<i>Cryptosporidium</i>species in humans and animals: current understanding and research needs

Ryan, Una; Fayer, Ronald; Xiao, Lihua

doi:10.1017/s0031182014001085

Cited by 572 publications

(594 citation statements)

References 219 publications

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“…The majority of human cases are caused by five species, including C. hominis, C. parvum, C. meleagridis, C. felis, and C. canis (1). However, 13 additional species as well as horse and skunk genotypes are occasionally found in humans (1,2). Cryptosporidium chipmunk genotype I appears to be an emerging pathogen in humans.…”

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Subtyping Novel Zoonotic Pathogen Cryptosporidium Chipmunk Genotype I

et al. 2015

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h Cryptosporidium chipmunk genotype I is an emerging zoonotic pathogen in humans. The lack of subtyping tools makes it impossible to determine the role of zoonotic transmission in epidemiology. To identify potential subtyping markers, we sequenced the genome of a human chipmunk genotype I isolate. Altogether, 9,509,783 bp of assembled sequences in 853 contigs were obtained, with an N50 of 117,886 bp and >200-fold coverage. Based on the whole-genome sequence data, two genetic markers encoding the 60-kDa glycoprotein (gp60) and a mucin protein (ortholog of cgd1_470) were selected for the development of a subtyping tool. The tool was used for characterizing chipmunk genotype I in 25 human specimens from four U.S. states and Sweden, one specimen each from an eastern gray squirrel, a chipmunk, and a deer mouse, and 4 water samples from New York. At the gp60 locus, although different subtypes were seen among the animals, water, and humans, the 15 subtypes identified differed mostly in the numbers of trinucleotide repeats (TCA, TCG, or TCT) in the serine repeat region, with only two single nucleotide polymorphisms in the nonrepeat region. Some geographic differences were found in the subtype distribution of chipmunk genotype I from humans. In contrast, only two subtypes were found at the mucin locus, which differed from each other in the numbers of a 30-bp minisatellite repeat. Thus, Cryptosporidium chipmunk genotype I isolates from humans and wildlife are genetically similar, and zoonotic transmission might play a potential role in human infections.

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Subtyping Novel Zoonotic Pathogen Cryptosporidium Chipmunk Genotype I

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“…Nearly 20 species and genotypes of Cryptosporidium have been isolated from human stool (2). While Cryptosporidium parvum and Cryptosporidium hominis account for the majority of human cases of cryptosporidiosis, many other species and genotypes, most of which are acknowledged as zoonotic, appear to occur sporadically or rarely in outbreaks all over the world (3)(4)(5)(6)(7).…”

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Development and Application of a gp60-Based Typing Assay for Cryptosporidium viatorum

et al. 2015

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The apicomplexan intestinal parasites of the genus Cryptosporidium take a major toll on human and animal health and are frequent causes of waterborne outbreaks. Several species and genotypes can infect humans, including Cryptosporidium viatorum, which, to date, has only been found in humans. Molecular characterization of Cryptosporidium spp., critical to epidemiological analyses, is commonly based on gp60 gene analysis, which appears to require bespoke species-or group-specific PCR primers due to extensive genetic diversity across the genus. In this study, we amplified, sequenced, and characterized the gp60 gene of C. viatorum for the first time. Moreover, we developed and validated a gp60 typing assay for this species and applied it to 27 isolates originating from Asia, Africa, and Central America. A single subtype family, XVa, was identified containing multiple alleles. Cryptosporidium is one of the leading causes of infant and childhood morbidity (1). Nearly 20 species and genotypes of Cryptosporidium have been isolated from human stool (2). While Cryptosporidium parvum and Cryptosporidium hominis account for the majority of human cases of cryptosporidiosis, many other species and genotypes, most of which are acknowledged as zoonotic, appear to occur sporadically or rarely in outbreaks all over the world (3-7). The availability of relevant, precise, and robust typing tools is therefore critical to outbreak investigation, surveillance, and control of the parasite.Molecular characterization of Cryptosporidium based on gp60 gene data has proved to have high epidemiological relevance (8).To date, the resolution of the gp60 locus has enabled a subtle classification of species and genotypes into subtype families, which in turn can be differentiated at the subtype level. However, the high resolution and genetic variability existing in the gp60 locus also entails a challenge in terms of developing primers applicable to the many species and genotypes of Cryptosporidium (4, 9-11). The primers commonly used for gp60 subtyping of C. parvum and C. hominis (12) do not reliably amplify many other Cryptosporidium species. For example, new primers have been published for Cryptosporidium meleagridis (9) and Cryptosporidium ubiquitum (11). Similarly, the C. parvum/C. hominis primers do not apply to C. viatorum (4, 10), one of the panoply of Cryptosporidium species infecting humans and first described in 2012 (10); the 10 cases identified in the United Kingdom at that point all had a history of recent return from traveling to the Indian subcontinent. Later, C. viatorum was identified in patients in Nigeria (13) and Ethiopia (14) and in Swedish patients who had travelled to Kenya or Guatemala (4, 5).The aims of the present study were, first, to amplify, sequence, and characterize the gp60 gene of C. viatorum, and second, to develop, validate, and apply primers appropriate for gp60 typing of C. viatorum, thus complementing the panel of Cryptosporidium gp60 primers and contributing to C. viatorum gp60 data useful for epidemiologica...

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“…Cryptosporidium is a widespread zoonotic intestinal protozoan parasite belonging to the phylum Apicomplexa that contains 30 species with more than 50 genotypes and infects a wide range of vertebrate animals, including mammalians, avians, amphibians, reptiles, and fish species as well as humans by the fecal-oral route via ingestion of sporulated oocysts (1)(2)(3). Cryptosporidium spp.…”

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Molecular Study of Cryptosporidium spp. in Dogs from Southwest of Iran

Tavalla

Kord

Abdizadeh

et al. 2017

Jundishapur J Microbiol

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Background: Cryptosporidium is a protozoan parasite that effects rodents, dogs, calves, humans, and cats. Infection with this parasite is known as cryptosporidiosis. Cryptosporidium spp. may induce clinical or subclinical signs in infected hosts. In the life cycle of this parasite infected dogs freely living in urban and rural areas of Khuzestan province are the definitive hosts that should be considered as a real problem in public health for humans. Objectives: This study aimed at determining the frequency of cryptosporidiosis in dogs in southwest of Iran. Methods: Overall, 350 fresh fecal samples were collected from domestic dogs living in 43 villages, from June 2012 to September 2013. All samples were investigated by Sheather's concentration method and fecal smears were stained with modified Ziehl-Neelsen followed by light microscope examination, and polymerase chain reaction (PCR). Results:The results revealed that frequency of Cryptosporidium infection was 8% and 12.3%, using direct smear and molecular method, respectively. Conclusions: The present findings indicated that domestic dog feces from southwest of Iran may contain zoonotic parasites such as Cryptosporidium spp. and may be a potential risk for humans and other animals, especially when they contaminate the environment. The role of dogs as source of human infection should be investigated by further studies.

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Cryptosporidiumspecies in humans and animals: current understanding and research needs

Cited by 572 publications

References 219 publications

Subtyping Novel Zoonotic Pathogen Cryptosporidium Chipmunk Genotype I

Subtyping Novel Zoonotic Pathogen Cryptosporidium Chipmunk Genotype I

Development and Application of a gp60-Based Typing Assay for Cryptosporidium viatorum

Molecular Study of Cryptosporidium spp. in Dogs from Southwest of Iran

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