Identification of human pathogenic Enterocytozoon bieneusi, Cyclospora cayetanensis, and Cryptosporidium parvum on the surfaces of vegetables and fruits in Henan, China

One Health approach for prioritization of potential foodborne pathogens: Risk-ranking, Delphi survey, and criteria evaluation pre- and post-COVID-19 pandemic

Frequent foodborne illnesses with unknown causative agents highlight the need to explore zoonotic potential foodborne pathogens (PFPs). An effective PFP prioritization tool is indispensable, especially after experiencing the recent pandemic caused by zoonotic SARS-CoV-2. Risk information on pathogens (excluding 30 known foodborne pathogens) provided by governmental and international organizations was reviewed to generate a list of PFPs. Risk-ranking of PFPs was conducted based on a literature review of food poisoning or detection cases, and the ranks were determined with a decision tree. PFPs were prioritized by infectious disease (ID), veterinary medicine (VET), and food safety (FS) experts through a pre- and postpandemic Delphi survey, and key criteria in their decisions were illuminated. Among 339 PFPs, 32 rank-1 PFPs were involved in the foodborne outbreak(s). Discrepancies in opinions on prioritization between experts in different fields deepened after the pandemic. Only VET and FS experts valued the plausibility of foodborne transmission in evaluating bacteria and viruses, and a significant correlation between their selection of PFPs was found (p < .05). The impact of the pandemic induced all fields to focus more on human transmission and severity/fatality in prioritizing viruses, and only FS experts emphasized the plausibility of foodborne transmission after the pandemic. In contrast to prioritizing bacteria or viruses, ID and VET experts are unusually focused on foodborne transmission when prioritizing parasites. Criteria of consensus deduced by interdisciplinary experts with different interests and the criteria directly related to foodborne transmission should be acknowledged for adequate PFP prioritization.

Prevalence and risk estimates of Cryptosporidium oocysts infection associated with consumption of raw-eaten vegetables in Maiduguri metropolis LGAs, Northeast Nigeria

Cryptosporidium is one of the most important protozoan parasitic pathogens, and it is a common cause of diarrhoea in humans, domestic animals, and wild vertebrates and has serious public health threats. A cross-sectional study was designed to determine the prevalence of Cryptosporidium oocysts in raw-eaten vegetables in Maiduguri Metropolitan Council (MMC) and Jere Local Government Areas (LGAs). A total of 400 samples were collected from four (4) different locations, namely Tashan Bama, Gomboru, and Monday Markets (n = 100), while fifty (n = 50) each from 202-Vegetable-Vendors and Unimaid Commercials. A total of 16 visits were conducted in all the sampling areas (twenty-five samples per visit). The Cryptosporidium oocysts were detected using the Modified Ziehl-Neelsen Staining Technique. The locations, sources, and types of raw-eaten vegetables were also assessed. The oocysts were confirmed (100×) as bright pink spherules. Data generated were analyzed using IBM-SPSS V23.0, and p ≤ 0.05 was considered significant. Out of the total samples (n = 400) analyzed, cabbage appeared to have the highest number of 10 (12.5%) of Cryptosporidium oocysts detected, while Tomato and garden egg had 9 (11.3%) and 1 (1.2%), respectively. There was a statistically significant association (χ2 = 12.5, P = 0.014) between the presence of Cryptosporidium oocysts in raw-eaten vegetables and vegetable types. Among the sources of the vegetables sampled, Alau had the highest number of Cryptosporidium oocysts, 15 (12.5%), followed by Kilari-Abdullahi and Zabarmari sources with 4 (10.0%) and 4 (5.0%), respectively. However, Jetete appeared to have the least number 2 (2.5%) of oocysts, and there was a statistically significant association (χ2= 10.4, P = 0.034) between the presence of Cryptosporidium oocysts and the sources of vegetables and fruits. The study concludes that the raw-eaten vegetables sampled from Maiduguri Metropolis were contaminated with Cryptosporidium oocysts. The study recommends that all raw-eaten vegetables should be from cleaned sources and washed before consumption. Consumers should be enlightened on the hygienic measures in the food chain in line with the Hazard Analysis and Critical Control Points (HACCP) principles.

Cyclospora cayetanensis: A Perspective (2020-2023) with Emphasis on Epidemiology and Detection Methods

Cyclospora cayetanensis infections are prevalent worldwide, and the parasite has become a major public health and food safety concern. Although important efforts have been dedicated to advance toward preventing and reducing incidences of cyclosporiasis, there are still several knowledge gaps that hamper the implementation of effective measures to prevent the contamination of produce and water with Cyclospora oocysts. Some of these data gaps can be attributed to the fact that access to oocysts is a limiting factor in C. cayetanensis research. There are no animal models or in vivo or in vitro culture systems to propagate the oocysts needed to facilitate C. cayetanensis research. Thus, researchers must rely upon limited supplies of oocysts obtained from naturally infected human patients considerably restricting what can be learnt about this parasite. Despite the limited supply of C. cayetanensis oocysts, several important advances have happened in the past 3 years. Great progress has been made in the Cyclospora field in the areas of molecular characterization of strains and species, generation of genomes, and development of novel detection methods. This comprehensive perspective summarizes research published from 2020 to 2023 and evaluates what we have learnt and identifies those aspects in which further research is needed.

Exploring genetic variability of Giardia duodenalis and Enterocytozoon bieneusi in raw vegetables and fruits: implications for food safety and public health in Mozambique

Giardia duodenalis and Enterocytozoon bieneusi are etiological agents of enteric diseases characterized by diarrhea that can progress to chronicity in humans, especially in children and in immunocompromised patients. This study aims to assess the genetic pattern of G. duodenalis and E. bieneusi detected in vegetables and fruits commercialized in Maputo markets, Mozambique and determine their public health importance. Eight study points were sampled: a farmer zone, a wholesale, four retail markets, and two supermarkets in Maputo city, where eight types of horticultural products were purchased. Using nested-PCR methods, 2.8% (9/321) and 1.3% (4/321) of samples monitored were positive for G. duodenalis and E. bieneusi, respectively. Based on the analysis of the β-giardin and ITS rRNA sequences of G. duodenalis and E. bieneusi detected, respectively, four different sequences of G. duodenalis (three novel sequences: BgMZ1, BgMZ2, and BgMZ3, and one known sequence) all from assemblage B and three genotypes of E. bieneusi (two novel sequences: EbMZ4 and EbMZ5, and one known sequence: KIN-1) from group 1. These microorganisms were found and characterized for the first time in horticultural products in Maputo markets. All identified G. duodenalis and E. bieneusi display high genetic similarity within their β-giardin and ITS rRNA sequences, respectively, having been clustered into assemblages and genotypes with high zoonotic transmission potential. Our study may represent a relevant step in the understanding of these intestinal pathogens in association with fresh vegetables and fruits for human consumption, for a better and broader "One Health" approach.

Global prevalence and genotype distribution of Microsporidia spp. in various consumables: a systematic review and meta-analysis

Water and food sources play a major role in the distribution and transfer of microsporidia infection to animals and humans. So, this systematic review and meta-analysis aimed to assess the status and genetic diversity of microsporidia infection in water, vegetables, fruits, milk, cheese, and meat. The standard protocol of Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines was followed. Scopus, PubMed, Web of Science, and Google Scholar were searched from 1 January 2000 and 1 February 2023. The point estimates and 95% confidence intervals (CIs) were calculated using a random-effects model. Of the 1,308 retrieved studies, 35 articles were included in the final meta-analysis. The pooled prevalence of microsporidia infection in mixed water, mixed fruits, mixed vegetables, and milk was 43.3% (95% CI, 33-54.2%; I², 94.86%), 35.8% (95% CI, 5.3-84.8%; I², 0), 12% (95% CI, 4.9-26.6%; I², 96.43%), and 5.8% (95% CI, 2.7-12%; I², 83.72%), respectively. Considering the genotypes, microsporidia with genotype D in water sources and genotype CD6 in vegetables/fruits were the highest reported genotypes. Given the relatively high prevalence of microsporidiosis (especially in water sources), designing strategies for control, and prevention of microsporidia infection in these sources should be recommended.

Molecular Epidemiological Investigation of Cyclospora spp. in Holstein Cattle in Partial Areas of the Yunnan Province, China

Cyclospora spp. is a food-borne intestinal protozoan, which is widely distributed in the world and poses the risk of zoonosis. In order to reveal the prevalence of Cyclospora spp. in Holstein cattle in partial areas of the Yunnan Province, 524 fresh fecal samples of Holstein cattle were collected from Dali, Kunming, Chuxiong, and Qujing in Yunnan Province. A nested PCR amplification of the small subunit (SSU) rRNA gene of Cyclospora spp. was carried out, and the products of the nested PCR were further analyzed by restriction fragment length polymorphism (RFLP) using Bsp E Ⅰ. The results of the present study showed that 13 samples were positive for Cyclospora spp., and the total infection rate of Cyclospora sp. was 2.48%. The infection of Cyclospora spp. was detected in Dali, Qujing, and Chuxiong. Chuxiong showed the highest infection rate (5.71%), and infection rate in Dali and Qujing was 2.19% and 3.16%, respectively. Interestingly, the infection of Cyclospora spp. was not detected in Kunming. The infection of Cyclospora spp. showed no significant differences among different regions (p > 0.05). Cyclospora sp. infection was detected in all ages and sexes, but the differences were not significant (p > 0.05). Sequencing and phylogenetic analysis showed that five Cyclospora spp. samples were closely related to the Cyclospora spp. of humans, and the others were closely related to the Cyclospora spp. of bovines. The results of the present study suggested that there was an infection of Cyclospora spp. in Holstein cattle in the Yunnan Province, and the Cyclospora spp. showed a risk of zoonosis. Thus, the prevention and control of Cyclospora spp. should be strengthened in the Yunnan Province, China. The results of this investigation provide data references for the further research of Cyclosporiasis in Holstein cattle in the Yunnan Province.

Health risks of Cryptosporidium and Giardia in the application of surface water and septic tank effluent in Chinese agriculture: Impact on cancer patients identified by quantitative microbial risk assessment

The protozoa Cryptosporidium and Giardia are major causes of diarrhea and are commonly found on vegetables in China. They pose a health risk, particularly to immunocompromised individuals, including cancer patients. A quantitative microbial risk assessment of Chinese data evaluated the risks of Cryptosporidium and Giardia exposure arising from the application of surface water and septic tank effluent to agricultural land. Exposure via agricultural produce consumption (consumers) and agricultural practices (farmers) was considered for subpopulations of cancer patients and immunocompetent people in urban and rural areas, and risk mitigation scenarios were modelled. The cumulative disease burdens attributable to cryptosporidiosis and giardiasis were, respectively, 9.68×10^-6 and 5.57×10^-5 disability-adjusted life years per person per year (DALYs pppy) for immunocompetent people, and 3.14×10^-5 and 1.51×10^-4 DALYs pppy for cancer patients. Cancer patients were approximately three times more likely to have an individual disease burden than immunocompetent people. The disease burden was higher for consumers than farmers, and higher in rural areas than urban areas (all exceeding the maximum recommended by the World Health Organization). The highest burdens were in provinces of high population, such as Henan, Guangdong, and Sichuan, while the burden associated with human and livestock fecal effluent application was higher than with surface water irrigation. Of the three vegetables studied, lettuce posed the greatest risk, followed by bok choy, while cucumber posed the least risk. Risk mitigation scenario analysis showed that pre-treatment of surface water and feces, and appropriate post-harvest handling of vegetables, including disinfection, cooking, and adequate surface heat treatment (75 °C for 60 s), should be considered when attempting to reduce disease burdens. The methodology and findings of this study are useful for evaluating and reducing the burden of Cryptosporidium and Giardia infections associated with agricultural irrigation and fertilization practices, particularly on cancer patients.

Molecular investigation of ready-to-eat salads for Giardia duodenalis and Cryptosporidium spp. in Portugal

Foodborne outbreaks are often associated with the consumption of salads. However, published studies on the detection of foodborne pathogens in ready-to-eat salads are scarce. The aim of this study was to detect Giardia duodenalis and Cryptosporidium DNA in ready-to-eat salads, by applying techniques of molecular biology to study the frequency of contamination in salads. A total of 100 packages of ready-to-eat salads containing assorted leafy green vegetables were randomly purchased from hypermarkets located in central regions of Portugal (Coimbra and Viseu). Nested-PCR and qPCR methods were used to detect G. duodenalis and Cryptosporidium DNA. Species and assemblages of the parasites were identified by sequence analysis and PCR. Eighteen of the 100 samples (18%) were positive for G. duodenalis and twelve were sequenced and identified as assemblage A. Cryptosporidium spp. were not detected in any salads. Overall, pre-harvest and post-harvest preventive measures may be need for G. duodenalis control throughout the food production industry, from the field to consumers.

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

Enterocytozoon bieneusi in patients with diarrhea and in animals in the northeastern Chinese city of Yichun: genotyping and assessment of potential zoonotic transmission

Enterocytozoon bieneusi is a common microsporidia species in humans and animals. Due to lack of effective vaccines and drugs, understanding of its epidemiological status and characteristics in different hosts is an important step in controlling the infection. The present study aimed at determining the prevalence of E. bieneusi in humans with diarrhea and animals in Yichun, in northeastern China, and assessing the epidemiological role of animals in the transmission of microsporidiosis. A total of 540 fecal samples were collected from diarrheal patients (n = 222) and 11 animal species (n = 318). Enterocytozoon bieneusi was identified and genotyped by polymerase chain reaction (PCR) and sequencing of the internal transcribed spacer (ITS) region of the rRNA gene. Enterocytozoon bieneusi was detected in 1.4% (3/222) of diarrheal patients, and genotype D and novel genotypes YCHH1 and YCHH2 were identified. Enterocytozoon bieneusi was detected in wild boars (7.7%), sika deer (8.2%), dogs (3.2%), and ostriches (10.7%), and genotypes D, Type IV, Peru6, BEB6 and novel genotypes YCHA1, YCHA2 and YCHA3 were identified. Genotypes YCHH1, YCHH2 and YCHA1 were phylogenetically assigned to group 1, while YCHA2 and YCHA3 to groups 2 and 11, respectively. The finding of genotype D in humans and animals, and the identification of zoonotic genotypes Peru6, Type IV, BEB6 in animal-derived E. bieneusi isolates indicate the potential of zoonotic transmission of microsporidiosis in the investigated area. The observation of the three novel genotypes in group 1 indicates their zoonotic potential.

Prevalence and new genotypes of Enterocytozoon bieneusi in wild rhesus macaque (Macaca mulatta) in China: A zoonotic concern

Enterocytozoon bieneusi is a zoonotic pathogen with a wide range of animal host. There are only few reports of E. bieneusi infection in wild Chinese rhesus macaques. Here, we determined the prevalence of E. bieneusi in nine wild rhesus macaque populations and assessed their zoonotic potential by performed genotype of ITS gene. A total of 324 fecal samples of rhesus macaque were collected in nine geographical populations from five Chinese provinces (Sichuan, Chongqing, Qinghai, Tibet and Hainan). 38 samples (11.7%) were found to be infected with E. bieneusi, and 11 genotypes were identified including three known genotypes (D, EbpC and SCC-2) and eight novel genotypes named Mul6∼13. Genotype D (63.2%) was the most prevalent, being observed in seven populations except XZ-2 and QH, and other genotypes were identified only in a single area. According to the phylogenetic analysis, Mul6∼9, Mul11∼13 and zoonotic genotype D were clustered into Group 1, indicating that these genotypes may be potentially zoonotic. Among nine populations, population SC-3 had the highest infection rate (26.3%), and the lowest was the wild QH population without infection, but the difference of infection rate among the nine populations is not significant. It is concluded that, rhesus macaque populations are generally infected E. bieneusi in many areas of China, and there may be a risk of cross infection with E. bieneusi in some areas found having zoonotic genotypes, and these areas should be paid more attention to prevent.

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Nine geographical populations (3 semi-wild and 6 wild) from five Chinese provinces (Sichuan, Chongqing, Qinghai, Tibet and Hainan).

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11 genotypes of Enterocytozoon bieneusi were identified.

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Three known genotypes (D, EbpC and SCC-2) and eight novel genotypes (Mul6∼13).

A Perspective on the Molecular Identification, Classification, and Epidemiology of Enterocytozoon bieneusi of Animals

The microsporidian Enterocytozoon bieneusi is an obligate intracellular pathogen that causes enteric disease (microsporidiosis) in humans and has been recorded in a wide range of animal species worldwide. The transmission of E. bieneusi is direct and likely occurs from person to person and from animal to person via the ingestion of spores in water, food, or the environment. The identification of E. bieneusi is usually accomplished by molecular means, typically using the sequence of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA. Currently, ~820 distinct genotypes of E. bieneusi have been recorded in at least 210 species of vertebrates (mammals, birds, reptiles, and amphibians) or invertebrates (insects and mussels) in more than 50 countries. In this chapter, we provide a perspective on (1) clinical aspects of human microsporidiosis; (2) the genome and DNA markers for E. bieneusi as well as molecular methods for the specific and genotypic identification of E. bieneusi; (3) epidemiological aspects of E. bieneusi of animals and humans, with an emphasis on the genotypes proposed to be zoonotic, human-specific, and animal-specific; and (4) future research directions to underpin expanded molecular studies to better understand E. bieneusi and microsporidiosis.

Incubation period, spore shedding duration, and symptoms of Enterocytozoon bieneusi genotype C infection in a foodborne outbreak in Denmark, 2020

Background

Microsporidia are rarely reported to cause outbreaks of diarrhea. We describe a foodborne outbreak of microsporidiosis from a workplace canteen in November 2020 in Denmark.

Methods

A probable case was defined as any person using the canteen between 4 November and 13 December 2020, reporting at least one gastrointestinal symptom, whereas a confirmed case also had an Enterocytozoon bieneusi positive stool sample. A web-based questionnaire was used to collect clinical, epidemiological, and food exposure data. We performed a retrospective cohort study and tested stool samples from affected individuals for bacterial, viral, and parasitic pathogens, including E. bieneusi.

Results

Altogether, 195 individuals completed the questionnaire. We identified 52 cases (65% male; median age 45 years [range 25–65]). Diarrhea (90%), fatigue (83%), and abdominal pain (79%) were the most commonly reported symptoms. Eight cases were laboratory-confirmed and had E. bieneusi genotype C. The incubation period was between 5 and 12 days, and polymerase chain reaction (PCR)-detectable spore shedding occurred up to 43 days after symptom onset. Disease was associated with consuming food from the workplace canteen on 4 November 2020 (relative risk [RR[, 2.8 [95% confidence interval [CI]: 1.4 – 5.4]) and lunchboxes containing open sandwiches (RR, 3.2 [95% CI: 1.4 – 7.2]) served that day.

Conclusions

This is the second documented foodborne outbreak of E. bieneusi genotype C-associated diarrhea worldwide. Epidemiological findings advocated an open sandwiches lunchbox from 4 November 2020, as a likely source. E. bieneusi may be an under-reported cause of outbreaks of diarrhea, and testing for it might be useful in foodborne outbreak investigations.

Occurrence of Intestinal Parasites of Public Health Significance in Fresh Horticultural Products Sold in Maputo Markets and Supermarkets, Mozambique

(1) Background: Giardia duodenalis and Cryptosporidium are important neglected parasites associated with diarrhea, such as the emerging Enterocytozoon bieneusi. All three are foodborne parasites raising concerns in public health. This study intended to understand the intestinal parasite occurrence with emphasis on G. duodenalis, Cryptosporidium, and E. bieneusi in fresh fruits/vegetables sold in the main municipal markets of Maputo city, Mozambique. (2) Methods: A total of 321 fresh horticultural products were purchased in the rainy and dry seasons (five markets/two supermarkets/one agricultural zone). Light microscopy (LM) and PCR analysis were performed. (3) Results: By LM and/or PCR, 29.3% of the samples presented at least one parasite (rainy season: 22.9%; dry season: 35.1%). The most contaminated horticultural products: collected in dry season, from Zimpeto and Fajardo markets, lettuce and pointed white cabbage. Overall, 3.7% of G. duodenalis, 1.3% of E. bieneusi, and other intestinal parasites (pathogenic and non-pathogenic) were identified. (4) Conclusions: Important pathogenic intestinal parasites were identified in fruits/vegetables commercially purchased in Maputo City. This fact must be taken into consideration when planning the management of these horticultural markets, in order to reduce the risk of contamination of fresh produce by intestinal parasites, and to prevent foodborne diseases.

Detection of Cyclospora cayetanensis, Echinococcus multilocularis, Toxocara spp. and microsporidia in fresh produce using molecular methods: - A review

The current trend for a healthy lifestyle corresponds with a healthy diet, which is associated with regular and frequent consumption of raw fruit and vegetables. However, consumption of ready-to-eat (RTE) food without heat treatment or sufficient washing may pose a risk to consumers. Among the well-known protozoan parasites associated with RTE food and water are Cryptosporidium spp., Giardia duodenalis and Toxoplasma gondii. These belong among prioritized parasitic pathogens, as they are associated with numerous disease outbreaks in humans all around the world. Nevertheless, other parasitic agents such as Cyclospora cayetanensis, Toxocara cati, Toxocara canis, Echinococcus multilocularis and zoonotic microsporidia should not be neglected. Although these selected parasites belong to phylogenetically diverse groups, they have common characteristics associated with fresh produce and each of them poses a health risk to humans. Ensuring healthy food is produced requires the standartization of laboratory methods for the detection of parasitic agents. This article reviews the molecular methods currently used in laboratories for detection of Cyclospora cayetanensis, Toxocara cati, Toxocara canis, Echinococcus multilocularis and zoonotic microsporidia in fresh produce.

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.

Detection of Cyclospora cayetanensis on bagged pre-cut salad mixes within their shelf-life and after sell by date by the U.S. food and drug administration validated method

Recently, outbreaks of Cyclospora cayetanensis in the U.S. were linked to the consumption of a variety of salads containing romaine and/or iceberg lettuce, carrots and/or red cabbage. The Bacteriological Analytical Manual (BAM) Chapter 19b method was validated for the detection of C. cayetanensis in carrots, cabbage and romaine lettuce, but has not been previously evaluated in ready-to-eat (RTE) salad mixes. In addition, the only samples available for traceback investigations are sometimes leftovers in bad conditions. This study evaluated the validated BAM method for detection of C. cayetanensis in two different RTE mixed salads (mix 1: romaine and iceberg lettuces, carrots, and red cabbage and mix 2: romaine and iceberg lettuces, carrots, red cabbage, radish, and pea pods) in good condition and after their sell by date. Individual samples (25 g) were seeded with five and 200 C. cayetanensis oocysts. Unseeded produce was used as negative control. The method included washing of the produce, concentration and extraction of C. cayetanensis DNA and molecular detection of C. cayetanensis 18 S rRNA gene. As few as five oocysts were detected in both fresh and after sell by date mix salads. All unseeded samples were negative, and all samples of both salad types seeded with 200 oocysts were positive. In samples seeded with 200 oocysts, average 18 S rRNA C. cayetanensis C_T values were significantly higher in fresh salad mix 1 compared to fresh salad mix 2; C_T values were significantly higher in the after sell by date salads compared to their respective fresh mixes (p < 0.05). In conclusion, the BAM method was able to detect as few as five oocysts even in after sell by date RTE mix salads. However, the differences in detection observed, highlight the importance of evaluating the performance of the validated C. cayetanensis detection method in different food matrices and conditions, in advance for future outbreak investigations.

Prevalence, genetic diversity and implications for public health of Enterocytozoon bieneusi in various rodents from Hainan Province, China

Background

Rodents, globally overpopulated, are an important source for zoonotic disease transmission to humans, including Enterocytozoon bieneusi (one of the most prevalent zoonotic pathogens). Here, we studied the prevalence and performed genetic analyses of E. bieneusi in rodents from the Hainan Province of China.

Methods

A total of 603 fresh fecal samples were gathered from 369 wild rats, 117 bamboo rats, 93 Asiatic brush-tailed porcupine and 24 red-bellied squirrels. The wild rats were identified to the species level by amplification of a 421-bp region of the cytb gene from fecal DNA using PCR. Genotype analysis was performed by amplification of the internal transcribed spacer (ITS) region of rDNA of E. bieneusi using PCR.

Results

Seven wild rat species were identified. The average rate of infection with E. bieneusi was 15.8% (95/603) with 18.7% (69/369) in wild rats, 11.9% (25/210) in farmed rodents and 4.2% (1/24) in red-bellied squirrels. Sixteen E. bieneusi genotypes were identified, including 9 known genotypes (D, Type IV, PigEBITS7, Peru8, Peru11, ESH02, S7, EbpA and CHG5), and 7 novel genotypes (HNR-I to HNR-VII). Genotype D (44.2%, 42/95) predominated, followed by PigEBITS7 (20.0%, 19/95), HNR-VII (15.8%, 15/95), Type IV (5.3%, 5/95), HNR-III (2.1%, 2/95), HNR-VI (2.1%, 2/95) and each of the remaining 10 genotypes (1.1%, 1/95). The phylogenetic analysis of the ITS region of E. bieneusi divided the identified genotypes into the following four groups: Group 1 (n = 13), Group 2 (n = 1), Group 12 (n = 1), and the novel Group 13 (n = 1).

Conclusions

To our knowledge, this is the first report on the identification of E. bieneusi in rodents from Hainan, China. The zoonotic potential of the identified E. bieneusi genotypes suggested that the rodents poses a serious threat to the local inhabitants. Thus, measures need to be taken to control the population of wild rats in the areas investigated in this study, along with identification of safe methods for disposal of farmed rodent feces. Additionally, the local people should be made aware of the risk of disease transmission from rodents to humans.

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.

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.

Update on Cryptosporidium spp.: highlights from the Seventh International Giardia and Cryptosporidium Conference

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

Advances in Cyclosporiasis Diagnosis and Therapeutic Intervention

Cyclosporiasis is caused by the coccidian parasite Cyclospora cayetanensis and is associated with large and complex food-borne outbreaks worldwide. Associated symptoms include severe watery diarrhea, particularly in infants, and immune dysfunction. With the globalization of human food supply, the occurrence of cyclosporiasis has been increasing in both food growing and importing countries. As well as being a burden on the health of individual humans, cyclosporiasis is a global public health concern. Currently, no vaccine is available but early detection and treatment could result in a favorable clinical outcome. Clinical diagnosis is based on cardinal clinical symptoms and conventional laboratory methods, which usually involve microscopic examination of wet smears, staining tests, fluorescence microscopy, serological testing, or DNA testing for oocysts in the stool. Detection in the vehicle of infection, which can be fresh produce, water, or soil is helpful for case-linkage and source-tracking during cyclosporiasis outbreaks. Treatment with trimethoprim-sulfamethoxazole (TMP-SMX) can evidently cure C. cayetanensis infection. However, TMP-SMX is not suitable for patients having sulfonamide intolerance. In such case ciprofloxacin, although less effective than TMP-SMX, is a good option. Another drug of choice is nitazoxanide that can be used in the cases of sulfonamide intolerance and ciprofloxacin resistance. More epidemiological research investigating cyclosporiasis in humans should be conducted worldwide, to achieve a better understanding of its characteristics in this regard. It is also necessary to establish in vitro and/or in vivo protocols for cultivating C. cayetanensis, to facilitate the development of rapid, convenient, precise, and economical detection methods for diagnosis, as well as more effective tracing methods. This review focuses on the advances in clinical features, diagnosis, and therapeutic intervention of cyclosporiasis.