0.01). This indicates that the occurrence of E. bieneusi in wastewater in Zhengzhou mainly originated from animals and was probably related to rainfall the day before sample collection. Given the zoonotic genotypes detected in wastewater, animal faeces should be treated appropriately before being drained into the water source., Jianbin Ye, Ji Yan, Jia Xu, Ke Ma, Xuepeng Yang., and Obsahuje bibliografii