-
Acta Tropica Feb 2001Microsporidia are eukaryotic spore forming obligate intracellular protozoan parasites first recognized over 100 years ago. These organisms infect all of the major animal... (Review)
Review
Microsporidia are eukaryotic spore forming obligate intracellular protozoan parasites first recognized over 100 years ago. These organisms infect all of the major animal groups and are now recognized as opportunistic pathogens of humans. Microsporidian spores are common in the environment and microsporidia pathogenic to humans have been found in water supplies. The genera Nosema, Vittaforma, Brachiola, Pleistophora, Encephalitozoon, Enterocytozoon, Septata (reclassified to Encephalitozoon) and Trachipleistophora have been found in human infections. These organisms have the smallest known eukaryotic genomes. Microsporidian ribosomal RNA sequences have proven useful as diagnostic tools as well as for phylogenetic analysis. Recent phylogenetic analysis suggests that Microsporidia are related to the fungi. These organisms are defined by the presence of a unique invasion organelle consisting of a single polar tube that coils around the interior of the spore. All microsporidia exhibit the same response to stimuli, that is, the polar tube discharges from the anterior pole of the spore in an explosive reaction. If the polar tube is discharged next to a cell, it can pierce the cell and transfer its sporoplasm into the cell. A technique was developed for the purification of polar tube proteins (PTPs) using differential extraction followed by reverse phase HPLC. This method was used to purify the PTPs from Glugea americanus, Encephalitozoon cuniculi, Enc. hellem and Enc. intestinalis. These PTPs demonstrate conserved characteristics such as solubility, hydrophobicity, mass, proline content and immunologic epitopes. The major PTP gene from Enc. cuniculi and Enc. hellem has been cloned and expressed in vitro. The gene sequences support the importance of ER and in the formation of the polar tube as suggested by morphologic studies. Analysis of the cloned proteins also indicates that secondary structural characteristics are conserved. These characteristics are probably important in the function of this protein during the eversion/assembly of the polar tube and in providing elasticity and resiliency for sporoplasm passage.
Topics: Amino Acid Sequence; Animals; Humans; Microsporidia; Microsporidiosis; Molecular Sequence Data; Phylogeny; Sequence Homology, Amino Acid
PubMed: 11230819
DOI: 10.1016/s0001-706x(00)00178-9 -
International Journal For Parasitology Nov 2000The environmental route of transmission is important for many protozoan and helminth parasites, with water, soil and food being particularly significant. Both the... (Review)
Review
The environmental route of transmission is important for many protozoan and helminth parasites, with water, soil and food being particularly significant. Both the potential for producing large numbers of transmissive stages and their environmental robustness, being able to survive in moist microclimates for prolonged periods of time, pose a persistent threat to public and veterinary health. The increased demands on natural resources increase the likelihood of encountering environments and produce contaminated with parasites. For waterborne diseases, the protozoa, Cryptosporidium, Giardia and Toxoplasma, are the most significant causes, yet, with the exception of Toxoplasma, the contribution of zoonotic transmission remains unclear due to the absence of 'standardised' methods. The microsporidia have been documented in one waterborne outbreak, but the role of animals as the cause of contamination was not elucidated. In foods, surface contamination is associated with the faecal-oral pathogens, and some data are available to indicate that animal wastes remain an important source of contamination (e.g. cattle faeces and apple cider outbreaks), however, further work should focus on examining the source of contamination on fruit and vegetables. Increasing recognition of the burden of human fascioliasis has occurred; it is now recognised as an emerging zoonosis by the WHO. Toxoplasma, Trichinella and Taenia spp. remain important meatborne parasites, however, others, including Pleistophora-like microsporidians may be acquired from raw or lightly cooked fish or crustaceans. With increased international travel, the public health importance of the foodborne trematodiases must also be realised. Global sourcing of food, coupled with changing consumer vogues, including the consumption of raw vegetables and undercooking to retain the natural taste and preserve heat-labile nutrients, can increase the risk of foodborne transmission. A greater awareness of parasite contamination of our environment and its impact on health has precipitated the development of better detection methods. Robust, efficient detection, viability and typing methods are required to assess risks and to further epidemiological understanding.
Topics: Animals; Cattle; Food Parasitology; Humans; Parasitic Diseases; Risk Factors; Water; Water Supply; Zoonoses
PubMed: 11113263
DOI: 10.1016/s0020-7519(00)00128-4 -
Parasitology Research Dec 2009The life cycle of a new microsporidian of the genus Pleistophora is described. This parasite infects the epithelial cells of the gut and the peritoneal cavity of the Red...
Ultrastructure, development, and host-parasite relationship of a new species of the genus Pleistophora--a microsporidian parasite of the marine fish Epinephelus chlorostignei.
The life cycle of a new microsporidian of the genus Pleistophora is described. This parasite infects the epithelial cells of the gut and the peritoneal cavity of the Red Sea fish, Epinephelus chlorostignei. All stages develop within a special structure, the sporophorocyst, which is covered by a thick dense wall. This wall grows along with the growth of the parasites inside. Meronts are uni- to binucleate, which divide and constantly give rise to sporonts. During transition to sporonts, the cell border of the meronts increases its thickness, temporarily featuring thick irregular projections. Eventually, a uniform thick sporont wall is formed; then, the sporont cells detach themselves from the wall (future wall of the sporophorous vesicle, SPV) and start a series of divisions to produce sporoblasts. The SPV wall is compact, has no pores, and consists of two layers. Mature spores measure about 2.0 x 1.8 microm. They possess a polar filament with 20-28 coils, a posterior vacuole, and a polaroplast made up of an outer part of dense and closely spaced lamellae encircling an inner part of widely spaced lamellae. All morphological and ultrastructural features indicate that the described microsporidian parasite belongs to the genus Pleistophora.
Topics: Animals; Bass; Epithelial Cells; Fish Diseases; Gastrointestinal Tract; Host-Parasite Interactions; Microscopy; Microscopy, Electron, Transmission; Microsporidiosis; Peritoneal Cavity; Pleistophora
PubMed: 19844744
DOI: 10.1007/s00436-009-1633-4 -
Archives of Pathology & Laboratory... Dec 1993The obligate intracellular protozoan parasites belonging to the phylum Microspora are ubiquitous. They parasitize insects and all five classes of vertebrates. Only one... (Comparative Study)
Comparative Study Review
The obligate intracellular protozoan parasites belonging to the phylum Microspora are ubiquitous. They parasitize insects and all five classes of vertebrates. Only one genus infects mammals and birds but at least four genera affect humans. Two genera have been isolated from human specimens and both infect experimental animals. Some genera (eg, Enterocytozoon and Pleistophora) seem to be limited to a very few tissues but others (Encephalitozoon and the Encephalitozoon-like genus Septata) can infect multiple organs. Lesions range from classic microgranulomas to foci of infected cells unaccompanied by any inflammatory response. The most commonly occurring microsporidia infection of man (Enterocytozoon bieneusi) is characterized by infection of enterocytes of the villus tips of the small intestine, accompanied by villus blunting, crypt hyperplasia, sloughing of infected villus tip cells, and increased numbers of intraepithelial lymphocytes.
Topics: Animals; Humans; Microsporida; Microsporidiosis
PubMed: 8250691
DOI: No ID Found -
Folia Parasitologica 1994Microsporidiosis is an increasingly important opportunistic infection in HIV-positive patients. Five species of microsporidia (Enterocytozoon bieneusi, Encephalitozoon... (Review)
Review
Microsporidiosis is an increasingly important opportunistic infection in HIV-positive patients. Five species of microsporidia (Enterocytozoon bieneusi, Encephalitozoon hellem and E. cuniculi, Septata 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.
Topics: AIDS-Related Opportunistic Infections; Animals; Biopsy; Culture Techniques; Cytological Techniques; Humans; Microscopy, Electron; Microsporida; Microsporidiosis; Serologic Tests
PubMed: 7927059
DOI: No ID Found -
Journal of Invertebrate Pathology Jul 1971
Topics: Annelida; Apicomplexa; Female; Microscopy, Electron; Ovum; Spores
PubMed: 4999158
DOI: 10.1016/0022-2011(91)90002-8 -
Archives of Razi Institute Aug 2022Pebrine disease is the most important and dangerous disease of silkworm caused by as an obligate intracellular parasitic fungus. It has caused tremendous economic...
Pebrine disease is the most important and dangerous disease of silkworm caused by as an obligate intracellular parasitic fungus. It has caused tremendous economic losses in the silk industry in recent years. Given the fact that light microscopy method (with low accuracy) is the only method for diagnosing pebrine disease in the country, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods were adopted in this study for accurate morphological identification of the spores causing pebrine disease. Infected larvae and mother moth samples were collected from several farms (Parand, Parnian, Shaft, and Iran Silk Research Center in Gilan province, Iran). The spores were then purified using the sucrose gradient method. From each region, 20 and 10 samples were prepared for SEM and TEM analysis, respectively. In addition, an experiment was performed to evaluate the symptoms of pebrine disease by treating fourth instars with the spores purified for the present study, along with a control group. The results of SEM analysis showed that the mean±SD length and width of spores were 1.99±0.25 to 2.81±0.32 μm, respectively. Based on the obtained results, the size of spores was smaller than the () as the classic species that cause pebrine disease. In addition, transmission electron microscopy (TEM) pictures showed that the grooves of the adult spores were deeper than those of other species, Vairomorpha, and Pleistophora, and resembled in other studies. Examination of pathogenicity of the studied spores indicated that the disease symptoms in controlled conditions were similar to those in the sampled farms. The most important symptom in fourth and fifth instrars were the small size and no growth in the treatment group compared with the control group. Findings of SEM and TEM analysis showed better morphological and structural details of parasite compared with light microscopy, and demonstrated that the studied species were a native strain of specific to Iran, whose size and other characteristics were unique and introduced for the first time in this study.
Topics: Animals; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Nosema
PubMed: 36883157
DOI: 10.22092/ARI.2022.356482.1853 -
The Journal of Eukaryotic Microbiology 1998Using the polymerase chain reaction (PCR) and two primers for conserved regions of the small subunit ribosomal RNA (SSU-rRNA) of Microsporidia, a DNA segment about 1,195...
Using the polymerase chain reaction (PCR) and two primers for conserved regions of the small subunit ribosomal RNA (SSU-rRNA) of Microsporidia, a DNA segment about 1,195 base pairs long was amplified from a DNA template prepared from purified spores of the microsporidian species Pleistophora anguillarum. These spores had been isolated from adult eels (Anguilla japonica) with "Beko Disease." A comparison of sequence data from other microsporidian species showed P. anguillarum SSU-rRNA to be most similar to Vavraia oncoperae. When juvenile eels were artificially infected with P. anguillarum, enzyme-linked immunosorbent assay could detect a positive infection only 12 days post-infection. However, when suitable PCR primers were used, a DNA fragment of about 0.8 kb was detected from these juvenile eels after only 3 days post infection. No PCR product was obtained with templates prepared from clinically healthy control animals.
Topics: Anguilla; Animals; Base Sequence; DNA Primers; DNA, Protozoan; DNA, Ribosomal; Fish Diseases; Genes, Protozoan; Microsporida; Molecular Sequence Data; Polymerase Chain Reaction; Protozoan Infections, Animal; RNA, Protozoan; RNA, Ribosomal; Spores
PubMed: 9783458
DOI: 10.1111/j.1550-7408.1998.tb05116.x -
Clinical Microbiology Reviews Jan 1993Nine cases of unusual infections in humans are presented. In each case, we present the clinical history, histopathologic changes (if indicated), morphologic features of... (Review)
Review
Nine cases of unusual infections in humans are presented. In each case, we present the clinical history, histopathologic changes (if indicated), morphologic features of the causative organism, diagnosis, discussion, differential diagnosis, therapy, and current literature. All of the cases are illustrated with pertinent photographs. The nine cases are as follows: (i) acanthocephaliasis, the first acquired human infection by Moniliformis moniliformis in the United States; (ii) dipylidiasis, an uncommon infection caused by the dog tapeworm, Dipylidium caninum; (iii) granulomatous amebic encephalitis, caused by the recently identified leptomyxid group of amebae; (iv) schistosomiasis, a dual infection of the urinary bladder with the rare presentation of both adult worms and eggs of Schistosoma haematobium and Schistosoma mansoni in tissue sections; (v) syphilitic gastritis, an uncommon presentation of Treponema pallidum infection, in a patient with an additional incidental infection by Helicobacter pylori; (vi) microsporidiosis, the only infection caused by a Pleistophora sp. in humans; (vii) sporotrichosis, a rare disseminated infection caused by Sporothrix schenckii with numerous yeast cells in the scrotum; (viii) angiostrongyliasis, the first and only infection caused by Angiostrongylus costaricensis acquired in either Puerto Rico or the United States; and (ix) botryomycosis of the skin and subcutaneous tissue, caused by gram-positive cocci with an unusually large number of granules.
Topics: Adult; Aged; Amebiasis; Bacterial Infections; Cestode Infections; Diagnosis, Differential; Female; Helminthiasis; Humans; Infant; Male; Middle Aged; Protozoan Infections; Schistosomiasis; Sporotrichosis; Syphilis
PubMed: 8457979
DOI: 10.1128/CMR.6.1.34 -
The Journal of Parasitology Feb 1977
Topics: Animals; Eukaryota; Female; Fish Diseases; Fishes; Ovary; Protozoan Infections; Protozoan Infections, Animal
PubMed: 845729
DOI: No ID Found