High Diversity of Cryptosporidium Species and Subtypes Identified in Cryptosporidiosis Acquired in Sweden and Abroad

Deciphering a cryptic minefield: A guide to Cryptosporidium gp60 subtyping

For 25 years, analysis of the gp60 gene has been the cornerstone of Cryptosporidium subtyping, particularly for Cryptosporidium hominis and Cryptosporidium parvum, during population-based and epidemiological studies. This gene, which encodes a 60 kDa glycoprotein, is highly polymorphic with several variable features that make it particularly useful for differentiating within Cryptosporidium species. However, while this variability has proven useful for subtyping, it has on occasion resulted in alternative interpretations, and descriptions of novel and unusual features have been added to the nomenclature system, resulting in inconsistency and confusion. The components of the gp60 gene sequence used in the nomenclature that are discussed here include "R" repeats, "r" repeats, alphabetical suffixes, "variant" designations, and the use of the Greek alphabet as a family designation. As the subtyping scheme has expanded over the years, its application to different Cryptosporidium species has also made the scheme more complex. For example, key features may be absent, such as the typical TCA/TCG/TCT serine microsatellite that forms a major part of the nomenclature in C. hominis and C. parvum. As is to be expected in such a variable gene, different primer sets have been developed for the amplification of the gp60 in various species and these have been collated. Here we bring together all the current components of gp60, including a guide to the nomenclature in various species, software to assist in analysing sequences, and links to useful reference resources with an aim to promote standardisation of this subtyping tool.

Cryptosporidium in Rabbits: A Global Systematic Review and Meta-Analysis of Prevalence, Species/Genotypes Distribution and Zoonotic Significance

BACKGROUND

This systematic review and meta-analysis assessed the global prevalence, species/genotype distribution and zoonotic impact of Cryptosporidium in rabbits.

METHODS

A systematic search of PubMed, Scopus and Web of Science was performed for studies from 2000 to 25 October 2024 on Cryptosporidium spp. in rabbits. Data on publication/implementation years, prevalence rates, rabbit types, diagnostics, countries and species/genotypes were collected. A meta-analysis with random-effects models estimated overall prevalence and assessed heterogeneity using the I2 index. A sensitivity analysis evaluated the robustness of the results.

RESULTS

This systematic review included 26 studies with 6093 rabbits from 9 countries, revealing a pooled Cryptosporidium spp. prevalence of 9% (95% CI: 6%-13.4%). Three zoonotic species were found in rabbits: Cryptosporidium cuniculus in 18 studies and each of C. parvum and C. andersoni in 1 study. The isolates included 2 genotypes of C. cuniculus (Va, Vb) and 1 genotype of C. parvum (IIc), along with 18 subtypes of C. cuniculus (VaA16, VaA18, VaA31, VbA18, VbA19, VbA21, VbA22, VbA23, VbA24, VbA25, VbA26, VbA28, VbA29, VbA31, VbA32, VbA33, VbA35 and VbA36). Among these, 11 subtypes (VbA19, VbA22-VbA26, VbA28, VbA29 and VbA31-VbA33) are identified as zoonotic. Pet rabbits had the highest Cryptosporidium spp. pooled prevalence at 21.9% (95% CI: 14.7%-31.3%), followed by farmed rabbits at 9.7% (95% CI: 5.1%-17.8%), wild rabbits at 8.8% (95% CI: 4.8%-15.5%) and laboratory rabbits at 1% (95% CI: 0.3%-3.1%), with higher rates noted in Africa and the AFR WHO region.

CONCLUSIONS

This study assessed the global distribution of Cryptosporidium spp. in rabbits, highlighting its zoonotic implications. It serves as a key resource for researchers, veterinarians and public health officials for future studies and control strategies.

Molecular identification and genetic diversity analysis of Cryptosporidium spp. infecting dogs from central and northern Jordan: Detection of zoonotic genotype IId

Cryptosporidium spp. are common causes of gastrointestinal disease in both humans and animals. This was a cross-sectional study conducted to determine the infection rate and genetic characteristics of Cryptosporidium infecting dogs in Jordan. A total of 249 faecal samples were collected from stray, pet, and breeding dogs from kennels (independent of their clinical condition) across three governorates in Jordan (Amman and Zarqa in Central Jordan and Irbid in Northern Jordan). Faecal samples were screened for Cryptosporidium using polymerase chain reaction (PCR) targeting the 18S rRNA gene, revealing an overall infection rate of 18.9% (47 out of 249). Cryptosporidiosis was significantly associated with indoor dogs, dogs cohabiting with other animals, and consuming raw food. Among the successfully sequenced samples, 25 (58.1%) were Cryptosporidium canis, 15 (34.9%) were Cryptosporidium parvum, and three (7.0%) were Cryptosporidium baileyi. Multiple diversity tests were employed, indicating low genetic differentiation between the studied populations of C. parvum and C. canis. Stability was observed for C. parvum, with minimal expansion observed for C. canis. Notably, each species exhibited a single dominant haplotype, consistent with the AMOVA results, where most of the variability occurred within populations. Further genotyping of C. parvum and C. canis was conducted by sequencing the gp60 gene. C. parvum isolates worldwide displayed solely the zoonotic IId genotypes, namely, IIdA20G1, IIdA22G1, IIdA18G1, and IIdA19G1. In contrast, the C. canis isolates exhibited the animal subtypes XXe and XXd. Consequently, dogs may serve as a source of infection with C. parvum and pose a public health risk in Jordan.

Gut Microbial Signatures Associated with Cryptosporidiosis: A Case Series

Cryptosporidium spp. are zoonotic protozoan parasites with a global prevalence, with both gastrointestinal and pulmonary involvement. Though symptoms can often be relatively mild, they can become severe and even fatal in children under five, the elderly, and in immunocompromised individuals, making cryptosporidiosis a leading cause of morbidity and mortality in fragile populations. Furthermore, there is an urgent clinical need for alternative therapies against cryptosporidiosis, as currently available FDA-approved treatments are ineffective in the immunocompromised. Recent evidence in animal models suggests that the gut microbiota (GM) can influence both host and parasite biology to influence the course of Cryptosporidium infection. Here, we present GM profiles in five cases of cryptosporidiosis, associated with varying underlying pathologies. We found that moderate-severe cryptosporidiosis was characterized by a reduction in alpha-diversity and an enrichment of Enterococcus spp., while decreases in Bifidobacterium, Gemmiger, and Blautia were detectable in the milder manifestations of the disease. Our results suggest that severe cryptosporidiosis is associated with a stronger change on the GM than is age or underlying pathology. Together with previously published studies in animal models, we believe that these results suggest that the GM could be a potential therapeutic target for human patients as well, particularly in the immunocompromised for whom anti-Cryptosporidium treatment remains largely ineffective.

Molecular identification and characterization of waterborne protozoa among stranded Dugong dugon

The Persian Gulf hosts the second-largest population of Dugongs. The International Union for the Conservation of Nature (IUCN) lists them as Vulnerable to Extinction species. Incidental fishing, vessel strikes, environmental pollution, habitat degradation, and infectious diseases currently threaten these sirenians. While research focused on the abovementioned threats, little is known about pathogen infections, particularly waterborne parasites. The current study aimed to investigate the prevalence of the waterborne parasites, namely Blastocystis, Cryptosporidium, Dientamoeba fragilis, Giardia duodenalis, and Toxoplasma gondii in the Qatar Dugongs population. Hence, twenty-three tissues from stranded Dugongs' carcasses were collected postmortem and subjected to DNA extraction and parasite qPCR screening. Only Blastocystis and Cryptosporidium species were detected in different tissues across the tested animals harboring genotypes ST1 and Cryptosporidium hominis IbA9G3, respectively, with the first-time report of Blastocystis sp. within sirenian hosts. Continuous monitoring should be provided to shed lights about the contamination sources of these endangered species and clarify the zoonotic potential transmission routes between wildlife and humans.

Prevalence of Cryptosporidium parvum, Giardia duodenalis and Eimeria spp. in diarrhoeic suckling calves from north-western Spain and analysis of their interactions

Although Cryptosporidium parvum, Giardia duodenalis and some Eimeria species are frequently involved in neonatal calf diarrhoea (NCD), detailed studies on their interactions are scarce. Therefore, a cross-sectional study including faecal samples from 404 diarrhoeic calves aged 0-30 days was performed. Cryptosporidium oocysts and G. duodenalis cysts were detected by immunofluorescence antibody test and positive samples were molecularly characterized. Eimeria oocysts were microscopically detected using the modified McMaster technique and morphometric species identification was performed. Cryptosporidium infections (53.7%) predominated over those by G. duodenalis (12.4%) and Eimeria spp. (6.9%). Three Cryptosporidium species were identified: C. parvum (98.0%), C. bovis (1.0%) and C. ryanae (1.0%). Eleven C. parvum zoonotic subtypes were detected, with IIaA15G2R1 as the most common; only G. duodenalis assemblage E was identified. Moreover, 10 Eimeria species were found, being Eimeria ellipsoidalis (96.4%), Eimeria bovis (85.7%), and Eimeria zuernii (71.4%) predominant. A significant positive association between G. duodenalis and Eimeria spp. was detected as well as a negative association between C. parvum and Eimeria spp. Our results showed that C. parvum wasprevalent in diarrhoeic calves under 21 days of life; Eimeria spp. and G. duodenalis were especially common in animals in their fourth week of life. Concurrent infections increased with age. Moreover, the study also revealed potential public health risks since a noticeable percentage of animals were infected with C. parvum zoonotic subtypes. Further studies are needed for determining the role of these parasites in co-infections with other enteropathogens and their implications in the pathogenicity of NCD.

Multicopy subtelomeric genes underlie animal infectivity of divergent Cryptosporidium hominis subtypes

The anthroponotic Cryptosporidium hominis differs from the zoonotic C. parvum in its lack of infectivity to animals, but several divergent subtypes have recently been found in nonhuman primates and equines. Here, we sequence 17 animal C. hominis isolates and generate a new IbA12G3 genome at the chromosome level. Comparative analysis with 222 human isolates shows significant genetic divergence of the animal isolates, with genetic recombination among them. They have additional subtelomeric insulinase and MEDLE genes. In interferon-γ knockout mice, three monkey isolates show differences in infectivity and induce higher and longer oocyst shedding than a reference C. parvum isolate. Deletion of the MEDLE genes significantly reduces the growth and pathogenicity of a virulent strain in mice. Co-infection of two fluorescence-tagged C. hominis subtypes produces bicolored oocysts, supporting the conclusion that mixed subtype infections can lead to genetic recombination. These data provide insight into potential determinants of host infectivity in Cryptosporidium, and a convenient animal model for biological studies of C. hominis.

From the field: a cryptosporidiosis outbreak among veterinary students associated with activities during the lambing period in Norway during 2024

A recent outbreak of cryptosporidiosis (Cryptosporidium parvum, subtype IIdA23G1) among veterinary students associated with extracurricular activities concerned with lambs is described from Norway. Although cryptosporidiosis outbreaks among veterinary students have been frequently reported, this is among the first from lamb contact. Cryptosporidium oocysts were detected in samples from two students and three lambs. A questionnaire distributed immediately after the outbreak was recognized, identified an assumed attack rate of 50% based on exposure and illness among exposed students (28 of 56), despite most reporting good or very good hygiene measures. Laboratory diagnostics confirmed infection in two of these. The illness lasted over a week in most students (up to 15 days), but contact with health services was negligible. In addition to implementing measures to reduce the likelihood of further such outbreaks among veterinary students, it is recommended that future outbreaks of diarrhoea among ruminants on the farm should be investigated for aetiological agents.

Current status of intestinal parasitosis and microsporidiosis in industrialized countries: Results from a prospective study in France and Luxembourg

BACKGROUND

Human intestinal parasitosis and microsporidiosis are a global health concern, mostly in endemic areas but should not be neglected elsewhere. Recent nationwide epidemiological data are scarce, especially from primary health care and developed countries. Diagnosis by molecular tools are increasing and several commercial gastrointestinal panel assays including protozoans and/or helminths are now available. These news tools improve the knowledge into real human parasite epidemiology. This study provides an epidemiological update on intestinal parasites found in primary health care in France and Luxembourg.

METHODOLOGY/PRINCIPAL FINDINGS

Two thousand fifty-six stools from primary health care patients were analyzed for the presence of intestinal parasites (IPs) during two different seasons of 2022, the winter and the summer, corresponding to more than 1500 patients from all over France and Luxembourg. Parasite detection was performed combining standard microscopy (merthiolate-iodine-formaldehyde and Bailenger concentration procedures) with two molecular panel assays (AMPLIQUICK Fecal Pretreatment, AMPLIQUICK Protozoans and AMPLIQUICK Helminths, BIOSYNEX, France). The prevalence of IPs in primary care patients reached 33.2%. Blastocystis sp. and Dientamoeba fragilis were the most frequently detected parasites in 20.5% and 13.1% of patients, respectively. Coinfection with two or more parasites was detected in 9.9% of patients. For some parasites, patterns according to gender, age, geography or season have been observed.

CONCLUSION/SIGNIFICANCE

The high prevalence of pathogenic IPs (about 7%) underlines the importance of investigating gastrointestinal disorders through parasite examination, even in developed countries. The detection of parasites, pathogenic or not, remains a marker of the faecal-oral route of transmission and results should be interpreted accordingly. Parasites molecular characterization give new insights and should encourage further research as industrialized countries are not exempt of parasitic circulation and a better survey is necessary.

Cryptosporidium species and subtypes in Norway: predominance of C. parvum and emergence of C. mortiferum

PCR-based diagnostics has revealed the previously largely unknown Cryptosporidium transmission and infections in high-income countries. This study aimed to determine domestic and imported subtypes of Cryptosporidium species in Norway, evaluate their demographic distribution, and identify potential small outbreaks. Cryptosporidium-positive human faecal samples were obtained from six medical microbiology laboratories between February 2022 and January 2024, together with 22 Cryptosporidium-positive animal samples. Species and subtypes were identified by sequencing PCR products from gp60 and SSU rRNA genes. Most cryptosporidiosis cases occurred during late summer/early autumn, primarily in children and young adults. Of 550 human samples, 359 were successfully characterized molecularly (65%), revealing infection with 10 different Cryptosporidium species. C. parvum occurred in 245 (68%) human isolates with IIa and IId being major allele families, with distinct regional distribution patterns of common subtypes. A kindergarten outbreak with 5 cases was due to C. parvum IIaA14G1R1. C. mortiferum was identified in 33 (9.2%) human cases of which 24 were known to be of domestic origin, making it the second most common species in human autochthonous cases in Norway. All C. mortiferum isolates were of the same genotype; XIVaA20G2T1, including 13 cases from a suspected small outbreak in Trøndelag. C. hominis occurred in 68 typed cases (19%), but mostly in infections acquired abroad, with allele families Ib and If occurring most often. In conclusion, this study of recent Cryptosporidium spp. and subtypes in Norway, highlights the predominance of C. parvum and the emergence of C. mortiferum among autochthonous cases.

Cryptosporidium from sheep herds around water tributaries of the Malakand region of Pakistan

This study was designed to determine the prevalence of Cryptosporidium infections in sheep herds around tributaries in Pakistan and to evaluate the influence of potential risk factors. In total, 448 samples from 26 sheep herds were screened microscopically and then confirmed through polymerase chain reaction (PCR) amplification of the 18S SSU rRNA gene. Our result revealed that, out of 448 samples, 107 were found positive by microscopy and 77 positive by PCR, with prevalence rates of 23.88% and 17.18% in different breeds of sheep. A high statistical difference exists between the p-value (p <0.05) when comparing diarrheic and non-diarrheic sheep, breeds, ages, genders, and seasons. The highest infection rate was found in the Australian breed (8.25%); season-wise, the highest prevalence was recorded in summer. Furthermore, sheep-secreting diarrheal faces were 41% young sheep and lambs. This reveals that young animals are more susceptible to infection than adults, and cryptosporidial infection decreases with increasing age of the animal. This report is the first on the prevalence of Cryptosporidium in sheep sampled near the tributaries in Pakistan. The implications of this study's findings are clear; immediate action is necessary to prevent further spread and potentially devasting harm.

Food and Waterborne Cryptosporidiosis from a One Health Perspective: A Comprehensive Review

A sharp rise in the global population and improved lifestyles has led to questions about the quality of both food and water. Among protozoan parasites, Cryptosporidium is of great importance in this regard. Hence, Cryptosporidium's associated risk factors, its unique characteristics compared to other protozoan parasites, its zoonotic transmission, and associated economic losses in the public health and livestock sectors need to be focused on from a One Health perspective, including collaboration by experts from all three sectors. Cryptosporidium, being the fifth largest food threat, and the second largest cause of mortality in children under five years of age, is of great significance. The contamination of vegetables, fresh fruits, juices, unpasteurized raw milk, uncooked meat, and fish by Cryptosporidium oocysts occurs through infected food handlers, sewage-based contamination, agricultural effluents, infected animal manure being used as biofertilizer, etc., leading to severe foodborne outbreaks. The only Food and Drug Administration (FDA)-approved drug, Nitazoxanide (NTZ), provides inconsistent results in all groups of patients, and currently, there is no vaccine against it. The prime concerns of this review are to provide a deep insight into the Cryptosporidium's global burden, associated water- and foodborne outbreaks, and some future perspectives in an attempt to effectively manage this protozoal disease. A thorough literature search was performed to organize the most relevant, latest, and quantified data, justifying the title. The estimation of its true burden, strategies to break the transmission pathways and life cycle of Cryptosporidium, and the search for vaccine targets through genome editing technology represent some future research perspectives.

No longer stuck in the past: new advances in artificial intelligence and molecular assays for parasitology screening and diagnosis

PURPOSE OF REVIEW

Emerging technologies are revolutionizing parasitology diagnostics and challenging traditional methods reliant on microscopic analysis or serological confirmation, which are known for their limitations in sensitivity and specificity. This article sheds light on the transformative potential of artificial intelligence and molecular assays in the field, promising more accurate and efficient detection methods.

RECENT FINDINGS

Artificial intelligence has emerged as a promising tool for blood and stool parasite review, when paired with comprehensive databases and expert oversight result in heightened specificity and sensitivity of diagnoses while also increasing efficiency. Significant strides have been made in nucleic acid testing for multiplex panels for enteric pathogen. Both multiplex and single target panels for Plasmodium , Babesia , filaria, and kinetoplastids have been developed and garnered regulatory approval, notably for blood donor screening in the United States. Additional technologies such as MALDI-TOF, metagenomics, flow cytometry, and CRISPR-Cas are under investigation for their diagnostic utility and are currently in the preliminary stages of research and feasibility assessment.

SUMMARY

Recent implementation of artificial intelligence and digital microscopy has enabled swift smear screening and diagnosis, although widespread implementation remains limited. Simultaneously, molecular assays - both targeted and multiplex panels are promising and have demonstrated promise in numerous studies with some assays securing regulatory approval recently. Additional technologies are under investigation for their diagnostic utility and are compelling avenues for future proof-of-concept diagnostics.

Complete sequencing of the Cryptosporidium suis gp60 gene reveals a novel type of tandem repeats-Implications for surveillance

Cryptosporidiosis is an infectious enteric disease caused by species (some of them zoonotic) of the genus Cryptosporidium that in many countries are under surveillance. Typing assays critical to the surveillance of cryptosporidiosis typically involve characterization of Cryptosporidium glycoprotein 60 genes (gp60). Here, we characterized the gp60 of Cryptosporidium suis from two samples-a human and a porcine faecal sample-based on which a preliminary typing scheme was developed. A conspicuous feature of the C. suis gp60 was a novel type of tandem repeats located in the 5' end of the gene and that took up 777/1635 bp (48%) of the gene. The C. suis gp60 lacked the classical poly-serine repeats (TCA/TCG/TCT), which is usually subject to major genetic variation, and the length of the tandem repeat made a typing assay incorporating this region based on Sanger sequencing practically unfeasible. We therefore designed a typing assay based on the post-repeat region only and applied it to C. suis-positive samples from suid hosts from Norway, Denmark, and Spain. We were able to distinguish three different subtypes; XXVa-1, XXVa-2, and XXVa-3. Subtype XXVa-1 had a wider geographic distribution than the other subtypes and was also observed in the human sample. We think that the present data will inform future strategies to develop a C. suis typing assay that could be even more informative by including a greater part of the gene, including the tandem repeat region, e.g., by the use of long-read next-generation sequencing.

Genetic characterization of Cryptosporidium spp. in the North African hedgehog (Atelerix algirus) in the Canary Islands, Spain

The North African hedgehog (Atelerix algirus) is an introduced species from Northwest Africa and is currently distributed in the Canary Islands. This species of hedgehog has been studied as a reservoir of enteropathogens, including Cryptosporidium spp. However, there are no data at species level. Therefore, the aim of the present study was to identify the Cryptosporidium species present in a population of hedgehogs (n = 36) in the Canary Islands. Molecular screening was performed using conventional polymerase chain reaction (PCR) targeting the small subunit ribosomal RNA (18S rRNA) gene of Cryptosporidium spp. Seven of the 36 fecal samples (19.45%) were positive and confirmed by nested PCR targeting the 18S rRNA gene and Sanger sequencing. Cryptosporidium parvum and Cryptosporidium muris were identified in 11.1% (4/36) and 5.6% (2/36) of the samples, respectively, while one sample could only be identified at the genus level. The zoonotic subtypes IIdA15G1 (n = 1), IIdA16G1b (n = 1), and IIdA22G1 (n = 1) of C. parvum were identified by nested PCR followed by analysis of the 60 kDa glycoprotein (gp60) gene sequence. This study is the first genetic characterization of Cryptosporidium spp. in A. algirus, identifying zoonotic species and subtypes of the parasite.

Marked increase in cryptosporidiosis cases, Spain, 2023

BackgroundBy mid-September 2023, several event notifications related to cryptosporidiosis had been identified from different regions in Spain. Therefore, a request for urgent notification of cryptosporidiosis cases to the National Surveillance Network was launched.AimWe aimed at assessing the extent of the increase in cases, the epidemiological characteristics and the transmission modes and compared to previous years.MethodsWe analysed data on case notifications, outbreak reports and genotypes focusing on June-October 2023 and compared the results to 2016-2022.ResultsIn 2023, 4,061 cryptosporidiosis cases were notified in Spain, which is an increase compared to 2016-2022. The cumulative incidence was 8.3 cases per 100,000 inhabitants in 2023, sixfold higher than the median of 1.4 cases per 100,000 inhabitants 2016-2022. Almost 80% of the cases were notified between June and October. The largest outbreaks were related to contaminated drinking water or swimming pools. Cryptosporidium hominis was the most common species in the characterised samples (115/122), and the C. hominis IfA12G1R5 subtype, previously unusual in Spain, was detected from 76 (62.3%) of the 122 characterised samples.ConclusionsA substantial increase in cryptosporidiosis cases was observed in 2023. Strengthening surveillance of Cryptosporidium is essential for prevention of cases, to better understand trends and subtypes circulating and the impact of adverse meteorological events.

Food and Drinking Water as Sources of Pathogenic Protozoans: An Update

This narrative review was aimed at collecting updated knowledge on the risk factors, illnesses caused, and measures for the prevention of protozoan infections transmitted by food and drinking water. Reports screened dated from 2019 to the present and regarded global prevalence in food handlers, occurrence in food and drinking water, impact on human health, and recently reported outbreaks and cases of severe infections attributable to the dietary route. Cryptosporidium spp., Cyclospora cayetanensis, Entamoeba histolytica, and Cystoisospora belli were the protozoans most frequently involved in recently reported waterborne and foodborne outbreaks and cases. Blastocystis hominis was reported to be the most widespread intestinal protozoan in humans, and two case reports indicated its pathogenic potential. Dientamoeba fragilis, Endolimax nana, and Pentatrichomonas hominis are also frequent but still require further investigation on their ability to cause illness. A progressive improvement in surveillance of protozoan infections and infection sources took place in developed countries where the implementation of reporting systems and the application of molecular diagnostic methods led to an enhanced capacity to identify epidemiological links and improve the prevention of foodborne and waterborne protozoan infections.

Rodent-adapted Cryptosporidium infection in humans: Seven new cases and review of the literature

Cases of cryptosporidiosis in humans have been reported with strong indication of transmission from rodents. Here, we report seven new human cases of cryptosporidiosis involving rodent-adapted species (Cryptosporidium ditrichi [n = 1], Cryptosporidium mortiferum [n = 4; previously known as Cryptosporidium chipmunk genotype I], Cryptosporidium tyzzeri [n = 1], and Cryptosporidium viatorum [n = 1]) and review cases of human infection caused by these four species published to date. The seven new cases were detected in Denmark within a period of twelve months from 2022 to 2023. Only the C. tyzzeri and C. viatorum cases were associated with travel outside Denmark. The total number of human cases of cryptosporidiosis due to C. ditrichi and C. tyzzeri documented to date globally are still limited (4 and 7, respectively), whereas cases involving C. viatorum and C. mortiferum have been detected to a larger extent (43 and 63 cases, respectively). The four new cases of C. mortiferum were all of the XIVaA20G2T1 subtype, which is the only subtype identified so far in Scandinavia, and which is a subtype not yet found outside of Scandinavia. The new C. viatorum case was identified as the XVaA3g subtype. The C. tyzzeri case was subtyped as IXbA6. No subtype data were produced for C. ditrichi due to lack of a subtype assay. Review of existing data suggests the presence of C. ditrichi and C. mortiferum primarily in northern countries and C. tyzzeri and C. viatorum primarily in warmer climates. While our data may further support the role of Cryptosporidium as a cause of zoonotic disease, case descriptions should be obtained where possible to determine if Cryptosporidium species primarily adapted to rodents are the likely cause of symptoms or just an incidental finding.

Genetic characterizations of Cryptosporidium spp. from children with or without diarrhea in Wenzhou, China: high probability of zoonotic transmission

BACKGROUND

Cryptosporidium is a highly pathogenic parasite responsible for diarrhea in children worldwide. Here, the epidemiological status and genetic characteristics of Cryptosporidium in children with or without diarrhea were investigated with tracking of potential sources in Wenzhou City, China.

METHODS

A total of 1032 children were recruited, 684 of whom had diarrhea and 348 without, from Yuying Children's Hospital in Wenzhou, China. Samples of stool were collected from each participant, followed by extraction of DNA, genotyping, and molecular identification of Cryptosporidium species and subtypes.

RESULTS

Twenty-two of the 1032 (2.1%) children were infected with Cryptosporidium spp. with 2.5% (17/684) and 1.4% (5/348) in diarrhoeic and asymptomatic children, respectively. Four Cryptosporidium species were identified, including C. parvum (68.2%; 15/22), C. felis (13.6%; 3/22), C. viatorum (9.1%; 2/22), and C. baileyi (9.1%; 2/22). Two C. parvum subtypes named IIdA19G1 (n = 14) and IInA10 (n = 1), and one each of C. felis (XIXa) and C. viatorum (XVaA3g) subtype was found as well.

CONCLUSIONS

This is the first research that identified Cryptosporidium in children of Wenzhou, China, using PCR. Identification of zoonotic C. parvum, C. felis, C. viatorum, and their subtypes indicate potential cross-species transmission of Cryptosporidium between children and animals. Additionally, the presence of C. baileyi in children suggests that this species has a wider host range than previously believed and that it possesses the capacity to infect humans.

Rabbits as reservoirs: An updated perspective of the zoonotic risk from Cryptosporidium and Giardia

Rabbits are highly abundant in many countries and can serve as reservoirs of diseases for a diversity of pathogens including the enteric protozoan parasites, Cryptosporidium and Giardia. Both parasites shed environmentally robust environmental stages (oo/cysts) and have been responsible for numerous waterborne outbreaks of diseases. Cryptosporidium hominis and C. parvum are responsible for most infections in humans, while Giardia duodenalis assemblages A and B, cause most human cases of giardiasis. Cryptosporidium cuniculus, the dominant species infecting rabbits, is the only spceies other than C. hominis and C. parvum to have caused a waterborne outbreak of gastritis, which occurred in the United Kingdom in 2008. This review examines the prevalence of Cryptosporidium and Giardia species in rabbits to better understand the public health risks of contamination of water sources with Cryptosporidium and Giardia oo/cysts from rabbits. Despite the abundance of C. cuniculus in rabbits, reports in humans are relatively rare, with the exception of the United Kingdom and New Zealand, and reports of C. cuniculus in humans from the United Kingdom have declined substantially since the 2008 outbreak. Subtyping of C. cuniculus has supported the potential for zoonotic transmission. Relatively few studies have been conducted on Giardia, but assemblage B dominates. However, improved typing methods are required to better understand the transmission dynamics of Giardia assemblages in rabbits. Similarly, it is not well understood if pet rabbits or contaminated water are the main source of C. cuniculus infections in humans. Well-planned studies using high-resolution typing tools are required to understand the transmission dynamics better and quantify the public health risk of Cryptosporidium and Giardia from rabbits.

Critters and contamination: Zoonotic protozoans in urban rodents and water quality

Rodents represent the single largest group within mammals and host a diverse array of zoonotic pathogens. Urbanisation impacts wild mammals, including rodents, leading to habitat loss but also providing new resources. Urban-adapted (synanthropic) rodents, such as the brown rat (R. norvegicus), black rat (R. rattus), and house mouse (Mus musculus), have long successfully adapted to living close to humans and are known carriers of zoonotic pathogens. Two important enteric, zoonotic protozoan parasites, carried by rodents, include Cryptosporidium and Giardia. Their environmental stages (oocysts/cysts), released in faeces, can contaminate surface and wastewaters, are resistant to common drinking water disinfectants and can cause water-borne related gastritis outbreaks. At least 48 species of Cryptosporidium have been described, with C. hominis and C. parvum responsible for the majority of human infections, while Giardia duodenalis assemblages A and B are the main human-infectious assemblages. Molecular characterisation is crucial to assess the public health risk linked to rodent-related water contamination due to morphological overlap between species. This review explores the global molecular diversity of these parasites in rodents, with a focus on evaluating the zoonotic risk from contamination of water and wasterwater with Cryptosporidium and Giardia oocysts/cysts from synanthropic rodents. Analysis indicates that while zoonotic Cryptosporidium and Giardia are prevalent in farmed and pet rodents, host-specific Cryptosporidium and Giardia species dominate in urban adapted rodents, and therefore the risks posed by these rodents in the transmission of zoonotic Cryptosporidium and Giardia are relatively low. Many knowledge gaps remain however, and therefore understanding the intricate dynamics of these parasites in rodent populations is essential for managing their impact on human health and water quality. This knowledge can inform strategies to reduce disease transmission and ensure safe drinking water in urban and peri‑urban areas.

Detection of zoonotic Cryptosporidium spp. in small wild rodents using amplicon-based next-generation sequencing

Rodents may serve as reservoirs of zoonotic species of Cryptosporidium; however, data from molecular surveys in support of this hypothesis are still scarce. In this study, we screened faeces and rectal content from murid and cricetid rodents (N = 58) caught around three farms in Zealand, Denmark, for Cryptosporidium spp. by amplicon-based next-generation sequencing (NGS) of ribosomal genes. Selected samples were further examined using nested conventional PCR targeting SSU rRNA, gp60, and actin genes. Cryptosporidium-specific DNA was identified in 40/58 (69%) samples, and in 12 (30%) of the 40 positive animals, mixed cryptosporidial infections were observed. Cryptosporidium ditrichi was the species most commonly identified, found in 28 (48%) of the animals. Cryptosporidium parvum was identified in 4 (7%) of the animals, all of which were co-infected with C. ditrichi. The present study is the first to utilize NGS-based screening for Cryptosporidium species in wild rodents. Moreover, it is the first study to provide molecular data on Cryptosporidium in rodents sampled in Denmark and to detect DNA of C. ditrichi in Mus musculus, Myodes glareolus, and Microtus agrestis. The NGS approach was successfully applied to yield new knowledge, and the results showed that zoonotic species of Cryptosporidium are common in murid and cricetid rodents in Zealand, Denmark.

Cryptosporidium species and subtypes identified in human domestic cases through the national microbiological surveillance programme in Sweden from 2018 to 2022

BACKGROUND

The intestinal protozoan parasite Cryptosporidium is an important cause of diarrheal disease worldwide. A national microbiological surveillance programme was implemented in Sweden in 2018 in order to increase knowledge of the molecular epidemiology of human cryptosporidiosis to better understand transmission patterns and potential zoonotic sources. This article summarises the results of the first five years of the surveillance programme.

METHODS

Cryptosporidium-positive faecal and DNA samples from domestically acquired infections were collected from clinical microbiological laboratories in Sweden. Species and subtype determination was performed using 60 kDa glycoprotein and/or small subunit ribosomal RNA gene analysis.

RESULTS

Between 2018 and 2022, 1654 samples were analysed and 11 different species were identified: C. parvum (n = 1412), C. mortiferum (n = 59), C. hominis (n = 56), C. erinacei (n = 11), C. cuniculus (n = 5), C. meleagridis (n = 3), C. equi (n = 2), C. ubiquitum (n = 2), and one each of C. canis, C. ditrichi and C. felis. Subtyping revealed seven subtype families of C. parvum (new subtype families IIy and IIz) and 69 different subtypes (11 new subtypes). The most common C. parvum subtypes were IIdA22G1c, IIdA24G1, IIdA15G2R1 and IIaA16G1R1b. For C. hominis, four different subtype families and nine different subtypes (two new subtypes) were identified. For additional species, two new subtype families (IIIk and VId) and nine new subtypes were identified. All successfully subtyped C. mortiferum cases were subtype XIVaA20G2T1, confirming previous findings in Sweden. Several outbreaks were identified of which the majority were foodborne and a few were due to direct contact with infected animals.

CONCLUSION

Infection with C. parvum is the leading cause of human cryptosporidiosis acquired in Sweden, where more than 90% of domestic cases are caused by this zoonotic species and only a small proportion of cases are due to infection with other species. The rodent-associated C. mortiferum is considered an emerging zoonotic species in Sweden and the number of domestically acquired human cases has surpassed that of infection with C. hominis. A high diversity of species and subtypes, as well as diversity within the same subtype, was detected. Also, cryptosporidiosis appears to affect adults to a great extent in Sweden.

Detection and Molecular Diversity of Cryptosporidium spp. and Giardia duodenalis in the Endangered Iberian Lynx (Lynx pardinus), Spain

Cryptosporidium spp. and Giardia duodenalis are the main non-viral causes of diarrhoea in humans and domestic animals globally. Comparatively, much less information is currently available in free-ranging carnivore species in general and in the endangered Iberian lynx (Lynx pardinus) in particular. Cryptosporidium spp. and G. duodenalis were investigated with molecular (PCR and Sanger sequencing) methods in individual faecal DNA samples of free-ranging and captive Iberian lynxes from the main population nuclei in Spain. Overall, Cryptosporidium spp. and G. duodenalis were detected in 2.4% (6/251) and 27.9% (70/251) of the animals examined, respectively. Positive animals to at least one of them were detected in each of the analysed population nuclei. The analysis of partial ssu rRNA gene sequences revealed the presence of rodent-adapted C. alticolis (n = 1) and C. occultus (n = 1), leporid-adapted C. cuniculus (n = 2), and zoonotic C. parvum (n = 2) within Cryptosporidium, and zoonotic assemblages A (n = 5) and B (n = 3) within G. duodenalis. Subgenotyping analyses allowed for the identification of genotype VaA19 in C. cuniculus (gp60 locus) and sub-assemblages AI and BIII/BIV in G. duodenalis (gdh, bg, and tpi loci). This study represents the first molecular description of Cryptosporidium spp. and G. duodenalis in the Iberian lynx in Spain. The presence of rodent/leporid-adapted Cryptosporidium species in the surveyed animals suggests spurious infections associated to the Iberian lynx's diet. The Iberian lynx seems a suitable host for zoonotic genetic variants of Cryptosporidium (C. parvum) and G. duodenalis (assemblages A and B), although the potential risk of human transmission is regarded as limited due to light parasite burdens and suspected low excretion of infective (oo)cysts to the environment by infected animals. More research should be conducted to ascertain the true impact of these protozoan parasites in the health status of the endangered Iberian lynx.

Prevalence of Cryptosporidium spp. infection in a working horse population in Egypt

Working horses support the livelihoods of smallholder farmers in Egypt. No previous study has investigated the prevalence of cryptosporidiosis in working horses in Egypt. Faecal samples were collected from 607 working horses recruited from thirty-seven villages/areas in two Egyptian governorates and examined for Cryptosporidium spp. infection using the modified Zielh-Neelsen staining technique. Data on signalment, history of recent diarrhoea, and strongyle burden were collected. The prevalence of Cryptosporidium spp. infection was calculated using a bootstrap method and potential risk factors for infection were investigated using mixed-effects logistic regression models that included sampling location as a random-effects variable. The prevalence of Cryptosporidium spp. infection was 28.7% (95% confidence interval = 23.5-33.9). None of the variables investigated, which include age, sex of the animals, and strongyle burden, were associated with risk of infection. This study provided evidence-based information on the prevalence of Cryptosporidium spp. infection in the study area. However, the potential zoonotic risk of Cryptosporidium cannot be confirmed until further studies are conducted to genotype these parasites.

Changing Molecular Profiles of Human Cryptosporidiosis Cases in Scotland as a Result of the Coronavirus Disease, COVID-19 Pandemic

Cryptosporidium, the most frequently reported parasite in Scotland, causes gastrointestinal illness resulting in diarrhoea, nausea and cramps. Two species are responsible for most cases: Cryptosporidium hominis (C. hominis) and Cryptosporidium parvum (C. parvum). Transmission occurs faecal-orally, through ingestion of contaminated food and water, or direct contact with faeces. In 2020, the COVID-19 pandemic led to global restrictions, including national lockdowns to limit viral transmission. Such interventions led to decreased social mixing, and reduced/no local and international travel, which are factors associated with transmission of multiple communicable diseases, including cryptosporidiosis. This report assessed the impact of the pandemic on Scottish cryptosporidiosis cases, and identified changes in circulating molecular variants of Cryptosporidium species. Molecular data generated using real time PCR and GP60 nested-PCR assays on laboratory-confirmed cryptosporidiosis cases reported during 2018-22 were analysed. The Scottish Microbiology Reference Laboratories (SMiRL), Glasgow, received 774 Cryptosporidium-positive faeces during 2018-22, of which 486 samples were successfully subtyped. During this time period, C. hominis (n = 155; 21%) and C. parvum (n = 572; 77%) were the most commonly detected species. The total number of cases during 2020, which was greatly affected by the pandemic, was markedly lower in comparison to case numbers in the 2 years before and after 2020. The most predominant C. hominis family detected prior to 2020 was the Ib family which shifted to the Ie family during 2022. The most common C. parvum variant during 2018-22 was the IIa family, however a rise in the IId family was observed (n = 6 in 2018 to n = 25 in 2022). The dominant C. hominis subtype IbA10G2, which accounted for 71% of C. hominis subtypes in 2018-19 was superseded by three rare subtypes: IeA11G3T3 (n = 15), IdA16 (n = 8) and IbA9G3 (n = 3) by 2022. Frequently reported C. parvum subtypes in 2018-19 were IIaA15G2R1 and IIaA17G1R1, accounting for 59% of total C. parvum subtypes. By 2022, IIaA15G2R1 remained the most common (n = 28), however three unusual subtypes in Scotland emerged: IIdA24G1 (n = 7), IIaA16G3R1 (n = 7) and IIaA15G1R2 (n = 7). Continuous monitoring of Cryptosporidium variants following the pandemic will be essential to explore further changes and emergence of strains with altered virulence.

Prevalence and molecular characterization of Cryptosporidium spp. in dairy cattle in Central Inner Mongolia, Northern China

BACKGROUND

Cryptosporidium is a gastrointestinal protozoan that widely exists in nature, it is an established zoonotic pathogen. Infected cattle are considered to be associated with cryptosporidiosis outbreaks in humans. In the present study, we aimed to assess the prevalence and species distribution of Cryptosporidium in dairy cattle in Central Inner Mongolia.

METHODS

We focused on the small subunit ribosomal RNA gene (SSU rRNA) of Cryptosporidium and 60-kDa glycoprotein gene (gp60) of Cryptosporidium parvum. We collected 505 dairy cattle manure samples from 6 sampling sites in Inner Mongolia in 2021; the samples were divided into 4 groups based on age. DNA extraction, polymerase chain reaction (PCR), sequence analysis, and restriction fragment length polymorphism (RFLP) using SspI and MboII restriction endonucleases were performed. RFLP analysis was performed to determine the prevalence and species distribution of Cryptosporidium.

RESULTS

SSU rRNA PCR revealed that the overall prevalence of Cryptosporidium infection was 29.90% (151/505), with a prevalence of 37.67% (55/146) and 26.74% (96/359) in diarrheal and nondiarrheal samples, respectively; these differences were significant. The overall prevalence of Cryptosporidium infection at the 6 sampling sites ranged from 0 to 47.06% and that among the 4 age groups ranged from 18.50 to 43.81%. SSU rRNA sequence analysis and RFLP analysis revealed the presence of 4 Cryptosporidium species, namely, C. bovis (44.37%), C. andersoni (35.10%), C. ryanae (21.85%), and C. parvum (11.92%), along with a mixed infection involving two or three Cryptosporidium species. Cryptosporidium bovis or C. andersoni was the most common cause of infection in the four age groups. The subtype of C. parvum was successfully identified as IIdA via gp60 analysis; all isolates were identified as the subtype IIdA19G1.

CONCLUSIONS

To the best of our knowledge, this is the first report of dairy cattle infected with four Cryptosporidium species in Inner Mongolia, China, along with a mixed infection involving two or three Cryptosporidium species, with C. bovis and C. andersoni as the dominant species. Moreover, this is the first study to identify C. parvum subtype IIdA19G1 in cattle in Inner Mongolia. Our study findings provide detailed information on molecular epidemiological investigation of bovine cryptosporidiosis in Inner Mongolia, suggesting that dairy cattle in this region are at risk of transmitting cryptosporidiosis to humans.

Cryptosporidium parvum: an emerging occupational zoonosis in Finland

BACKGROUND

Cryptosporidiosis has increased in recent years in Finland. We aimed to identify risk factors for human cryptosporidiosis and to determine the significance of Cryptosporidium parvum as a causative agent. Based on notifications to the Finnish Infectious Disease Register (FIDR), we conducted a case-control study and genotyped Cryptosporidium species from patient samples from July to December 2019. We also retrieved the occupational cryptosporidiosis cases from 2011 to 2019 from the Finnish Register of Occupational Diseases (FROD).

RESULTS

Of 272 patient samples analyzed, 76% were C. parvum and 3% C. hominis. In the multivariable logistic regression analysis of 82 C. parvum cases and 218 controls, cryptosporidiosis was associated with cattle contact (OR 81, 95% confidence interval (CI) 26-251), having a family member with gastroenteritis (OR 34, 95% CI 6.2-186), and spending time at one's own vacation home (OR 15, 95% CI 4.2-54). Of the cases, 65% had regular cattle contact. The most common gp60 subtypes identified were IIaA15G2R1 and IIaA13G2R1. In FROD, 68 recognized occupational cryptosporidiosis cases were registered in 2011-2019.

CONCLUSIONS

C. parvum is the most common Cryptosporidium species found in humans in Finland and poses a moderate to high risk of occupational infection for people working with cattle. The number of occupational notifications of cryptosporidiosis increased between 2011 and 2019. Cryptosporidiosis should be recognized as an important occupational disease among persons working with livestock in Finland, criteria to identify occupational cryptosporidiosis need to be created, and occupational safety in cattle-related work should be improved.

Identification and Evaluation of Cryptosporidium Species from New York City Cases of Cryptosporidiosis (2015 to 2018): a Watershed Perspective

Watersheds that supply residents with drinking water have the potential for contamination with Cryptosporidium oocysts. To evaluate any potential similarities between Cryptosporidium species previously found in the New York City (NYC) watershed and those causing disease in NYC, the species were identified in stool specimens from residents with cryptosporidiosis. Genetic analysis was performed on 628 positive stool samples collected from NYC residents between 2015 and 2018 to determine the species present. A total of 547 samples yielded positive results by real-time PCR. Of these samples, 512 (93.6%) were identified to the species level, with 94.7% positive for either Cryptosporidium hominis or Cryptosporidium parvum (56.4% and 38.5%, respectively), including one coinfection. Less common Cryptosporidium species identified included C. felis, C. canis, C. ubiquitum, C. meleagridis, and a Cryptosporidium sp. chipmunk genotype. Results were evaluated and compared to species and genotypes of Cryptosporidium previously identified from stormwater collected within the NYC watershed. While there was overlap with some of the rare species found in case specimens, the prevalence and distribution of species did not suggest a connection between sources previously identified in the watershed and the species causing human cases of cryptosporidiosis in NYC residents. IMPORTANCE It is important to identify the species causing human cryptosporidiosis in a population in order to investigate possible sources or routes of contamination. Many species of Cryptosporidium are host-adapted and therefore have the potential to be tracked back to specific sources that can subsequently be managed. There has been no evidence to suggest that the water supply has ever been a source of cryptosporidiosis cases in NYC, and since 2013, the New York City Department of Environmental Protection has further reduced the risk of disease through the use of ultraviolet treatment to inactivate any Cryptosporidium present in the source water. However, as one of the largest unfiltered water supplies in the country, it is important to evaluate watershed sources for potential impacts to public health. In this unique study, species of Cryptosporidium causing disease in NYC residents were identified and compared with previously identified species from the watershed.

Molecular identification and genetic characteristics of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi in human immunodeficiency virus/acquired immunodeficiency syndrome patients in Shanghai, China

BACKGROUND

Opportunistic infections are a ubiquitous complication in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) patients. Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi are common opportunistic intestinal pathogens in humans. In China, despite the number of HIV/AIDS patients being extremely large, only a few studies have investigated opportunistic infections caused by intestinal pathogens in this patient population. The aims of this study were to elucidate the occurrence and genetic characteristics of Cryptosporidium spp., G. duodenalis, and E. bieneusi in HIV/AIDS patients.

METHODS

We collected fecal specimens from 155 HIV/AIDS patients (one from each patient). All of the specimens were examined for the presence of the pathogens by genotyping using polymerase chain reaction and sequencing of the small subunit ribosomal RNA gene for Cryptosporidium spp.; the triosephosphate isomerase, β-giardin and glutamate dehydrogenase genes for G. duodenalis; and the internal transcribed spacer region of the rRNA gene for E. bieneusi. The Cryptosporidium-positive specimens were further subtyped by polymerase chain reacion and sequencing of the 60-kDa glycoprotein gene.

RESULTS

Six (3.9%), three (1.9%), and eight (5.2%) HIV/AIDS patients were positive for Cryptosporidium spp., G. duodenalis, and E. bieneusi, respectively. No statistical differences were observed in occurrence rate between the groups by gender, clinical symptom (diarrhea), and CD4⁺ cell count. Four Cryptosporidium species were identified: Cryptosporidium hominis (n = 2), Cryptosporidium parvum (n = 1), Cryptosporidium meleagridis (n = 1), and Cryptosporidium andersoni (n = 2). Furthermore, two C. hominis subtypes (IeA12G3T3 and IaA28R4) were detected. Three G. duodenalis-positive specimens were successfully amplified and sequenced at the triosephosphate isomerase and β-giardin loci, which led to the identification of assemblages C and B, respectively. Seven genotypes (D, Type IV, EbpC, Peru11, EbpD, A, and I) were identified in E. bieneusi-positive specimens.

CONCLUSIONS

Our findings should increase awareness of AIDS-related opportunistic intestinal pathogens, and indicate the need for routine examination in clinical practice for the detection of Cryptosporidium spp., G. duodenalis, and E. bieneusi. Homology analyses of the three intestinal pathogens at the nucleotide and/or amino acid levels indicated their zoonotic potential.

Cryptosporidiosis in Finland is predominantly of domestic origin: investigation of increased reporting, 1995-2020

BACKGROUND

Cryptosporidiosis is gastroenteritis caused by Cryptosporidium. Since 2017, reporting of cryptosporidiosis has increased in Finland.

METHODS

We describe demographics of cryptosporidiosis cases notified to Finnish Infectious Disease Register (FIDR) during a 21-year surveillance period, 1995-2020, and a retrospective investigation of increased cryptosporidiosis in Ostrobothnian hospital districts in summer 2018.

RESULTS

Incidence of cryptosporidiosis during the period 2017-2020 represented 20-fold increase from the period 1995-2016, with the highest incidence detected in Ostrobothnia. In 2018, cryptosporidiosis in Ostrobothnia was associated with living on or visiting a farm where the production animals had diarrhoea, noticing more flies than usual, gardening or handling manure and having a family member with gastroenteritis. Four gp60 subtypes were identified in patient samples: IIaA18G1R1, IIaA15G2R1, IIaA13G2R1 and IIaA15G1R1.

CONCLUSIONS

In Finland, Cryptosporidium has been included in gastrointestinal PCR diagnostic panels in most clinical laboratories since 2016. Since then, the number of reported cases has subsequently increased, indicating improved diagnostics and awareness of the illness. In 2018, several C. parvum subtypes were identified in patients suggesting that the increase was not caused by a single source. Cryptosporidiosis increased in Finland in 2020 despite hand washing recommendations and travel restrictions imposed during the COVID-19 pandemic, indicating that domestic cases are more frequent than previously considered. To monitor cause and origin of cryptosporidiosis and the effect of control measures, Cryptosporidium should be identified at subspecies level, and travel history should be included in FIDR notification. Those working with cattle and calves require precise instructions on how to prevent C. parvum infection.

Multiple introductions and recombination events underlie the emergence of a hyper-transmissible Cryptosporidium hominis subtype in the USA

The parasite Cryptosporidium hominis is a leading cause of the diarrheal disease cryptosporidiosis, whose incidence in the United States has increased since 2005. Here, we show that the newly emerged and hyper-transmissible subtype IfA12G1R5 is now dominant in the United States. In a comparative analysis of 127 newly sequenced and 95 published C. hominis genomes, IfA12G1R5 isolates from the United States place into three of the 14 clusters (Pop6, Pop13, and Pop14), indicating that this subtype has multiple ancestral origins. Pop6 (IfA12G1R5a) has an East Africa origin and has recombined with autochthonous subtypes after its arrival. Pop13 (IfA12G1R5b) is imported from Europe, where it has recombined with the prevalent local subtype, whereas Pop14 (IfA12G1R5c) is a progeny of secondary recombination between Pop6 and Pop13. Selective sweeps in invasion-associated genes have accompanied the emergence of the dominant Pop14. These observations offer insights into the emergence and evolution of hyper-transmissible pathogens.

Development, Optimisation and Validation of a Novel Multiplex Real-Time PCR Method for the Simultaneous Detection of Cryptosporidium spp., Giardia duodenalis and Dientamoeba fragilis

The enteric protozoan parasites Cryptosporidium spp., Giardia duodenalis and Dientamoeba fragilis are-to various extents-contributors to the burden of gastrointestinal illness in high-income countries. Detection of these pathogens by microscopy examination is challenging because of the limited sensitivity and need for specific staining procedures. We developed and optimised a new multiplex real-time PCR assay for the simultaneous detection of Cryptosporidium spp., G. duodenalis and D. fragilis in clinical (stool) samples. The diagnostic performance of the assay was evaluated against a large panel of well-characterised DNA samples positive for Cryptosporidium spp. (n = 126), G. duodenalis (n = 132) and D. fragilis (n = 49). The specificity of the test was assessed against a DNA panel from other intestinal or phylogenetically related parasites (n = 105) and faecal DNA from individuals without clinical manifestations (n = 12). The assay exhibited a diagnostic sensitivity of 0.90-0.97 and a diagnostic specificity of 1. The limit of detection was estimated for Cryptosporidium (1 oocyst) and G. duodenalis (5 × 10-4 cysts). The method allowed the detection of four Cryptosporidium species (C. hominis, C. parvum, C. meleagridis and C. cuniculus) and five G. duodenalis assemblages (A-E) without cross-reacting with other parasites belonging to the phyla Amoebozoa, Apicomplexa, Euglenozoa, Microsporidia, Nematoda and Platyhelminthes. This newly developed multiplex real-time PCR assay represents a novel alternative for the rapid and accurate detection of Cryptosporidium, G. duodenalis and D. fragilis in clinical settings.

Divergent Cryptosporidium species and host-adapted Cryptosporidium canis subtypes in farmed minks, raccoon dogs and foxes in Shandong, China

Cryptosporidium spp. are common parasitic pathogens causing diarrhea in humans and various animals. Fur animals are widely farmed in Shandong Province, China, but the prevalence and genetic identity of Cryptosporidium spp. in them are unclear. In this study, 1,211 fecal samples were collected from 602 minks, 310 raccoon dogs and 299 foxes on two farms in Shandong and analyzed for Cryptosporidium spp. by nested PCR and sequence analyses of the small subunit rRNA gene. The overall infection rate of Cryptosporidium spp. was 31.5% (381/1,211), with a higher infection rate in raccoon dogs (37.7%, 117/310) than in foxes (32.4%, 97/299) and minks (27.7%, 167/602). By age, the highest infection rates of Cryptosporidium spp. were observed in raccoon dogs of 1-2 months, minks of 5-6 months, and foxes of > 12 months. Three Cryptosporidium species and genotypes were detected, including C. canis (n = 279), C. meleagridis (n = 65) and Cryptosporidium mink genotype (n = 37). Among the three major host species, raccoon dogs were infected with C. canis only (n = 117), while foxes were infected with both C. canis (n = 32) and C. meleagridis (n = 65), and minks with C. canis (n = 130) and Cryptosporidium mink genotype (n = 37). Subtyping of C. canis by sequence analysis of the 60 kDa glycoprotein gene identified eight subtypes. They belonged to two known subtype families, XXa and XXd, and two novel subtype families XXf and XXg, with host adaptation at the subtype family level. Notably, C. canis from foxes was genetically distant from those in other hosts. Further subtyping analysis identified three subtypes (IIIeA21G2R1, IIIeA19G2R1 and IIIeA17G2R1) of C. meleagridis and two novel subtype families Xf and Xg of the Cryptosporidium mink genotype. The presence of zoonotic C. canis subtypes in raccoon dogs and C. meleagridis subtypes in foxes suggests that these fur animals might be potential reservoirs for human-pathogenic Cryptosporidium spp.

Decline in Cryptosporidium Infection in Free-Ranging Rhesus Monkeys in a Park After Public Health Interventions

Nonhuman primates (NHPs) are considered an important source of parasitic zoonoses. A study in 2010 revealed high prevalence of Cryptosporidium spp. in free-ranging rhesus monkeys (Macaca mulatta) in a public park in Guiyang, southwestern China, which called for the control of disease in animals and long-term epidemiological tracking of Cryptosporidium spp. After the initiation of a series of public health interventions, we collected 2,402 fecal samples from monkeys and 123 water samples from lakes in the park on six occasions during 2013-2019. They were analyzed and genotyped for Cryptosporidium spp. using PCR and sequence analyses of the small subunit rRNA gene. The C. hominis and C. parvum identified were further subtyped by sequence analysis of the 60 kDa glycoprotein gene. Compared with the high prevalence of Cryptosporidium spp. in fecal samples (10.9% or 45/411) and water samples (47.8% or 11/23) in 2010, only 18 (0.7%) fecal samples and 3 (2.4%) water samples collected in the present study were positive for Cryptosporidium spp., including C. hominis (n = 9) and C. parvum (n = 12). The former belonged to the NHP-adapted IfA17G2R3 subtype, while the latter mostly belonged to rodent-adapted IIpA9. Therefore, the detection rate and genetic diversity of Cryptosporidium spp. during this study period were much lower than those before the public health interventions, and there was a switch from common occurrence of anthroponotic C. hominis subtypes to sporadic occurrence of NHP-adapted C. hominis and rodent-adapted C. parvum subtypes.

Sympatric Recombination in Zoonotic Cryptosporidium Leads to Emergence of Populations with Modified Host Preference

Genetic recombination plays a critical role in the emergence of pathogens with phenotypes such as drug resistance, virulence, and host adaptation. Here, we tested the hypothesis that recombination between sympatric ancestral populations leads to the emergence of divergent variants of the zoonotic parasite Cryptosporidium parvum with modified host ranges. Comparative genomic analyses of 101 isolates have identified seven subpopulations isolated by distance. They appear to be descendants of two ancestral populations, IIa in northwestern Europe and IId from southwestern Asia. Sympatric recombination in areas with both ancestral subtypes and subsequent selective sweeps have led to the emergence of new subpopulations with mosaic genomes and modified host preference. Subtelomeric genes could be involved in the adaptive selection of subpopulations, while copy number variations of genes encoding invasion-associated proteins are potentially associated with modified host ranges. These observations reveal ancestral origins of zoonotic C. parvum and suggest that pathogen import through modern animal farming might promote the emergence of divergent subpopulations of C. parvum with modified host preference.

Molecular detection and genetic characteristics of Cryptosporidium spp. in Chinese racehorses

BACKGROUND

Cryptosporidium is a protozoan parasite causing diarrhoea in humans and animals. Although Cryptosporidium has been found in domestic horses (farmed or kept at pasture), there has been only one published study of Cryptosporidium infections in Chinese racehorses, which was restricted to a very small geographical area.

OBJECTIVES

To investigate the presence of Cryptosporidium spp. in the faeces of racehorses in China and to perform molecular characterisation of the parasite.

STUDY DESIGN

Cross-sectional.

METHODS

A total of 621 fresh faecal samples were collected for DNA extraction from racehorses at 17 equestrian clubs from 12 provinces of China from December 2016 to May 2018. All the DNA were analysed for the presence of Cryptosporidium species/genotypes and subtypes by PCR amplification of the small subunit ribosomal RNA and 60 kDa glycoprotein genes, respectively.

RESULTS

PCR analysis revealed that 11 samples (1.8%) were positive for Cryptosporidium spp. Among them 7 samples were identified as C. parvum and 4 were C. hominis. The C. parvum isolates were identified as subtype IIdA14G1 (n = 4) and IIdA15G1 (n = 3), while all C. hominis isolates were identified as subtype IkA18G1 (n = 4).

MAIN LIMITATIONS

A single faecal sample from each horse was used instead of multiple samples that could improve the detection rates of the parasite.

CONCLUSIONS

Although Cryptosporidium infection rate was relatively low in the investigated racehorses, the presence of zoonotic subtypes IIdA14G and 1IIdA15G1 of C. parvum and IkA18G1 of C. hominis, suggesting that these animals are a potential source of Cryptosporidium in humans.

Dominance of the zoonotic pathogen Cryptosporidium meleagridis in broiler chickens in Guangdong, China, reveals evidence of cross-transmission

Background

Cryptosporidium is one of the most prevalent parasites infecting both birds and mammals. To examine the prevalence of Cryptosporidium species and evaluate the public health significance of domestic chickens in Guangdong Province, southern China, we analyzed 1001 fecal samples from 43 intensive broiler chicken farms across six distinct geographical regions.

Methods

Individual DNA samples were subjected to nested PCR-based amplification and sequencing of the small subunit of the nuclear ribosomal RNA gene (SSU rRNA). Analysis of the 60 kDa glycoprotein gene (gp60) was performed to characterize the subtypes of C. meleagridis.

Results

The overall prevalence of Cryptosporidium was 13.2% (95% CI 11.1–15.3) (24 of 43 farms), with C. meleagridis (7.8%), C. baileyi (4.8%) and mixed infections (0.6%). Using the gp60 gene, three subtype families, IIIb, IIIe and IIIg, were identified, including six subtypes: one novel (IIIgA25G3R1a) and five previously reported (IIIbA23G1R1c, IIIbA24G1R1, IIIbA21G1R1a, IIIeA17G2R1 and IIIeA26G2R1). Within these subtypes, five known subtypes were genetically identical to those identified in humans.

Conclusions

This is the first report of C. meleagridis in chickens from Guangdong. The frequent occurrence of C. meleagridis in domestic chickens and the common C. meleagridis subtypes identified in both humans and chickens is of public health significance. Our study indicates that broiler chickens represent a potential zoonotic risk for the transmission of Cryptosporidium in this region.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05267-x.

Molecular prevalence and subtyping of Cryptosporidium spp. in fecal samples collected from stray cats in İzmir, Turkey

Background

Cryptosporidium spp. are obligate intracellular apicomplexan parasites transmitted to humans and other animals by contaminated water, food, or direct contact. They mainly cause gastrointestinal symptoms, although subclinical infections are also common. Cats are primarily infected by host-adapted Cryptosporidium felis while C. parvum and C. muris have also been detected in some cases. In this study, the molecular prevalence of Cryptosporidium spp. was investigated by screening 399 fecal samples collected from stray cats using nested PCR targeting the 18S rRNA gene for the first time in Turkey. Additionally, Cryptosporidium PCR-positive samples were genotyped by nested PCR- restriction fragment length polymorphism (RFLP), and subsequently, amplicons of 18S SSU rRNA were sequenced. They were further subtyped by amplification and sequencing of the gp60 gene.

Results

Among fecal samples screened, 12 of them (3%) were found to be Cryptosporidium-positive, and according to RFLP and sequencing of 18S rRNA gene, all positive samples were identified as C. felis. Subtyping analyses at the gp60 gene showed that C. felis isolates belonged to the XIXa subtype family, which are closely related to human subtypes of the parasite.

Conclusions

The results of this study are important in terms of indicating the potential role of stray cats for transmission of Cryptosporidium spp. to humans or other animals. Also, the presence of XIXa, which is the dominant subtype family of C. felis in cats and humans was shown for the first time in stray cats of İzmir, Turkey.

Use of metagenomic microbial source tracking to investigate the source of a foodborne outbreak of cryptosporidiosis

Cryptosporidium is a protozoan parasite of global public health importance that causes gastroenteritis in a variety of vertebrate hosts, with many human outbreaks reported yearly, often from ingestion of contaminated water or food. Despite the major public health implications, little is typically known about sources of contamination of disease outbreaks caused by Cryptosporidium. Here, we study a national foodborne outbreak resulted from infection with Cryptosporidium parvum via romaine lettuce, with the main goal to trace the source of the parasite. To do so, we combined traditional outbreak investigation methods with molecular detection and characterization methods (i.e. PCR based typing, amplicon and shotgun sequencing) of romaine lettuce samples collected at the same farm from which the contaminated food was produced. Using 18S rRNA typing, we detected C. parvum in two out of three lettuce samples, which was supported by detections in the metagenome analysis. Microbial source tracking analysis of the lettuce samples suggested sewage water as a likely source of the contamination, albeit with some uncertainty. In addition, the high degree of overlap in bacterial species content with a public human gut microbial database corroborated the source tracking results. The combination of traditional and molecular based methods applied here is a promising tool for future source tracking investigations of food- and waterborne outbreaks of Cryptosporidium spp. and can help to control and mitigate contamination risks.

Molecular Detection of Cryptosporidium cuniculus in Rabbits (Oryctolagus cuniculus) from Tenerife, Canary Islands, Spain

Cryptosporidium cuniculus is a zoonotic parasite responsible for cryptosporidiosis cases and outbreaks in both humans and rabbits. Since there are no molecular Cryptosporidium spp. infection data in rabbits (Oryctolagus cuniculus) from Spain, our aim was to gather information about this parasite in wild European rabbits from Tenerife, Canary Islands (Spain). A total of 100 faecal samples were collected from rabbits from eight municipalities of Tenerife. Microscopic analysis showed that 4.0% of the samples presented structures compatible with Cryptosporidium oocyst. A nested polymerase chain reaction (PCR) targeting 18S ribosomal RNA (rRNA) gene fragments was carried out, and sequencing confirmed the identity of C. cuniculus in one sample (1.0%). The sample was successfully subtyped using nested PCR analysis of the 60-kDa glycoprotein (gp60) gene as the subtype VbA26R3. This study confirms the presence of C. cuniculus in wild rabbits from Tenerife, providing new information on the occurrence of this zoonotic parasite. Further studies are required to better understand the epidemiology of Cryptosporidium spp. in wild rabbits in Spain and their possible public health repercussions.

Association of Common Zoonotic Pathogens With Concentrated Animal Feeding Operations

Animal farming has intensified significantly in recent decades, with the emergence of concentrated animal feeding operations (CAFOs) in industrialized nations. The congregation of susceptible animals in CAFOs can lead to heavy environmental contamination with pathogens, promoting the emergence of hyper-transmissible, and virulent pathogens. As a result, CAFOs have been associated with emergence of highly pathogenic avian influenza viruses, hepatitis E virus, Escherichia coli O157:H7, Streptococcus suis, livestock-associated methicillin-resistant Staphylococcus aureus, and Cryptosporidium parvum in farm animals. This has led to increased transmission of zoonotic pathogens in humans and changes in disease patterns in general communities. They are exemplified by the common occurrence of outbreaks of illnesses through direct and indirect contact with farm animals, and wide occurrence of similar serotypes or subtypes in both humans and farm animals in industrialized nations. Therefore, control measures should be developed to slow down the dispersal of zoonotic pathogens associated with CAFOs and prevent the emergence of new pathogens of epidemic and pandemic potential.

Emergence of zoonotic Cryptosporidium parvum in China

Zoonotic cryptosporidiosis is a major public health problem in industrialized nations; in those countries it is caused mainly by Cryptosporidium parvum IIa subtypes that are prevalent in dairy calves. Because of the short history of intensive animal farming in China, strains of C. parvum are found only on some dairy farms in this country and are the IId subtypes. However, the prevalence of C. parvum is increasing rapidly, with IIa subtypes recently detected in a few grazing animals, and both IIa and IId subtypes are emerging in humans. As animal farming intensifies, China may follow in the footsteps of industrialized nations where zoonotic cryptosporidiosis is rampant. One Health and biosecurity measures are urgently needed to slow down the dispersal of autochthonous IId subtypes and imported IIa subtypes.

In vitro and in vivo anti-Cryptosporidium and anti-inflammatory effects of Aloe vera gel in dexamethasone immunosuppressed mice

Cryptosporidiosis has been considered as a serious diarrheal disease, especially in immunodeficient patients, where they failed to clear the infection leading to several consequences of infection (i.e death). The role of cell mediated immunity in clearing the infection was demonstrated by the increased susceptibility of HIV/AIDS patients to infection. To date, no specific treatment has been proven for cryptosporidiosis in immunodeficient patients. The study aimed to evaluate the efficacy of Aloe vera gel for the treatment of cryptosporidiosis in immunocompetent and dexamethasone immunosuppressed mice in comparison to that of nitazoxanide. Mice were orally administrated with Aloe vera gel, in a daily dose of 250 mg/L in drinking water, for 14 consecutive days post infection. Parasitological, molecular and immunological measurements were recorded on the 7th, 14th, 21st and 32nd days post infection. Our in vitro results showed that 250 mg/L of prepared gel achieved the highest parasitic reduction. The body weights of Aloe vera treated mice on the 21st and 32nd day post infection, either in immunocompetent or immunosuppressed groups, were nearly the same as those of their corresponding control groups. Aloe vera gel succeeded in clearing cryptosporidiosis with a percent reduction of 100% in immunocompetent mice and 99.67% in immunosuppressed mice. The anti-inflammatory effect of Aloe vera reduced the levels of IFN-γ, IL-4, -6 and -17. The success of Aloe vera gel, in clearing cryptosporidiosis in immunosuppressed mice, was obvious either from the reduction of Cryptosporidium DNA or the oocysts in stool samples; and from the improvement of histopathological sections.

An Update on Zoonotic Cryptosporidium Species and Genotypes in Humans

The enteric parasite, Cryptosporidium is a major cause of diarrhoeal illness in humans and animals worldwide. No effective therapeutics or vaccines are available and therefore control is dependent on understanding transmission dynamics. The development of molecular detection and typing tools has resulted in the identification of a large number of cryptic species and genotypes and facilitated our understanding of their potential for zoonotic transmission. Of the 44 recognised Cryptosporidium species and >120 genotypes, 19 species, and four genotypes have been reported in humans with C. hominis, C. parvum, C. meleagridis, C. canis and C. felis being the most prevalent. The development of typing tools that are still lacking some zoonotic species and genotypes and more extensive molecular epidemiological studies in countries where the potential for transmission is highest are required to further our understanding of this important zoonotic pathogen. Similarly, whole-genome sequencing (WGS) and amplicon next-generation sequencing (NGS) are important for more accurately tracking transmission and understanding the mechanisms behind host specificity.

Taxonomy and molecular epidemiology of Cryptosporidium and Giardia - a 50 year perspective (1971-2021)

The protozoan parasites Cryptosporidium and Giardia are significant causes of diarrhoea worldwide and are responsible for numerous waterborne and foodborne outbreaks of diseases. Over the last 50 years, the development of improved detection and typing tools has facilitated the expanding range of named species. Currently at least 44 Cryptosporidium spp. and >120 genotypes, and nine Giardia spp., are recognised. Many of these Cryptosporidium genotypes will likely be described as species in the future. The phylogenetic placement of Cryptosporidium at the genus level is still unclear and further research is required to better understand its evolutionary origins. Zoonotic transmission has long been known to play an important role in the epidemiology of cryptosporidiosis and giardiasis, and the development and application of next generation sequencing tools is providing evidence for this. Comparative whole genome sequencing is also providing key information on the genetic mechanisms for host specificity and human infectivity, and will enable One Health management of these zoonotic parasites in the future.