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Abstract
Microsporidia are pathogenic organism related to fungi. They cause infections in a wide variety of mammals as well as in avian, amphibian, and reptilian hosts. Many microsporidia species play an important role in the development of serious diseases that have significant implications in human and veterinary medicine. While microsporidia were originally considered to be opportunistic pathogens in humans, it is now understood that infections also occur in immune competent humans. Encephalitozoon cuniculi, Encephalitozoon intestinalis, and Enterocytozoon bieneusi are primarily mammalian pathogens. However, many other species of microsporidia that have some other primary host that is not a mammal have been reported to cause sporadic mammalian infections. Experimental models and observations in natural infections have demonstrated that microsporidia can cause a latent infection in mammalian hosts. This chapter reviews the published studies on mammalian microsporidiosis and the data on chronic infections due to these enigmatic pathogens.
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Affiliation(s)
- Bohumil Sak
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic.
| | - Martin Kváč
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Agriculture, University of South Bohemia in České Budějovice, České Budějovice, Czech Republic
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Robertson LJ, Clark CG, Debenham JJ, Dubey J, Kváč M, Li J, Ponce-Gordo F, Ryan U, Schares G, Su C, Tsaousis AD. Are molecular tools clarifying or confusing our understanding of the public health threat from zoonotic enteric protozoa in wildlife? Int J Parasitol Parasites Wildl 2019; 9:323-341. [PMID: 31338293 PMCID: PMC6626983 DOI: 10.1016/j.ijppaw.2019.01.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/30/2019] [Accepted: 01/31/2019] [Indexed: 12/13/2022]
Abstract
Emerging infectious diseases are frequently zoonotic, often originating in wildlife, but enteric protozoa are considered relatively minor contributors. Opinions regarding whether pathogenic enteric protozoa may be transmitted between wildlife and humans have been shaped by our investigation tools, and have led to oscillations regarding whether particular species are zoonotic or have host-adapted life cycles. When the only approach for identifying enteric protozoa was morphology, it was assumed that many enteric protozoa colonized multiple hosts and were probably zoonotic. When molecular tools revealed genetic differences in morphologically identical species colonizing humans and other animals, host specificity seemed more likely. Parasites from animals found to be genetically identical - at the few genes investigated - to morphologically indistinguishable parasites from human hosts, were described as having zoonotic potential. More discriminatory molecular tools have now sub-divided some protozoa again. Meanwhile, some infection events indicate that, circumstances permitting, some "host-specific" protozoa, can actually infect various hosts. These repeated changes in our understanding are linked intrinsically to the investigative tools available. Here we review how molecular tools have assisted, or sometimes confused, our understanding of the public health threat from nine enteric protozoa and example wildlife hosts (Balantoides coli - wild boar; Blastocystis sp. - wild rodents; Cryptosporidium spp. - wild fish; Encephalitozoon spp. - wild birds; Entamoeba spp. - non-human primates; Enterocytozoon bieneusi - wild cervids; Giardia duodenalis - red foxes; Sarcocystis nesbitti - snakes; Toxoplasma gondii - bobcats). Molecular tools have provided evidence that some enteric protozoa in wildlife may infect humans, but due to limited discriminatory power, often only the zoonotic potential of the parasite is indicated. Molecular analyses, which should be as discriminatory as possible, are one, but not the only, component of the toolbox for investigating potential public health impacts from pathogenic enteric protozoa in wildlife.
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Affiliation(s)
- Lucy J. Robertson
- Parasitology Laboratory, Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, PO Box 369 Sentrum, 0102, Oslo, Norway
| | - C. Graham Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom
| | - John J. Debenham
- Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, PO Box 369 Sentrum, 0102, Oslo, Norway
| | - J.P. Dubey
- United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD, 20705-2350, USA
| | - Martin Kváč
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, 370 05, České Budějovice, Czech Republic
- Faculty of Agriculture, University of South Bohemia in České Budějovice, Studentská 1668, 370 05, Czech Republic
| | - Junqiang Li
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China
| | - Francisco Ponce-Gordo
- Department of Microbiology and Parasitology, Faculty of Pharmacy, Complutense University, Plaza Ramón y Cajal s/n, 28040, Madrid, Spain
| | - Una Ryan
- Centre for Sustainable Aquatic Ecosystems, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, WA, 6150, Australia
| | - Gereon Schares
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, 17493, Greifswald, Insel Riems, Germany
| | - Chunlei Su
- Department of Microbiology, University of Tennessee, Knoxville, TN, 37996-1937, USA
| | - Anastasios D. Tsaousis
- Laboratory of Molecular & Evolutionary Parasitology, RAPID Group, School of Biosciences, University of Kent, Canterbury, UK
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Shibasaki K, Tokiwa T, Sukegawa A, Kondo H, Tamukai K, Haga Y, Ike K. First report of fatal disseminated microsporidiosis in two inland bearded dragons Pogona vitticeps in Japan. JMM Case Rep 2017; 4:e005089. [PMID: 29026616 PMCID: PMC5630957 DOI: 10.1099/jmmcr.0.005089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/20/2017] [Indexed: 11/18/2022] Open
Abstract
Introduction.Encephalitozoon pogonae is a newly described pathogen belonging to the phylum Microsporidia. In Austria and the USA, this species has been isolated from fatal and disseminated cases of captive-bred inland bearded dragons. Here, we report the case of fatal disseminated microsporidiosis caused by E. pogonae in two bearded dragons in Japan. Case Presentation. The two lizards from different private households in Tokyo, Japan, had been brought to an animal hospital for examination. In both cases, the animal presented with a history of weight loss for several weeks. There were no improvements in clinical symptoms and the lizards deteriorated and finally died. Histopathological examination demonstrated necrotizing granulomatous inflammation attributed to disseminated microsporidian infection. Nucleotide sequencing of the nuclear ribosomal internal transcribed spacer region identified the microsporidian as E. pogonae with sequence identity of 100 %. Conclusion. We report the first case, to our knowledge, of disseminated microsporidiosis caused by E. pogonae in inland bearded dragons in Japan. Although it is difficult to diagnose prenatally since the signs are nonspecific, the disease should be considered in the differential diagnosis of chronic infections that do not respond to antibiotics.
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Affiliation(s)
- Kojiro Shibasaki
- Allieys Animal Hospital, 1-30-3 Sasazuka, Shibuya-ku, Tokyo, Japan
| | - Toshihiro Tokiwa
- Laboratory of Veterinary Parasitology, Nippon Veterinary and Life Science University, 1-7-1 Kyonancho, Musashino, Tokyo, Japan
| | - Akihiro Sukegawa
- Allieys Animal Hospital, 1-30-3 Sasazuka, Shibuya-ku, Tokyo, Japan
| | - Hirotaka Kondo
- Synergy Animal General Hospital, 815 Ishigami, Kawaguchi, Saitama, Japan
| | - Kenichi Tamukai
- Den-en-chofu Animal Hospital, 2-1-3 Denenchofu, Ota-ku, Tokyo, Japan
| | - Yumiko Haga
- Laboratory of Veterinary Parasitology, Nippon Veterinary and Life Science University, 1-7-1 Kyonancho, Musashino, Tokyo, Japan
| | - Kazunori Ike
- Laboratory of Veterinary Parasitology, Nippon Veterinary and Life Science University, 1-7-1 Kyonancho, Musashino, Tokyo, Japan
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Li J, Gu F, Wu R, Yang J, Zhang KQ. Phylogenomic evolutionary surveys of subtilase superfamily genes in fungi. Sci Rep 2017; 7:45456. [PMID: 28358043 PMCID: PMC5371821 DOI: 10.1038/srep45456] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 02/28/2017] [Indexed: 01/10/2023] Open
Abstract
Subtilases belong to a superfamily of serine proteases which are ubiquitous in fungi and are suspected to have developed distinct functional properties to help fungi adapt to different ecological niches. In this study, we conducted a large-scale phylogenomic survey of subtilase protease genes in 83 whole genome sequenced fungal species in order to identify the evolutionary patterns and subsequent functional divergences of different subtilase families among the main lineages of the fungal kingdom. Our comparative genomic analyses of the subtilase superfamily indicated that extensive gene duplications, losses and functional diversifications have occurred in fungi, and that the four families of subtilase enzymes in fungi, including proteinase K-like, Pyrolisin, kexin and S53, have distinct evolutionary histories which may have facilitated the adaptation of fungi to a broad array of life strategies. Our study provides new insights into the evolution of the subtilase superfamily in fungi and expands our understanding of the evolution of fungi with different lifestyles.
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Affiliation(s)
- Juan Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, P.R. China
| | - Fei Gu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, P.R. China
| | - Runian Wu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, P.R. China
| | - JinKui Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, P.R. China
| | - Ke-Qin Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, P.R. China
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Abstract
It was widely believed in the late 1960s that infectious diseases had been conquered by vaccines and antibiotics and humans were no longer under threat by microbial pathogens. Yet, since that time more than 60 pathogens have been discovered that can cause serious emerging infectious diseases. Molecular methods have played critical roles in the discovery, monitoring, and clinical diagnostics of emerging pathogens. In this chapter, we present well-recognized emerging pathogens. We provide examples of the utility of molecular assays in research and clinical care of emerging infectious diseases. We also discuss some theoretical and practical limitations of molecular tests and the future prospects of expanding molecular diagnostics for emerging pathogens based on new advances of knowledge and technologies.
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Sagastume S, Martín-Hernández R, Higes M, Henriques-Gil N. Genotype diversity in the honey bee parasite Nosema ceranae: multi-strain isolates, cryptic sex or both? BMC Evol Biol 2016; 16:216. [PMID: 27756211 PMCID: PMC5069816 DOI: 10.1186/s12862-016-0797-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 10/11/2016] [Indexed: 11/10/2022] Open
Abstract
Background There is great controversy as to whether Microsporidia undergo a sexual cycle. In the paradigmatic case of Nosema ceranae, although there is no morphological evidence of sex, some meiosis-specific genes are present in its reduced genome and there is also high intraspecific variability, with incongruent phylogenies having been systematically obtained. The possibility of sexual recombination is important from an epidemiological standpoint, particularly as N. ceranae is considered to be a major factor in the current disquieting epidemic of widespread bee colony losses. This parasite apparently originated in oriental honey bees, spreading out of Asia and Australia to infect honey bees worldwide. This study had three main objectives: i) to obtain genetic markers that are not part of known multi-copy arrays for strain determination; ii) to shed light on the intraspecific variability and recombination of N. ceranae; and iii) to assess the variability in N. ceranae populations. The answers to these questions are critical to understand the capacity of adaptation of microsporidia. Results Biallelic polymorphisms were detected at a number of specific points in the five coding loci analyzed from European and Australian isolates of N. ceranae. Heterozygous genotypes were abundant and cloning experiments demonstrate that they reflect the existence of multiple alternative sequences in each isolate. The comparisons of different clones and genotypes clearly indicate that new haplotypes are generated by homologous recombination. Conclusions The N. ceranae isolates from honey bees correspond to genotypically distinct populations, revealing that individual honey bees may not be infected by a particular clone but rather, a pool of different strains. Homologous recombination implies the existence of a cryptic sex cycle yet to be described in N. ceranae. There are no diagnostic alleles associated with Australian or European origins, nor are there differences between the two hosts, A. cerana and A. mellifera, supporting the absence of biological barriers for N. ceranae transmission. Diversity is high among microsporidia of both these origins, and the maintenance of a high heterozygosis in the recently invaded European populations, could hypothetically underlie the stronger virulence of N. ceranae observed in A. mellifera.
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Affiliation(s)
- Soledad Sagastume
- Centro Apícola Regional, Bee Pathology Laboratory, 19180, Marchamalo, Guadalajara, Spain.
| | - Raquel Martín-Hernández
- Centro Apícola Regional, Bee Pathology Laboratory, 19180, Marchamalo, Guadalajara, Spain.,Instituto de Recursos Humanos para la Ciencia y la Tecnología (INCRECYT), Parque Científico de Albacete, Spain
| | - Mariano Higes
- Centro Apícola Regional, Bee Pathology Laboratory, 19180, Marchamalo, Guadalajara, Spain
| | - Nuno Henriques-Gil
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad CEU San Pablo, Campus de Montepríncipe, 28668, Madrid, Spain
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Hinney B, Sak B, Joachim A, Kváč M. More than a rabbit's tale - Encephalitozoon spp. in wild mammals and birds. Int J Parasitol Parasites Wildl 2016; 5:76-87. [PMID: 28560162 PMCID: PMC5439460 DOI: 10.1016/j.ijppaw.2016.01.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/23/2015] [Accepted: 01/05/2016] [Indexed: 11/25/2022]
Abstract
Within the microsporidian genus Encephalitozoon, three species, Encephalitozoon cuniculi, Encephalitozoon hellem and Encephalitozoon intestinalis have been described. Several orders of the Class Aves (Passeriformes, Psittaciformes, Apodiformes, Ciconiiformis, Gruiformes, Columbiformes, Suliformes, Podicipediformes, Anseriformes, Struthioniformes, Falconiformes) and of the Class Mammalia (Rodentia, Lagomorpha, Primates, Artyodactyla, Soricomorpha, Chiroptera, Carnivora) can become infected. Especially E. cuniculi has a very broad host range while E. hellem is mainly distributed amongst birds. E. intestinalis has so far been detected only sporadically in wild animals. Although genotyping allows the identification of strains with a certain host preference, recent studies have demonstrated that they have no strict host specificity. Accordingly, humans can become infected with any of the four strains of E. cuniculi as well as with E. hellem or E. intestinalis, the latter being the most common. Especially, but not exclusively, immunocompromised people are at risk. Environmental contamination with as well as direct transmission of Encephalitozoon is therefore highly relevant for public health. Moreover, endangered species might be threatened by the spread of pathogens into their habitats. In captivity, clinically overt and often fatal disease seems to occur frequently. In conclusion, Encephalitozoon appears to be common in wild warm-blooded animals and these hosts may present important reservoirs for environmental contamination and maintenance of the pathogens. Similar to domestic animals, asymptomatic infections seem to occur frequently but in captive wild animals severe disease has also been reported. Detailed investigations into the epidemiology and clinical relevance of these microsporidia will permit a full appraisal of their role as pathogens.
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Affiliation(s)
- Barbara Hinney
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, A-1210 Vienna, Austria
| | - Bohumil Sak
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, v.v.i. Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Anja Joachim
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, A-1210 Vienna, Austria
| | - Martin Kváč
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, v.v.i. Branišovská 31, 370 05 České Budějovice, Czech Republic
- Faculty of Agriculture, University of South Bohemia in České Budějovice, Studentská 13, 370 05 České Budějovice, Czech Republic
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