Authors: Rachel M Chalmers, Angharad P Davies, Kevin Tyler...

The protozoan Cryptosporidium is notorious for its resistance to chlorine disinfection, a mainstay of water treatment. Human infections, mainly of the small intestine, arise from consumption of faecally contaminated food or water, environmental exposure, and person-to-person or animal-to-person spread. Acute gastrointestinal symptoms can be prolonged but are usually self-limiting. Problems arise with immune-deficient, including malnourished, people including chronic diarrhoea, hepato-biliary tree and extra-gastrointestinal site infection, and few options for treatment or prevention exist. Although genomics has enabled refined classification, identification of chemotherapeutic targets and vaccine candidates, and putative factors for host adaption and pathogenesis, their confirmation has been hampered by a lack of biological tools.

Topics: Animals; Cryptosporidiosis; Cryptosporidium; Genome, Protozoan; Humans; Phylogeny

PubMed: 31268415
DOI: 10.1099/mic.0.000764

Review

Authors: Giovanni Widmer, David Carmena, Martin Kváč...

While cryptosporidiosis is recognized as being among the most common causes of human parasitic diarrhea in the world, there is currently limited knowledge on Cryptosporidium infection mechanisms, incomplete codification of diagnostic methods, and a need for additional therapeutic options. In response, the Seventh International Giardia and Cryptosporidium Conference (IGCC 2019) was hosted from 23 to 26 June 2019, at the Rouen Normandy University, France. This trusted event brought together an international delegation of researchers to synthesize recent advances and identify key research questions and knowledge gaps. The program of the interdisciplinary conference included all aspects of host-parasite relationships from basic research to applications to human and veterinary medicine, and environmental issues associated with waterborne parasites and their epidemiological consequences. In relation to Cryptosporidium and cryptosporidiosis, the primary research areas for which novel findings and the most impressive communications were presented and discussed included: Cryptosporidium in environmental waters, seafood, and fresh produce; Animal epidemiology; Human cryptosporidiosis and epidemiology; Genomes and genomic evolution encompassing: Comparative genomics of Cryptosporidium spp., Genomic insights into biology, Acquiring and utilizing genome sequences, Genetic manipulation; Host-parasite interaction (immunology, microbiome); and Diagnosis and treatment. High quality presentations discussed at the conference reflected decisive progress and identified new opportunities that will engage investigators and funding agencies to spur future research in a "one health" approach to improve basic knowledge and the clinical and public health management of zoonotic cryptosporidiosis.

Topics: Animals; Congresses as Topic; Cryptosporidiosis; Cryptosporidium; Diarrhea; Feces; France; Genotype; Giardia; Giardiasis; Humans; One Health

PubMed: 32167464
DOI: 10.1051/parasite/2020011

Review

Authors: Amandine Guérin, Boris Striepen

Cryptosporidium emerged as a leading global cause of severe diarrheal disease in children. The parasite occupies a unique intracellular niche at the brush border of intestinal epithelial cells, where it undergoes a complex sexual life cycle. How this life cycle unfolds and how host and parasite interact remain largely to be discovered. A series of technical advances now offer genetic and immunological tools for mechanistic investigation of the parasite. Here we introduce the pathogen and disease and highlight important questions to tackle onward. We invite scientists to consider this versatile parasite model to probe the biology and immunology of the intestine.

Topics: Cryptosporidiosis; Cryptosporidium; Cytoplasm; Epithelial Cells; Female; Host Specificity; Host-Parasite Interactions; Humans; Intestinal Diseases, Parasitic; Intestines; Male; Microvilli

PubMed: 33031769
DOI: 10.1016/j.chom.2020.09.007

Authors: Marion Lefebvre, Romy Razakandrainibe, Damien Schapman...

Free-Living Amebae (FLA) and Cryptosporidium oocysts occasionally share the same environment. From 2004 to 2016, Cryptosporidium was responsible for 60% of 905 worldwide waterborne outbreaks caused by protozoan parasites. The aim of this study was to evaluate interactions between C. parvum oocysts and two common FLAs (Acanthamoeba castellanii and Vermamoeba vermiformis) in a water environment. Encystment and survival of FLAs were evaluated by microscopy using trypan blue vital coloration. Oocysts were numerated on microscopy. Interactions were studied over time in conditions both unfavorable and favorable to phagocytosis. Potential phagocytosis was directly evaluated by several microscopic approaches and indirectly by numeration of microorganisms and oocyst infectivity evaluation. Occasional phagocytosis of C. parvum by FLAs was documented. However, oocyst concentrations did not decrease significantly, suggesting resistance of oocysts to phagocytosis. A temporary decrease of oocyst infectivity was observed in the presence of A. castellanii. The effect of these interactions on C. parvum infectivity is particularly interesting. The biofilm condition could favor the persistence or even the proliferation of oocysts over time. This study demonstrated interactions between C. parvum and FLAs. Further knowledge of the mechanisms involved in the decrease of oocyst infectivity in the presence of A. castellanii could facilitate the development of new therapeutic approaches.

Topics: Animals; Cryptosporidium parvum; Amoeba; Cryptosporidium; Cryptosporidiosis; Disease Outbreaks; Oocysts

PubMed: 37606589
DOI: 10.1051/parasite/2023033

Authors: Sebastian Shaw, Ian S Cohn, Rodrigo P Baptista...

Parasites and their hosts are engaged in reciprocal coevolution that balances competing mechanisms of virulence, resistance, and evasion. This often leads to host specificity, but genomic reassortment between different strains can enable parasites to jump host barriers and conquer new niches. In the apicomplexan parasite , genetic exchange has been hypothesized to play a prominent role in adaptation to humans. The sexual lifecycle of the parasite provides a potential mechanism for such exchange; however, the boundaries of sex are currently undefined. To explore this experimentally, we established a model for genetic crosses. Drug resistance was engineered using a mutated phenylalanyl tRNA synthetase gene and marking strains with this and the previously used Neo transgene enabled selection of recombinant progeny. This is highly efficient, and genomic recombination is evident and can be continuously monitored in real time by drug resistance, flow cytometry, and PCR mapping. Using this approach, multiple loci can now be modified with ease. We demonstrate that essential genes can be ablated by crossing a Cre recombinase driver strain with floxed strains. We further find that genetic crosses are also feasible between species. Crossing a parasite of cattle and humans, and a mouse parasite resulted in progeny with a recombinant genome derived from both species that continues to vigorously replicate sexually. These experiments have important fundamental and translational implications for the evolution of and open the door to reverse- and forward-genetic analysis of parasite biology and host specificity.

Topics: Crosses, Genetic; Cryptosporidiosis; Cryptosporidium; Cryptosporidium parvum; Life Cycle Stages

PubMed: 38147547
DOI: 10.1073/pnas.2313210120

Review

Authors: Maha Bouzid, Paul R Hunter, Rachel M Chalmers...

Cryptosporidium is a protozoan parasite of medical and veterinary importance that causes gastroenteritis in a variety of vertebrate hosts. Several studies have reported different degrees of pathogenicity and virulence among Cryptosporidium species and isolates of the same species as well as evidence of variation in host susceptibility to infection. The identification and validation of Cryptosporidium virulence factors have been hindered by the renowned difficulties pertaining to the in vitro culture and genetic manipulation of this parasite. Nevertheless, substantial progress has been made in identifying putative virulence factors for Cryptosporidium. This progress has been accelerated since the publication of the Cryptosporidium parvum and C. hominis genomes, with the characterization of over 25 putative virulence factors identified by using a variety of immunological and molecular techniques and which are proposed to be involved in aspects of host-pathogen interactions from adhesion and locomotion to invasion and proliferation. Progress has also been made in the contribution of host factors that are associated with variations in both the severity and risk of infection. Here we provide a review comprised of the current state of knowledge on Cryptosporidium infectivity, pathogenesis, and transmissibility in light of our contemporary understanding of microbial virulence.

Topics: Animals; Cryptosporidiosis; Cryptosporidium; Gastroenteritis; Host-Pathogen Interactions; Humans; Virulence; Virulence Factors

PubMed: 23297262
DOI: 10.1128/CMR.00076-12

Authors: Jahid Hasan Tipu, Audun Sivertsen, Jan-Egil Afset...

PCR-based diagnostics has revealed the previously largely unknown transmission and infections in high-income countries. This study aimed to determine domestic and imported subtypes of species in Norway, evaluate their demographic distribution, and identify potential small outbreaks. -positive human faecal samples were obtained from six medical microbiology laboratories between February 2022 and January 2024, together with 22 -positive animal samples. Species and subtypes were identified by sequencing PCR products from gp60 and SSU rRNA genes. Most cryptosporidiosis cases occurred during late summer/early autumn, primarily in children and young adults. Of 550 human samples, 359 were successfully characterized molecularly (65%), revealing infection with 10 different species. occurred in 245 (68%) human isolates with IIa and IId being major allele families, with distinct regional distribution patterns of common subtypes. A kindergarten outbreak with 5 cases was due to IIaA14G1R1. was identified in 33 (9.2%) human cases of which 24 were known to be of domestic origin, making it the second most common species in human autochthonous cases in Norway. All isolates were of the same genotype; XIVaA20G2T1, including 13 cases from a suspected small outbreak in Trøndelag. occurred in 68 typed cases (19%), but mostly in infections acquired abroad, with allele families Ib and If occurring most often. In conclusion, this study of recent spp. and subtypes in Norway, highlights the predominance of and the emergence of among autochthonous cases.

Topics: Cryptosporidiosis; Humans; Norway; Cryptosporidium; Child; Child, Preschool; Adult; Feces; Genotype; Animals; Female; Male; Adolescent; Young Adult; Infant; Middle Aged; Phylogeny; Disease Outbreaks; Aged; Cryptosporidium parvum; DNA, Protozoan

PubMed: 39361548
DOI: 10.1080/22221751.2024.2412624

Review

Authors: Seema Bhalchandra, Hymlaire Lamisere, Honorine Ward...

Cryptosporidium is a leading cause of diarrhea and death in young children and untreated AIDS patients in resource-poor settings, and of waterborne outbreaks of disease in developed countries. However, there is no consistently effective treatment for vulnerable populations. Progress towards development of therapeutics for cryptosporidiosis has been hampered by lack of optimal culture systems to study it. New advances in organoid/enteroid technology have contributed to improved platforms to culture and propagate Cryptosporidium. Here we discuss recent breakthroughs in the field and highlight different models for functional ex vivo organoid or enteroidderived culture systems. These systems will lead to a better understanding of the mechanisms of host-parasite interactions in vivo.

Topics: Animals; Cell Culture Techniques; Cryptosporidiosis; Cryptosporidium; Humans; Intestines; Models, Biological; Organoids

PubMed: 33113480
DOI: 10.1016/j.mib.2020.10.002

Review

Authors: Ross G Douglas, Robert W Moon, Friedrich Frischknecht...

Apicomplexan parasites are a group of eukaryotic protozoans with diverse biology that have affected human health like no other group of parasites. These obligate intracellular parasites rely on their cytoskeletal structures for giving them form, enabling them to replicate in unique ways and to migrate across tissue barriers. Recent progress in transgenesis and imaging tools allowed detailed insights into the components making up and regulating the actin and microtubule cytoskeleton as well as the alveolate-specific intermediate filament-like cytoskeletal network. These studies revealed interesting details that deviate from the cell biology of canonical model organisms. Here we review the latest developments in the field and point to a number of open questions covering the most experimentally tractable parasites: , the causative agent of malaria; , the causative agent of toxoplasmosis; and , a major cause of diarrhea.

Topics: Cytoskeleton; Humans; Toxoplasma; Animals; Apicomplexa; Plasmodium; Microtubules; Cryptosporidium

PubMed: 39094056
DOI: 10.1146/annurev-micro-041222-011539

Authors: Bethan A Wallbank, Ryan D Pardy, Igor E Brodsky...

UNLABELLED

Infection with the apicomplexan parasite is a leading cause of diarrheal disease. Cryptosporidiosis is of particular importance in infants and shows a strong association with malnutrition, both as a risk factor and as a consequence. invades and replicates within the small intestine epithelial cells. This is a highly dynamic tissue that is developmentally stratified along the villus axis. New cells emerge from a stem cell niche in the crypt and differentiate into mature epithelial cells while moving toward the villus tip, where they are ultimately shed. Here, we studied the impact of infection on this dynamic architecture. Tracing DNA synthesis in pulse-chase experiments we quantified the genesis and migration of epithelial cells along the villus. We found proliferation and epithelial migration to be elevated in response to infection. Infection also resulted in significant cell loss documented by imaging and molecular assays. Consistent with these observations, single-cell RNA sequencing of infected intestines showed a gain of young and a loss of mature cells. Interestingly, enhanced epithelial cell loss was not a function of enhanced apoptosis of infected cells. To the contrary, -infected cells were less likely to be apoptotic than bystanders, and experiments in tissue culture demonstrated that infection provided enhanced resistance to chemically induced apoptosis to the host but not bystander cells. Overall, this study suggests that may modulate cell apoptosis and documents pronounced changes in tissue homeostasis due to parasite infection, which may contribute to its long-term impact on the developmental and nutritional state of children.

IMPORTANCE

The intestine must balance its roles in digestion and nutrient absorption with the maintenance of an effective barrier to colonization and breach by numerous potential pathogens. An important component of this balance is its constant turnover, which is modulated by a gain of cells due to proliferation and loss due to death or extrusion. Here, we report that infection changes the dynamics of this process increasing both gain and loss of enterocytes speeding up the villus elevator. This leads to a much more immature epithelium and a reduction of the number of those cells typically found toward the villus apex best equipped to take up key nutrients including carbohydrates and lipids. These changes in the cellular architecture and physiology of the small intestine may be linked to the profound association between cryptosporidiosis and malnutrition.

Topics: Cryptosporidiosis; Animals; Epithelial Cells; Cryptosporidium; Mice; Intestinal Mucosa; Apoptosis; Humans; Cell Proliferation; Cell Movement; Intestine, Small

PubMed: 38995074
DOI: 10.1128/mbio.01720-24