Identification of Cryptosporidium Species in Fish from Lake Geneva (Lac Léman) in France

Mixed Eimeria and Cryptosporidium infection and its effects on pathology and clinical outcomes in juvenile Asian seabass (Lates calcarifer) cultured in Thailand

Coccidiosis is an important disease in juvenile fish because of severe intestinal injury during infection. We first reported the mixed infection of intestinal coccidia and its association with health status and pathological findings in juvenile Asian seabass (Lates calcarifer) cultured in Thailand. Two groups of Asian seabass, 60-day fish and 90-day fish, were sampled to investigate prevalence and coccidian infection intensity using morphological characterization and PCR. Phylogenetic analysis of 18S rRNA gene amplified from the intestines revealed Eimeria sp. and Cryptosporidium sp. infection. The prevalence of Eimeria sp. and Cryptosporidium sp. in sampled fish was 100%. Clinical outcomes assessed, using health assessment index (HAI) scoring and semi-quantitative grading of intestinal lesions and inflammation, demonstrated that all fish developed variety of pathology and clinical illness; however, infection intensity in 60-day fish was significantly higher (p < .05) than 90-day fish. The HAI score of 60-day fish was poorer than 90-day fish, which correlated to a high infection intensity (r = .397), analysed by Pearson correlation coefficient. Overproduction of intestinal oxidants contributing to mucosal injury was examined by nitrotyrosine expression. The high production of reactive nitrogen species indicated severe inflammatory response, and intestinal injuries occurred mainly in the 60-day fish.

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.

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.

First Epidemiological Report on the Prevalence and Associated Risk Factors of Cryptosporidium spp. in Farmed Marine and Wild Freshwater Fish in Central and Eastern of Algeria

PURPOSE

The present study aimed to estimate the prevalence and molecular characterization of Cryptosporidium spp. in six different fish species both from marine and freshwater environments.

METHODS

During a period of 2 years (2018-2020), a total of 415 fecal samples and 565 intestinal scrapings were collected in seven provinces from the central and eastern Algeria. From those, 860 fish belonged to six different species, two of which are cultured marine and four are wild freshwater fish. All samples were screened for Cryptosporidium spp. presence using molecular techniques. Nested PCR approach was performed to amplify partial sequences of the small subunit ribosomal RNA (SSU rRNA) and 60-kDa glycoprotein (GP60) genes for Cryptosporidium genotyping and subtyping. Detailed statistical analysis was performed to assess the prevalence variation of Cryptosporidium infection according to different risk factors.

RESULTS

Nested PCR analysis of SSU gene revealed 173 Cryptosporidium positive fish, giving an overall prevalence of 20.11% (17.5-23.0). Cryptosporidium spp. was detected in 8.93% (42/470) of cultured marine fish and 33.58% (131/390) of wild freshwater fish. Overall, the prevalence was affected by all studied risk factors, except the gender. Molecular characterization and subtyping of Cryptosporidium isolates showed occurrence of IIaA16G2R1 and IIaA17G2R1 subtypes of C. parvum in the fish species Sparus aurata.

CONCLUSION

The present study provides the first epidemiological data on the prevalence and associated risk factors of Cryptosporidium spp. in farmed marine and wild freshwater fish and the first molecular data on the occurrence of zoonotic C. parvum in fish from North Africa (Algeria).

Molecular Characterization of Cryptosporidium spp. in Cultivated and Wild Marine Fishes from Western Mediterranean with the First Detection of Zoonotic Cryptosporidium ubiquitum

Fish not only harbor host-specific species/genotypes of Cryptosporidium, but also species like zoonotic C. parvum or anthroponotic C. hominis, which can pose a risk for fish consumers. This study aims to investigate fish cryptosporidiosis in an important aquaculture and fishery area of the Western Mediterranean (Comunidad Valenciana, Spain). We analyzed 404 specimens belonging to the following three groups: cultivated fish (N = 147), wild synanthropic fish (N = 147) and wild fish from extractive fisheries (N = 110). Nested PCR targeting the 18S rRNA gene, followed by sequencing and phylogenetic analysis, were performed. Positive isolates were also amplified at the actin gene locus. An overall prevalence of 4.2% was detected, with the highest prevalence in the synanthropic group (6.1%). C. molnari was identified in thirteen specimens from seven different host species. Zoonotic C. ubiquitum was detected in two European sea bass (Dicentrarchus labrax). One isolate similar to C. scophthalmi was detected in a cultivated meagre (Argyrosomus regius), and one isolate, highly divergent from all the Cryptosporidium species/genotypes described, was identified from a synanthropic round sardinella (Sardinella aurita). This study contributes to increasing the molecular data on fish cryptosporidiosis, expanding the range of known hosts for C. molnari and identifying, for the first time, zoonotic C. ubiquitum in edible marine fishes, pointing out a potential health risk.

Prevalence and Molecular Epidemiology of Cryptosporidium Infection in Clarias gariepinus Fish in Egypt

PURPOSE

This study investigated the prevalence and molecular detection of Cryptosporidium spp. in catfish (Clarias gariepinus).

METHODS

A total of 300 Carias gariepinus fish were collected from two freshwater sources: the Nile River (180) and drainage canals (120). The stomach and intestine epithelium of each individual fish sample were screened by modified Ziehl-Neelsen (mZN) staining technique for the detection of Cryptosporidium oocysts followed by the serological survey for detection of Cryptosporidium antibodies using Enzyme-Linked Immunosorbent Assay (ELISA) and molecular characterization using complemented DNA polymerase chain reaction (cPCR).

RESULTS

ELISA showed higher prevalence of 69.3% than that prevalence obtained by mZN, 64% for the total examined Clarias gariepinus fish. Also, higher prevalence of Cryptosporidium infection 65.5% and 75.8% obtained by ELISA than 61.1% and 68.3% by mZN, in both fish groups from Nile River and Drainage canal, respectively. PCR analysis revealed the expected positive bands at 1056 bp. DNA sequencing and phylogenetic analysis proved that the positive-PCR Cryptosporidium isolate identified in the present study was Cryptosporidium molnari.

CONCLUSION

Freshwater fishes (Clarias gariepinus) are subjected to a high infection rate with Cryptosporidium spp.; the drainage canals obtained fishes showed higher prevalence than that collected from Nile River which indicates an important public health problem and a potential risk of drainage canals in Egypt. ELISA showed higher prevalence of cryptosporidiosis than mZN, for the total examined Clarias gariepinus fish and phylogenetic analyses confirmed this protozoal organism to be a novel species of Cryptosporidium molnari.

A review of the current status of Cryptosporidium in fish

Species of the genus Cryptosporidium (phylum Apicomplexa) infect the epithelium of the gastrointestinal tract of several vertebrate hosts, including humans and domestic and wild animals. In the past 20 years, several studies have focused on Cryptosporidium in fish. To date, a total of four piscine-host-specific species (Cryptosporidium molnari, Cryptosporidium huwi, Cryptosporidium bollandi and Cryptosporidium abrahamseni), nine piscine genotypes and more than 29 unnamed genotypes have been described in fish hosts. In addition, Cryptosporidium species and genotypes typical of other groups of vertebrates have also been identified. This review summarizes the history, biology, pathology and clinical manifestations, as well as the transmission, prevalence and molecular epidemiology of Cryptosporidium in wild, cultured and ornamental fish from both marine and freshwater environments. Finally, the potential role of piscine hosts as a reservoir of zoonotic Cryptosporidium species is also discussed.

Cross-Border Investigations on the Prevalence and Transmission Dynamics of Cryptosporidium Species in Dairy Cattle Farms in Western Mainland Europe

Cryptosporidium is an apicomplexan parasitic protist, which infects a wide range of hosts, causing cryptosporidiosis disease. In farms, the incidence of this disease is high in animals such as cows, leading to extensive economic loss in the livestock industry. Infected cows may also act as a major reservoir of Cryptosporidium spp., in particular C. parvum, the most common cause of cryptosporidiosis in these animals. This poses a risk to the trading of livestock, to other farms via breeding centres, and to human health. This study is a part of a global project aimed at strategies to tackle cryptosporidiosis. To reach this target, it was essential to determine whether prevalence was dependent on the studied countries or if the issue was borderless. Indeed, C. parvum occurrence was assessed across dairy farms in certain regions of Belgium, France, and the Netherlands. At the same time, the animal-to-animal transmission of the circulating C. parvum subtypes was studied. To accomplish this, we analysed 1084 faecal samples, corresponding to 57 dairy farms from all three countries. To this end, 18S rRNA and gp60 genes fragments were amplified, followed by DNA sequencing, which was subsequently used for detection and subtyping C. parvum. Bioinformatic and phylogenetic methods were integrated to analyse and characterise the obtained DNA sequences. Our results show 25.7%, 24.9% and 20.8% prevalence of Cryptosporidium spp. in Belgium, France, and the Netherlands respectively. Overall, 93% of the farms were Cryptosporidium positive. The gp60 subtyping demonstrated a significant number of the C. parvum positives belonged to the IIa allelic family, which has been also identified in humans. Therefore, this study highlights how prevalent C. parvum is in dairy farms and further suggests cattle as a possible carrier of zoonotic C. parvum subtypes, which could pose a threat to human health.

CRYPTOSPORIDIUM SPP. IN PET DWARF WINTER WHITE RUSSIAN HAMSTERS (PHODOPUS SUNGORIS SUNGORIS) IN CHINA

Cryptosporidium spp. have been identified in a wide range of hosts, such as humans and domestic and wild animals, while less information about the prevalence of Cryptosporidium spp. in pet hamsters is documented. A total of 351 dwarf winter white Russian hamsters' fecal specimens were collected from 6 pet markets from the cities of Luzhou and Ziyang in Sichuan province in the southwestern part of China. The prevalence of Cryptosporidium spp. determined with nested-PCR amplification of the partial small-subunit (SSU) rRNA gene was 39.32% (138/351). The highest prevalence of Cryptosporidium spp. was in pet market 5 (79.49%, 62/78), followed by pet market 6 (38.64%, 17/44). The lowest prevalence of Cryptosporidium spp. was observed in pet market 3 (14.89%, 7/47). Statistically significant differences in the prevalence of Cryptosporidium spp. were observed among different pet markets (χ2 = 76.386, df = 5, P < 0.05), and a further post hoc test revealed that only pet market 5 was significantly different from other pet markets. Molecular analysis showed that 4 different Cryptosporidium species or genotypes were identified: Cryptosporidium parvum (n = 127), Cryptosporidium chipmunk genotype III (n = 6), Cryptosporidium andersoni (n = 4), and Cryptosporidium wrairi (n = 1). The identification of Cryptosporidium spp. was further tested with the 60-kDa glycoprotein (GP60) gene, and the positive rate was 29.7% (41/138). This is the first molecular report on Cryptosporidium spp. infection in dwarf winter white Russian hamsters in China. With C. parvum and C. andersoni being identified in both humans and pet hamsters, these findings suggest that pet hamsters may be potential reservoirs of zoonotic Cryptosporidium species and subtypes.

Cryptosporidium in fish: Implications for aquaculture and beyond

Aquaculture industries are expanding worldwide and control of Cryptosporidium is of great importance. Cryptosporidiosis is a serious waterborne/foodborne disease, responsible for infectious outbreaks globally. Current knowledge on the Cryptosporidium species in the aquatic environment and their occurrence in piscine hosts is steadily increasing since the Cryptosporidium species have been detected in marine, freshwater, cultured, captive and ornamental fish in a wide range of geographical regions. The zoonotic potential of these parasites and their pathological impact on piscine hosts have been increasingly reported and the fishborne zoonotic risk from Cryptosporidium spp. is of major importance from a public health point of view. Zoonotic subtypes in fish have been described in various studies and are probably related to water contamination from animal and human wastes. This review critically evaluated existing scientific data, related to Cryptosporidium species in piscine hosts, emphasizing transmission routes and the potential impact of piscine cryptosporidiosis in aquaculture. This knowledge will facilitate consumers, authorities and water industries such as fisheries and aquaculture, the prevention and control of waterborne and fishborne cryptosporidiosis in fish products.

Cryptosporidium abrahamseni n. sp. (Apicomplexa: Cryptosporidiiae) from red-eye tetra (Moenkhausia sanctaefilomenae)

The morphological, biological, and molecular characterisation of Cryptosporidium piscine genotype 7 from red-eye tetras (Moenkhausia sanctaefilomenae) are described, and the species name Cryptosporidium abrahamseni n. sp. is proposed. Histological analysis of intestinal tissue identified large numbers of Cryptosporidium organisms along the epithelial lining of the intestine. Sequence and phylogenetic analysis at 18S rRNA (18S) and actin loci conducted on intestinal scrapings revealed that C. abrahamseni n. sp. was genetically distinct from other Cryptosporidium species. At the 18S locus, it was most closely related to C. huwi (3.2% genetic distance) and exhibited genetic distances ranging from 5.9 to 6.5% (C. molnari) to 14.9% (C. scolpthalmi) from all other Cryptosporidium species. At the actin locus, the genetic distances were larger and C. abrahamseni n. sp. exhibited 10.3% genetic distance from C. huwi, and 17.6% (C. molnari) to 28% (C. canis) genetic distance from other Cryptosporidium spp. Phylogenetic analysis of concatenated 18S and actin sequences confirmed that C. abrahamseni n. sp. shares the closest genetic relationship with C. huwi (6.7% genetic distance), while the genetic distance between C. abrahamseni n. sp. and other Cryptosporidium spp. ranged from 12.1% (C. molnari) to 20.4% (C. canis). Based on genetic and histological data, C. abrahamseni n. sp. is validated as a separate species.

Potential Risk of Three Zoonotic Protozoa (Cryptosporidium spp., Giardia duodenalis, and Toxoplasma gondii) Transmission from Fish Consumption

In recent decades, worldwide fish consumption has increased notably worldwide. Despite the health benefits of fish consumption, it also can suppose a risk because of fishborne diseases, including parasitic infections. Global changes are leading to the emergence of parasites in new locations and to the appearance of new sources of transmission. That is the case of the zoonotic protozoa Cryptosporidium spp., Giardia duodenalis, and Toxoplasma gondii; all of them reach aquatic environments and have been found in shellfish. Similarly, these protozoa can be present in other aquatic animals, such as fish. The present review gives an overview on these three zoonotic protozoa in order to understand their potential presence in fish and to comprehensively revise all the evidences of fish as a new potential source of Cryptosporidium spp., Giardia duodenalis, and Toxoplasma gondii transmission. All of them have been found in both marine and freshwater fishes. Until now, it has not been possible to demonstrate that fish are natural hosts for these protozoa; otherwise, they would merely act as mechanical transporters. Nevertheless, even if fish only accumulate and transport these protozoa, they could be a "new" source of infection for people.

Molecular Characterization of Novel Cryptosporidium Fish Genotypes in Edible Marine Fish

Current knowledge of Cryptosporidium species/genotypes in marine fish is limited. Following phylogenetic analysis at the 18S rDNA locus, a recent study identified six new genotypes of Cryptosporidium colonizing edible fish found in European seas. Of these, five grouped in a clade together (#Cryptofish 1-5) and one grouped separately (#Cryptofish 7). In the present study, after phylogenetic analyses of #Cryptofish1, #Cryptofish2, #Cryptofish4, #Cryptofish5 and #Cryptofish7 at the actin locus, the presence of two major clades was confirmed. In addition, when possible, longer 18S amplicons were generated. In conclusion, the small genetic distances between these genotypes designated as a novel marine genotype I (#Cryptofish 1-5) suggest that they may be genetic variants of the same species, while the designated novel marine genotype 2 (#Cryptofish 7) is clearly representative of a separate species.

[New eating habits, new parasitic risks: The example of fish]

Introduction

In the past decades, the massive explosion of "Japanese" restaurants serving raw fish popularised new culinary habits in France. At the same time, consumers have made a habit of preparing raw or pickled fish dishes themselves at home. As a result, the identification of live parasitic worm larvae in raw fish flesh is common and a source of concern for professionals or amateur cooks. Sometimes, these worms are spit out or removed after fibroscopy in patients developing severe epigastric pain quickly after eating raw fish. This paper is aiming at having a quick review of the main parasites transmitted to humans by eating raw fish in France.

Methods

This article is based on the personal experience of the authors, on references preferentially from the French literature and on the results of the Fish Parasites (ANR) research program.

Results

From 2011 to 2014, Fish-Parasites (ANR) assessed the prevalence of parasitism in sea and freshwater fish belonging to 29 species. About 57% of sea fish were parasitised by Anisakidae. Larvae of Dibothriocephalus latus were found in pike, perch, and burbot in Lake Geneva but in none of the fish examined from Annecy or Le Bourget lakes. Concerning human anisakidosis, a retrospective survey was carried out in the years 2010 to 2014 among all medical parasitology laboratories from university hospitals in France. Thirty-seven cases of anisakidosis have been reported, including 18 cases of allergic anisakidosis. Six additional cases of severe Anisakidae allergy were reported to the National Allergovigilance Network over the same period.

Conclusions

Despite the increase in consumption of raw fish, and compared to previous studies, cases of anisakidosis are decreasing, but their allergenic potential is increasing. The incidence of dibothriocephalosis, after some trend of emergence on the shores of Lake Geneva some 20 years ago, is currently decreasing, but sporadic cases of importation are still reported. Actions with professionals (investigation, providing of information) and research programs on management of parasitic risk control are being pursued and have resulted in an update of the technical instruction of the French General Directorate for Food on the control of parasitic risk in fish.

Cryptosporidium bollandi n. sp. (Apicomplexa: Cryptosporidiiae) from angelfish (Pterophyllum scalare) and Oscar fish (Astronotus ocellatus)

The species name Cryptosporidium bollandi n. sp. is proposed for Cryptosporidium piscine genotype 2 based on morphological, biological and molecular characterisation. Phylogenetic analyses of 18S rRNA (18S) sequences revealed that C. bollandi n. sp. was most closely related to piscine genotype 4 (5.1% genetic distance) and exhibited genetic distances of 10.0%, 12.2% and 25.2% from Cryptosporidium molnari, Cryptosporidium huwi and Cryptosporidium scophthtalmi, respectively. At the actin locus, C. bollandi n. sp. was again most closely related to piscine genotype 4 (6.8% genetic distance) and exhibited 15.5% (C. molnari), 18.4% (C. huwi), 22.9% (C. scophthalmi) and up to 27.5% genetic distance from other Cryptosporidium spp. (Cryptosporidium felis). Phylogenetic analysis of concatenated 18S and actin sequences showed that C. bollandi n. sp. exhibited 12.9% (C. molnari) to 21.1% (C. canis) genetic distance from all other Cryptosporidium spp. Genetic data as well as previous histological analysis clearly supports the validity of C. bollandi n. sp. as a separate species.

Conserving the Amazon River Basin: The case study of the Yahuarcaca Lakes System in Colombia

Colombia is the fourth contributor to the Amazon River Basin (ARB) by surface, and the third by mean annual runoff. The Yahuarcaca Lakes System (YLS), consisting of four large interconnected water bodies situated on the floodplain of Amazon River, was identified as one of the key areas for the conservation of freshwater biodiversity in the Colombian ARB. This review aimed to provide a general overview of YLS, present its environmental and biological features, identify main ecological and health threats, and propose mitigation strategies and future research prospects. A systematic search was performed using various databases. In summary, YLS harbors significant biodiversity and provides a number of ecological services for local communities, encompassing fish and drinking water supply and utilization of the floodplain for agriculture. Ensuring its sustainability requires attention from local and international authorities, collaboration with indigenous communities and future interdisciplinary research.

Are molecular tools clarifying or confusing our understanding of the public health threat from zoonotic enteric protozoa in wildlife?

Emerging infectious diseases are frequently zoonotic, often originating in wildlife, but enteric protozoa are considered relatively minor contributors. Opinions regarding whether pathogenic enteric protozoa may be transmitted between wildlife and humans have been shaped by our investigation tools, and have led to oscillations regarding whether particular species are zoonotic or have host-adapted life cycles. When the only approach for identifying enteric protozoa was morphology, it was assumed that many enteric protozoa colonized multiple hosts and were probably zoonotic. When molecular tools revealed genetic differences in morphologically identical species colonizing humans and other animals, host specificity seemed more likely. Parasites from animals found to be genetically identical - at the few genes investigated - to morphologically indistinguishable parasites from human hosts, were described as having zoonotic potential. More discriminatory molecular tools have now sub-divided some protozoa again. Meanwhile, some infection events indicate that, circumstances permitting, some "host-specific" protozoa, can actually infect various hosts. These repeated changes in our understanding are linked intrinsically to the investigative tools available. Here we review how molecular tools have assisted, or sometimes confused, our understanding of the public health threat from nine enteric protozoa and example wildlife hosts (Balantoides coli - wild boar; Blastocystis sp. - wild rodents; Cryptosporidium spp. - wild fish; Encephalitozoon spp. - wild birds; Entamoeba spp. - non-human primates; Enterocytozoon bieneusi - wild cervids; Giardia duodenalis - red foxes; Sarcocystis nesbitti - snakes; Toxoplasma gondii - bobcats). Molecular tools have provided evidence that some enteric protozoa in wildlife may infect humans, but due to limited discriminatory power, often only the zoonotic potential of the parasite is indicated. Molecular analyses, which should be as discriminatory as possible, are one, but not the only, component of the toolbox for investigating potential public health impacts from pathogenic enteric protozoa in wildlife.

Prevalence, Molecular Identification, and Risk Factors for Cryptosporidium Infection in Edible Marine Fish: A Survey Across Sea Areas Surrounding France

Cryptosporidium, a zoonotic pathogen, is able to infect a wide range of hosts including wild and domestic animals, and humans. Although it is well known that some parasites are both fish pathogens and recognized agents of zoonosis with a public health impact, little information is available concerning the prevalence of Cryptosporidium in wild aquatic environments. To evaluate the prevalence of Cryptosporidium spp. in commercially important edible marine fish in different European seas (English channel, North sea, Bay of Biscay, Celtic sea and Mediterranean sea), 1,853 specimens were collected as part of two surveys. Nested PCR followed by sequence analysis at the 18S rRNA gene locus was used to identify Cryptosporidium spp. The overall prevalence of Cryptosporidium spp. in sampled fish reached 2.3% (35 out of 1,508) in a first campaign and 3.2% (11 out of 345) in a second campaign. Sequence and phylogenetic analysis of positive samples identified Cryptosporidium parvum (n = 10) and seven genotypes which exhibited between 7.3 and 10.1% genetic distance from C. molnari, with the exception of one genotype which exhibited only 0.5–0.7% genetic distance from C. molnari. Among 31 analyzed fish species, 11 (35.5%) were identified as potential hosts for Cryptosporidium. A higher prevalence of Cryptosporidium spp. was observed in larger fish, in fish collected during the spring-summer period, and in those caught in the North East Atlantic. Pollachius virens (saithe) was the most frequently Cryptosporidium positive species. In fish infected by other parasites, the risk of being Cryptosporidium positive increased 10-fold (OR: 9.95, CI: 2.32–40.01.04, P = 0.0002). Four gp60 subtypes were detected among the C. parvum positive samples: IIaA13G1R1, IIaA15G2R1, IIaA17G2R1, and IIaA18G3R1. These C. parvum subtypes have been previously detected in terrestrial mammals and may constitute an additional source of infection for other animals and in particular for humans. Microscopical examination of histological sections confirmed the presence of round bodies suggestive of the development of C. parvum within digestive glands. We report herein the first epidemiological and molecular data concerning the detection of Cryptosporidium in edible marine fish in European seas surrounding France broadening its host range and uncovering potential novel infection routes.

First detection of Cryptosporidium spp. in red-bellied tree squirrels (Callosciurus erythraeus) in China

Cryptosporidium spp. are opportunistic pathogens that cause diarrhea in a variety of animal hosts. Although they have been reported in many animals, no information has been published on the occurrence of Cryptosporidium spp. in red-bellied tree squirrels (Callosciurus erythraeus). A total of 287 fecal specimens were collected from Sichuan province in China; the prevalence of Cryptosporidium spp., measured by nested-PCR amplification of the partial small-subunit (SSU) rRNA gene, was 1.4% (4/287). Three different Cryptosporidium species or genotypes were identified: Cryptosporidium parvum (n = 1), Cryptosporidium wrairi (n = 1), and Cryptosporidium rat genotype II (n = 2). The present study is the first report of Cryptosporidium infection in red-bellied tree squirrels in China. Although there is a relatively low occurrence of Cryptosporidium, the presence of C. parvum and C. wrairi, which were previously reported in humans, indicates that red-bellied tree squirrels may be a source of zoonotic cryptosporidiosis in China.

Molecular epidemiology of Cryptosporidium spp. in calves in Estonia: high prevalence of Cryptosporidium parvum shedding and 10 subtypes identified

We investigated the molecular epidemiology of Cryptosporidium spp. in Estonia by testing fecal samples from 486 calves aged &lt;2 months, raised on 53 cattle farms, for the presence of Cryptosporidium DNA. The parasites were identified and characterized by sequencing of the 18S rRNA gene and of the 60 kDa glycoprotein (gp60) gene. Moreover, using a questionnaire, we surveyed factors that could be relevant for animal-to-human and human-to-animal transmission of Cryptosporidium spp. on the farms. Cryptosporidium spp. were shed by 23% of the investigated calves and at least one shedding calf was found on 66% of the farms. Cryptosporidium parvum was the most common species shed, while C. bovis and C. ryanae were also detected. More than half of the calves aged 8-14 days shed C. parvum. Nine previously described C. parvum subtypes (IIaA14G1R1, IIaA16G1R1, IIaA17G1R1, IIaA18G1R1, IIaA19G1R1, IIaA20G1R1, IIaA21G1R1, IIaA22G1R1 and IIaA16G2R1) and an apparently novel subtype IIlA21R2 were found. Calves from farms that reported spreading manure on fields during spring had 10 times higher odds to shed Cryptosporidium spp. in their feces than calves from farms that did not. Calves aged 8-14 days had higher odds to shed IIa18G1R1 as well as IIaA16G1R1 than younger calves.

Identification of a novel piscine Cryptosporidium genotype and Cryptosporidium parvum in cultured rainbow trout (Oncorhynchus mykiss)

This study reports for the first time the presence and molecular characterization of Cryptosporidium in farmed rainbow trout (Oncorhynchus mykiss Walbaum, 1792). A total of 360 fish, with no apparent clinical signs of disease, were collected and classified into groups according to their size. Cryptosporidium oocysts were detected by immunofluorescence microscopy in 33 specimens (9.2%), which were located in pyloric caeca samples (42.4%), intestinal scrapings (39.4%), or at both locations (18.2%). In the smallest (youngest) fish group, a higher percentage of positive samples were detected in the pyloric caeca relative to the intestinal location (58.8 vs. 17.6%; P = 0.01), including a cluster with more than 10 oocysts observed in the pyloric caeca of one specimen. PCR amplification and sequencing of fragments of SSU-rDNA and hsp70 genes identified a novel Cryptosporidium piscine genotype (genotype 9) in two specimens and Cryptosporidium parvum in seven fish, including the specimen in which the oocyst cluster was observed. Moreover, Cryptosporidium oocysts were detected in farm water samples (41.7 and 16.7% from influent and effluent, respectively). Although Giardia was not found in gastrointestinal samples, Giardia cysts were observed in 50.0 and 33.3% of the influent and effluent water samples, respectively. The results support the existence of natural infections by C. parvum in freshwater cultured fish, suggesting that the rainbow trout could shed infectious oocysts in aquatic environments and it may be a potential source of human infection when this edible fish is handled.

First report of Cryptosporidium parvum in a dromedary camel calf from Western Australia

Cryptosporidium is an important enteric parasite that can contribute large numbers of infectious oocysts to drinking water catchments. As a result of its resistance to disinfectants including chlorine, it has been responsible for numerous waterborne outbreaks of gastroenteritis. Wildlife and livestock play an important role in the transmission of Cryptosporidium in the environment. Studies conducted outside Australia have indicated that camels may also play a role in the transmission of zoonotic species of Cryptosporidium. Despite Australia being home to the world's largest camel herd, nothing is known about the prevalence and species of Cryptosporidium infecting camels in this country. In the present study, C. parvum was identified by PCR amplification and sequencing of a formalin-fixed intestinal tissue specimen from a one-week old dromedary camel (Camelus dromedarius). Subtyping analysis at the glycoprotein 60 (gp60) locus identified C. parvum subtype IIaA17G2R1, which is a common zoonotic subtype reported in humans and animals worldwide. Histopathological findings also confirmed the presence of large numbers of variably-sized (1-3 µm in diameter) circular basophilic protozoa - consistent with Cryptosporidium spp.- adherent to the mucosal surface and occasionally free within the lumen. Further analysis of the prevalence and species of Cryptosporidium in camel populations across Australia are essential to better understand their potential for contamination of drinking water catchments.

Seasonal dynamics of freshwater pathogens as measured by microarray at Lake Sapanca, a drinking water source in the north-eastern part of Turkey

Monitoring drinking water quality is an important public health issue. Two objectives from the 4 years, six nations, EU Project μAqua were to develop hierarchically specific probes to detect and quantify pathogens in drinking water using a PCR-free microarray platform and to design a standardised water sampling program from different sources in Europe to obtain sufficient material for downstream analysis. Our phylochip contains barcodes (probes) that specifically identify freshwater pathogens that are human health risks in a taxonomic hierarchical fashion such that if species is present, the entire taxonomic hierarchy (genus, family, order, phylum, kingdom) leading to it must also be present, which avoids false positives. Molecular tools are more rapid, accurate and reliable than traditional methods, which means faster mitigation strategies with less harm to humans and the community. We present microarray results for the presence of freshwater pathogens from a Turkish lake used drinking water and inferred cyanobacterial cell equivalents from samples concentrated from 40 into 1 L in 45 min using hollow fibre filters. In two companion studies from the same samples, cyanobacterial toxins were analysed using chemical methods and those dates with highest toxin values also had highest cell equivalents as inferred from this microarray study.

Prevalence, transmission, and host specificity of Cryptosporidium spp. in various animal groups from two French zoos

Cryptosporidium represents a major cause of gastrointestinal illness in humans and animals including domestic, wild, and in captivity animals, and more than 30 validated species of Cryptosporidium are recognized as infectious to different hosts such as mammals, birds, reptiles, amphibians, and fish. Therefore, numerous investigations have been conducted worldwide in order to shed light on the epidemiology of this parasite and to explore its potential reservoirs. Few surveys, targeting humans and animals have been carried out regarding the epidemiology of Cryptosporidium spp. in France and no data are available about the circulation of this parasite in French zoological gardens. Herein, we determined the prevalence of Cryptosporidium in animals housed in two French zoos. A total of 307 fecal samples belonging to 161 species were screened by nested PCR. Overall, Cryptosporidium DNA was detected in 1.9% of the 161 species and 1% of the total number of fecal samples tested. Additionally, three Cryptosporidium species were identified: C. galli, C. andersoni, and C. tyzzeri. To our knowledge, this is the first molecular study focused on Cryptosporidium infection in captivity animals in France. This study is of interest considering the exposure of a large number of humans and animals to this waterborne protozoan, found ubiquitously in the environment.

Cryptosporidium in humans and animals-a one health approach to prophylaxis

Cryptosporidium is a major cause of moderate-to-severe diarrhoea in humans worldwide, second only to rotavirus. Due to the wide host range and environmental persistence of this parasite, cryptosporidiosis can be zoonotic and associated with foodborne and waterborne outbreaks. Currently, 31 species are recognized as valid, and of these, Cryptosporidium hominis and Cryptosporidium parvum are responsible for the majority of infections in humans. The immune status of the host, both innate and adaptive immunity, has a major impact on the severity of the disease and its prognosis. Immunocompetent individuals typically experience self-limiting diarrhoea and transient gastroenteritis lasting up to 2 weeks and recover without treatment, suggesting an efficient host antiparasite immune response. Immunocompromised individuals can suffer from intractable diarrhoea, which can be fatal. Effective drug treatments and vaccines are not yet available. As a result of this, the close cooperation and interaction between veterinarians, health physicians, environmental managers and public health operators is essential to properly control this disease. This review focuses on a One Health approach to prophylaxis, including the importance of understanding transmission routes for zoonotic Cryptosporidium species, improved sanitation and better risk management, improved detection, diagnosis and treatment and the prospect of an effective anticryptosporidial vaccine.

Molecular characterisation of a disseminated Cryptosporidium infection in a Koi carp (Cyprinus carpio)

Cryptosporidium is a protozoan parasite that infects a wide range of hosts, yet relatively little is known about the epidemiology of cryptosporidiosis in fish. Here we report a disseminated Cryptosporidium infection in a male Koi carp (Cyprinus carpio), with parasite stages identified deep within the epithelium of the intestine, kidneys, spleen, liver and gills causing severe granulomatous inflammatory lesions. Molecular characterization at two loci; 18S ribosomal RNA (rRNA) and actin, revealed this to be a novel Cryptosporidium genotype, most closely related to Cryptosporidium molnari.

Public health significance of zoonotic Cryptosporidium species in wildlife: Critical insights into better drinking water management

Cryptosporidium is an enteric parasite that is transmitted via the faecal-oral route, water and food. Humans, wildlife and domestic livestock all potentially contribute Cryptosporidium to surface waters. Human encroachment into natural ecosystems has led to an increase in interactions between humans, domestic animals and wildlife populations. Increasing numbers of zoonotic diseases and spill over/back of zoonotic pathogens is a consequence of this anthropogenic disturbance. Drinking water catchments and water reservoir areas have been at the front line of this conflict as they can be easily contaminated by zoonotic waterborne pathogens. Therefore, the epidemiology of zoonotic species of Cryptosporidium in free-ranging and captive wildlife is of increasing importance. This review focuses on zoonotic Cryptosporidium species reported in global wildlife populations to date, and highlights their significance for public health and the water industry.

Genetic diversity of Cryptosporidium in fish at the 18S and actin loci and high levels of mixed infections

Cryptosporidium is an enteric parasite that infects humans and a wide range of animals. Relatively little is known about the epidemiology and taxonomy of Cryptosporidium in fish. In the present study, a total of 775 fish, belonging to 46 species and comprising ornamental fish, marine fish and freshwater fish were screened for the prevalence of Cryptosporidium by PCR. The overall prevalence of Cryptosporidium in fish was 5.3% (41/775), with prevalences ranging from 1.5 to 100% within individual host species. Phylogenetic analysis of these Cryptosporidium isolates as well as 14 isolates from previous studies indicated extensive genetic diversity as well as evidence for mixed infections. At the 18S locus the following species were identified; Cryptosporidium molnari-like genotype (n=14), Cryptosporidium huwi (n=8), piscine genotype 2 (n=4), piscine genotype 3-like (n=1), piscine genotype 4 (n=2), piscine genotype 5 (n=13), piscine genotype 5-like (n=1) and five novel genotypes (n=5). At the actin locus, species identification agreed with the 18S locus for only 52.3% of isolates sequenced, indicating high levels of mixed infections. Future studies will need to employ both morphological characterization and deep sequencing amplicon-based technologies to better understand the epidemiological and phylogenetic relationships of piscine-derived Cryptosporidium species and genotypes, particularly when mixed infections are detected.