Detection of Cryptosporidium parvum in environmental soil and vegetables

Cryptosporidium and agriculture: A review

Cryptosporidiosis is a significant contributor to global foodborne and waterborne disease burden. It is a widespread cause of diarrheal diseases that affect humans and animals worldwide. Agricultural environments can become a source of contamination with Cryptosporidium species through faecal material derived from humans and animals. This review aims to report the main findings of scientific research on Cryptosporidium species related to various agricultural sectors, and highlights the risks of cryptosporidiosis in agricultural production, the contamination sources, the importance of animal production in transmission, and the role of farmed animals as hosts of the parasites. Agricultural contamination sources can cause water pollution in groundwater and different surface waters used for drinking, recreational purposes, and irrigation. The application of contaminated manure, faecal sludge management, and irrigation with inadequately treated water are the main concerns associated with foodborne and waterborne cryptosporidiosis related to agricultural activities. The review emphasizes the public health implications of agriculture concerning the transmission risk of Cryptosporidium parasites and the urgent need for a new concept in the agriculture sector. Furthermore, the findings of this review provide valuable information for developing appropriate measures and monitoring strategies to minimize the risk of infection.

Transmission of Cryptosporidium by Fresh Vegetables

ABSTRACT

Consumption of fresh fruits and vegetables is increasing thanks to a greater awareness of the human health benefits. Vegetables may become contaminated by enteric pathogens (protozoan parasites, bacteria, and viruses) by irrigation with contaminated water, fertilization with fresh animal manure, or by infected food handlers. Cryptosporidium spp. are fecal-oral protozoan parasites, known to be highly persistent in the environment. Efficient methods were developed for releasing and concentrating Cryptosporidium oocysts from leafy vegetables, and sensitive and specific methods were applied for detection. The aims of this review are to discuss the development and optimization of methods applied to elute, concentrate, and detect oocysts from leafy vegetables, to review the prevalence of Cryptosporidium oocysts on fresh leafy vegetables from various parts of the world, and to discuss cryptosporidiosis outbreaks resulting from the consumption of leafy vegetables. Three solutions were used with comparable efficiency to release oocysts from leafy vegetables: 1 M glycine solution; 0.1% Alconox; and filter elution buffer, with an efficiency of 36.2, 72.6, and 44%, respectively. The prevalence of Cryptosporidium oocysts was reported in developed, as well as from developing countries, although simple detection methods were applied. Most of the cryptosporidiosis outbreaks were reported in developed countries, which can be related to the efficient surveillance system. Transmission of infectious pathogens, such as Cryptosporidium, may be facilitated by fresh vegetables, which are imported and transferred from less developed to highly developed countries and consumed uncooked. Monitoring of Cryptosporidium oocysts by sensitive detection methods may enhance measures to prevent transmission by freshly consumed vegetables.

HIGHLIGHTS

What on earth? The impact of digestates and composts from farm effluent management on fluxes of foodborne pathogens in agricultural lands

The recycling of biomass is the cornerstone of sustainable development in the bioeconomy. In this context, digestates and composts from processed agricultural residues and biomasses are returned to the soil. Whether or not the presence of pathogenic microorganisms in these processed biomasses is a threat to the sustainability of the current on-farm practices is still the subject of debate. In this review, we describe the microbial pathogens that may be present in digestates and composts. We then provide an overview of the current European regulation designed to mitigate health hazards linked to the use of organic fertilisers and soil improvers produced from farm biomasses and residues. Finally, we discuss the many factors that underlie the fate of microbial pathogens in the field. We argue that incorporating land characteristics in the management of safety issues connected with the spreading of organic fertilisers and soil improvers can improve the sustainability of biomass recycling.

Molecular Epidemiology of Cryptosporidium parvum and Giardia lamblia in Different Water Bodies, Soil, and Vegetables in Pakistan

There is a dearth of knowledge regarding transmission of Cryptosporidium (C) and Giardia (G) species through water and water-related sources in Pakistan. To this end, we conducted a study to evaluate the prevalence of these parasites in different water bodies, soil, and mixed raw vegetables in Pakistan. Researchers collected 200 samples from each reservoir including municipal water, sewage water, canal water, raw vegetables, soil of public parks, and soil of grazing areas. Researchers amplified the 18S ribosomal RNA gene of parasites using newly designed genus-specific primers through polymerase chain reaction testing. The sequencing analysis revealed that the obtained sequences belonged to C parvum and G lamblia. Phylogenetic clustering and sequence analysis of C parvum showed that the C parvum Pak1 (OM540369) and C parvum Pak2 (OM540370) as well as C parvum Pak3 (OM510450) and C parvum Pak6 (OM510445) were closely similar to each other. In the case of G lamblia, all the sequences appeared in the same clade. The epidemiological data showed lower prevalence of C parvum (11.5%) in all reservoirs, compared with G lamblia (20.5%). Among different reservoirs, prevalence of Cryptosporidium and Giardia was observed in sewage water (C = 13%, G = 26.5%), municipal water (C = 10%, G = 35%), canal water (C = 9.5%, G = 18.5%), raw vegetables (C = 5.5%, G = 8%), soil of public parks (C = 13%, G = 14%), and soil of grazing areas (C = 18.5%, G = 21.5%). Among targeted risk factors, poor hygienic conditions significantly affected the prevalence of parasites in sewage water (C = 20%, G = 41.2%), municipal water (C = 14.7%, G = 48.8.5%), raw vegetables (C = 11.3%, G = 15.1%), and soil of public parks (C = 19.5%, G = 21.9%). Similarly, contamination with sewage waste significantly affected (P < .05) the prevalence of these parasites in municipal water (C = 13.6%, G = 41.1%), canal water (C = 13.3%, G = 25%), raw vegetables (C = 12.1%, G = 15.1%), and soil of public parks (C = 23.3%, G = 15%). Results of this study illustrated a high risk of parasitic zoonosis through water bodies, soil, and vegetables.

Cryptosporidiosis outbreak in Amazonia, French Guiana, 2018

BACKGROUND

Cryptosporidiosis outbreaks in South America are poorly documented. In March 2018, 51 cases of cryptosporidiosis were reported in Maripasoula, a village located in a remote forest area along the border between Surinam and French Guiana.

METHOD

To identify the origin of the epidemic, we performed epidemiological, microbiological, and environmental investigations. Only the cases involving diarrhoea and Cryptosporidium-positive stool were considered as bona fide, while cases involving diarrhoea and close contact with a confirmed case were classified as "possible".

RESULTS

We identified 16 confirmed cases and 35 possible ones. Confirmed cases comprised nine children (median age of 18 months, range: 6-21), one immunocompromised adult and six soldiers. One child required a hospitalisation for rehydration. All 16 Cryptosporidium stools were PCR positive, and sequencing of the gp60 gene confirmed only one Cryptosporidium hominis subtype IbA10G2. Tap water consumption was the only common risk factor identified. Contamination of the water network with Cryptosporidium parvum subtype IIdA19G2 was found.

CONCLUSION

Water quality is a major public health issue in Amazonian French Guiana, especially for population at risk (children, people with comorbidity, travelers). For them, alternative water supply or treatment should be implemented.

Diverse Genotypes and Species of Cryptosporidium in Wild Rodent Species from the West Coast of the USA and Implications for Raw Produce Safety and Microbial Water Quality

Cryptosporidium spp. are protozoan parasites that infect perhaps all vertebrate animals, with a subset of species and genotypes that function as food- and waterborne pathogens. The objective of this work was to collate the Cryptosporidium species and genotypes from common wild rodents on the west coast of the USA and update the information regarding the zoonotic potential of Cryptosporidium from these ubiquitous wild species. Representative sequences of the 18S rRNA gene for a unique set of Cryptosporidium isolates obtained from deer mice, house mice, mountain beavers, yellow-bellied marmot, long-tailed vole, California ground squirrels, Belding’s ground squirrels, and a golden-mantled ground squirrel in GenBank were selected for phylogenetic analysis. Phylogenetic and BLAST analysis indicated that 4 (18%) of the 22 unique Cryptosporidium sequences from these wild rodent species were 99.75% to 100% identical to known zoonotic species (C. parvum, C. ubiquitum, C. xiaoi), suggesting that a minority of these representative Cryptosporidium isolates could have a public health impact through food and waterborne routes of human exposure. These zoonotic isolates were shed by deer mice and a yellow-bellied marmot from California, and from a mountain beaver trapped in Oregon. In addition, the group of unique Cryptosporidium isolates from deer mice and ground dwelling squirrels exhibited considerable DNA diversity, with multiple isolates appearing to be either host-limited or distributed throughout the various clades within the phylogenetic tree representing the various Cryptosporidium species from host mammals. These results indicate that only a subset of the unique Cryptosporidium genotypes and species obtained from wild rodents on the US west coast are of public health concern; nevertheless, given the geographic ubiquity of many of these host species and often high density at critical locations like municipal watersheds or produce production fields, prudent pest control practices are warranted to minimize the risks of water- and foodborne transmission to humans.

Establishment and preliminary application of nanoparticle-assisted PCR assay for detection of Cryptosporidium spp

Cryptosporidium is an important intestinal protozoan parasite that causes diarrhoea in humans and animals. To rapidly and specifically detect Cryptosporidium spp., we designed a pair of primers based on the small subunit ribosomal RNA (SSU rRNA) gene of Cryptosporidium spp. to be used in a new nanoparticle-assisted PCR (nano-PCR) assay. The minimum detectable concentration (1.02 pg) of this nano-PCR was 10 times more sensitive than conventional PCR using the same primer pair. The DNA samples of C. parvum, C. baileyi, C. xiaoi, C. ryanae, and C. andersoni were successfully detected by the nano-PCR. No amplifications were evident with DNA samples of some common intestinal pathogens, including Eimeria tenella, Blastocystis sp., Giardia lamblia, Enterocytozoon bieneusi, and Balantidium coli. To validate the clinical usefulness of the novel nano-PCR, a total of 40 faecal samples from goats, camels, calves, and chickens were examined. The positive rate of Cryptosporidium spp. was 27.5% (11/40), which was consistent with that of an established nested PCR. These results indicate that the novel nano-PCR assay enables the rapid, specific, and accurate detection of Cryptosporidium infection in animals. The findings provide a technical basis for the clinical diagnosis, prevention, and control of cryptosporidiosis.

Cryptosporidium spp., Giardia duodenalis and Toxoplasma gondii detection in fresh vegetables consumed in Marrakech, Morocco

BACKGROUND

Protozoan parasites such as Toxoplasma gondii, Giardia duodenalis, and Cryptosporidium spp., can be transmitted to humans via accidental consumption of contaminated water, fresh produce and foodstuffs. There is a lack of epidemiological data about these pathogens in Morocco. Hence the aim of this study, which is the determination of their prevalence in some leafy greens and root vegetables sold in Marrakech.

METHODS

A total of 132 vegetable samples including carrot, coriander, lettuce, parsley and radish were purchased monthly from three different markets in Marrakech from March 2017 to January 2018, pre-treated and subjected to microscopic and molecular analyses.

RESULTS

Of the 132 samples of vegetables analyzed by qPCR, the overall rate of protozoan was 21.21% (28/132); 22 samples were found to be contaminated with T. gondii, 6 with G. duodenalis, and none was positive for C. parvum/hominis. Whereas, modified Ziehl-Neelsen staining allowed the detection of Cryptosporidium spp. in 3% (4/132) of examined samples.

CONCLUSION

This survey on the presence of protozoan parasites in fresh vegetables revealed that vegetables sold in Marrakech are contaminated by these protozoan parasites, as it showed that leafy green vegetables were more susceptible for parasitic contamination than root ones.

Dairy Calves in Uruguay Are Reservoirs of Zoonotic Subtypes of Cryptosporidium parvum and Pose a Potential Risk of Surface Water Contamination

Cryptosporidium parvum, a major cause of diarrhea in calves, is of concern given its zoonotic potential. Numerous outbreaks of human cryptosporidiosis caused by C. parvum genetic subtypes are reported yearly worldwide, with livestock or water being frequently identified sources of infection. Although cryptosporidiosis has been reported from human patients in Uruguay, particularly children, epidemiologic information is scant and the role of cattle as reservoirs of zoonotic subtypes of C. parvum has not been explored. In this study, we aimed to (a)-identify C. parvum subtypes infecting dairy calves in Uruguay (including potentially zoonotic subtypes), (b)-assess their association with calf diarrhea, (c)-evaluate their spatial clustering, and (d)-assess the distance of infected calves to surface watercourses draining the farmlands and determine whether these watercourses flow into public water treatment plants. Feces of 255 calves that had tested positive for Cryptosporidium spp. by antigen ELISA were selected. Samples had been collected from 29 dairy farms in seven Uruguayan departments where dairy farming is concentrated and represented 170 diarrheic and 85 non-diarrheic calves. Selected samples were processed by nested PCRs targeting the 18S rRNA and gp60 genes followed by sequencing to identify C. parvum subtypes. Of seven C. parvum subtypes detected in 166 calves, five (identified in 143 calves on 28/29 farms) had been identified in humans elsewhere and have zoonotic potential. Subtype IIaA15G2R1 was the most frequent (53.6%; 89/166), followed by IIaA20G1R1 (24.1%; 40/166), IIaA22G1R1 (11.4%; 19/166), IIaA23G1R1 (3.6%; 6/166), IIaA17G2R1 (3%; 5/166), IIaA21G1R1 (2.4%; 4/166), and IIaA16G1R1 (1.8%; 3/166). There were no significant differences in the proportions of diarrheic and non-diarrheic calves infected with any of the C. parvum subtypes. Two spatial clusters were detected, one of which overlapped with Uruguay's capital city and its main water treatment plant (Aguas Corrientes), harvesting surface water to supply ~1,700,000 people. Infected calves on all farms were within 20–900 m of a natural surface watercourse draining the farmland, 10 of which flowed into six water treatment plants located 9–108 km downstream. Four watercourses flowed downstream into Aguas Corrientes. Calves are reservoirs of zoonotic C. parvum subtypes in Uruguay and pose a public health risk.

Detection of human intestinal protozoan parasites in vegetables and fruits: a review

Diarrheal diseases caused by intestinal protozoan parasites are a major food-borne public health problem across the world. Vegetables and fruits provide important nutrients and minerals, but are also common sources of some food-borne human pathogenic microorganisms. The contamination of raw vegetables and fruits with human pathogenic parasites are now a global public health threat, despite the health benefits of these foods in non-pharmacological prophylaxes against diseases. A large number of reports have documented the contamination of vegetables or fruits with human pathogenic microorganisms. In this paper, we reviewed the contamination and detection methods of human pathogenic intestinal protozoans that are frequently recovered from raw vegetables and fruits. The protozoan parasites include Cryptosporidium spp., Giardia duodenalis, Cyclospora cayetanensis, Entamoeba spp., Toxoplasma gondii, Balantioides coli, Blastocystis sp., Cystoisospora belli and Enterocytozoon bieneusi. The risk factors involved in the contamination of vegetables and fruits with parasites are also assessed.

Cold Atmospheric Plasma Jet Inactivates Cryptosporidium parvum Oocysts on Cilantro

ABSTRACT

Cilantro was recently identified as a vehicle for protozoan illness. Current postharvest practices are not sufficient to inactivate protozoa on cilantro. Cold plasma is an emerging nonthermal waterless technology with potential applications in food processing that are currently being investigated to enhance the safety of herbs. The purpose of this study was to determine the impact of cold atmospheric plasma (CP) on the viability of Cryptosporidium parvum oocysts on cilantro. C. parvum oocysts were inoculated onto cilantro and treated with a CP jet for 0, 30, 90, and 180 s at a working distance of 10 cm with a flow of 1.42 × 10-3 m3/s. Oocyst viability was determined using HCT-8 cell culture infectivity assays. Overall, each treatment significantly reduced oocyst infectivity compared with the 0-s treatment control (P ≤ 0.02). Log inactivations of oocysts observed on cilantro were 0.84, 1.23, and 2.03 for the 30-, 90-, and 180-s treatment times, respectively. Drying and darkening of cilantro leaves was observed with treatments longer than 30 s. CP can reduce C. parvum infectivity on cilantro. With further research and optimization, this treatment technology has potential applications in postharvest processing of cilantro.

HIGHLIGHTS

Detection of Cryptosporidium oocysts and Giardia cysts in vegetables from street markets from the Qinghai Tibetan Plateau Area in China

Cryptosporidium and Giardia are well-known parasitic protozoans responsible for waterborne and foodborne diarrhoeal diseases. However, data are not available on market vegetables contaminated with Cryptosporidium and Giardia in China. In the present study, 642 different vegetable samples were collected from Xining City street vendors in the Qinghai Province to study the Cryptosporidium and Giardia contamination rates via PCR and sequence analyses. Cryptosporidium spp. and Giardia duodenalis were detected in 16 (2.5%) and 73 (11.4%) samples, respectively. Two species of Cryptosporidium, C. parvum (n = 11) and C. andersoni (n = 5), were identified. G. duodenalis assemblage B was identified in almost all positive samples (n = 72), except one sample that contained G. duodenalis assemblage E. We report on the rate of Cryptosporidium and Giardia contamination in vegetables for the first time from the Qinghai Tibetan Plateau Area (QTPA) in China.

Detection methods and prevalence of transmission stages of Toxoplasma gondii, Giardia duodenalis and Cryptosporidium spp. in fresh vegetables: a review

One of the ways of human parasitic infection is the accidental ingestion of vegetables contaminated with parasites, which represents a major human health hazard. This non-exhaustive review aims to evaluate studies carried out on five types of vegetables (lettuce, parsley, coriander, carrot and radish) since 2000, particularly the methods used for recovery, concentration, detection and identification of protozoan parasites such as Toxoplasma gondii, Giardia duodenalis and Cryptosporidium spp., and the results of each work. Various studies have determined the presence of pathogenic parasites in fresh vegetables with different rates; this variation in rate depends particularly on the detection method used which is related to each parasite and each vegetable type. The variation in parasitic prevalence in food could be due to different factors such as the geographical location, the size of analysed samples and the methods used for parasite detection.

E, Timothy J. W. Emergency Department Visits for Acute Gastrointestinal Illness After a Major Water Pipe Break in 2010

BACKGROUND

When a water pipe breaks, contaminants can enter the drinking water system and cause waterborne illnesses such as acute gastrointestinal illness. In May 2010, a major water pipe broke near Boston, MA, and a boil water order was issued to nearly two million residents.

METHODS

Using a case-crossover study design, we examined the association between the water pipe break and subsequent emergency department visits for acute gastrointestinal illness. We identified cases of illness according to ICD-9-CM diagnosis codes and selected control dates 2 weeks before and after each case. We estimated the risk of visiting the emergency department during the 0-3 and 4-7 days after the water pipe break using conditional logistic regression models.

RESULTS

Our analysis included 5,726 emergency department visits for acute gastrointestinal illness from 3 April 2010 to 5 June 2010. Overall, there was a 1.3-fold increased odds for visiting the emergency department for acute gastrointestinal illness during the 0-3 days after the water pipe break (odds ratio [OR] = 1.3; 95% confidence interval [CI] = 1.1, 1.4) compared with referent dates selected 2 weeks before and after. During the 4-7 days after the break, the association diminished overall (OR = 1.1; 95% CI = 0.96, 1.2). However, in communities over 12 miles from the break, the 4- to 7-day association was elevated (OR = 1.4; 95% CI = 1.1, 1.8).

CONCLUSIONS

This study suggests that a major water pipe break was associated with emergency department visits for acute gastrointestinal illness, particularly during the 0-3 days after the break, when a boil water order was in effect.

Accumulation of oocysts of Cryptosporidium parvum in Biomphalaria glabrata (Pulmonata:Planorbidae) under experimental conditions

INTRODUCTION

Cryptosporidium oocysts are easily transported to various aquatic environments. The objective of this study was to evaluate B. glabrata mollusks exposed to food containing C. parvum oocysts.

METHODS

Six experimental groups were used with B. glabrata either exposed or not to C. parvum oocysts. Microscopic and molecular diagnostics were conducted in water samples and tissues of B. glabrata.

RESULTS

By light microscopy, C. parvum oocysts were identified in the water of the exposed groups. C. parvum DNA was not detected in water but was detected in tissue samples.

CONCLUSIONS

Further studies should be conducted under natural conditions.

Prevalence of parasitic contamination of raw vegetables in Nakhon Si Thammarat province, southern Thailand

Background

Soil-transmitted helminth (STH) infections are major public health problems in poor and developing countries that require fecal contamination of the environment for transmission. The consumption of raw vegetables without proper washing is one of the main routes of intestinal parasite acquisition. Therefore, this study was designed to detect the prevalence of intestinal parasitic contamination in commonly consumed raw vegetables sold in three central open-air markets in Nakhon Si Thammarat province, southern Thailand.

Methods

A total of 265 fresh vegetable samples consisting of peppermint, lettuce, coriander, leek, gotu kola, celery, Chinese cabbage, culantro, Thai basil, and Chinese morning glory were purchased from three central open-air markets in the Mueang, Thasala and Sichon districts from December 2016 to March 2017. Each sample was washed with physiological saline, shaken for 15 min, and then allowed to sediment. Finally, sedimentation was performed via the sedimentation concentration technique and examined using light microscopy for the detection of pathogenic parasites.

Results

The overall prevalence of parasitic contamination was 35.1% (93/265). The most predominant parasite was hookworms (42.9%), followed by Strongyloides stercoralis (10.6%), Trichuris trichiura (2.6%), Ascaris lumbricoides (2.6%), and Toxocara spp. (2.6%). The highest level of contamination was found in celery, with a prevalence rate of 63.3% (19/30), while the lowest contamination level was found in Chinese morning glory, with a prevalence rate of 2.0% (2/30). The prevalence of intestinal parasite contamination in Mueang district (51.5%) was significantly higher than that in Thasala district (17.9%) and Sichon district (30.6%) (P < 0.001).

Conclusion

The results of the present study demonstrate that consumption of vegetables with parasite contamination in this area represents a potential route for the transmission of parasitic infection, particularly hookworm infection. Therefore, it is necessary for health authorities to educate consumers about the proper washing of vegetables prior to consumption. Preventive methods such as wearing gloves and washing hands after handling vegetables should also be advocated to sellers who are at risk of acquiring STH infections via skin penetration.

Methods for the detection of Cryptosporidium and Giardia: From microscopy to nucleic acid based tools in clinical and environmental regimes

The detection and characterization of genotypes and sub genotypes of Cryptosporidium and Giardia is essential for their enumeration, surveillance, prevention, and control. Different diagnostic methods are available for the analysis of Cryptosporidium and Giardia including conventional phenotypic tools that face major limitations in the specific diagnosis of these protozoan parasites. The substantial advancement in the development of genetic signature based molecular tools for the quantification, diagnosis and genetic variation analysis has increased the understanding of the epidemiology and preventive measures of related infections. The conventional methods such as microscopy, antibody and enzyme based approaches, offer better detection results when combined with advanced molecular methods. Gene based approaches increase the precision of identification, for example, many signatures detected in environmental matrices represent species/genotype that are not infectious to humans. This review summarizes the available methods and the advantages and limitations of advance detection techniques like nucleic acid-based approaches for the detection of viable oocysts and cysts of Cryptosporidium and Giardia along with the conventional and widely accepted detection techniques like microscopy, antibody and enzyme based ones. This technical article also encourages the wide application of molecular methods in genetic characterization of distinct species of Cryptosporidium and Giardia, to adopt necessary preventive measures with reliable identification and mapping the source of contamination.

Assessing viability and infectivity of foodborne and waterborne stages (cysts/oocysts) of Giardia duodenalis, Cryptosporidium spp., and Toxoplasma gondii: a review of methods

Giardia duodenalis, Cryptosporidium spp. and Toxoplasma gondii are protozoan parasites that have been highlighted as emerging foodborne pathogens by the Food and Agriculture Organization of the United Nations and the World Health Organization. According to the European Food Safety Authority, 4786 foodborne and waterborne outbreaks were reported in Europe in 2016, of which 0.4% were attributed to parasites including Cryptosporidium, Giardia and Trichinella. Until 2016, no standardized methods were available to detect Giardia, Cryptosporidium and Toxoplasma (oo)cysts in food. Therefore, no regulation exists regarding these biohazards. Nevertheless, considering their low infective dose, ingestion of foodstuffs contaminated by low quantities of these three parasites can lead to human infection. To evaluate the risk of protozoan parasites in food, efforts must be made towards exposure assessment to estimate the contamination along the food chain, from raw products to consumers. This requires determining: (i) the occurrence of infective protozoan (oo)cysts in foods, and (ii) the efficacy of control measures to eliminate this contamination. In order to conduct such assessments, methods for identification of viable (i.e. live) and infective parasites are required. This review describes the methods currently available to evaluate infectivity and viability of G. duodenalis cysts, Cryptosporidium spp. and T. gondii oocysts, and their potential for application in exposure assessment to determine the presence of the infective protozoa and/or to characterize the efficacy of control measures. Advantages and limits of each method are highlighted and an analytical strategy is proposed to assess exposure to these protozoa.

Parasite contamination of berries: Risk, occurrence, and approaches for mitigation

Fresh fruits and vegetables, including berries, are essential components of a healthy diet and are relevant in the prevention of chronic non-communicable diseases such as cancer and heart disease. Associations between diet and health are becoming an increasing focus of consumers, and, in response, consumption of fresh berries has been increasing rapidly in recent decades. However, increased consumption of berries may be associated with an increased risk of acquiring foodborne infections, including parasites. In this review, we describe how parasite contamination of berries may occur at several points on the farm-to-fork pathway, starting from the use of contaminated water for irrigation and pesticide application, and contact with animal and human faeces during cultivation, through contaminated harvesting equipment, and including unhygienic practices of berry pickers in the production field or others handling berries prior to consumption. Parasite transmission stages tend to be robust and therefore likely to survive from contamination in the field, through the various stages of harvesting, packaging, and sale, until consumption. We describe outbreaks of parasitic disease associated with consumption of berries - so far only described for Cyclospora and Trypanosoma cruzi, both of which are briefly introduced - but also show from survey data summarised in this review that sporadic infections or undetected outbreaks associated with contaminated berries may also occur. In addition, we describe methods for assessing whether berries are contaminated with parasite transmission stages, with emphasis on the challenges associated with analysing this particular matrix. Emphasis on current possibilities for mitigation and control are addressed; avoidance of contamination and implementation of good management practices and a hazard analysis and critical control points (HACCP) approach are essential.

An overview of methods/techniques for the detection of Cryptosporidium in food samples

Cryptosporidium is one of the most important parasitic protozoa of concern within the food production industry, worldwide. This review describes the evolution and its development, and it monitors the methodology that has been used for Cryptosporidium in food material since 1984, when the first publication appeared regarding the detection of Cryptosporidium parvum in food materials. The methods that are currently being used for the detection of Cryptosporidium oocysts in food material (mainly vegetables) and all of the other available published methods are discussed in this review. Generating more consistent and reliable data should lead to a better understanding of the occurrence, transport and fate of the oocysts in food material. Improvements in monitoring and developing effective methodology, along with food security, offer more practical possibilities for both the developed and developing worlds.

Foodborne cryptosporidiosis

Foodborne illness, the majority of which is caused by enteric infectious agents, costs global economies billions of dollars each year. The protozoan parasite Cryptosporidium is particularly suited to foodborne transmission and is responsible for >8 million cases of foodborne illness annually. Procedures have been developed for sensitive detection of Cryptosporidium oocysts on fresh produce and molecular diagnostic assays have been widely used in case linkages and infection source tracking, especially during outbreak investigations. The integrated use of advanced diagnostic techniques with conventional epidemiological studies is essential to improve our understanding of the occurrence, source and epidemiology of foodborne cryptosporidiosis. The implementation of food safety management tools such as Good Hygienic Practices (GHP), Hazard Analysis and Critical Control Points (HACCP), and Quantitative Microbial Risk Assessment (QMRA) in industrialised nations and Water, Sanitation, and Hygiene (WASH) in developing countries is central for prevention and control and foodborne cryptosporidiosis in the future.

Simultaneous Molecular Detection of Cryptosporidium and Cyclospora from Raw Vegetables in Korea

Cryptosporidium and Cyclospora are well-known coccidian protozoa that can cause waterborne and foodborne diarrheal illnesses. There have been a few reports regarding contamination in different vegetables with Cryptosporidium, but no data are available regarding the sources of Cyclospora infections in Korea. In the present study, we collected 6 kinds of vegetables (perilla leaves, winter-grown cabbages, chives, sprouts, blueberries, and cherry tomatoes) from July 2014 to June 2015, and investigated contamination by these 2 protozoa using multiplex quantitative real-time PCR. Among 404 vegetables, Cryptosporidium and Cyclospora were detected in 31 (7.7%) and 5 (1.2%) samples, respectively. In addition, Cryptosporidium was isolated from all 6 kinds of vegetables, whereas Cyclospora was detected in 4 kinds of vegetables (except perilla leaves and chives). Cryptosporidium (17.8%) and Cyclospora (2.9%) had the highest detection rates in chives and winter-grown cabbages, respectively. Cryptosporidium was detected all year long; however, Cyclospora was detected only from October to January. In 2 samples (sprout and blueberry), both Cryptosporidium and Cyclospora were detected. Further investigations using TaqI restriction enzyme fragmentation and nested PCR confirmed Cryptosporidium parvum and Cyclospora cayetanensis, respectively. In conclusion, we detected C. cayetanensis in vegetables for the first time in Korea. This suggests that screening should be employed to prevent these protozoal infections in Korea.

Cryptosporidium Contamination and Attributed Risks in Yunlong Lake in Xuzhou, China

Swimming in surface water bodies (e.g., lakes, rivers) can expose the human body to substantial risk of infection by Cryptosporidium. These findings are from a one-year investigation on the occurrence and distribution of the protozoan parasite Cryptosporidium in Yunlong Lake, Xuzhou, China. Cryptosporidium oocysts were detected by immunofluorescence microscopy. From January to November of 2015, 180 samples (120 water samples and 60 sediment samples) were collected and analyzed. Among them, 42 (35%) water samples and 28 (47%) sediment samples tested positive for Cryptosporidium. The concentration of Cryptosporidium oocysts in the water samples was 0-8/10 L and 0-260/g in sediment samples. Results revealed that July was the highest risk period for both swimming and diving with an estimated probability of infection from swimming of greater than 18 per 10,000 swim sessions. It was concluded that swimming or diving in Yunlong Lake has a higher risk of Cryptosporidium infection than the acceptable risk level set by the United States Environmental Protection Agency. Thus, regular monitoring of water quality in recreation water bodies is strongly recommended.

Detection and quantification of Cryptosporidium oocysts in environmental surfaces of an Equine Perinatology Unit

The presence of Cryptosporidium in institutions such as veterinary teaching hospitals, where students and staff are in frequent contact with animals, could represent a serious public health risk. In this study the detection and quantification of the Cryptosporidium oocysts present on the environmental surfaces of an Equine Perinatology Unit (EPU) were investigated. During 3 foaling seasons 175 samples obtained by swabbing an area of the floor and walls of boxes and utility rooms of EPU with sterile gauze, in 3 different moments. Samples were collected at the end of foaling season (July), after washing procedures (September) and after washing and disinfecting procedures, at the beginning of a new foaling season (December). All the samples were subjected to nested-PCR, followed by genotyping and sub-typing methods and to qPCR, allowing the oocyst quantification. Cryptosporidium spp. was detected in 14 samples, of which 11 were from walls and three were from floors. The highest number of oocysts was found in a sample collected from the floor of one utility room used for setting up therapies and treatments. In most cases, oocyst numbers, estimated by qPCR, were reduced or eliminated after washing and disinfecting procedures. The genotyping and sub-typing methods allowed identification of 2 subtypes of C. parvum (IIaA15G2R1 and IIdA23G1) and 1 of Cryptosporidium horse genotype (VIaA15G4) that were described in foals hospitalized at the EPU in the same years. The results of the present study show that qPCR can be used to evaluate Cryptosporidium contamination of environmental surfaces of a veterinary teaching hospital and the efficacy of the disinfection procedures.

Detection of Encephalitozoon spp. from human diarrheal stool and farm soil samples in Korea

Microsporidia are eukaryotic organisms that cause zoonosis and are major opportunistic pathogens in HIV-positive patients. However, there is increasing evidence that these organisms can also cause gastrointestinal and ocular infections in immunocompetent individuals. In Korea, there have been no reports on human infections with microsporidia to date. In the present study, we used real-time PCR and nucleotide sequencing to detect Encephalitozoon intestinalis infection in seven of 139 human diarrheal stool specimens (5%) and Encephalitozoon hellem in three of 34 farm soil samples (8.8%). Genotype analysis of the E. hellem isolates based on the internal transcribed spacer 1 and polar tube protein genes showed that all isolates were genotype 1B. To our knowledge, this is the first report on human E. intestinalis infection in Korea and the first report revealing farm soil samples as a source of E. hellem infection. Because microsporidia are an important public health issue, further large-scale epidemiological studies are warranted.