Cryptosporidium species differ in host range. Parasite–host coevolution, host adaptation, and geographic segregation have led to the formation of subtype families with unique phenotypic traits within ...the major human-pathogenic species C. parvum and C. hominis. Transmission intensity, genetic diversity, and occurrence of genetic recombination and selective pressure have further shaped their population genetic structures. Panmixia appears to be common within the zoonotic C. parvum, especially its hypertransmissible IIaA15G2R1 subtype. Genetic recombination in C. hominis, in contrast, is more restricted to virulent subtypes, especially IbA10G2. Nonhuman primates and equine animals are commonly infected with genetically divergent C. hominis populations. Systematic studies of these and other host-adapted Cryptosporidium spp. are likely leading to improved understanding of population structures underlying various transmission patterns and intensities of Cryptosporidium.
Cryptosporidium species and subtypes differ in host range and public health significance.
Host-adapted subtype families exist in the human-pathogenic species C. parvum and C. hominis.
Genetic recombination is common within the zoonotic C. parvum, especially its hypertransmissible IIaA15G2R1 subtype.
Genetic recombination in C. hominis is mostly restricted to its virulent subtypes, especially IbA10G2.
Host and geographical segregation, genetic recombination, and selective pressure shape the population structure of C. parvum and C. hominis, leading to the emergence of host-adapted, virulent, and hypertransmissible subtypes with public health significance.
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•We present a review of 50 years of Cryptosporidium and Giardia taxonomy.•Historical and current understanding of Cryptosporidium and Giardia epidemiology are compared.•Research needs ...including more comparative genomic analysis and studies in developing countries are discussed.
The protozoan parasites Cryptosporidium and Giardia are significant causes of diarrhoea worldwide and are responsible for numerous waterborne and foodborne outbreaks of diseases. Over the last 50 years, the development of improved detection and typing tools has facilitated the expanding range of named species. Currently at least 44 Cryptosporidium spp. and >120 genotypes, and nine Giardia spp., are recognised. Many of these Cryptosporidium genotypes will likely be described as species in the future. The phylogenetic placement of Cryptosporidium at the genus level is still unclear and further research is required to better understand its evolutionary origins. Zoonotic transmission has long been known to play an important role in the epidemiology of cryptosporidiosis and giardiasis, and the development and application of next generation sequencing tools is providing evidence for this. Comparative whole genome sequencing is also providing key information on the genetic mechanisms for host specificity and human infectivity, and will enable One Health management of these zoonotic parasites in the future.
Cryptosporidium and Giardia are important causes of diarrhoeal illness. Adequate knowledge of the molecular diversity and geographical distribution of these parasites and the environmental and ...climatic variables that influence their prevalence is important for effective control of infection in at-risk populations, yet relatively little is known about the epidemiology of these parasites in Africa. Cryptosporidium is associated with moderate to severe diarrhoea and increased mortality in African countries and both parasites negatively affect child growth and development. Malnutrition and HIV status are also important contributors to the prevalence of Cryptosporidium and Giardia in African countries. Molecular typing of both parasites in humans, domestic animals and wildlife to date indicates a complex picture of both anthroponotic, zoonotic and spill-back transmission cycles that requires further investigation. For Cryptosporidium, the only available drug (nitazoxanide) is ineffective in HIV and malnourished individuals and therefore more effective drugs are a high priority. Several classes of drugs with good efficacy exist for Giardia, but dosing regimens are suboptimal and emerging resistance threatens clinical utility. Climate change and population growth are also predicted to increase both malnutrition and the prevalence of these parasites in water sources. Dedicated and co-ordinated commitments from African governments involving "One Health" initiatives with multidisciplinary teams of veterinarians, medical workers, relevant government authorities, and public health specialists working together are essential to control and prevent the burden of disease caused by these parasites.
Whilst considerable information is available for avian cryptosporidiosis, scant information is available for
Cryptosporidium infections in fish and amphibians. The present review details recent ...studies in avian cryptosporidiosis and our current knowledge of piscine and amphibian infections.
The enteric parasite, Cryptosporidium is a major cause of diarrhoeal illness in humans and animals worldwide. No effective therapeutics or vaccines are available and therefore control is dependent on ...understanding transmission dynamics. The development of molecular detection and typing tools has resulted in the identification of a large number of cryptic species and genotypes and facilitated our understanding of their potential for zoonotic transmission. Of the 44 recognised Cryptosporidium species and >120 genotypes, 19 species, and four genotypes have been reported in humans with C. hominis, C. parvum, C. meleagridis, C. canis and C. felis being the most prevalent. The development of typing tools that are still lacking some zoonotic species and genotypes and more extensive molecular epidemiological studies in countries where the potential for transmission is highest are required to further our understanding of this important zoonotic pathogen. Similarly, whole-genome sequencing (WGS) and amplicon next-generation sequencing (NGS) are important for more accurately tracking transmission and understanding the mechanisms behind host specificity.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Enteric parasites are major contributors to the global diarrhoeal disease load, infecting >67.2 million people. Their prevalence and clinical impact, however, are underestimated due to lack of ...adequate detection, which is largely still based on microscopy, particularly in developing countries. New commercially available enteric panel assays, which detect parasites (as well as bacteria and/or viruses) using multiplex PCR, offer enhanced sensitivity and specificity as well as the ability to detect mixed infections, and will play an important role in epidemiological surveillance and outbreak investigations. A major limitation of these technologies, however, particularly for developing countries, is the costs involved. Emerging technologies for low-resource, point-of-care (POC) settings have the potential to dramatically improve the cost and accuracy of enteric parasite detection in the future.
Parasites of the genus Cryptosporidium are a major cause of diarrhoea and ill-health in humans and animals and are frequent causes of waterborne outbreaks. Until recently, it was thought that ...Cryptosporidium was an obligate intracellular parasite that only replicated within a suitable host, and that faecally shed oocysts could survive in the environment but could not multiply. In light of extensive biological and molecular data, including the ability of Cryptosporidium to complete its life cycle in the absence of a host and the production of novel extracellular stages, Cryptosporidium has been formally transferred from the Coccidia, to a new subclass, Cryptogregaria, with gregarine parasites. In this review, we discuss the close relationship between Cryptosporidium and gregarines and discuss the implications for the water industry.
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•Cryptosporidium now grouped with gregarine parasites.•Both epicellular and extracellular development.•Can diagnostic antibodies cross-react with novel stages?•Susceptibility of novel stages to disinfection?•Growth in biofilms?
The tick microbiome comprises communities of microorganisms, including viruses, bacteria and eukaryotes, and is being elucidated through modern molecular techniques. The advent of next-generation ...sequencing (NGS) technologies has enabled the genes and genomes within these microbial communities to be explored in a rapid and cost-effective manner. The advantages of using NGS to investigate microbiomes surpass the traditional non-molecular methods that are limited in their sensitivity, and conventional molecular approaches that are limited in their scalability. In recent years the number of studies using NGS to investigate the microbial diversity and composition of ticks has expanded. Here, we provide a review of NGS strategies for tick microbiome studies and discuss the recent findings from tick NGS investigations, including the bacterial diversity and composition, influential factors, and implications of the tick microbiome.
The order Piroplasmida encompasses two main families: Babesiidae and Theileriidae, containing tick-borne pathogens of veterinary and medical importance worldwide. While only three genera (Babesia, ...Cytauxzoon and Theileria) comprising piroplasm parasites are currently recognised, phylogenetic studies at the 18S rRNA (18S) gene suggest that these organisms represent at least ten lineages, one of which comprises the relatively unique and highly diverse Theileria spp. from Australian marsupials and ticks. As an alternative to analysing 18S sequences alone, sequencing of mitochondrial genes has proven to be useful for the elucidation of evolutionary relationships amongst some groups of piroplasms. This research aimed to characterise piroplasms from Australian native mammals and ticks using multiple genetic markers (18S, cytochrome c, oxidase subunit III (cox3) and cytochrome B (cytB)) and microscopy. For this, nearly complete piroplasm-18S sequences were obtained from 32 animals belonging to six marsupial species: eastern bettong (Bettongia gaimardi), eastern quoll (Dasyurus viverrinus), eastern grey kangaroo (Macropus giganteus), swamp wallaby (Wallabia bicolor), quokka (Setonix brachyurus) and Gilbert's potoroo (Potorous gilbertii). The organisms detected represented eight novel Theileria genotypes, which formed five sub-clades within the main marsupial clade containing previously reported Australian marsupial and tick-derived Theileria spp. A selection of both novel and previously described Australian piroplasms at the 18S were also successfully characterised, for the first time, at the cox3 and cytB loci, and corroborated the position of Australian native theilerias in a separate, well-supported clade. Analyses of the cox3 and cytB genes also aided in the taxonomic resolution within the clade of Australian Piroplasmida. Importantly, microscopy and molecular analysis at multiple loci led to the discovery of a unique piroplasm species that clustered with the Australian marsupial theilerias, for which we propose the name Theileria lupei n. sp.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In developed nations, monitoring for drug-induced liver injury through serial measurements of serum transaminases aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in at-risk ...individuals is the standard of care. Despite the need, monitoring for drug-related hepatotoxicity in resource-limited settings is often limited by expense and logistics, even for patients at highest risk. This article describes the development and clinical testing of a paper-based, multiplexed microfluidic assay designed for rapid, semiquantitative measurement of AST and ALT in a fingerstick specimen. Using 223 clinical specimens obtained by venipuncture and 10 fingerstick specimens from healthy volunteers, we have shown that our assay can, in 15 min, provide visual measurements of AST and ALT in whole blood or serum, which allow the user to place those values into one of three readout "bins" <3× upper limit of normal (ULN), 3 to 5× ULN, and >5× ULN, corresponding to tuberculosis/HIV treatment guidelines with >90% accuracy. These data suggest that the ultimate point-of-care fingerstick device will have high impact on patient care in low-resource settings.
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