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Microbiology (Reading, England) May 2019The protozoan Cryptosporidium is notorious for its resistance to chlorine disinfection, a mainstay of water treatment. Human infections, mainly of the small intestine,...
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 -
Parasites & Vectors May 2015Toxoplasmosis, caused by the obligate intracellular protozoan Toxoplasma gondii, is an important zoonosis with medical and veterinary importance worldwide. The disease... (Review)
Review
Toxoplasmosis, caused by the obligate intracellular protozoan Toxoplasma gondii, is an important zoonosis with medical and veterinary importance worldwide. The disease is mainly contracted by ingesting undercooked or raw meat containing viable tissue cysts, or by ingesting food or water contaminated with oocysts. The diagnosis and genetic characterization of T. gondii infection is crucial for the surveillance, prevention and control of toxoplasmosis. Traditional approaches for the diagnosis of toxoplasmosis include etiological, immunological and imaging techniques. Diagnosis of toxoplasmosis has been improved by the emergence of molecular technologies to amplify parasite nucleic acids. Among these, polymerase chain reaction (PCR)-based molecular techniques have been useful for the genetic characterization of T. gondii. Serotyping methods based on polymorphic polypeptides have the potential to become the choice for typing T. gondii in humans and animals. In this review, we summarize conventional non-DNA-based diagnostic methods, and the DNA-based molecular techniques for the diagnosis and genetic characterization of T. gondii. These techniques have provided foundations for further development of more effective and accurate detection of T. gondii infection. These advances will contribute to an improved understanding of the epidemiology, prevention and control of toxoplasmosis.
Topics: Animals; Diagnostic Tests, Routine; Humans; Toxoplasma; Toxoplasmosis
PubMed: 26017718
DOI: 10.1186/s13071-015-0902-6 -
Frontiers in Cellular and Infection... 2021As a common parasitic disease in animals, coccidiosis substantially affects the health of the host, even in the absence of clinical symptoms and intestinal tract... (Review)
Review
As a common parasitic disease in animals, coccidiosis substantially affects the health of the host, even in the absence of clinical symptoms and intestinal tract colonization. Gut microbiota is an important part of organisms and is closely related to the parasite and host. Parasitic infections often have adverse effects on the host, and their pathogenic effects are related to the parasite species, parasitic site and host-parasite interactions. Coccidia-microbiota-host interactions represent a complex network in which changes in one link may affect the other two factors. Furthermore, coccidia-microbiota interactions are not well understood and require further research. Here, we discuss the mechanisms by which coccidia interact directly or indirectly with the gut microbiota and the effects on the host. Understanding the mechanisms underlying coccidia-microbiota-host interactions is important to identify new probiotic strategies for the prevention and control of coccidiosis.
Topics: Animals; Coccidia; Coccidiosis; Gastrointestinal Microbiome; Intestines; Microbiota
PubMed: 34660347
DOI: 10.3389/fcimb.2021.751481 -
Clinics in Laboratory Medicine Jun 2015The coccidians Cryptosporidium spp, Cyclospora cayetanensis, and Cystoisospora belli and the flagellate Giardia duodenalis are pathogenic protozoa associated with... (Review)
Review
The coccidians Cryptosporidium spp, Cyclospora cayetanensis, and Cystoisospora belli and the flagellate Giardia duodenalis are pathogenic protozoa associated with gastrointestinal manifestations. Diagnosis relies heavily on microscopy, and although ova-and-parasite examinations can detect Giardia and Cystoisospora, Cryptosporidium and Cyclospora often require specific diagnostic requests. Approved non-microscopy methods are available for Giardia and Cryptosporidium, although negative results are frequently followed by microscopic assays. Polymerase chain reaction-based methods are not frequently used for diagnosis of Giardia and Cryptosporidium and have been used primarily for epidemiologic or outbreak investigations of Giardia and Cryptosporidium.
Topics: Antigens, Protozoan; Coccidia; Coccidiosis; Diagnosis, Differential; Giardia lamblia; Giardiasis; Humans; Immunoassay; Sensitivity and Specificity; Specimen Handling
PubMed: 26004650
DOI: 10.1016/j.cll.2015.02.010 -
Clinical Microbiology and Infection :... Jan 2018
Topics: Aged; Diarrhea; Feces; Humans; Isospora; Isosporiasis; Male; Paraproteinemias
PubMed: 28712665
DOI: 10.1016/j.cmi.2017.07.009 -
International Journal For Parasitology Aug 2023The subclass Coccidia comprises a large group of protozoan parasites, including important pathogens of humans and animals such as Toxoplasma gondii, Neospora caninum,... (Review)
Review
The subclass Coccidia comprises a large group of protozoan parasites, including important pathogens of humans and animals such as Toxoplasma gondii, Neospora caninum, Eimeria spp., and Cystoisospora spp. Their life cycle includes a switch from asexual to sexual stages and is often restricted to a single host species. Current research on coccidian parasites focuses on cell biology and the underlying mechanisms of protein expression and trafficking in different life stages, host cell invasion and host-parasite interactions. Furthermore, novel anticoccidial drug targets are evaluated. Given the variety of research questions and the requirement to reduce and replace animal experimentation, in vitro cultivation of Coccidia needs to be further developed and refined to meet these requirements. For these purposes, established culture systems are constantly improved. In addition, new in vitro culture systems lately gained considerable importance in research on Coccidia. Well established and optimized in vitro cultures of monolayer cells can support the viability and development of parasite stages and even allow completion of the life cycle in vitro, as shown for Cystoisospora suis and Eimeria tenella. Furthermore, new three-dimensional cell culture models are used for propagation of Cryptosporidium spp. (close relatives of the coccidians), and the infection of three-dimensional organoids with T. gondii also gained popularity as the interaction between the parasite and host tissue can be studied in more detail. The latest advances in three-dimensional culture systems are organ-on-a-chip models, that to date have only been tested for T. gondii but promise to accelerate research in other coccidians. Lastly, the completion of the life cycle of C. suis and Cryptosporidium parvum was reported to continue in a host cell-free environment following the first occurrence of asexual stages. Such axenic cultures are becoming increasingly available and open new avenues for research on parasite life cycle stages and novel intervention strategies.
Topics: Animals; Humans; Parasites; Cryptosporidiosis; Cryptosporidium; Toxoplasma; Sarcocystidae; Life Cycle Stages
PubMed: 36400306
DOI: 10.1016/j.ijpara.2022.10.002 -
Folia Parasitologica Sep 2009This article summarises the current knowledge of the rabbit coccidia and the disease they cause. Various aspects, such as life cycles, localisation in the host,... (Review)
Review
This article summarises the current knowledge of the rabbit coccidia and the disease they cause. Various aspects, such as life cycles, localisation in the host, pathology and pathogenicity, immunity and control, are discussed.
Topics: Animals; Coccidiosis; Eimeria; Rabbits
PubMed: 19827358
DOI: 10.14411/fp.2009.019 -
Nature Communications Mar 2023The apical complex is a specialized collection of cytoskeletal and secretory machinery in apicomplexan parasites, which include the pathogens that cause malaria and...
The apical complex is a specialized collection of cytoskeletal and secretory machinery in apicomplexan parasites, which include the pathogens that cause malaria and toxoplasmosis. Its structure and mechanism of motion are poorly understood. We used cryo-FIB-milling and cryo-electron tomography to visualize the 3D-structure of the apical complex in its protruded and retracted states. Averages of conoid-fibers revealed their polarity and unusual nine-protofilament arrangement with associated proteins connecting and likely stabilizing the fibers. Neither the structure of the conoid-fibers nor the architecture of the spiral-shaped conoid complex change during protrusion or retraction. Thus, the conoid moves as a rigid body, and is not spring-like and compressible, as previously suggested. Instead, the apical-polar-rings (APR), previously considered rigid, dilate during conoid protrusion. We identified actin-like filaments connecting the conoid and APR during protrusion, suggesting a role during conoid movements. Furthermore, our data capture the parasites in the act of secretion during conoid protrusion.
Topics: Toxoplasma; Neospora; Electron Microscope Tomography; Tubulin; Cytoskeleton; Cell Membrane
PubMed: 36997532
DOI: 10.1038/s41467-023-37327-w -
Parasitology Research Jul 2019Coccidiosis is a parasitic disease of a wide variety of animals caused by coccidian protozoa. The coccidia are responsible for major economic losses of the livestock... (Review)
Review
Coccidiosis is a parasitic disease of a wide variety of animals caused by coccidian protozoa. The coccidia are responsible for major economic losses of the livestock industry. For example, the annual cost due to coccidiosis to the global poultry industry has been estimated to exceed US$ 3 billion annually. Currently available drugs for the control of this disease are either polyether ionophorous antibiotics that are derived from fermentation products, or synthetic compounds, produced by chemical synthesis. Unfortunately, no new drugs in either category have been approved for use for decades. Resistance has been documented for all those of the drugs currently employed and therefore the discovery of novel drugs with unique modes of action is imperative if chemotherapy is to remain the principal means to control this disease. This chapter aims to give an overview of the efficacy and mode of action of the current compounds used to control coccidiosis in livestock and provides a brief outlook of research needs for the future.
Topics: Animals; Coccidia; Coccidiosis; Coccidiostats; Livestock; Poultry; Poultry Diseases
PubMed: 31152233
DOI: 10.1007/s00436-019-06343-5 -
Advances in Parasitology 1988In this review I have examined the vast literature which has accumulated on Cryptosporidium, particularly in the past 3 years, in an attempt to highlight areas in which... (Review)
Review
In this review I have examined the vast literature which has accumulated on Cryptosporidium, particularly in the past 3 years, in an attempt to highlight areas in which progress has been made in relation to the organism and the disease, and to indicate areas in which knowledge is still lacking. Since 1982, a global effort by scientists and clinicians has been directed towards determining the nature of the disease in humans and the relative contribution of cryptosporidiosis to gastroenteritis. From published data, the incidence of diarrhoea is 1-5% in most developed countries, and 4-7% in less developed countries, when measured throughout the year and in all age groups. The frequency of cryptosporidiosis is highest in children aged between 6 months and 3 years, and in particular locations (e.g., day-care centres) and at particular times of the year. Although susceptibility to infection is life-long, one suspects that the lower prevalence among older children and adults is due to immunity acquired from frequent exposure. Other important factors contributing to higher prevalence are the season--it is more frequent in a wet, warm climate--association with travel to particular destinations, poor hygiene, intimate contact with certain animals, and congregation of large numbers of young previously unexposed children in day-care centres. The association between cryptosporidiosis and giardiasis presumably results from the existence of a common source of infection. The immune status of the host appears to be a major determinant of whether the infection is self-limiting or persistent. It is clear that both branches of the immune system are required for complete recovery, since T-lymphocyte dysfunction or hypogammaglobulinaemia can both lead to persistent illness. Chronic diarrhoea and malabsorption attributed to cryptosporidiosis also occur in the absence of evidence of immune defect. The importance of respiratory tract infection in humans, other than in the terminal stages of chronic illness, requires investigation. The infection has now been identified in all classes of vertebrates; it has been observed in all domestic animals including pets, and a wide range of wildlife including birds. Cryptosporidiosis seems to cause diarrhoea in young ruminants, less frequently in pets. In birds the parasite has been observed in the gastrointestinal tract, without ill effect, and in the respiratory tract, in which clinical symptoms of variable severity have been described. The mucosal response of the gastrointestinal tract to infection appears to vary among mammals and may be the key to the variable clinical manifestations observed.(ABSTRACT TRUNCATED AT 400 WORDS)
Topics: Acquired Immunodeficiency Syndrome; Animals; Cell Line; Coccidia; Cryptosporidiosis; Cryptosporidium; Diarrhea; Humans; Immune Tolerance; Respiratory Tract Infections
PubMed: 3289331
DOI: 10.1016/s0065-308x(08)60353-x