Published Quarterly Mangalore, South India ISSN 0972-5997 Volume 5, Issue 3; Jul - Sep 2006

Review

Human Microsporidial Infections

Authors Omalu ICJ, Unit of Entomology and Parasitology, University of Jos, Nigeria Duhlinska DD, Unit of Entomology and Parasitology, University of Jos, Nigeria Anyanwu GI, Unit of Entomology and Parasitology, University of Jos, Nigeria Pam VA, Veterinary Research Institute, Vom – Plateau State, Nigeria Inyama PU, Unit of Entomology and Parasitology, University of Jos, Nigeria

Address For Correspondence Omalu ICJ Unit of Entomology and Parasitology, University of Jos, Nigeria E-mail: [email protected]

Citation Omalu ICJ, Duhlinska DD, Anyanwu GI, Pam VA, Inyama PU. Human Microsporidial Infections. Online J Health Allied Scs. 2006;3:2

URL http://www.ojhas.org/issue19/2006-3-2.htm

Open Access Archives http://cogprints.ecs.soton.ac.uk/view/subjects/OJHAS.html http://openmed.nic.in

Submitted: Nov 09, 2005; Revised: Jan 19, 2006; Accepted: Jan 22, 2006; Published: Mar 31, 2006

OJHAS Vol 5 Issue 3(2): Human Microsporidial Infections www.ojhas.org/issue19/2006-3-2.htm 1

Abstract: are eukaryotic, forming obligate intracellular parasites, first recognised over 100 years ago. diseases. The AIDS epidemic has revealed Microsporidia are becoming increasingly their propensity for infecting man, although recognised as infectious causing it is still not known whether microsporidia intestinal and extra-intestinal diseases in cause strictly opportunistic or both immuno-competent and immuno- exist in healthy people as latent infections, suppressed patients. They are which becomes exacerbated when the characterised by the production of resistant patients becomes immuno-compromised. that vary in size depending on the The ability of these parasites to cause species; and poses a unique organelle, the disease in immuno-competent persons is polar tubule (polar filament), which is still being elucidated. Microsporidia can coiled inside the spore as demonstrated by cause a variety of human diseases, its ultra structure. Other unusual involving multiple organ systems, which characteristics are the lack of mitochondria include intestinal, ocular, sinus, pulmonary, and the prokaryotic-like ribosomes, which muscular and renal diseases in both indicate the primitive nature of the group. immuno-competent and immuno- Presently there are seven genera, compromised patients.2 The first case of Enterocytozoon, Encephalitozoon, Nosema, intestinal microsporidiosis in Nigeria was Pleistophora, Trachi pleistophora, reported in 2002.3 Brachiola, vittaforma species which have been reported from human hosts as agents of systemic, ocular, intestinal and muscular This review aimed to summerise the infections are described and the diagnosis, unusual features of the biology of treatment, and source of infections microsporidia, update ourselves with the discussed. new clinical manifestation, latest techniques of identification and the new treatment modalities to overcome these Key Words: Microsporidia, infections. Enterocytozoon, Encephalitozoon, Nosema, Pleistophora, Diagnosis Classification and Taxonomy: Introduction: The viability of the silk industry was Microsporidia are intracellular spore- th forming protozoa that are increasingly threatened in the 19 century, because of being recognized as pathogens in humans. a mysterious disease of silk worms, They are ubiquitous in the environment Bombyx mori. The causative agent was and can infect a wide range of vertebrate first named microsporidian Nosema and invertebrate hosts, including insects, bombycis, which was classified as Schizomycetes which, at the time include birds, fish and mammals. The spores vary 4 in size, but those that infect humans are and bacteria. The order typically oval and one to two μm in Microsporidia was defined and separated into the Phylum Microspora within the diameter. They are highly resistant to 5,6 degradation, and can survive in the zoological kingdom, protozoa. Landmarks environment for up to four months. Their in the recording of microsporidian species since these early beginnings are the structure is distinguished by the presence 7 of a polar filament within the spore which is monograph of Kudo in which 14 genera involved in injecting spore contents into and about 170 species were listed, the host cell. Sprague, in which 44 genera and over 700 species were listed6, Canning and Hollister, in which 96 genera and almost 1000 Although microsporidia were discovered species were listed8 and to date 143 more than 100 years ago, the first well genera and more than 1200 species have documented case of human 1 been described as parasites infecting a microsporidiosis was reported in 1959. It wide range of vertebrate and invertebrate could not have been anticipated when hosts.9 Microsporidia were classified and these organisms were first described that grouped taxonomically on the basis of their they would be recognized as the agents of natural host and ultra structural features distressing and life-threatening human such as size of the developing and mature organisms, nucleus arrangement OJHAS Vol 5 Issue 3(2): Human Microsporidial Infections www.ojhas.org/issue19/2006-3-2.htm 2 (monokaryon or diplokaryon), number of electron-lucent slits, which are probably polar filament coils, interface with the host expanded and irregularly elongate. There is cell during development (direct contact markedly precocious development of spore with host cell cytoplasm, replication within organelles in sporonts, including a host cell derived parasitophorous morphogenesis of polar-tube from electron- vacuole, replication of organisms dense discs. The endospore layer of the surrounded by endoplasmic reticulum, spore wall is poorly developed. Example is sporogony within a parasite generated known only from sporophorous vesicle and mode of cell and small intestinal enterocytes of AIDS nuclear division (binary division, patients. Spores measure approximately karyokinesis with delayed cytokinesis).10 1.1 - 1.6 x 0.7 - 1.0μm, are ellipsoidal with Molecular biology methods have 5 – 7.5 coils of the polar tube.8 subsequently been used to further classify the microsporidia. The eukaryotic Nosema Species microsporidia that possessed prokaryotic- like ribosomes because the ribosomal genes encoded 16S and 23S subunits Numerous species have been described without an independent 5.3S subunit that is chiefly in invertebrates. Development typically observed in has been occurs in direct contact with host-cell reported.11,12 These results suggested that cytoplasm, i.e., there are no the microsporidia were early branching parasitophorous vacuoles or sporophorous protozoa. vesicles. Nuclei are paired (diplokaryotic). Sporonts are disporoblastic. Examples are Nosema connori spores are oval with 11 Morphology of Genera and Species coils of the polar tube and Nosema Infecting Man: corneum with about 6 coils of the polar Encephalitozoon Species tube they measure 4.0 - 4.5 x 2.0 - 2.5μm.8

Encephalitozoon is parasitic in vertebrates. Pleistophora Species Development occurs in parasitophorous vacuoles in host cells. Meronts lie close to the vacuolar membrane, which is of host Pleistophora is a parasite of vertebrates, origin, and divide mainly by binary fission. chiefly fish. A thick amorphous surface coat Sporonts become free in the centre of the surrounds Meronts, which are multi- vacuole, divide into two sporoblasts sporous culminating in a large and variable (disporoblastic), which mature into spores. number of spores within the persisting Mature parasitophorous vacuoles are vesicle. Nuclei are unpaired. Pleistophora packed with spores. Nuclei of all stages are species has been found, parasitic in the unpaired. muscles of an immuno-compromised, but HIV – negative man. The oval spores appear less rounded with 11 coils of the Examples are polar tube and measure approximately 3.2 which measure approximately 2.5–3.2 x – 3.4 x 2.8μm.8 1.2–1.6μm with 4.5–5 coils of the polar tube, although 5–7 coils have been recorded in isolates from dogs and Microsporidium Species Encephalitozoon hellem which are more rounded, measuring 2.0 – 2.5 x 1.0 – Microsporidium is a collective generic name 1.5μm.8 given to species for which the genus cannot be determined on available Enterocytozoon Species information. Examples are Microsporidium ceylonensis and Microsporidium africanus. Spores have 11–13 coils of the polar tube Enterocytozoon is a parasite of vertebrates. and measure about 3.5 x 1.5μm.8 Table 1 Development takes place in direct contact shows the pathologic spectrum of with host cell cytoplasm. Meronts and microsporidia infecting man. sporonts are multinucleate, traversed by

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Table 1: Pathologic Spectrum of Microsporidia Infecting Man13

Species Size of Spore(μm) Habitat References Small intestinal Orenstein et al., 1990 epithelial epithelium

Small intestinal sub Schwartz et al. 1994 b epithelial infection

Biliary tract Pol et al. 1993; Bryan et al., 1993 and Enterocytozoon 1.1-1.6x0.7-1.0 epithelium Mcwhinney et al., 1991 bieneusi Gall bladder Pol et al. 1993 and Bryan et al., 1993 epithelium

Pancreatic duct Bryan et. a1993 epithelium Bronchial epithelium Weber et al., 1993

Corneal and Schwartz et al., 1993b and Cali et al., conjunctival 1993b.c epithelium Canning et al., 1992 and Schwartz et al., Sino-Nasal epithelium 1993a

Encephalitozoon Tracheo-bronchial 2.0-2.5x1.0-1.5 Schwartz e. al., 1992 and 1993c.d hellem mucosa Renal tube infection Schwartz et al., 1992

Urethral and urinary Schwartz e. al., 1992 bladder mucosa Protastic abscess Schwartz et al., 1994 a

Bronchial and Bronchiolar DeGroot et. al., 1995 E. cuniculi 2.5-3.2x1.2-1.6 epithelium Tongue DeGroot et al., 1995 Peritonitis Zender et al., 1989

Hepatitis Terada et al., 1987 E. intestinalis 1.2 x 2.2 Small intestine Accoceberry et al., 1999

Nosema conori 4.0-4.5x2.0-2.5 All organs Canning and Hollister, 1992

N. corneum 3.7 x 1.0 Corneal Stroma Canning and Hollister ,1992

Pleistophora Sp. 3.2 – 3.4 x 2.8 Skeletal Muscles Chupp et al., 1993

Microsporidium 3.5 x 1.5 Corneal Stroma Canning and Hollister, 1992 ceylonensis

M. africanum 4.5 x 2.5 Corneal Stroma Canning and Hollister, 1992.

OJHAS Vol 5 Issue 3(2): Human Microsporidial Infections www.ojhas.org/issue19/2006-3-2.htm 4 Biology of Microsporidia: size and shape. Sporoblasts are usually Spores have a resistant wall composed larger and the measurements together of an outer proteinaceous exospore with mature spores bring disputed and a thicker electro-lucent endospore, variability in descriptions of spore size. which contains chitin. The wall In ultra-thin sections, mature spores surrounds the infective sporoplasm, are usually dark and not differentiated which may be uninucleate or in their interior, and only young spores binucleate, and an extrusion are differentiated in the cross sections apparatus, which controls infection of of the polar filaments. The number of new cells. The extrusion apparatus coils in cross-section and the location consists of a polar tube, coiled in the (parallel coils, tilt) is characteristic for posterior half of the spores and the species.8,14 connecting via a straight section with an anterior anchoring disc, the polar In development, they have a sac. The straight section of the polar- proliferative phase of binary or tube is surrounded by an array of multiple fission, termed merogony; the membranes being continuous with the stages have simple unit membranes at outer membrane of the polar tube. the surface and little differentiation of When stimulated by the cells, usually the cytoplasm. This is followed by a in the gut of a new host, the polar tube sporulation phase, initiated when a is everted and the sporoplasm passes dense surface coat is secreted on cells through it and, if the tip of the tube called sporonts, which divided into chances to penetrate a host-cell sporoblasts that mature into spores as membrane, the sporoplasm is described above. In some genera, the inoculated into the cell. This infection spores lie free in the host-cell mechanism is unique in the animal cytoplasm; in others, the spores kingdom. derived from a single sporont are grouped together within a The spore is the only stage surviving in sporophorous vesicle of parasite origin the open air and serving to aid [Figure 1]. The vesicle arises as an transmission to the new host in additional envelope on the surface of contaminated water and food. In the sporonts and separates from the water, spores usually live more than surface as development progresses. one year at 4oC; in infected tissues, Microsporidia spread rapidly in most they survive even longer. Spores also tissues as a result of the extensive pass across the placenta in animals to proliferation in merogony and infect the foetus and infection acquired sometimes when there is autonomous, transplacentally is severe. Spores are hatching of spores.8 refringent, oval, usually all of the same

OJHAS Vol 5 Issue 3(2): Human Microsporidial Infections www.ojhas.org/issue19/2006-3-2.htm 5 Fig 1: Spore structures and life cycles of Microsporidia (Source: Canning and Hollister,1992)

.

OJHAS Vol 5 Issue 3(2): Human Microsporidial Infections www.ojhas.org/issue19/2006-3-2.htm 6 Life Cycle of Microsporidia: E. intestinalis). Either free in the 1) Spores are ingested by a host (man cytoplasm or inside a parasitophorous or animal). 2) The spore extrudes its vacuole, microsporidia develop by polar tubule and infects the host cell. sporogony to mature spores. 6) 3) The spore injects the infective During sporogony, a thick wall is sporoplasm into the eukaryotic host formed around the spore, which cell through the polar tubule. 4) Inside provides resistance to adverse the host cell, the sporoplasm environmental conditions. When the undergoes extensive multiplication spores increase in number and either by merogony (binary fission) or completely fill the host cell cytoplasm, schizogony (multiple fission). 5) This the cell membrane is disrupted and development can occur either in direct releases the spores to the surrounding contact with the host cell cytoplasm [Figure 2]. 7) These free mature spores (e.g. Ent. bieneusi) or inside a vacuole can infect new cells thus continuing termed parasitophorous vacuole (e.g the cycle.9

Figure 2: Generalized life cycles of microsporidia

OJHAS Vol 5 Issue 3(2): Human Microsporidial Infections www.ojhas.org/issue19/2006-3-2.htm 7 microsporidia might have been Geographic Distribution: acquired from the goat, because Microsporidia are being increasingly tapeworms infesting goats are frequently hyper-parasitised with recognized as opportunistic infectious 16 agents worldwide. Cases of Nosema helminthorum. However, the microsporidiosis have been reported in spore sizes are widely different. In a developed as well as in developing later study of Encephalitozoon cuniculi countries, including: Argentina, in the lenses of a rabbit, the absence Australia, Botswana, Brazil, Canada, of infection in the ocular envelope and Czech Republic, France, Germany, not in the lenses indicated that the India, Italy, Japan, The Netherlands, infection had entered the eye from a New Zealand, Spain, Sri Lanka, systemic source before the lens Sweden, Switzerland, Thailand, capsule had matured and thus that the infection had been acquired Uganda, United Kingdom, United 17 States of America, and Zambia.9 Lately transplacentally. Nosema corneum cases of microsporidia have been was isolated from a woman in reported in Nigeria.3,15 Botswana who had no previous history of trauma in the eye.18 A man from whom Nosema corneum was isolated Origin/ Sources of Acquisition of also had no history of trauma; and the Microsporidia: probable source of infection could be Faecal oral transmission is the likely from his travel to the Caribbean and route of infections in humans with Central America, where infections in intestinal microsporidiosis when spores invertebrates were likely to be more contaminate the environment. common, and also the fact that he Infection can occur by both inhalation lived near (and perhaps swam in) a and ingestion. Encephalitozoon large recreational lake, in which spores cuniculi is known to pass across the of invertebrate origin could have been placenta in animals to infect the abundant.19 The restriction of Nosema foetus. E. cuniculi infects a wide range corneum to the epithelium of the of mammals, including carnivores, and cornea and conjunctiva suggests that dogs are likely source of infection to infections are acquired topically. Of man. other cases observed, one person had owned a parrot; another had looked The microsporidium Enterocytozoon after a cat for several days but only bieneusi is known from AIDS patients after his infection had developed. only. It is thought that it might have a There did not appear to be a common worldwide distribution. This and its animal source for the infections. high prevalence suggest that it may be a natural parasite of man, perhaps Pleistophora species are common causing transient diarrhoea, but parasites of fish, in which the normally remaining below the myofibrils are infected in a similar detection level, only becoming a manner to the deltoid and quadriceps problem in severely immuno- muscles of a man.20 As the man was compromised people. It is not known immuno-compromised, it is possible whether there is an animal reservoir. that infection was acquired by eating The only other known species infects fish but the fish would have had to be salmonid fish but as well as being an uncooked. unlikely source of human infection, it has different morphological characteristics. The sources of the eye infections are just as mysterious. A Tamil boy had been gored in the eye by a goat 6 years before onset of his infection and it suggested that the

OJHAS Vol 5 Issue 3(2): Human Microsporidial Infections www.ojhas.org/issue19/2006-3-2.htm 8 Clinical Aspects of Human acquired transplacentally or Microsporidiosis: perinatally. Four cases, identified as E. cuniculi have been reported in man. The well documented case of The identifications were based on microsporidian infections in humans morphological data before evidence was presented of the existence of a was reported in 1959, in a Japanese 1, 22,23 boy exposed to farm animals who second species, E. hellem, in man. presented with headache, convulsion and recurrent fever. Examination of Ocular Infections the cerebrospinal fluid revealed organisms identified as microsporidia, Several different types of genus Encephalitozoon.1 The next two microsporidia have been found in the reports were in 1973: An immuno- human eye. Interestingly, the compromised infant with athymic infections in immuno-competent aplsia died of severe diarrhoea and people have extended deeply into the malabsorption.21 The microsporidiium corneal stroma, whereas those in AIDS Nosema connori were identified in patients have been restricted to the most organs. The other report was of superficial epithelium. The cornea of corneal involvement in a 11-year old the right eye of an 11-year-old Tamil boy of Sri-Lanka.16 Human boy in Sri-Lanka was scarred and microsporidiosis can be classified as vascularised, and granulomatous below: tissue was present over the conjunctival surface of the upper lid.16 Systemic Infection The spores lay free and in macrophages deep in the cornea but A single case was described of a not below Descemet’s membrane. The newborn infant with thymic deficiency genus of the organism could not be and presented with acute respiratory identified and was later placed in the collective Microsporidium and named distress, diarrhoea and malabsorption. 24 The respiratory problem was linked M. ceylonensis. with Pneumocystis carnii infection. The patient died at 4 months of age and a The left eye of a 26-year-old woman in post-mortem examination revealed an Botswana was removed because of a overwhelming disseminated infection painfully inflammed conjunctiva and no 18 with microsporidia, Nosema connori in light perception. A perforated corneal almost every organ. There was a ulcer was found, adjacent to which the predilection for muscular tissue but the corneal stroma was necrotic and kidney, adrenal cortex, lungs and liver infiltrated with inflammatory cells. were also infected. The spleen was not Again, the stroma was packed with infected and the central nervous microsporidial spores both free and system was not examined. Although, phagocytosed. The genus was not may have established, although Nosema was been the primary cause of death, there suggested, and the isolate was later 24 is little doubt that the microsporidiosis named Microsporidium africanum. was the contributory cause.21 The combined , with Bilateral infections in the superficial marked leucopenia and epithelium of the cornea and hypogammaglobulinaemia, due to the conjunctiva of AIDS patients have been defective lymphoid system, clearly reported several times in patients in enabled the microsporidia to take hold the United States.25,26 The clinical and multiply, but the mystery lies in manifestations in five of these patients the source of the infection. The child have been summarized.27 All had fell ill shortly after birth, so that it is conjunctival inflammation and not clear whether the infection was decreased visual acuity and diffuse

OJHAS Vol 5 Issue 3(2): Human Microsporidial Infections www.ojhas.org/issue19/2006-3-2.htm 9 punctate keratopathy. One patient had parasites. Several parasites can be corneal inflammation and another had found in one cell. There is no bulbous corneal ulceration. These appearing as ridges or long tongues of microsporidial infections are visible as tissue.27 Infected cells are sloughed fine or coarse epithelial opacities into the lumen of the intestine. The causing redness and irritation of the diarrhoea caused by this species is eye and most patients also suffered debilitating and life threatening, with photophobia. Corneal or conjunctival as many as ten episodes each day, and scrapings appeared identical to E. does not respond satisfactorily to cuniculi when examined by electron therapy. It must be considered as a microscopy, but the new isolates were significant cause of deaths in these differentiated from E. cuniculi on their patients. Two additional infections by protein profiles separated by SDS – unidentified microsporidia have been PAGE and by immunoblotting. The new reported in the intestine of AIDS species was named E. hellem.28 An patients. The species involved in the infection, probably due to the same first case was reported to exceed the species has also been identified in level of infection normally achieved by Britain.29 In this case, the infection also Ent. bieneusi in the jejunum and spread to the basal mucosa, which duodenum and invades the histiocytes became inflammed and hypertrophic. as well as the enterocytes.27 Examination showed multiple nasal Identification in the second case was polyps and a CT- Scan showed not possible on available evidence and, opacities in the nasal sinuses. The as it occurred as a double infection chronic nasal obstruction did not with Ent. bieneusi, its pathogenicity respond to antimicrobial therapy.30 could not be assessed.34

Intestinal Infections Muscle Infections

Intestinal infections have been found A 20-year-old man with a low T- only in AIDS patients and the helper/suppressor cell ratio presented commonest of these is due to with an illness of 7 months duration Enterocytozoon bieneusi. This species characterised by generalized muscle was described and named by weakness and contractures, Desportes et al., and further studies at generalized non-tender the ultra structural level by Curry et lymphadenopathy, fever and an 18kg al.31,32 First diagnosed in a Haitian man loss of weight.20 Muscle biopsy from in France, the species has, to date, the arm, taken on admission and 5 been found in about 150 patients. It months later showed masses of spores causes severe watery, non-bloody amid trophic and degenerating muscle diarrhoea, which is exacerbated by fibres with an intense inflammatory food intake. There is slow weight loss reaction. The spores were identified as of about 1kg per week. In groups of Pleistophora species, as they were patients with persistent diarrhoea, who grouped in large numbers within were negative for other specific enteric sporophorous vesicles. Ten months pathogens by normal microbial after diagnosis, and after some examinations, prevalence of Ent. antibiotic therapy, he was afebrile and bieneusi ranged between 27% - the myopathy had improved slightly. 30%.27,33

Parasites are restricted to the small intestinal enterocytes and were rather more common in the jejunum than in the duodenum. They lie between unaltered brush-border and the cell nucleus, which is often indented by the OJHAS Vol 5 Issue 3(2): Human Microsporidial Infections www.ojhas.org/issue19/2006-3-2.htm 1 Laboratory Diagnoses of antibodies in human sera.35,36 It has Microsporidiosis: been mentioned that serological testing is most useful. Serological Diagnosis of microsporidia in general is testing is not useful in immuno- based on the microscopic identification compromised persons and reagents of the organism, the electronic not available commercially. microscopic findings, nucleic acid Immunofloresence may also be used. methods and serological assays. Several groups of workers have Molecular techniques are beginning to therefore developed microsporidial be applied to microsporidial problems, spore staining methods for particularly for use in the examination of faecal samples. Spores differentiation of species and their has also been detected in sputum, detection in clinical samples. Random nasal washings, conjunctival scrapings amplified polymorphic DNA (RAPD) and vaginal swab samples. obtained by means of the polymerase Microsporidial spores are of the same chain reaction (PCR), as well as order of size, as bacteria so that restriction enzyme digests (RED), have staining has to differentiate between shown clear differences among the spores and faecal bacteria. The isolates. Ribosomal DNA gene methods must also allow the sequences are available for microscopist to differentiate between Enterocytozoon and Encephalitozoon microsporidial spores and those of species. PCR analyses are performed yeasts and fungi as well as the oocysts using specific primers. To raise the of coccidian protozoal parasites. sensitivity of PCR, powerful and fast DNA extraction method including stool Spores stain light blue with Giemsa, sedimentation, glass bead disruption, red with Ziehl Neelsen, magenta with and proteinase K and chitinase Gram’s stains, spore wall stains pink to digestion. Primer pairs V1-PMP2, V!- red and the interior of the spore is EB450, and V1-SI500, are used for this unstained with a diagonal line analysis, and the nature of the PCR products are confirmed by southern representing the polar tube with 37 Trichrome stain, and spores appear blot hybridization. bluish white at a wavelength of 395 to 415 nm with Calcoflor white stain; on Treatment of Microsporidiosis: their own these stains are not specific Microsporidial infections are difficult to but the different colourations treat because of their intracellular collectively build up a reliable habit and the resistant nature of the diagnostic picture. Any lingering spores. Enteric microsporidial doubts can be removed by revealing infections have been treated with spore structure by electron varying degree of success with several microscopy. drugs. The most promising anti- microsporidial drug to date is Infections in the eye can be diagnosed albendazole.34 It does not eliminate by slit-lamp examination and by infection with E. bieneusi but in many detection of parasites in corneal or cases alleviates the diarrhoea. The conjunctival scrapings. species, which develop in parasitophorous vacuoles, appear to A variety of serological tests have be more susceptible to albendazole, as been developed to detect residual indicated by the disappearance of E. antibodies to E. cuniculi. Of these, the intestinalis from the intestine38 and indirect immunoflourescent test (IFAT) regression of hypertrophic nasal and enzyme linked immunosorbent epithelium in a patient with sinusitis assay (ELISA) are probably the most due to Encephalitozoon species.30 useful. Both have been used to detect Several drugs are reported to reduce OJHAS Vol 5 Issue 3(2): Human Microsporidial Infections www.ojhas.org/issue19/2006-3-2.htm 1 levels of microsporidial infections in Vittaforma cornea. SCID mice were invertebrates, notably; Fumagillin also been infected by oral inoculation which includes topical fumagillin for of Encephalitozoon cuniculi spores.48 treatment of keratoconjunctivitis39, Successful transmission of Benomyl40, Buquinolate41, Toltrazuril42 Encephalitozoon cuniculi to rabbits by and Itraconazole.43 administration of spores orally and rectally has been reported.44 No sustained improvement has been reported for the diarrhoea due to Ent. Conclusions: bieneusi. Chemotherapy for Microsporidia are an important cause microsporidial disease is clearly a of disease in AIDS patients and are priority area of research. now increasingly also recognized as pathogens in non-HIV-infected patients with or without immuno-suppression. Disinfection of Microsporidia: Therefore, a high index of suspicion is Disinfection of surfaces contaminated needed for both clinicians, with microsporidia has received little parasitologists, pathologists and attention. A rabbit isolate of E. cuniculi microbiologists. cultured in a rabbit choroid plexus (RCP) cell line has been used for in As is true for many other new and vitro experiments in testing the factors emerging pathogens, we have just influencing the infectivity and scratched the surface of a complex replication of this organism in RCP and evolving relation between cells32 Aliquots of cells used for testing microsporidia and humans. There is contained variable proportions of need for an in-depth study on spores, sporoblasts, sporonts and application of molecular techniques to schizonts, although a typical pool diagnosis, species differentiation and contained about 80% spores, are made phylogenetic analysis of microsporidia visible by electron microscopy. which will increase the knowledge of Penicillin, Streptomycin or Gentamicin these organisms and help greatly in did not affect E.cuniculi, nor was it evaluating its threat to health in affected by sonication, freezing and Nigeria. thawing or distilled water. Organisms survive for 60 minutes but not up to 120 minutes at 56 oC. They were killed References: after 10 minutes of autoclaving at 12 oC or exposure to 2% (v/v) lysol, 10% 1. Matsubayashi H, Koike T, Mikata I, Takei (v/v) formalin and 70% (v/v) ethyl H, Hagiwara S. A case of Encephlitozoon alcohol for 10 minutes. It is not known - like body in man. Archives of Pathology 1959;67:181–187. whether all microsporidia are affected 2. Weber R, Bryan RT, Schwatts DA, Owen to the same degrees as E. cuniculi by RL. Human Microsporidial the physical conditions and chemicals infections. Clinical Microbiology Reviews used in the study.32 1994;7:426–461. 3. Omalu ICJ, Duhlinska DD, Anyanwu GI, Yako AB. Prevalence of Microsporidiosis Animal Model: in Immunocounprised patients in Kano State. Proceedings of the 4th National Conference of the League of Several animal models have been Researchers in Nigeria in Law established to study microsporidial Auditorium of University of Jos. 28th infection24,44,45 as well as for producing October, 2002. monoclonal antibodies13,46,47 Balb/c and 4. Nageli KW. Uber die neue krankheit der C57B1/6 athymic mice have been used seidenraupe und verwante organismen. Bot Zeit 1857;15: 760 – 761. and have been injected 5. Balbiani M. Sur les microsporidies ou intraperitoneally with Encephalitozoon psorospermies des articules. C R cuniculi, Encephalitozoon hellem or Academy of Science 1882;95: 1168– 1171. OJHAS Vol 5 Issue 3(2): Human Microsporidial Infections www.ojhas.org/issue19/2006-3-2.htm 1 6. Sprague V. Annotated lists of species of 19. Shadduck JA, Meccoli RA, Davis R, Font microsporidia. In: Bulla LA, Cheng TC, R. Isolation of a Microsporidian from a eds. Comparative pathobiology, vol. 2: human patient. Journal of Infectious Systematics of the microsporidia. New Diseases 1990;162:773-776. York: Plenum press. 1976;331-334 20. Ledford DK, Overman MD, Gonzalvo A, 7. Kudo R. A biologic and taxonomic study Cali A, Mester SW, Lockey RF. of the microsporidia. III Biological Microsporidiosis myositis in a patient Monograph 1924;9:1–268 with acquired immunodeficiency 8. Canning EU, Hollister WS. Human sydrome. Annals of internal Medicine infections with Microsporidia. Reviews 1985;102:628-630. in Medical Microbiology 1992;3:35-42, 21. Margileth AM, Strano AJ, Chandra R, 9. CDC. Microsporidiosis Parasite and Neafie R, Blum M, McCully RM. Health. 2004;1–3pp. Disseminated nosematosis in an immunological compromised infant. Joseph J, Vemuganti GK, Sharma S. 10. Archives of Pathology 1973;95:145– Microsporidia: Emerging ocular 150. Pathogens. Indian Journal of Medical Microbiology 2005;23:80–91. 22. Bergquist NR, Stintzing G, Smedman L, Wallert T. Diagnosis of Vossbrinck CR, Maddox JV, Friedman S, 11. encephalitozoonosis in Man by Debrunner-Vossbrinck BA, Woese CR. Serological tests. British Medical Journal Ribosomal RNA sequence suggests 1984;288:902-903 Microsporidia are extremely ancient eukryotes. Nature 1987;326:411-414. 23. Terada S, Reddy KR, Jeffers LJ, Cali A, Schiff ER. Microsporidian hepatitis in the Weiss L, Vossbrinck C. Molecular 12. Acquired Immunodefiency Syndrome. biology, molecular phylogeny, and Annals of internal Medicine molecular diagnostic approaches to the 1987;107:61-62. microsporidia. In Wittner M, Weiss L, editors, The Microsporidia and 24. Canning EU, Lom J. The Microsporidia of Microsporidiosis, Washington DC: Vertebrates. London. Academic Press, nd American Society of Microbiology 2 Edition. 1986;289p. 1999;pp. 120–271 25. Lowder CY, Meisler DM, McMahon JT, 13. Schwartz DA, Bryan RT, Weber R, Longworth DL, Rutherford I. Visvesvara GS. Microsporidiosis in HIV Microsporidia infection of the cornea in positive patients: Current methods for a man seropositive for human diagnosis using biopsy, Cytologic, immunodeficiency virus. American techniques. Folia parasitologica Journal of Ophthamology 1990;109: 1994;41:101-109. 242-244. 14. Lom J. Introductory remarks on 26. Friedberg DN, Stenson SM, Orenstein Microsporidia in the AIDS era. Folia JM, Tierno PM, Charles NC. Parasitologica 1993;40:255-256. Microsporidial keratoconjunctivitis in acquired immunodeficiency sydrome. Omalu ICJ, Duhlinska DD, Anyanwu GI, 15. Ophthamology 1990;108:504-508. Yako AB, Inyama PU. Detection of Encephalitozoon species in urine and 27. Orenstein JM, Chiang J, Steinberg W, sputum samples of Smith PD, Rotterdam H, Kotler DP. immunocompromised patients in Kano Intestinal Microsporidiosis as a cause of State. A paper presented at the 2nd diarrhoea in human immunodeficiency Annual Conference of the Zoological virus infected patients: a report of 20 Society of Nigeria held at the Institute cases. Human Pathology of Development Reseach at Ahmadu 1990;21(5):475-481. Bello University Zaria on 8th – 9th of 28. Didier ES, Didier PJ, Friedberg DN et al. November, 2004. Isolation and characterization of new 16. Ashton N, Wirasinha PA. human microsporidian, Encephalitozoon Encephlitozoonosis (nematosis) of the hellem (n.sp) from three AIDS patients cornea. British Journal of with keratoconjunctivitis. Journal of Ophthamology 1973;57:669–674 Infectious Diseases 1991;163:617-621. 17. Ashton N, Cook C, Clegg F. 29. Metcalfe, T, Doran R, Rowland P, Curry Encephlitozoonosis (nematosis) causing A, Lacey CJN. (). Microsporidial bilateral cataract in a rabbit. British Keratoconjunctivitis in a British patient Journal of Ophthamology 1976;60:618 – with AIDS. British Journal of 631. Ophthamology 1992;76:177-178. 18. Pinnolis M, Egbert PR, Font RL, Winter 30. Lacey CJ, Clark A, Frazer P, Metcalfe T, FC. Nosematosis of the Cornea. Case Bonsor G, Curry A. Chronic report, including electron Microscopic Microsporidian infection in the Nasal studies. Achives of Ophthamology Mucosae, Sinuses, and conjunctivae in 1981;99:1044-1047. HIV disease. Genitourinary Medicine 1992;68:179-181.

OJHAS Vol 5 Issue 3(2): Human Microsporidial Infections www.ojhas.org/issue19/2006-3-2.htm 1 31. Desportes L, LeCharpentier Y, Galian A, 43. Lin TP, Murick GR. Deformities in the Bernard F, Cochand-Priollet B, spores of Nosema apis as induced by Larvergae A, Ravisse P, Modigliani R. itraconazole. Parasitological Research Occurrence of a new Microsporidian, 1989;75:498-502. Enterocytozoon bieneusi n.g., n.sp., in 44. Cox JC, Hamilton RC, Attwood HD. An the enterocytes of a human patient with investigation of the route and AIDS. Journal of Protozoology progression of Encephalitozoon cuniculi 1985;32:250-254. infection in adult rabbits. Journal of 32. Curry A, Canning EU. Human Protozoology 1979;26:260–265. Microspodiosis. Journal of Infection 45. Didier ES, Varner PW, Didier PJ et al. 1993;27:229-236. Experimental Microsporidiosis in 33. Van-Gool T, Hollister WS, Eeftinck- Immunocompetent and Schattenkerk J et al. Diagnosis of Immunodeficient Mice and Monkeys. Enterocytozoon bieneusi Folia Parasitologica 1994;41:1-11 Microsporidiosis in AIDS patients by 46. Visvesvara GS, Leitch GJ, Da silva AG, recovery of spores from faces. The Croppo GP, Moura H, Wallace S. Lancet 1990;336:697-698. Polyclonal and Monoclonal antibody and 34. Blanshard C, Ellis DS, Tovey DG, Dowell PCR-amplified small sub-unit rRNA S, Gazzard BG. Treatment of intestinal identification of microsporidia; Microsporidiosis with albendazole in Encephliyozoon hellem, isolated from patients with AIDS. AIDS 1992;6:311– an AIDS patient with disseminated 313. infection. Journal of Clinical Mirobiology 35. Hollister WS, Canning EU. An Enzyme 1994;32:2760–2768. Linked Immunosorbent Assay (ELISA) 47. Visvesvara GS, Da silva AG, Croppo GP, for detection of antibodies to Pieniazek NJ, Lietch GJ, Ferguson D. In Encephalitozoon cuniculi and its use vitro culture and serologic and in determination of infections in molecular identification of Septata man. Parasitology 1987;94:209-219. intestinalis isolated from urine of a 36. Hollister WS, Canning EU, Wilcox A. patient with AIDS. Journal of Clinical Evidence for Widespread Occurrence of Mirobiology 1995;33:930–936. antibodies to Encephalitozoon cuniculi 48. Koudela B, Vitovec J, Kucerova Z, Ditrich (Microspora) in man provided by ELISA O, Travnicek J. The severe combined and other serological tests. Parasitology immunodeficiency mouse as a Model for 1991;102:33-43. Encephalitozoon cuniculi 37. Muller A, Stellermann K, Hartmann P et Microsporidiosis. Folia Parasitologica al. A Powerful DNA extraction method 1993;40:279-286. and PCR for detection of Microsporidia in clinical stool specimens. Journal of Infectious Diseases 1999;44:22-25. 38. Orenstein JM, Dieterich DT, Kotler DP. Albendazole as a treatment for disseminated microsporidiosis due to Encephalitozoon intestinalis in AIDS patients. AIDS 1993;6:311–313. 39. Katznelson H, Jamieson CA. Control of nosema disease of honeybees with fumagilin. Sciences 1952;115 70–71. 40. Hsiao TH, Hsiao C. Benomyl: a novel drug for controlling a microsporidian disease of alfafa weevil. Journal of Invertebrate pathology 1973;22:303– 304. 41. Overstreet RM. Buquinolate as a preventive drug to control microporidiosis in the blue crab. Journal of Invertebrate Pathology 1975;25:213– 216. 42. Mehlhorn H, Schmahl G, Haberkorn A. Toltrazuril effective against a broad spetrum of Protozoan parasities. Parasitological Research 1988;75:64- 66.

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