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Srisuphanunt M, Wilairatana P, Kooltheat N, Damrongwatanapokin T, Karanis P. Occurrence of Cryptosporidium oocysts in commercial oysters in southern Thailand. Food Waterborne Parasitol 2023; 32:e00205. [PMID: 37577105 PMCID: PMC10412772 DOI: 10.1016/j.fawpar.2023.e00205] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 07/23/2023] [Accepted: 07/26/2023] [Indexed: 08/15/2023] Open
Abstract
The enteric parasite Cryptosporidium is spread through the fecal-oral pathway, most commonly by the consumption of contaminated water but also through food. Because eating raw or barely cooked shellfish might put consumers at risk for cryptosporidiosis, identifying the parasite in oysters is important for public health. A total of 240 oysters, collected from two shellfish aquaculture sites in Thailand's Gulf coast, Nakhon Si Thammarat and Surat Thani, were tested for the presence of Cryptosporidium. Escherichia coli, enterococci, and thermotolerant coliform total levels were measured to assess seawater quality in the shellfish production regions. Oocysts of Cryptosporidium spp. were detected in 13.8% of the samples processed by immunofluorescence analyses. The detection of Cryptosporidium spp. oocysts in oysters obtained from Surat Thani (17.5%) was higher than in those obtained from Nakhon Si Thammarat (9.2%). The difference in detection of positive samples obtained from Nakhon Si Thammarat and those obtained from Surat Thani may be attributed to the effects of physical, ecological, and anthropogenic conditions, resulting in an increased level of marine water contamination by Cryptosporidium spp. oocysts. These findings demonstrate that native commercial oysters obtained from Thailand's southern Gulf coast contained Cryptosporidium spp. oocysts which might serve as a source of human infection. Consequently, these findings pose a serious public health concern and suggest that more quality control measures need to be implemented by the oyster aquaculture business to ensure the safety of seafood.
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Affiliation(s)
- Mayuna Srisuphanunt
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
- Centre for One Health, Walailak University, Nakhon Si Thammarat 80161, Thailand
- Hematology and Transfusion Science Research Center, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Polrat Wilairatana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Nateelak Kooltheat
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
- Hematology and Transfusion Science Research Center, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Thanis Damrongwatanapokin
- Akkhraratchakumari Veterinary College, Walailak University, Nakhon Si Thammarat 80160, Thailand
- Centre for One Health, Walailak University, Nakhon Si Thammarat 80161, Thailand
| | - Panagiotis Karanis
- University of Nicosia Medical School, Department of Basic and Clinical Sciences, Egkomi 2408, Cyprus
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Marquis ND, Bishop TJ, Record NR, Countway PD, Fernández Robledo JA. Molecular Epizootiology of Toxoplasma gondii and Cryptosporidium parvum in the Eastern Oyster ( Crassostrea virginica) from Maine (USA). Pathogens 2019; 8:E125. [PMID: 31412532 PMCID: PMC6789735 DOI: 10.3390/pathogens8030125] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/01/2019] [Accepted: 08/08/2019] [Indexed: 11/17/2022] Open
Abstract
Shellfish are known as a potential source of Toxoplasma gondii (responsible for toxoplasmosis), and Cryptosporidium parvum, which is one of the major causes of gastroenteritis in the world. Here we performed a comprehensive qPCR-based monthly survey for T. gondii and C. parvum during 2016 and 2017 in oysters (Crassostrea virginica) (n = 1440) from all six sites along the coast of Maine (USA). Pooled samples (mantle, gills, and rectum) from individual oysters were used for DNA extraction and qPCR. Our study resulted in detections of qPCR positives oysters for T. gondii and C. parvum at each of the six sites sampled (in 31% and 10% of total oysters, respectively). The prevalence of T. gondii was low in 2016, and in September 2017 several sites peaked in prevalence with 100% of the samples testing positive. The prevalence of C. parvum was very low except in one estuarine location (Jack's Point) in June 2016 (58%), and in October of 2016, when both prevalence and density of C. parvum at most of the sampling sites were among the highest values detected. Statistical analysis of environmental data did not identify clear drivers of retention, but there were some notable statistically significant patterns including current direction and nitrate along with the T. gondii prevalence. The major C. parvum retention event (in October 2016) corresponded with the month of highest dissolved oxygen measurements as well as a shift in the current direction revealed by nearby instrumentation. This study may guide future research to locate any contributing parasite reservoirs and evaluate the potential risk to human consumption.
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Affiliation(s)
| | - Theodore J Bishop
- Bigelow Laboratory for Ocean Sciences, Boothbay, ME 04544, USA
- Southern Maine Community College, South Portland, ME 04106, USA
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Koutsoumanis K, Allende A, Alvarez-Ordóñez A, Bolton D, Bover-Cid S, Chemaly M, Davies R, De Cesare A, Herman L, Hilbert F, Lindqvist R, Nauta M, Peixe L, Ru G, Simmons M, Skandamis P, Suffredini E, Cacciò S, Chalmers R, Deplazes P, Devleesschauwer B, Innes E, Romig T, van der Giessen J, Hempen M, Van der Stede Y, Robertson L. Public health risks associated with food-borne parasites. EFSA J 2018; 16:e05495. [PMID: 32625781 PMCID: PMC7009631 DOI: 10.2903/j.efsa.2018.5495] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Parasites are important food‐borne pathogens. Their complex lifecycles, varied transmission routes, and prolonged periods between infection and symptoms mean that the public health burden and relative importance of different transmission routes are often difficult to assess. Furthermore, there are challenges in detection and diagnostics, and variations in reporting. A Europe‐focused ranking exercise, using multicriteria decision analysis, identified potentially food‐borne parasites of importance, and that are currently not routinely controlled in food. These are Cryptosporidium spp., Toxoplasma gondii and Echinococcus spp. Infection with these parasites in humans and animals, or their occurrence in food, is not notifiable in all Member States. This Opinion reviews current methods for detection, identification and tracing of these parasites in relevant foods, reviews literature on food‐borne pathways, examines information on their occurrence and persistence in foods, and investigates possible control measures along the food chain. The differences between these three parasites are substantial, but for all there is a paucity of well‐established, standardised, validated methods that can be applied across the range of relevant foods. Furthermore, the prolonged period between infection and clinical symptoms (from several days for Cryptosporidium to years for Echinococcus spp.) means that source attribution studies are very difficult. Nevertheless, our knowledge of the domestic animal lifecycle (involving dogs and livestock) for Echinoccocus granulosus means that this parasite is controllable. For Echinococcus multilocularis, for which the lifecycle involves wildlife (foxes and rodents), control would be expensive and complicated, but could be achieved in targeted areas with sufficient commitment and resources. Quantitative risk assessments have been described for Toxoplasma in meat. However, for T. gondii and Cryptosporidium as faecal contaminants, development of validated detection methods, including survival/infectivity assays and consensus molecular typing protocols, are required for the development of quantitative risk assessments and efficient control measures.
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Hernroth BE, Baden SP. Alteration of host-pathogen interactions in the wake of climate change - Increasing risk for shellfish associated infections? ENVIRONMENTAL RESEARCH 2018; 161:425-438. [PMID: 29202413 DOI: 10.1016/j.envres.2017.11.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 11/19/2017] [Accepted: 11/20/2017] [Indexed: 06/07/2023]
Abstract
The potential for climate-related spread of infectious diseases through marine systems has been highlighted in several reports. With this review we want to draw attention to less recognized mechanisms behind vector-borne transmission pathways to humans. We have focused on how the immune systems of edible marine shellfish, the blue mussels and Norway lobsters, are affected by climate related environmental stressors. Future ocean acidification (OA) and warming due to climate change constitute a gradually increasing persistent stress with negative trade-off for many organisms. In addition, the stress of recurrent hypoxia, inducing high levels of bioavailable manganese (Mn) is likely to increase in line with climate change. We summarized that OA, hypoxia and elevated levels of Mn did have an overall negative effect on immunity, in some cases also with synergistic effects. On the other hand, moderate increase in temperature seems to have a stimulating effect on antimicrobial activity and may in a future warming scenario counteract the negative effects. However, rising sea surface temperature and climate events causing high land run-off promote the abundance of naturally occurring pathogenic Vibrio and will in addition, bring enteric pathogens which are circulating in society into coastal waters. Moreover, the observed impairments of the immune defense enhance the persistence and occurrence of pathogens in shellfish. This may increase the risk for direct transmission of pathogens to consumers. It is thus essential that in the wake of climate change, sanitary control of coastal waters and seafood must recognize and adapt to the expected alteration of host-pathogen interactions.
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Affiliation(s)
- Bodil E Hernroth
- The Royal Swedish Academy of Sciences, Kristineberg 566, SE-451 78 Fiskebäckskil, Sweden; Dept. of Natural Science, Kristianstad University, SE-291 88 Kristianstad, Sweden.
| | - Susanne P Baden
- Dept. of Biological and Environmental Sciences, University of Gothenburg, Kristineberg 566, SE-451 78 Fiskebäckskil, Sweden
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Willis JE, McClure J, McClure C, Spears J, Davidson J, Greenwood SJ. Bioaccumulation and elimination of Cryptosporidium parvum oocysts in experimentally exposed Eastern oysters (Crassostrea virginica) held in static tank aquaria. Int J Food Microbiol 2014; 173:72-80. [DOI: 10.1016/j.ijfoodmicro.2013.11.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 11/16/2013] [Accepted: 11/28/2013] [Indexed: 10/25/2022]
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Global occurrence of Cryptosporidium and Giardia in shellfish: Should Canada take a closer look? Food Res Int 2013. [DOI: 10.1016/j.foodres.2013.02.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Palos Ladeiro M, Bigot A, Aubert D, Hohweyer J, Favennec L, Villena I, Geffard A. Protozoa interaction with aquatic invertebrate: interest for watercourses biomonitoring. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 20:778-789. [PMID: 23001759 DOI: 10.1007/s11356-012-1189-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 09/06/2012] [Indexed: 06/01/2023]
Abstract
Toxoplasma gondii, Cryptosporidium parvum, and Giardia duodenalis are human waterborne protozoa. These worldwide parasites had been detected in various watercourses as recreational, surface, drinking, river, and seawater. As of today, water protozoa detection was based on large water filtration and on sample concentration. Another tool like aquatic invertebrate parasitism could be used for sanitary and environmental biomonitoring. In fact, organisms like filter feeders could already filtrate and concentrate protozoa directly in their tissues in proportion to ambient concentration. So molluscan shellfish can be used as a bioindicator of protozoa contamination level in a site since they were sedentary. Nevertheless, only a few researches had focused on nonspecific parasitism like protozoa infection on aquatic invertebrates. Objectives of this review are twofold: Firstly, an overview of protozoa in worldwide water was presented. Secondly, current knowledge of protozoa parasitism on aquatic invertebrates was detailed and the lack of data of their biological impact was pointed out.
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Affiliation(s)
- M Palos Ladeiro
- Unité Interactions Animal-Environnement, EA 4689, UFR Sciences Exactes et Naturelles, Université de Reims Champagne Ardenne, Campus du Moulin de la Housse, 51100, Reims, France
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Grigorakis K, Rigos G. Aquaculture effects on environmental and public welfare - the case of Mediterranean mariculture. CHEMOSPHERE 2011; 85:899-919. [PMID: 21821276 DOI: 10.1016/j.chemosphere.2011.07.015] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 07/07/2011] [Accepted: 07/10/2011] [Indexed: 05/08/2023]
Abstract
Aquatic farming has been considered, during the last decades, as the fastest growing food production industry powered by governmental and technological impulsion. Compensation for fisheries decline, creation of new jobs and source of financial windfall are the most important benefits. However, similar to most of the human food-production activities, aquaculture raised several issues related to the environmental welfare and consumer safety. An effort to record the aquaculture-environment and -human safety interactions with regard to the Mediterranean mariculture, is attempted herein. We focused on this geographical area due to its individualities in both the hydrological and physicochemical characteristics and the forms of aquaculture activities. The cage farming of euryhaline marine fish species and more recently of bluefin tuna and mollusk farming are the dominating aquaculture activities. The impacts of these activities to the environment, through wastes offloads, introduction of alien species, genetic interactions, disease transfer, release of chemicals, use of wild recourses, alterations of coastal habitats and disturbance of wildlife, are analytically considered. Also the consumer safety issues related to the farming are assessed, including generation of antibiotic-resistant microorganisms, contaminants transferred to humans though food chain and other hazards from consumption of aquacultured items. Within these, the major literature findings are critically examined and suggestions for scientific areas that need further development are made. The major tasks for future aquaculture development in this region are: (i) to ensure sustainability and (ii) to balance the risks to public or environmental health with the substantial economical benefits. In regard with monitoring, tools must be created or adapted to predict the environmental costs and estimate consumer impact. At a canonistic and legal basis, the establishment of appropriate legal guidelines and common policies from all countries involved should be mandatory.
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Affiliation(s)
- K Grigorakis
- Laboratory of Fish Nutrition and Pathology, Institute of Aquaculture, Hellenic Centre for Marine Research (HCMR), Aghios Kosmas 16777, Athens, Greece
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GRIZZLE JOHNM, BRUNNER CINDYJ. Infectious Diseases of Freshwater Mussels and Other Freshwater Bivalve Mollusks. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/10641260902879000] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Robertson LJ, Gjerde B. Development and use of a pepsin digestion method for analysis of shellfish for Cryptosporidium oocysts and Giardia cysts. J Food Prot 2008; 71:959-66. [PMID: 18522030 DOI: 10.4315/0362-028x-71.5.959] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Investigation of shellfish for Cryptosporidium oocysts and Giardia cysts is of public health interest because shellfish may concentrate these pathogens in their bodies, and because shellfish are frequently eaten raw or lightly cooked. To date, the methods used for the analysis of shellfish for these parasites are based on those originally designed for water concentrates or fecal samples; the reported recovery efficiencies are frequently relatively low and the amount of sample examined is small. Here, we describe the development and use of a pepsin digestion method for analyzing shellfish samples for these parasites. The conditions of the isolation method did not affect subsequent parasite detection by immunofluorescent antibody test, and allowed examination of 3-g samples of shellfish homogenate, with recovery efficiencies from blue mussel homogenates of between 70 and 80%, and similar recoveries from horse mussel and oyster homogenates. Although exposure of the parasites to the conditions used in the technique affected their viability, as assessed by vital dyes, the maximum reduction in viability after 1-h incubation in digestion solution was 20%. In a preliminary survey of shellfish collected from the Norwegian coast, Cryptosporidium oocysts were detected in blue mussel homogenates in 6 (43%) of 14 batches and Giardia cysts in 7 (50%) of these batches. However, this relatively high occurrence, compared with other surveys, may be due to the higher recovery efficiency of the new method, and the relatively large sample size analyzed. A more comprehensive study of the occurrence of these parasites in shellfish would be of pertinence to the Norwegian shellfish industry.
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Affiliation(s)
- L J Robertson
- Parasitology Laboratory, Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, 0033 Oslo, Norway.
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Abstract
Waterborne trematode and protozoan infections inflict considerable morbidity on healthy, i.e., immunocompetent people, and may cause life-threatening diseases among immunocompromised and immunosuppressed populations. These infections are common, easily transmissible, and maintain a worldwide distribution, although waterborne trematode infections remain predominantly confined to the developing countries. Waterborne transmission of trematodes is enhanced by cultural practices of eating raw or inadequately cooked food, socio-economical factors, and wide zoonotic and sylvatic reservoirs of these helminths. Waterborne protozoan infections remain common in both developed and developing countries (although better statistics exist for developed countries), and their transmission is facilitated via contacts with recreational and surface waters, or via consumption of contaminated drinking water. The transmissive stages of human protozoan parasites are small, shed in large numbers in feces of infected people or animals, resistant to environmental stressors while in the environment, and few are (e.g., Cryptosporidium oocysts) able to resist standard disinfection applied to drinking water.
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Affiliation(s)
- Thaddeus K Graczyk
- Division of Environmental Health Engineering, Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
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The potential for marine bivalve shellfish to act as transmission vehicles for outbreaks of protozoan infections in humans: a review. Int J Food Microbiol 2007; 120:201-16. [PMID: 17928081 DOI: 10.1016/j.ijfoodmicro.2007.07.058] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 05/03/2007] [Accepted: 07/22/2007] [Indexed: 11/22/2022]
Abstract
Most marine molluscan bivalve shellfish feed on suspended phytoplankton which are trapped from water pumped across the gills by ciliary action. Pathogenic microorganisms in the water may be filtered by the gills during feeding, and become concentrated in the digestive glands/tract. If these pathogens are not excreted or inactivated by the shellfish, or in subsequent preparatory processes, they may be ingested by consumers, the shellfish thereby acting as vehicles of infection. The protozoan parasites Cryptosporidium spp., Giardia duodenalis and Toxoplasma gondii have the potential to be transmitted in this way, and here we review the accumulating knowledge on the occurrence and survival of the transmission stages of these parasites in shellfish, whilst also emphasising the considerable gaps in our knowledge. Relevant information is particularly lacking for T. gondii, which, in comparison with Cryptosporidium spp. and G. duodenalis, has been relatively under-researched in this context. Although it seems evident that these shellfish can accumulate and concentrate all three of these parasites from the surrounding water, whether Giardia cysts remain viable and infectious is unknown, and some evidence suggests that they may be inactivated by the shellfish. Although both Toxoplasma and Cryptosporidium apparently retain their infectivity for prolonged periods in shellfish, the actual public health threat posed by these parasites via these shellfish is unclear, largely because there is minimal evidence of infection transmission. Reasons for this apparent lack of infection transmission are discussed and it is recommended that the potential for transmission via shellfish consumption is recognised by those concerned with investigating transmission of these infections.
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King BJ, Monis PT. Critical processes affecting Cryptosporidium oocyst survival in the environment. Parasitology 2006; 134:309-23. [PMID: 17096874 DOI: 10.1017/s0031182006001491] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 08/21/2006] [Accepted: 08/21/2006] [Indexed: 11/07/2022]
Abstract
Cryptosporidium are parasitic protozoans that cause gastrointestinal disease and represent a significant risk to public health. Cryptosporidium oocysts are prevalent in surface waters as a result of human, livestock and native animal faecal contamination. The resistance of oocysts to the concentrations of chlorine and monochloramine used to disinfect potable water increases the risk of waterborne transmission via drinking water. In addition to being resistant to commonly used disinfectants, it is thought that oocysts can persist in the environment and be readily mobilized by precipitation events. This paper will review the critical processes involved in the inactivation or removal of oocysts in the terrestrial and aquatic environments and consider how these processes will respond in the context of climate change.
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Affiliation(s)
- B J King
- The Co-operative Research Centre for Water Quality and Treatment, Australian Water Quality Centre, SA Water Corporation, Salisbury, South Australia 5108, Australia
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Izumi T, Yagita K, Endo T, Ohyama T. Detection system of Cryptosporidium parvum oocysts by brackish water benthic shellfish (Corbicula japonica) as a biological indicator in river water. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2006; 51:559-66. [PMID: 16998637 DOI: 10.1007/s00244-005-0174-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2005] [Accepted: 10/27/2005] [Indexed: 05/12/2023]
Abstract
The brackish water benthic shellfish, Corbicula japonica, was experimentally exposed to Cryptosporidium parvum oocysts at 1.51x10(4)oocysts/clam/day for 7 or 14 days. Oocysts were predominantly eliminated through the feces of Corbicula japonica in both cases by microscopic and PCR methods. The fecal excretion rates of oocysts within 4 days after the last exposure to Corbicula japonica were 87.6% for the 7-day exposure group and 86.0% for the 14-day exposure group. The tissue residue level of oocysts in the gastrointestinal tract 3 days after the last exposure was 2.7% of total exposed oocysts and that of 7 days was 1.1% for the 7-day exposure case and 1.6 and 0.5% for the 14-day exposure case, respectively, maintaining infectivity to cultured cells (HCT-8) in vitro. At the same time, field tests of Corbicula japonica for collecting oocysts showed that this clam could certainly collect Cryptosporidium parvum oocysts in the natural river and, furthermore, the gene type of C. parvum could be also identified proving its effectiveness as a biological indicator. The present study showed that the brackish water benthic shellfish Corbicula japonica may be capable of gathering and preserving Cryptosporidium parvum oocysts to a considerable extent under the natural ecological conditions, and further suggests the effectiveness of Corbicula japonica as a practical and general bioindicator for estimates of river water contamination by oocysts of Cryptosporidium parvum.
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Affiliation(s)
- T Izumi
- Section of Drinking Water Chemistry, Division of Environmental Hygiene, Hokkaido Institute of Public Health, North 19, West 12, North Ward, Sapporo, 060-0819, Japan.
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Gómez-Couso H, Freire-Santos F, Hernández-Córdova GA, Ares-Mazás ME. A histological study of the transit of Cryptosporidium parvum oocysts through clams (Tapes decussatus). Int J Food Microbiol 2005; 102:57-62. [PMID: 15925002 DOI: 10.1016/j.ijfoodmicro.2004.12.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Revised: 05/18/2004] [Accepted: 12/27/2004] [Indexed: 11/29/2022]
Abstract
A histological study was carried out to investigate the transit of Cryptosporidium parvum oocysts through the clam Tapes decussatus. Spat of approximately 5-7 mm shell length were maintained in a tank of natural sea water contaminated with purified C. parvum oocysts. The experiment lasted 240 h and, every 24 h, five specimens were killed, placed in Bouin's fixative, and processed routinely for histological examination. Sections (3 mum) cut from the all body tissues were stained with modified Gomori's trichrome for their accurate identification; the oocysts were detected by a direct immunofluorescence procedure. Oocysts were detected in siphons, gills, stomach, digestive diverticula, and intestine. The oocysts present in the intestine were free or mixed with the intestinal contents; therefore release of these oocysts with the feces should favour dissemination of contamination. Oocysts were found in branchial mucus and within the interfilamentary spaces, which suggests the occurrence of repeated filtrations and the possibility that the retained oocysts maintain their infective capacity.
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Affiliation(s)
- H Gómez-Couso
- Laboratorio de Parasitología, Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, Santiago de Compostela 15782, A Coruña, Spain
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Graczyk TK, Tamang L, Graczyk H. Human protozoan parasites in molluscan shellfish. ADVANCES IN FOOD AND NUTRITION RESEARCH 2005; 50:79-100. [PMID: 16263428 DOI: 10.1016/s1043-4526(05)50003-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Affiliation(s)
- Thaddeus K Graczyk
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA
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17
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Cryptosporidium in foodstuffs—an emerging aetiological route of human foodborne illness. Trends Food Sci Technol 2002. [DOI: 10.1016/s0924-2244(02)00135-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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