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Gunasekera S, Clode PL, King B, Monis P, Thierry B, Carr JM, Chopra A, Watson M, O'Dea M, Hijjawi N, Ryan U. Comparison of in vitro growth characteristics of Cryptosporidium hominis (IdA15G1) and Cryptosporidium parvum (Iowa-IIaA17G2R1 and IIaA18G3R1). Parasitol Res 2023; 122:2891-2905. [PMID: 37776335 PMCID: PMC10667462 DOI: 10.1007/s00436-023-07979-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 09/14/2023] [Indexed: 10/02/2023]
Abstract
Cryptosporidium is a major cause of diarrhoeal disease and mortality in young children in resource-poor countries, for which no vaccines or adequate therapeutic options are available. Infection in humans is primarily caused by two species: C. hominis and C. parvum. Despite C. hominis being the dominant species infecting humans in most countries, very little is known about its growth characteristics and life cycle in vitro, given that the majority of our knowledge of the in vitro development of Cryptosporidium has been based on C. parvum. In the present study, the growth and development of two C. parvum isolates (subtypes Iowa-IIaA17G2R1 and IIaA18G3R1) and one C. hominis isolate (subtype IdA15G1) in HCT-8 cells were examined and compared at 24 h and 48 h using morphological data acquired with scanning electron microscopy. Our data indicated no significant differences in the proportion of meronts or merozoites between species or subtypes at either time-point. Sexual development was observed at the 48-h time-point across both species through observations of both microgamonts and macrogamonts, with a higher frequency of macrogamont observations in C. hominis (IdA15G1) cultures at 48-h post-infection compared to both C. parvum subtypes. This corresponded to differences in the proportion of trophozoites observed at the same time point. No differences in proportion of microgamonts were observed between the three subtypes, which were rarely observed across all cultures. In summary, our data indicate that asexual development of C. hominis is similar to that of C. parvum, while sexual development is accelerated in C. hominis. This study provides new insights into differences in the in vitro growth characteristics of C. hominis when compared to C. parvum, which will facilitate our understanding of the sexual development of both species.
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Affiliation(s)
- Samantha Gunasekera
- Harry Butler Institute, College of Environmental and Life Sciences, Murdoch University, Murdoch, Western Australia, 6150, Australia.
| | - Peta L Clode
- Centre for Microscopy, Characterisation, and Analysis and School of Biological Sciences, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Brendon King
- South Australian Water Corporation, Adelaide, South Australia, 5000, Australia
| | - Paul Monis
- South Australian Water Corporation, Adelaide, South Australia, 5000, Australia
| | - Benjamin Thierry
- Future Industries Institute, University of South Australia, Adelaide, South Australia, 5095, Australia
| | - Jillian M Carr
- College of Medicine and Public Health, Flinders Health and Medical Research Institute, Flinders University, Bedford Park, South Australia, 5042, Australia
| | - Abha Chopra
- Immunology and Infectious Diseases, Murdoch University, Murdoch, Western Australia, 6150, Australia
| | - Mark Watson
- Immunology and Infectious Diseases, Murdoch University, Murdoch, Western Australia, 6150, Australia
| | - Mark O'Dea
- Harry Butler Institute, College of Environmental and Life Sciences, Murdoch University, Murdoch, Western Australia, 6150, Australia
| | - Nawal Hijjawi
- Department of Medical Laboratory Sciences, Faculty of Applied Health Sciences, The Hashemite University, P.O. Box 150459, Zarqa, 13115, Jordan
| | - Una Ryan
- Harry Butler Institute, College of Environmental and Life Sciences, Murdoch University, Murdoch, Western Australia, 6150, Australia.
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In Vitro Susceptibility of Cryptosporidium parvum to Plant Antiparasitic Compounds. Pathogens 2022; 12:pathogens12010061. [PMID: 36678409 PMCID: PMC9863366 DOI: 10.3390/pathogens12010061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/20/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022] Open
Abstract
Cryptosporidium parvum is a significant cause of watery diarrhoea in humans and other animals worldwide. Although hundreds of novel drugs have been evaluated, no effective specific chemotherapeutic intervention for C. parvum has been reported. There has been much recent interest in evaluating plant-derived products in the fight against gastrointestinal parasites, including C. parvum. This study aimed to identify extracts from 13 different plant species that provide evidence for inhibiting the growth of C. parvum in vitro. Efficacy against C. parvum was detected and quantified using quantitative PCR and immunofluorescence assays. All plant extracts tested against C. parvum showed varying inhibition activities in vitro, and none of them produced a cytotoxic effect on HCT-8 cells at concentrations up to 500 µg/mL. Four plant species with the strongest evidence of activity against C. parvum were Curcuma longa, Piper nigrum, Embelia ribes, and Nigella sativa, all with dose-dependent efficacy. To the authors' knowledge, this is the first time that these plant extracts have proven to be experimentally efficacious against C. parvum. These results support further exploration of these plants and their compounds as possible treatments for Cryptosporidium infections.
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Cryptosporidiosis: From Prevention to Treatment, a Narrative Review. Microorganisms 2022; 10:microorganisms10122456. [PMID: 36557709 PMCID: PMC9782356 DOI: 10.3390/microorganisms10122456] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/02/2022] [Accepted: 12/06/2022] [Indexed: 12/15/2022] Open
Abstract
Cryptosporidiosis is a water- and food-borne zoonotic disease caused by the protozoon parasite of the genus Cryptosporidium. C. hominis and C. parvum are the main two species causing infections in humans and animals. The disease can be transmitted by the fecal-oral route as well as the respiratory route. The infective stage (sporulated oocysts) is resistant to different disinfectants including chlorine. Currently, no effective therapeutic drugs or vaccines are available to treat and control Cryptosporidium infection. To prevent cryptosporidiosis in humans and animals, we need to understand better how the disease is spread and transmitted, and how to interrupt its transmission cycle. This review focuses on understanding cryptosporidiosis, including its infective stage, pathogenesis, life cycle, genomics, epidemiology, previous outbreaks, source of the infection, transmission dynamics, host spectrum, risk factors and high-risk groups, the disease in animals and humans, diagnosis, treatment and control, and the prospect of an effective anti-Cryptosporidium vaccine. It also focuses on the role of the One Health approach in managing cryptosporidiosis at the animal-human-environmental interface. The summarized data in this review will help to tackle future Cryptosporidium infections in humans and animals and reduce the disease occurrence.
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In vitro cultivation methods for coccidian parasite research. Int J Parasitol 2022:S0020-7519(22)00153-9. [DOI: 10.1016/j.ijpara.2022.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/29/2022] [Accepted: 10/09/2022] [Indexed: 11/17/2022]
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Cryptosporidium and colorectal cancer: a review of epidemiology and possible association. FORUM OF CLINICAL ONCOLOGY 2022. [DOI: 10.2478/fco-2021-0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Cryptosporidiosis is an important protozoan disease with serious public health implications. The contribution of Cryptosporidium to colorectal cancer is still vaguely studied, but little evidence from experimental and epidemiological studies has suggested a possible association. This review discusses the epidemiology of cryptosporidiosis and colorectal cancer and attempts to unravel the possible link between the two diseases using epidemiological, pathological, molecular, and immunological evidence. The review stressed the need to undertake more studies in this relatively neglected field.
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Ryan UM, Feng Y, Fayer R, Xiao L. Taxonomy and molecular epidemiology of Cryptosporidium and Giardia - a 50 year perspective (1971-2021). Int J Parasitol 2021; 51:1099-1119. [PMID: 34715087 DOI: 10.1016/j.ijpara.2021.08.007] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/25/2021] [Accepted: 08/31/2021] [Indexed: 12/11/2022]
Abstract
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.
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Affiliation(s)
- Una M Ryan
- Harry Butler Institute, Murdoch University, Perth, Western Australia, Australia.
| | - Yaoyu Feng
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong, China
| | - Ronald Fayer
- Environmental Microbial and Food Safety Laboratory, Agricultural Research Service, United States Department of Agriculture, 10300 Baltimore Avenue, BARC-East, Building 173, Beltsville, MD 20705, USA
| | - Lihua Xiao
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong, China
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Cruz-Bustos T, Feix AS, Ruttkowski B, Joachim A. Sexual Development in Non-Human Parasitic Apicomplexa: Just Biology or Targets for Control? Animals (Basel) 2021; 11:ani11102891. [PMID: 34679913 PMCID: PMC8532714 DOI: 10.3390/ani11102891] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 12/17/2022] Open
Abstract
Simple Summary Cellular reproduction is a key part of the apicomplexan life cycle, and both mitotic (asexual) and meiotic (sexual) cell divisions produce new individual cells. Sexual reproduction in most eukaryotic taxa indicates that it has had considerable success during evolution, and it must confer profound benefits, considering its significant costs. The phylum Apicomplexa consists of almost exclusively parasitic single-celled eukaryotic organisms that can affect a wide host range of animals from invertebrates to mammals. Their development is characterized by complex steps in which asexual and sexual replication alternate and the fertilization of a macrogamete by a microgamete results in the formation of a zygote that undergoes meiosis, thus forming a new generation of asexual stages. In apicomplexans, sex is assumed to be induced by the (stressful) condition of having to leave the host, and either gametes or zygotes (or stages arising from it) are transmitted to a new host. Therefore, sex and meiosis are linked to parasite transmission, and consequently dissemination, which are key to the parasitic lifestyle. We hypothesize that improved knowledge of the sexual biology of the Apicomplexa will be essential to design and implement effective transmission-blocking strategies for the control of the major parasites of this group. Abstract The phylum Apicomplexa is a major group of protozoan parasites including gregarines, coccidia, haemogregarines, haemosporidia and piroplasms, with more than 6000 named species. Three of these subgroups, the coccidia, hemosporidia, and piroplasms, contain parasites that cause important diseases of humans and animals worldwide. All of them have complex life cycles involving a switch between asexual and sexual reproduction, which is key to their development. Fertilization (i.e., fusion of female and male cells) results in the formation of a zygote that undergoes meiosis, forming a new generation of asexual stages. In eukaryotes, sexual reproduction is the predominant mode of recombination and segregation of DNA. Sex is well documented in many protist groups, and together with meiosis, is frequently linked with transmission to new hosts. Apicomplexan sexual stages constitute a bottleneck in the life cycle of these parasites, as they are obligatory for the development of new transmissible stages. Consequently, the sexual stages represent attractive targets for vaccination. Detailed understanding of apicomplexan sexual biology will pave the way for the design and implementation of effective transmission-blocking strategies for parasite control. This article reviews the current knowledge on the sexual development of Apicomplexa and the progress in transmission-blocking vaccines for their control, their advantages and limitations and outstanding questions for the future.
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Gunasekera S, Zahedi A, O’Dea M, King B, Monis P, Thierry B, M. Carr J, Ryan U. Organoids and Bioengineered Intestinal Models: Potential Solutions to the Cryptosporidium Culturing Dilemma. Microorganisms 2020; 8:microorganisms8050715. [PMID: 32403447 PMCID: PMC7285185 DOI: 10.3390/microorganisms8050715] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/06/2020] [Accepted: 05/08/2020] [Indexed: 12/19/2022] Open
Abstract
Cryptosporidium is a major cause of severe diarrhea-related disease in children in developing countries, but currently no vaccine or effective treatment exists for those who are most at risk of serious illness. This is partly due to the lack of in vitro culturing methods that are able to support the entire Cryptosporidium life cycle, which has led to research in Cryptosporidium biology lagging behind other protozoan parasites. In vivo models such as gnotobiotic piglets are complex, and standard in vitro culturing methods in transformed cell lines, such as HCT-8 cells, have not been able to fully support fertilization occurring in vitro. Additionally, the Cryptosporidium life cycle has also been reported to occur in the absence of host cells. Recently developed bioengineered intestinal models, however, have shown more promising results and are able to reproduce a whole cycle of infectivity in one model system. This review evaluates the recent advances in Cryptosporidium culturing techniques and proposes future directions for research that may build upon these successes.
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Affiliation(s)
- Samantha Gunasekera
- Vector and Waterborne Pathogens Research Group, College of Science, Health, Engineering and Education, Murdoch University, Murdoch 6150, Western Australia, Australia;
- Correspondence: (S.G.); (U.R.); Tel.: +61-8-9360-2495 (S.G.); +61-8-9360-2482 (U.R.)
| | - Alireza Zahedi
- Vector and Waterborne Pathogens Research Group, College of Science, Health, Engineering and Education, Murdoch University, Murdoch 6150, Western Australia, Australia;
| | - Mark O’Dea
- Antimicrobial Resistance and Infectious Diseases Laboratory, College of Science, Health, Engineering and Education, Murdoch University, Murdoch 6150, Western Australia, Australia; m.o’
| | - Brendon King
- South Australian Water Corporation, Adelaide 5000, South Australia, Australia; (B.K.); (P.M.)
- College of Medicine and Public Health, Flinders University, Adelaide 5042, South Australia, Australia;
| | - Paul Monis
- South Australian Water Corporation, Adelaide 5000, South Australia, Australia; (B.K.); (P.M.)
- Future Industries Institute and ARC Centre of Excellence for Convergent Bio and Nano Science, University of South Australia, Adelaide 5095, South Australia, Australia;
| | - Benjamin Thierry
- Future Industries Institute and ARC Centre of Excellence for Convergent Bio and Nano Science, University of South Australia, Adelaide 5095, South Australia, Australia;
| | - Jillian M. Carr
- College of Medicine and Public Health, Flinders University, Adelaide 5042, South Australia, Australia;
| | - Una Ryan
- Vector and Waterborne Pathogens Research Group, College of Science, Health, Engineering and Education, Murdoch University, Murdoch 6150, Western Australia, Australia;
- Correspondence: (S.G.); (U.R.); Tel.: +61-8-9360-2495 (S.G.); +61-8-9360-2482 (U.R.)
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Bones AJ, Jossé L, More C, Miller CN, Michaelis M, Tsaousis AD. Past and future trends of Cryptosporidium in vitro research. Exp Parasitol 2018; 196:28-37. [PMID: 30521793 PMCID: PMC6333944 DOI: 10.1016/j.exppara.2018.12.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 11/09/2018] [Accepted: 12/02/2018] [Indexed: 12/15/2022]
Abstract
Cryptosporidium is a genus of single celled parasites capable of infecting a wide range of animals including humans. Cryptosporidium species are members of the phylum apicomplexa, which includes well-known genera such as Plasmodium and Toxoplasma. Cryptosporidium parasites cause a severe gastro-intestinal disease known as cryptosporidiosis. They are one of the most common causes of childhood diarrhoea worldwide, and infection can have prolonged detrimental effects on the development of children, but also can be life threatening to HIV/AIDS patients and transplant recipients. A variety of hosts can act as reservoirs, and Cryptosporidium can persist in the environment for prolonged times as oocysts. While there has been substantial interest in these parasites, there is very little progress in terms of treatment development and understanding the majority of the life cycle of this unusual organism. In this review, we will provide an overview on the existing knowledge of the biology of the parasite and the current progress in developing in vitro cultivation systems. We will then describe a synopsis of current and next generation approaches that could spearhead further research in combating the parasite.
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Affiliation(s)
- Alexander J Bones
- Laboratory of Molecular and Evolutionary Parasitology, RAPID Group, School of Biosciences, University of Kent, Canterbury, Kent, UK
| | - Lyne Jossé
- Laboratory of Molecular and Evolutionary Parasitology, RAPID Group, School of Biosciences, University of Kent, Canterbury, Kent, UK
| | - Charlotte More
- Laboratory of Molecular and Evolutionary Parasitology, RAPID Group, School of Biosciences, University of Kent, Canterbury, Kent, UK
| | - Christopher N Miller
- Laboratory of Molecular and Evolutionary Parasitology, RAPID Group, School of Biosciences, University of Kent, Canterbury, Kent, UK
| | | | - Anastasios D Tsaousis
- Laboratory of Molecular and Evolutionary Parasitology, RAPID Group, School of Biosciences, University of Kent, Canterbury, Kent, UK; School of Biosciences, University of Kent, Canterbury, Kent, UK.
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Melicherová J, Hofmannová L, Valigurová A. Response of cell lines to actual and simulated inoculation with Cryptosporidium proliferans. Eur J Protistol 2017; 62:101-121. [PMID: 29316479 DOI: 10.1016/j.ejop.2017.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 12/08/2017] [Accepted: 12/13/2017] [Indexed: 10/18/2022]
Abstract
The need for an effective treatment against cryptosporidiosis has triggered studies in the search for a working in vitro model. The peculiar niche of cryptosporidia at the brush border of host epithelial cells has been the subject of extensive debates. Despite extensive research on the invasion process, it remains enigmatic whether cryptosporidian host-parasite interactions result from an active invasion process or through encapsulation. We used HCT-8 and HT-29 cell lines for in vitro cultivation of the gastric parasite Cryptosporidium proliferans strain TS03. Using electron and confocal laser scanning microscopy, observations were carried out 24, 48 and 72 h after inoculation with a mixture of C. proliferans oocysts and sporozoites. Free sporozoites and putative merozoites were observed apparently searching for an appropriate infection site. Advanced stages, corresponding to trophozoites and meronts/gamonts enveloped by parasitophorous sac, and emptied sacs were detected. As our observations showed that even unexcysted oocysts became enveloped by cultured cell projections, using polystyrene microspheres, we evaluated the response of cell lines to simulated inoculation with cryptosporidian oocysts to verify innate and parasite-induced behaviour. We found that cultured cell encapsulation of oocysts is induced by parasite antigens, independent of any active invasion/motility.
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Affiliation(s)
- Janka Melicherová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
| | - Lada Hofmannová
- Department of Pathological Morphology and Parasitology, University of Veterinary and Pharmaceutical Sciences, Palackého tř. 1946/1, 612 42 Brno, Czech Republic
| | - Andrea Valigurová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic.
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Abstract
Cryptosporidium research has focused on the development of infection control, and effective therapy that has thus far been hampered by the inability to culture Cryptosporidium in vitro. Other limitations include inadequate animal models, cumbersome screening procedures for chemotherapeutic approaches and a lack of tools for genetic manipulation. These limitations can, however, be eased by the improvement and focused development of in vitro cultivation. The ability to culture relevant Cryptosporidium isolates in vitro and to propagate the life cycle stages that are responsible for causing disease in an infected host is still a critical link. This ability will facilitate other relevant approaches, e.g., the ability to knockout genes and the application of broader screening for drug discoveries and vaccine developments, in combination with new discoveries on the parasite's basic biology, genetic manipulation and new life cycle stages. Success in this effort represents an essential step towards significant progress in the control of cryptosporidiosis.
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Ryan U, Paparini A, Monis P, Hijjawi N. It's official - Cryptosporidium is a gregarine: What are the implications for the water industry? WATER RESEARCH 2016; 105:305-313. [PMID: 27639055 DOI: 10.1016/j.watres.2016.09.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 09/07/2016] [Accepted: 09/08/2016] [Indexed: 06/06/2023]
Abstract
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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Affiliation(s)
- Una Ryan
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, 6150, Australia.
| | - Andrea Paparini
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, 6150, Australia
| | - Paul Monis
- Australian Water Quality Centre, South Australian Water, Adelaide, Australia
| | - Nawal Hijjawi
- Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, The Hashemite University, PO Box 150459, Zarqa, 13115, Jordan
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Miyamoto Y, Eckmann L. Drug Development Against the Major Diarrhea-Causing Parasites of the Small Intestine, Cryptosporidium and Giardia. Front Microbiol 2015; 6:1208. [PMID: 26635732 PMCID: PMC4652082 DOI: 10.3389/fmicb.2015.01208] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 10/16/2015] [Indexed: 12/23/2022] Open
Abstract
Diarrheal diseases are among the leading causes of morbidity and mortality in the world, particularly among young children. A limited number of infectious agents account for most of these illnesses, raising the hope that advances in the treatment and prevention of these infections can have global health impact. The two most important parasitic causes of diarrheal disease are Cryptosporidium and Giardia. Both parasites infect predominantly the small intestine and colonize the lumen and epithelial surface, but do not invade deeper mucosal layers. This review discusses the therapeutic challenges, current treatment options, and drug development efforts against cryptosporidiosis and giardiasis. The goals of drug development against Cryptosporidium and Giardia are different. For Cryptosporidium, only one moderately effective drug (nitazoxanide) is available, so novel classes of more effective drugs are a high priority. Furthermore, new genetic technology to identify potential drug targets and better assays for functional evaluation of these targets throughout the parasite life cycle are needed for advancing anticryptosporidial drug design. By comparison, for Giardia, several classes of drugs with good efficacy exist, but dosing regimens are suboptimal and emerging resistance begins to threaten clinical utility. Consequently, improvements in potency and dosing, and the ability to overcome existing and prevent new forms of drug resistance are priorities in antigiardial drug development. Current work on new drugs against both infections has revealed promising strategies and new drug leads. However, the primary challenge for further drug development is the underlying economics, as both parasitic infections are considered Neglected Diseases with low funding priority and limited commercial interest. If a new urgency in medical progress against these infections can be raised at national funding agencies or philanthropic organizations, meaningful and timely progress is possible in treating and possibly preventing cryptosporidiosis and giardiasis.
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Affiliation(s)
- Yukiko Miyamoto
- Department of Medicine, University of California at San Diego, La Jolla CA, USA
| | - Lars Eckmann
- Department of Medicine, University of California at San Diego, La Jolla CA, USA
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Paziewska-Harris A, Singer M, Schoone G, Schallig H. Quantitative analysis of Cryptosporidium growth in in vitro culture--the impact of parasite density on the success of infection. Parasitol Res 2015; 115:329-37. [PMID: 26435485 DOI: 10.1007/s00436-015-4751-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 09/17/2015] [Indexed: 11/29/2022]
Abstract
Cryptosporidium is an important waterborne pathogen for which no treatment or vaccination is available. This study set out to quantify DNA replication of Cryptosporidium parvum in vitro. Cryptosporidium DNA could be detected at up to 60 % of input level in both host-cell-free and host cell containing cultures 6 days after infection with living sporozoites, but was lost within 2 days in cultures inoculated with UV-inactivated sporozoites. Total DNA increased between days 2 and 6, evidence of successful DNA replication in both cell-free and host-cell-containing cultures. Overall however, only a small fraction (up to 5 %) of parasite DNA could be found associated with host cells or bound to plastic of the cell-free cultures, and the majority of parasite DNA was present in the cell culture medium, separable by simple decantation. After 2 days, in host-cell-containing cultures, the parasite DNA could be concentrated by slow centrifugation, suggesting that it was associated with intact parasite cells, but at 6 days, the majority could not be centrifuged and is therefore thought to have represented copies associated with dead and degraded parasites. In cell-free cultures and in larger plates, the majority of DNA was in this form. Performance of the parasite was best in small culture plates, and least in the largest plate sizes. We interpret these results as suggesting that Cryptosporidium sporozoites first bind to the host cell monolayer or to the plasticware, but then by 2 days, there has been a substantial release of parasites back into the medium. Host-cell-free cultures also supported modest replication and may have represented DNA synthesis in cells beginning merogony. The role of the host cells is unclear, as so much of the parasite DNA is released into the medium. Host cells may provide a feeder role, conditioning the medium for Cryptosporidium development.
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Affiliation(s)
- Anna Paziewska-Harris
- KIT Biomedical Research, Royal Tropical Institute, Meibergdreef 39, 1105 AZ, Amsterdam, The Netherlands.
| | - Martin Singer
- Current address: Laboratory of Immunogenetics, Department of Medical Microbiology and Infection Control, VU University Medical Center, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
| | - Gerard Schoone
- KIT Biomedical Research, Royal Tropical Institute, Meibergdreef 39, 1105 AZ, Amsterdam, The Netherlands
| | - Henk Schallig
- KIT Biomedical Research, Royal Tropical Institute, Meibergdreef 39, 1105 AZ, Amsterdam, The Netherlands
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Challenges and Innovative Strategies to Interrupt Cryptosporidium Transmission in Resource-Limited Settings. CURRENT TROPICAL MEDICINE REPORTS 2015. [DOI: 10.1007/s40475-015-0057-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Wang JH, Xue XH, Zhou J, Fan CY, Xie QQ, Wang P. Cloning and Iron Transportation of Nucleotide Binding Domain of Cryptosporidium andersoni ATP-Binding Cassette (CaABC) Gene. THE KOREAN JOURNAL OF PARASITOLOGY 2015; 53:335-9. [PMID: 26174828 PMCID: PMC4510675 DOI: 10.3347/kjp.2015.53.3.335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 03/30/2015] [Accepted: 04/10/2015] [Indexed: 12/03/2022]
Abstract
Cryptosporidium andersoni ATP-binding cassette (CaABC) is an important membrane protein involved in substrate transport across the membrane. In this research, the nucleotide binding domain (NBD) of CaABC gene was amplified by PCR, and the eukaryotic expression vector of pEGFP-C1-CaNBD was reconstructed. Then, the recombinant plasmid of pEGFP-C1-CaNBD was transformed into the mouse intestinal epithelial cells (IECs) to study the iron transportation function of CaABC. The results indicated that NBD region of CaABC gene can significantly elevate the transport efficiency of Ca2+, Mg2+, K+, and HCO3- in IECs (P<0.05). The significance of this study is to find the ATPase inhibitors for NBD region of CaABC gene and to inhibit ATP binding and nutrient transport of CaABC transporter. Thus, C. andersoni will be killed by inhibition of nutrient uptake. This will open up a new way for treatment of cryptosporidiosis.
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Affiliation(s)
- Ju-Hua Wang
- College of Animal Science and Technology, Anhui Agriculture University, Hefei, Anhui, 230036, China
| | - Xiu-Heng Xue
- College of Tea & Food Technology, Anhui Agriculture University, Hefei, Anhui, 230036, China
| | - Jie Zhou
- College of Animal Science and Technology, Anhui Agriculture University, Hefei, Anhui, 230036, China
| | - Cai-Yun Fan
- College of Animal Science and Technology, Anhui Agriculture University, Hefei, Anhui, 230036, China
| | - Qian-Qian Xie
- College of Animal Science and Technology, Anhui Agriculture University, Hefei, Anhui, 230036, China
| | - Pan Wang
- College of Animal Science and Technology, Anhui Agriculture University, Hefei, Anhui, 230036, China
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Yang R, Elankumaran Y, Hijjawi N, Ryan U. Validation of cell-free culture using scanning electron microscopy (SEM) and gene expression studies. Exp Parasitol 2015; 153:55-62. [DOI: 10.1016/j.exppara.2015.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 01/13/2015] [Accepted: 03/03/2015] [Indexed: 10/23/2022]
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Ryan U, Hijjawi N. New developments in Cryptosporidium research. Int J Parasitol 2015; 45:367-73. [DOI: 10.1016/j.ijpara.2015.01.009] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 12/24/2022]
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Abstract
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.
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Affiliation(s)
- Vitaliano A Cama
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, MS D-65, Atlanta, GA 30341, USA.
| | - Blaine A Mathison
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, MS D-64, Atlanta, GA 30341, USA
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Huang L, Zhu H, Zhang S, Wang R, Liu L, Jian F, Ning C, Zhang L. An in vitro model of infection of chicken embryos by Cryptosporidium baileyi. Exp Parasitol 2014; 147:41-7. [DOI: 10.1016/j.exppara.2014.10.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 10/01/2014] [Accepted: 10/16/2014] [Indexed: 11/16/2022]
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Jefferies R, Yang R, Woh CK, Weldt T, Milech N, Estcourt A, Armstrong T, Hopkins R, Watt P, Reid S, Armson A, Ryan UM. Target validation of the inosine monophosphate dehydrogenase (IMPDH) gene in Cryptosporidium using Phylomer(®) peptides. Exp Parasitol 2014; 148:40-8. [PMID: 25447124 DOI: 10.1016/j.exppara.2014.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 11/07/2014] [Indexed: 01/03/2023]
Abstract
Cryptosporidiosis, a gastroenteric disease characterised mainly by diarrheal illnesses in humans and mammals is caused by infection with the protozoan parasite Cryptosporidium. Treatment options for cryptosporidiosis are limited, with the current therapeutic nitazoxanide, only partly efficacious in immunocompetent individuals. The parasite lacks de novo purine synthesis, and is exclusively dependant on purine salvage from its host. Inhibition of the inosine 5' monophosphate dehydrogenase (IMPDH), a purine salvage enzyme that is essential for DNA synthesis, thereby offers a potential drug target against this parasite. In the present study, a yeast-two-hybrid system was used to identify Phylomer peptides within a library constructed from the genomes of 25 phylogenetically diverse bacteria that targeted the IMPDH of Cryptosporidium parvum (IMPcp) and Cryptosporidium hominis (IMPch). We identified 38 unique interacting Phylomers, of which, 12 were synthesised and screened against C. parvum in vitro. Two Phylomers exhibited significant growth inhibition (81.2-83.8% inhibition; P < 0.05), one of which consistently exhibited positive interactions with IMPcp and IMPch during primary and recapitulation yeast two-hybrid screening and did not interact with either of the human IMPDH proteins. The present study highlightsthe potential of Phylomer peptides as target validation tools for Cryptosporidium and other organisms and diseases because of their ability to bind with high affinity to target proteins and disrupt function.
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Affiliation(s)
- R Jefferies
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia; Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - R Yang
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - C K Woh
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia; Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - T Weldt
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - N Milech
- Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - A Estcourt
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - T Armstrong
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - R Hopkins
- Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - P Watt
- Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - S Reid
- School of Population Health, The University of Queensland, Herston, Queensland, Australia
| | - A Armson
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - U M Ryan
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia.
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Koh W, Thompson A, Edwards H, Monis P, Clode PL. Extracellular excystation and development of Cryptosporidium: tracing the fate of oocysts within Pseudomonas aquatic biofilm systems. BMC Microbiol 2014; 14:281. [PMID: 25403949 PMCID: PMC4236811 DOI: 10.1186/s12866-014-0281-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 10/30/2014] [Indexed: 11/29/2022] Open
Abstract
Background Aquatic biofilms often serve as environmental reservoirs for microorganisms and provide them with a nutrient-rich growth environment under harsh conditions. With regard to Cryptosporidium, biofilms can serve as environmental reservoirs for oocysts, but may also support the growth of additional Cryptosporidium stages. Results Here we used confocal laser scanning microscopy, scanning electron microscopy (SEM), and flow cytometry to identify and describe various Cryptosporidium developmental stages present within aquatic biofilm systems, and to directly compare these to stages produced in cell culture. We also show that Cryptosporidium has the ability to form a parasitophorous vacuole independently, in a host-free biofilm environment, potentially allowing them to complete an extracellular life cycle. Correlative data from confocal and SEM imaging of the same cells confirmed that the observed developmental stages (including trophozoites, meronts, and merozoites) were Cryptosporidium. These microscopy observations were further supported by flow cytometric analyses, where excysted oocyst populations were detected in 1, 3 and 6 day-old Cryptosporidium-exposed biofilms, but not in biofilm-free controls. Conclusions These observations not only highlight the risk that aquatic biofilms pose in regards to Cryptosporidium outbreaks from water distribution systems, but further indicate that even simple biofilms are able to stimulate oocyst excystation and support the extracellular multiplication and development of Cryptosporidium within aquatic environments. Electronic supplementary material The online version of this article (doi:10.1186/s12866-014-0281-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wan Koh
- School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch 6150, WA, Australia.
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25
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Protozoan Parasites. Food Microbiol 2014. [DOI: 10.1128/9781555818463.ch28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Armson A, Thompson RCA, Reynoldson JA. A review of chemotherapeutic approaches to the treatment of cryptosporidiosis. Expert Rev Anti Infect Ther 2014; 1:297-305. [PMID: 15482125 DOI: 10.1586/14787210.1.2.297] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This review focuses on chemotherapies used against the parasite, Cryptosporidium parvum, the causative agent of cryptosporidiosis. Populations at risk from severe morbidity or mortality from cryptosporidiosis are discussed with particular reference to those infected with HIV. The review then examines chemotherapies used in the clinical setting, as well as a number of in vitro and in vivo experimental studies. It begins with a discussion of the targets within Cryptosporidium that have been the foci of past treatments and then examines novel target sites that may present an exploitable alternative. Some of the novel target sites discussed include the recently discovered apicomplexan plastid and its associated pathways. Lastly, the review examines tubulin as a potential anticryptosporidial target in view of the fact that it has been exploited successfully for almost 50 years for the treatment of helminthiasis. The review concludes with a five-year outlook on the future of anticryptosporidial drug design.
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Affiliation(s)
- Anthony Armson
- Western Australian Biomedical Research Institute, Division of Health Sciences, Murdoch University, Perth. Western Australia.
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27
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Koh W, Clode PL, Monis P, Thompson RCA. Multiplication of the waterborne pathogen Cryptosporidium parvum in an aquatic biofilm system. Parasit Vectors 2013; 6:270. [PMID: 24330483 PMCID: PMC3848567 DOI: 10.1186/1756-3305-6-270] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 09/15/2013] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND In natural aquatic environments biofilms are known to act as environmental reservoirs for Cryptosporidium parvum oocysts. However, the fate of these oocysts within biofilms has yet to be determined. METHODS This study aimed to identify if biofilms have the ability to support the multiplication of Cryptosporidium by measuring the change in parasite number over time using quantitative polymerase chain reaction (qPCR) and detecting the possible extracellular developmental stages using a combination of confocal microscopy and immunolabelling techniques. Pseudomonas aeruginosa biofilm flow cell systems were established and C. parvum oocysts were constantly supplied over a six day period. RESULTS A significant (P<0.001) increase in Cryptosporidium was detected as the biofilm matured, with the total number of C. parvum multiplying 2-3 fold during this period. With this, various Cryptosporidium developmental stages (sporozoites, trophozoites, type I and II meronts) were identified from the biofilm. CONCLUSION This is the first study demonstrating that biofilms not only serve as an environmental reservoir for oocysts, but are also capable of supporting the multiplication of Cryptosporidium over time in an aquatic environment.
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28
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Müller J, Hemphill A. In vitro culture systems for the study of apicomplexan parasites in farm animals. Int J Parasitol 2012; 43:115-24. [PMID: 23000674 DOI: 10.1016/j.ijpara.2012.08.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 08/08/2012] [Accepted: 08/14/2012] [Indexed: 01/02/2023]
Abstract
In vitro culture systems represent powerful tools for the study of apicomplexan parasites such as Cryptosporidium, Eimeria, Sarcocystis, Neospora, Toxoplasma, Besnoitia, Babesia and Theileria, all with high relevance for farm animals. Proliferative stages of these parasites have been cultured in vitro employing a large variety of cell culture and explant approaches. For some, such as Cryptosporidium and Eimeria, the sexual development has been reproduced in cell cultures, while for others, animal experimentation is required to fulfill the life cycle. In vitro cultures have paved the way to exploit the basic biology of these organisms, and had a major impact on the development of tools for diagnostic purposes. With the aid of in vitro cultivation, studies on host-parasite interactions, on factors involved in innate resistance, stage conversion and differentiation, genetics and transfection technology, vaccine candidates and drug effectiveness could be carried out. The use of transgenic parasites has facilitated high-throughput screening of anti-microbial compounds that are active against the proliferative stages. Here, we review the basic features of cell culture-based in vitro systems for apicomplexan parasites that are relevant for farm animals, and discuss their applications with a focus on drug identification and studies of stage differentiation.
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Affiliation(s)
- Joachim Müller
- Institute of Parasitology, Vetsuisse Faculty, University of Berne, Länggass-Strasse 122, CH-3012 Berne, Switzerland.
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29
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In vitro determination of anticryptosporidial activity of phytogenic extracts and compounds. Parasitol Res 2012; 111:231-40. [PMID: 22278729 DOI: 10.1007/s00436-012-2824-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 01/10/2012] [Indexed: 12/25/2022]
Abstract
Cryptosporidiosis caused by Cryptosporidium spp. is an important diarrhoeal disease observed in farm animals and humans, especially in young or immunocompromised individuals. A novel cell culture assay for testing extracts and pure compounds against Cryptosporidium parvum in 96-well microplate format was established and evaluated. It is based on previously described indirect fluorescent antibody techniques and was optimised for higher sample throughput. Rapid assessment of minimal inhibitory concentrations (MICs) was done by checking each well microscopically for the presence or absence of parasite stages. As a novelty, parasite development was quantified by enumeration of clusters of secondary infection (CSI), which typically appeared upon infection with a distinct parasite inoculum after a defined incubation time. Host cell (HCT-8) viability was measured by an integrated non-destructive water-soluble tetrazolium salt assay (WST-1), which facilitated discrimination of antiparasitic activity from possible cytotoxic effects of a test compound against the host cells. Host cell viability was regarded unimpaired when cultures had 75% or more viability when compared to control cultures without test substance. In this study, a maximum density of distinguishable CSI was obtained when cultures were infected with 2.5 × 10(3) oocysts and incubated for 48 h. The applicable inoculum has to be optimised for each batch of oocysts and before each experimental series. Parasite development was inhibited completely by monensin at 134 nM and silymarin at 50 mg/mL. These concentrations were non-toxic to the host cells and comparable to literature data. The percentages of parasite inhibition were determined for monensin and a 50% inhibitory concentration (IC(50)) of 36.6 nM (27.4-45.5) and a 90% inhibitory concentration of 65.9 nM (54.8-90.2) were calculated. The introduced assay is economic because relatively low parasite numbers may be used. If MICs are determined, evaluation is fast, as each well is viewed only briefly under the fluorescence microscope for presence or absence of CSI. Furthermore it is highly critical because only full parasite inhibition is assessed. Counting of CSI is more laborious and time-consuming, but it allows calculation of parasite inhibition rates and parameters like the half maximal inhibitory concentration (IC(50)). This assay shall be used to assess anticryptosporidial activities of various plant waste materials and by-products from the food and the pharmaceutical industries in the course of the EU project SAFEWASTES. Comparison with in vivo models should be performed to further corroborate the results. Automated evaluation by flow cytometry might facilitate higher sample throughput and reduce operator bias.
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Labeling surface epitopes to identify Cryptosporidium life stages using a scanning electron microscopy-based immunogold approach. Mol Cell Probes 2011; 26:21-8. [PMID: 22100878 DOI: 10.1016/j.mcp.2011.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 11/02/2011] [Accepted: 11/02/2011] [Indexed: 11/22/2022]
Abstract
The Apicomplexan parasite Cryptosporidium parvum is responsible for the widespread disease cryptosporidiosis, in both humans and livestock. The nature of C. parvum infection is far from understood and many questions remain in regard to host-parasite interactions, limiting successful treatment of the disease. To definitively identify a range of C. parvum stages in cell culture and to begin to investigate host cell interactions in some of the lesser known life stages, we have utilized a combined scanning electron microscopy and immunolabeling approach, correlating high resolution microstructural information with definitive immunogold labeling of Cryptosporidium stages. Several life cycle stages, including oocysts, merozoites I, trophozoites, gamonts and microgametocytes, were successfully immunolabeled in an in vitro model system. Developing oocysts were clearly immunolabeled, but this did not persist once excystation had occurred. Immunolabeling visualized on the host cell surface adjacent to invasive merozoites is likely to be indicative of receptor shedding, with merozoites also initiating host responses that manifested as abnormal microvilli on the host cell surface. Small sub-micron stages such as microgametocytes, which were impossible to identify as single entities without immunolabeling, were readily visualized and observed to attach to host cells via novel membranous projections. Epicellular parasites also expressed Cryptosporidium-derived epitopes within their encapsulating membrane. These data have allowed us to confidently identify a variety of C. parvum stages in cell culture at high resolution. With this, we provide new insight into C. parvum - host cell interactions and highlight future opportunities for investigating and targeting receptor-mediated interactions between Cryptosporidium life cycle stages and host cells.
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Karanis P, Aldeyarbi HM. Evolution of Cryptosporidium in vitro culture. Int J Parasitol 2011; 41:1231-42. [PMID: 21889507 DOI: 10.1016/j.ijpara.2011.08.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 08/03/2011] [Accepted: 08/04/2011] [Indexed: 02/07/2023]
Abstract
This overview discusses findings from culturing Cryptosporidium spp. in cell and axenic cultures as well as factors limiting the development of this parasite in cultivation systems during recent years. A systematic review is undertaken of findings regarding the life cycle of the parasite, taking into account physiological, biochemical and genetic aspects, in the hope that this attempt will facilitate future approaches to research and developments in the understanding of Cryptosporidium biology.
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Affiliation(s)
- P Karanis
- University of Cologne, Center for Anatomy, Institute II, Molecular and Medical Parasitology, Joseph-Stelzmann-Street 9, Geb.35, 50937 Köln, Germany.
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Meireles MV. Cryptosporidium infection in Brazil: implications for veterinary medicine and public health. ACTA ACUST UNITED AC 2011; 19:197-204. [PMID: 21184694 DOI: 10.1590/s1984-29612010000400002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 11/09/2010] [Indexed: 11/22/2022]
Abstract
The aim of this review paper is to report the results of cryptosporidiosis research in Brazil, mainly its occurrence in animals and implications for veterinary medicine and public health. An increasing number of papers related to Cryptosporidium spp. infection in Brazil are available at national and international literature. The main focus described in these papers is the occurrence of Cryptosporidium spp. in food, environmental samples, in humans and several animal species, particularly birds, cattle, dogs and cats. Using molecular biology techniques, most Cryptosporidium species and genotypes identified in other countries have been described in Brazil. In mammals, there are descriptions of infection by C. bovis, C. canis, C. felis, C. meleagridis, C. parvum, and the cervine genotype; in birds, the following species and genotypes have been described: C. baileyi, C. galli, C. meleagridis, C. parvum and the avian genotypes I, II and III. Several species have been described in humans, such as C. parvum, C. hominis, and some species adapted to animal hosts such as C. canis, C. felis and C. meleagridis.
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Affiliation(s)
- Marcelo Vasconcelos Meireles
- Curso de Medicina Veterinária, Universidade Estadual Paulista, Rua Clóvis Pestana 793, Bairro Dona Amélia, Araçatuba-SP, Brazil.
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Navarro-i-Martinez L, del Águila C, Bornay-Llinares FJ. Cryptosporidium: un género en revisión. Situación en España. Enferm Infecc Microbiol Clin 2011; 29:135-43. [DOI: 10.1016/j.eimc.2010.12.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 12/01/2010] [Accepted: 12/03/2010] [Indexed: 01/27/2023]
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Hijjawi N, Estcourt A, Yang R, Monis P, Ryan U. Complete development and multiplication of Cryptosporidium hominis in cell-free culture. Vet Parasitol 2010; 169:29-36. [DOI: 10.1016/j.vetpar.2009.12.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 12/02/2009] [Accepted: 12/14/2009] [Indexed: 11/17/2022]
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35
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Cryptosporidium: New developments in cell culture. Exp Parasitol 2010; 124:54-60. [DOI: 10.1016/j.exppara.2009.05.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 05/06/2009] [Accepted: 05/26/2009] [Indexed: 11/18/2022]
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36
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Brescia CC, Griffin SM, Ware MW, Varughese EA, Egorov AI, Villegas EN. Cryptosporidium propidium monoazide-PCR, a molecular biology-based technique for genotyping of viable Cryptosporidium oocysts. Appl Environ Microbiol 2009; 75:6856-63. [PMID: 19749067 PMCID: PMC2772443 DOI: 10.1128/aem.00540-09] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 08/28/2009] [Indexed: 11/20/2022] Open
Abstract
Cryptosporidium is an important waterborne protozoan parasite that can cause severe diarrhea and death in the immunocompromised. The current methods used to monitor for Cryptosporidium oocysts in water are the microscopy-based USEPA methods 1622 and 1623. These methods assess total levels of oocysts in source waters, but do not determine oocyst viability or genotype. Recently, propidium monoazide (PMA) has been used in conjunction with molecular diagnostic tools to identify species and assess the viability of bacteria. The goal of this study was the development of a Cryptosporidium PMA-PCR (CryptoPMA-PCR) assay that includes PMA treatment prior to PCR analysis in order to prevent the amplification of DNA from dead oocysts. The results demonstrated that PMA penetrates only dead oocysts and blocks amplification of their DNA. The CryptoPMA-PCR assay can also specifically detect live oocysts within a mixed population of live and dead oocysts. More importantly, live oocysts, not dead oocysts, were detected in raw waste or surface water samples spiked with Cryptosporidium oocysts. This proof-of-concept study is the first to demonstrate the use of PMA for pre-PCR treatment of Cryptosporidium oocysts. The CryptoPMA-PCR assay is an attractive approach to specifically detect and genotype viable Cryptosporidium oocysts in the water, which is critical for human health risk assessment.
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Affiliation(s)
- Cristin C. Brescia
- National Exposure Research Laboratory, National Center for Environmental Assessment, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268
| | - Shannon M. Griffin
- National Exposure Research Laboratory, National Center for Environmental Assessment, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268
| | - Michael W. Ware
- National Exposure Research Laboratory, National Center for Environmental Assessment, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268
| | - Eunice A. Varughese
- National Exposure Research Laboratory, National Center for Environmental Assessment, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268
| | - Andrey I. Egorov
- National Exposure Research Laboratory, National Center for Environmental Assessment, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268
| | - Eric N. Villegas
- National Exposure Research Laboratory, National Center for Environmental Assessment, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268
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37
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Thompson RCA. Echinococcus, Giardia and Cryptosporidium: observational studies challenging accepted dogma. Parasitology 2009; 136:1529-35. [PMID: 19366481 DOI: 10.1017/s0031182009005897] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The development of in vitro culture systems that allow the maintenance, and support the development of Echinococcus, Giardia and Cryptosporidium in the laboratory have had a significant impact on their biology and taxonomy and the epidemiology of infections they cause. This short retrospective review demonstrates how radical shifts in our understanding have occurred as a result of being able to grow these organisms in culture, and how molecular tools have helped in the interpretation of such research that often reflects the observations of earlier workers.
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Affiliation(s)
- R C A Thompson
- World Health Organization Collaborating Centre for the Molecular Epidemiology of Parasitic Infections, School of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, WA 6150, Australia.
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Thompson RCA, Olson ME, Zhu G, Enomoto S, Abrahamsen MS, Hijjawi NS. Cryptosporidium and cryptosporidiosis. ADVANCES IN PARASITOLOGY 2009; 59:77-158. [PMID: 16182865 DOI: 10.1016/s0065-308x(05)59002-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Cryptosporidium is one of the most common enteric protozoan parasites of vertebrates with a wide host range that includes humans and domestic animals. It is a significant cause of diarrhoeal disease and an ubiquitous contaminant of water which serves as an excellent vehicle for transmission. A better understanding of the development and life cycle of Cryptosporidium, and new insights into its phylogenetic relationships, have illustrated the need to re-evaluate many aspects of the biology of Cryptosporidium. This has been reinforced by information obtained from the recent successful Cryptosporidium genome sequencing project, which has emphasised the uniqueness of this organism in terms of its parasite life style and evolutionary biology. This chapter provides an up to date review of the biology, biochemistry and host parasite relationships of Cryptosporidium.
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Affiliation(s)
- R C A Thompson
- Division of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, WA 6150, Australia.
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Morphological characterization of Cryptosporidium parvum life-cycle stages in an in vitro model system. Parasitology 2009; 137:13-26. [PMID: 19691870 DOI: 10.1017/s0031182009990837] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cryptosporidium parvum is a zoonotic protozoan parasite that mainly affects the ileum of humans and livestock, with the potential to cause severe enteric disease. We describe the complete life cycle of C. parvum in an in vitro system. Infected cultures of the human ileocecal epithelial cell line (HCT-8) were observed over time using electron microscopy. Additional data are presented on the morphology, development and behavioural characteristics of the different life-cycle stages as well as determining their time of occurrence after inoculation. Numerous stages of C. parvum and their behaviour have been visualized and morphologically characterized for the first time using scanning electron microscopy. Further, parasite-host interactions and the effect of C. parvum on host cells were also visualized. An improved understanding of the parasite's biology, proliferation and interactions with host cells will aid in the development of treatments for the disease.
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Wu L, Chen SX, Jiang XG, Shen YJ, Lu ZX, Tu GH, Fu XL, Cao JP. Effect of select medium supplements on in vitro development of Cryptosporidium andersoni in HCT-8 cells. Parasitol Res 2009; 105:1419-24. [PMID: 19641939 DOI: 10.1007/s00436-009-1576-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 07/15/2009] [Indexed: 11/30/2022]
Abstract
We evaluated the effect of fetal calf serum (FCS), glucose, ascorbic acid, calcium pantothenate, folic acid, and insulin on the growth of Cryptosporidium andersoni in human colon tumor (HCT-8) cells. After being incubated for 48 h, the proliferation of parasites was determined by real-time polymerase chain reaction (PCR) assay, and the development of C. andersoni was observed by transmission electron microscopy (TEM). Ten percent FCS was the best concentration for C. andersoni culture. Glucose, ascorbic acid, and insulin had a significant effect on the growth of C. andersoni when added into 10% FCS RPMI 1640. Calcium pantothenate had no significant effect and folic acid had the inhibited effect. We also observed the stages of trophozoite, macrogamont, microgamont, type I meront, type II meront, and sporozoite of C. andersoni in HCT-8 cells by TEM. Our results indicated that the best medium for C. andersoni was 10% FCS RPMI 1640 medium containing 50 mM glucose, 50 microg/ml ascorbic acid, and 0.3 U/ml insulin. Real-time PCR could provide a quick and precise technique to determine the proliferation of parasites. Cultivation of C. andersoni in HCT-8 cells will facilitate the study of interactions between parasites and host cells as well as provide a reliable system for evaluating anticryptosporidial compound efficacy.
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Affiliation(s)
- Liang Wu
- School of Medical Science and Laboratory Medicine, Jiangsu University, 212013 Zhenjiang, People's Republic of China
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Plutzer J, Karanis P. Genetic polymorphism in Cryptosporidium species: an update. Vet Parasitol 2009; 165:187-99. [PMID: 19660869 DOI: 10.1016/j.vetpar.2009.07.003] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 05/29/2009] [Accepted: 07/02/2009] [Indexed: 11/17/2022]
Abstract
Cryptosporidia, widely distributed protozoan parasites of vertebrates, have attracted increasing interest due to several serious waterborne outbreaks, the life-threatening nature of infection in immunocompromised patients, and the realization of economic losses caused by these pathogens in livestock. Genetic polymorphism within Cryptosporidium species is being detected at a continuously growing rate, owing to the widespread use of modern molecular techniques. The aim of this paper is to review the current status of taxonomy, genotyping and molecular phylogeny of Cryptosporidium species. To this date, 20 Cryptosporidium species have been recognized. Two named species of Cryptosporidium have been found in fish, 1 in amphibians, 2 in reptiles, 3 in birds, and 12 in mammals. Nearly 61 Cryptosporidium genotypes with uncertain species status have been found based on SSUrRNA sequences. The gp-60 gene showed a high degree of sequence polymorphism among isolates of Cryptosporidium species and several subtype groups and subgenotypes have been identified, of which the Cryptosporidium parvum IIa and IId subtype groups were found to be zoonotic. This review describes considerable progress in the identification, genetic characterization, and strain differentiation of Cryptosporidium over the last 20 years. All the valid species, genotypes and zoonotic subtypes of Cryptosporidium reported in the international literature are included in this paper with respect to the taxonomy, epidemiology, transmission and morphologic-genetic information for each species.
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Affiliation(s)
- Judit Plutzer
- National Institute of Environmental Health, Department of Water Hygiene, Gyáli ut 2-6, Budapest H-1096, Hungary.
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42
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Boxell A, Hijjawi N, Monis P, Ryan U. Comparison of various staining methods for the detection of Cryptosporidium in cell-free culture. Exp Parasitol 2008; 120:67-72. [DOI: 10.1016/j.exppara.2008.04.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 04/28/2008] [Accepted: 04/29/2008] [Indexed: 11/28/2022]
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Johny S, Merisko A, Whitman DW. Efficacy of eleven antimicrobials against a gregarine parasite (Apicomplexa: Protozoa). Ann Clin Microbiol Antimicrob 2007; 6:15. [PMID: 17997852 PMCID: PMC2214726 DOI: 10.1186/1476-0711-6-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Accepted: 11/12/2007] [Indexed: 11/21/2022] Open
Abstract
Background The Apicomplexa are a diverse group of obligate protozoan parasites infesting a wide range of invertebrate and vertebrate hosts including humans. These parasites are notoriously difficult to control and many species continue to evolve resistance to commercial antibiotics. In this study, we sought to find an effective chemotherapeutic treatment against arthropod gregarines (Apicomplexa), and to identify candidate compounds for testing against other groups of protozoan parasites. Methods We tested eleven commercial antibiotics against a gregarine parasite of Romalea microptera grasshoppers. Infected insects were fed daily, lettuce containing known amounts of specific antibiotics. On Days 15 or 20, we measured the number of gregarines remaining in the digestive tract of each grasshopper. Results Treatment with metronidazole and griseofulvin in host insects significantly reduced gregarine counts, whereas, gregarine counts of insects fed, albendazole, ampicillin, chloramphenicol, fumagillin, quinine, streptomycin, sulfadimethoxine, thiabendazole or tetracycline, were not significantly different from the controls. However, albendazole produced a strong, but non-significant reduction in gregarine count, and streptomycin exhibited a non-significant antagonistic trend. Conclusion Our results confirm that gregarine infections are difficult to control and suggest the possibility that streptomycin might aggravate gregarine infection. In addition, the insect system described here, provides a simple, inexpensive, and effective method for screening antibiotics.
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Affiliation(s)
- Shajahan Johny
- Department of Biological Sciences, Box 4120, Illinois State University, Normal, Illinois, 61790, USA.
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44
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Abstract
Gregarines are early diverging apicomplexans that appear to be closely related to Cryptosporidium. Most apicomplexans, including Plasmodium, Toxoplasma, and Eimeria, possess both plastids and corresponding plastid genomes. Cryptosporidium lacks both the organelle and the genome. To investigate the evolutionary history of plastids in the Apicomplexa, we tried to determine whether gregarines possess a plastid and/or its genome. We used PCR and dot-blot hybridization to determine whether the gregarine Gregarina niphandrodes possesses a plastid genome. We used an inhibitor of plastid function for any reduction in gregarine infection, and transmission electron microscopy to search for plastid ultrastructure. Despite an extensive search, an organelle of the appropriate ultrastructure in transmission electron microscopy, was not observed. Triclosan, an inhibitor of the plastid-specific enoyl-acyl carrier reductase enzyme, did not reduce host infection by G. niphandrodes. Plastid-specific primers produced amplicons with the DNA of Babesia equi, Plasmodium falciparum, and Toxoplasma gondii as templates, but not with G. niphandrodes DNA. Plastid-specific DNA probes, which hybridized to Babesia equi, failed to hybridize to G. niphandrodes DNA. This evidence indicates that G. niphandrodes is not likely to possess either a plastid organelle or its genome. This raises the possibility that the plastid was lost in the Apicomplexan following the divergence of gregarines and Cryptosporidium.
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Affiliation(s)
- Marc A Toso
- School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236, USA
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Perez Cordón G, Marin C, Romero D, Rosales C, Sánchez Moreno M, Rosales MJ. More productive in vitro culture of Cryptosporidium parvum for better study of the intra- and extracellular phases. Mem Inst Oswaldo Cruz 2007; 102:567-71. [PMID: 17710300 DOI: 10.1590/s0074-02762007005000071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Accepted: 06/20/2007] [Indexed: 11/21/2022] Open
Abstract
The great difficulties in treating people and animals suffering from cryptosporidiosis have prompted the development of in vitro experimental models. Due to the models of in vitro culture, new extracellular stages of Cryptosporidium have been demonstrated. The development of these extracellular phases depends on the technique of in vitro culture and on the species and genotype of Cryptosporidium used. Here, we undertake the molecular characterization by polymerase chain reaction-restriction fragment length polymorphism of different Cryptosporidium isolates from calves, concluding that all are C. parvum of cattle genotype, although differing in the nucleotide at positions 472 and 498. Using these parasites, modified the in vitro culture technique for HCT-8 cells achieving greater multiplication of parasites. The HCT-8 cell cultures, for which the culture had not been renewed in seven days, were infected with C. parvum sporozoites in RPMI-1640 medium with 10% IFBS, CaCl2 and MgCl2 1 mM at pH 7.2. Percentages of cell parasitism were increased with respect to control cultures (71% at 48 h vs 14.5%), even after two weeks (47% vs 1.9%). Also, the percentage of extracellular stages augmented (25.3% vs 1.1% at 96 h). This new model of in vitro culture of C. parvum will enable easier study of the developmental phases of C. parvum in performing new chemotherapeutic assays.
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Affiliation(s)
- G Perez Cordón
- Departamento de Parasitologia, Facultad de Ciencias, Instituto de Biotecnología, Universidad de Granada18071, España
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Abstract
Although they differ considerably with respect to their biology, both Giardia duodenalis and Cryptosporidium parvum are common in ruminants, whereas Cryptosporidium andersoni is not. G. duodenalis infections are acquired during the first few months of life, tend to be chronic, and may be a production-limiting disease of ruminants. C. parvum infections remain an important cause of diarrhea in neonatal ruminants. Abomasal cryptosporidiosis, caused by C. andersoni, is an emerging disease of cattle that may affect both beef and dairy herds. This article reviews the life cycles, production impacts, treatments, controls, and zoonotic potentials of these important ruminant parasites.
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Affiliation(s)
- Ryan M O'Handley
- Environmental Biotechnology Cooperative Research Centre, School of Veterinary and Biomedical Sciences, Murdoch University, South Street, Murdoch, Western Australia 6164, Australia
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Sunnotel O, Snelling WJ, Xiao L, Moule K, Moore JE, Millar BC, Dooley JSG, Lowery CJ. Rapid and sensitive detection of single cryptosporidium oocysts from archived glass slides. J Clin Microbiol 2006; 44:3285-91. [PMID: 16954262 PMCID: PMC1594691 DOI: 10.1128/jcm.00541-06] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study we report on the development and application of a novel method for efficiently extracting and detecting single Cryptosporidium oocysts from archived glass slides. Laser capture microscopy was used to extract low numbers of oocysts from archived glass slides. Highly sensitive real-time PCR methods were then developed to enable the rapid detection and identification of Cryptosporidium oocysts from these samples. The method was applied to fecal smears stained with a variety of standard oocyst stains and water samples. This application, with samples derived from both public health and water service laboratories, highlighted the strong potential of this method to be used as a rapid high-throughput screening tool for the routine monitoring of Cryptosporidium and other medically important pathogens from clinical, veterinary, and environmental water samples. Importantly, the application of our protocol could be used to type Cryptosporidium and other pathogens from stored archived glass slides in public health and water service laboratories, providing vital epidemiological updates and helping to identify and trace pathogens and their routes of infection and ultimately improve their control.
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Affiliation(s)
- O Sunnotel
- Department of Biomedical Sciences, Centre for Molecular Biosciences, School of Biomedical Sciences, Faculty of Life and Health Sciences, University of Ulster, Cromore Road, Coleraine, Northern Ireland BT52 1SA
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Boulter-Bitzer JI, Lee H, Trevors JT. Molecular targets for detection and immunotherapy in Cryptosporidium parvum. Biotechnol Adv 2006; 25:13-44. [PMID: 17055210 DOI: 10.1016/j.biotechadv.2006.08.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Revised: 08/14/2006] [Accepted: 08/22/2006] [Indexed: 11/21/2022]
Abstract
Cryptosporidium parvum is an obligate protozoan parasite responsible for the diarrheal illness cryptosporidiosis in humans and animals. Although C. parvum is particularly pathogenic in immunocompromised hosts, the molecular mechanisms by which C. parvum invades the host epithelial cells are not well understood. Characterization of molecular-based antigenic targets of C. parvum is required to improve the specificity of detection, viability assessments, and immunotherapy (treatment). A number of zoite surface (glyco)proteins are known to be expressed during, and believed to be involved in, invasion and infection of host epithelial cells. In the absence of protective treatments for this illness, antibodies targeted against these zoite surface (glyco)proteins offers a rational approach to therapy. Monoclonal, polyclonal and recombinant antibodies represent useful immunotherapeutic means of combating infection, especially when highly immunogenic C. parvum antigens are utilized as targets. Interruption of life cycle stages of this parasite via antibodies that target critical surface-exposed proteins can potentially decrease the severity of disease symptoms and subsequent re-infection of host tissues. In addition, development of vaccines to this parasite based on the same antigens may be a valuable means of preventing infection. This paper describes many of the zoite surface glycoproteins potentially involved in infection, as well as summarizes many of the immunotherapeutic studies completed to date. The identification and characterization of antibodies that bind to C. parvum-specific cell surface antigens of the oocyst and sporozoite will allow researchers to fully realize the potential of molecular-based immunotherapy to this parasite.
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Barta JR, Thompson RCA. What is Cryptosporidium? Reappraising its biology and phylogenetic affinities. Trends Parasitol 2006; 22:463-8. [PMID: 16904941 DOI: 10.1016/j.pt.2006.08.001] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Revised: 07/10/2006] [Accepted: 08/01/2006] [Indexed: 10/24/2022]
Abstract
In raising the question "What is Cryptosporidium?", we aim to emphasize a growing need to re-evaluate the affinities of Cryptosporidium species within the phylum Apicomplexa so as to better understand the biology and ecology of these parasites. Here, we have compiled evidence from a variety of molecular and biological studies to build a convincing case for distancing Cryptosporidium species from the coccidia conceptually, biologically and taxonomically. We suggest that Cryptosporidium species must no longer be considered unusual or unique coccidia but rather seen for what they are--a distantly related lineage of apicomplexan parasites that are not in fact coccidia but that do occupy many of the same ecological niches. Looking at Cryptosporidium species without traditional coccidian blinders is likely to reveal new avenues of investigation into pathogenesis, epidemiology, treatment and control of these ubiquitous pathogens.
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Affiliation(s)
- John R Barta
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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