Occurrence of zoonotic Cryptosporidium and Giardia duodenalis species/genotypes in urban rodents

Molecular identification and subtyping of Cryptosporidium spp. in laboratory mice and rats

Cryptosporidium species can infect humans and more than 260 animal species, including 54 rodent species. However, data on the occurrence and genetic characterizations of Cryptosporidium spp. in laboratory rodents are limited. The present study aimed to determine the occurrence rate and genetic characterizations of Cryptosporidium spp. in laboratory mice and rats. We collected 506 fresh combined fecal pellet specimens (457 from mice and 49 from rats) of more than 2,000 laboratory rodents in Heilongjiang Province and Shanghai City, China. Cryptosporidium spp. were identified and subtyped by DNA sequencing of the SSU rRNA and the gp60 genes, respectively. By sequence analysis of the SSU rRNA gene, the occurrence rate of Cryptosporidium spp. was 16.6% (84/506) in combined fecal specimens, with 18.2% (83/457) for mice and 2.0% (1/49) for rats. Cryptosporidium parvum (n = 39), C. tyzzeri (n = 33), and C. parvum + C. tyzzeri (n = 11) were identified in mice. Cryptosporidium parvum was only detected in one rat fecal specimen. At the gp60 locus, 71.4% (60/84) of the Cryptosporidium-positive specimens were successfully amplified, and they all came from mice. We identified five C. parvum subtypes (IIaA14G2R1, IIaA16G2R1, IIaA17G1R1, IIaA17G2R1, and IIaA18G2R1) and two C. tyzzeri subtypes (IXaA6R1 and IXbA8). Based on the identification in laboratory mice of C. parvum subtypes that have been reported previously in humans, the mice infected with this species may threaten human health, especially for people who have contact with the animals and their feces.

Zoonotic importance of ecto- and endoparasites in rodents in Malaysia: a review

IMPORTANCE

Rodents, particularly those inhabiting urban areas, are sources of infections that cause major human diseases. The number of recorded zoonotic infections has increased in recent decades, exacerbating public concerns. Zoonotic diseases in humans, such as capillariasis, hymenolepiasis, and toxoplasmosis, are life-threatening in severe cases, particularly in immunocompromised individuals. A thorough understanding of pathogens, particularly the parasites infecting rodents, is critical for predicting future zoonotic disease outbreaks and developing effective mitigation strategies. This review summarizes the information on parasites in rodents inhabiting Malaysia to identify the knowledge gaps that could serve as a foundation for future research.

OBSERVATIONS

Thirty-eight previous parasite studies in rodents conducted in Malaysia were reviewed, and 44 ectoparasites species and 58 endoparasites species across 19 rodent species were revealed. Six ectoparasite and eight endoparasite species were identified as zoonotic among these parasites. Morphological identification of parasite species typically succeeded only at the genus level because of their identical morphological characteristics. However, these studies used a molecular approach to identify parasites at the species level using species-specific primers. The pathological findings of various organs of infected rodents were also summarized, including gross and histological lesions exhibited by parasites.

CONCLUSIONS AND RELEVANCE

This review highlights the list of parasites infecting rodents in Malaysia, provides information on the molecular and pathological findings from previous studies, and identifies some of the limitations and knowledge gaps that suggest future research to address the issues, including the paucity of information on blood parasites, molecular, and histopathological studies of parasites in rodents.

Occurrence rate and species and subtypes of Cryptosporidium spp. in pet dogs in Yunnan Province, China

BACKGROUND

Cryptosporidium spp. is a ubiquitous, globally distributed intestinal protozoan infecting humans and at least 260 animal hosts. Due to close human contact with pet dogs and identification of zoonotic Cryptosporidium species and subtypes in these animals, dog health is not only a veterinarian issue but also a public health issue. This study aimed to understand occurrence and genetic characterization at both genotype and subtype levels in pet dogs in Yunnan Province, China.

RESULTS

A total of 589 fresh fecal specimens were collected from adult pet dogs in the rural areas of eight cities/autonomous prefectures of Yunnan Province, China. 16 fecal specimens were positive for Cryptosporidium spp. by polymerase chain reaction (PCR) amplification and sequence analysis of the small subunit ribosomal RNA (SSU rRNA) gene, with an average occurrence rate of 2.7% (16/589) being observed. Three zoonotic Cryptosporidium species were identified: C. parvum (n = 7), C. suis (n = 5) and C. canis (n = 4). At the 60-kDa glycoprotein (gp60) locus, only three C. parvum and two C. canis specimens were successfully amplified and sequenced, with subtype IIaA17G2R1 (n = 3) and subtypes XXa4 (n = 1) and XXa5 (n = 1) being identified, respectively.

CONCLUSIONS

The present finding of three zoonotic Cryptosporidium species in dogs implied that dogs infected with Cryptosporidium spp. may pose a threat to human health. C. suis was identified in dogs in this study for the first time, expanding the host range of this species. Identification of C. parvum subtype IIaA17G2R1 and C. canis subtypes XXa4 and XXa5 will be helpful to explore the source attribution of infection/contamination and assess the transmission dynamics of C. parvum and C. canis in the investigated areas in the future.

Minimal zoonotic risk of cryptosporidiosis and giardiasis from frogs and reptiles

The zoonotic potential of the protist parasites Cryptosporidium spp. and Giardia duodenalis in amphibians and reptiles raises public health concerns due to their growing popularity as pets. This review examines the prevalence and diversity of these parasites in wild and captive amphibians and reptiles to better understand the zoonotic risk. Research on Giardia in both groups is limited, and zoonotic forms of Cryptosporidium or Giardia have not been reported in amphibians. Host-adapted Cryptosporidium species dominate in reptiles, albeit some reptiles have been found to carry zoonotic (C. hominis and C. parvum) and rodent-associated (C. tyzzeri, C. muris and C. andersoni) species, primarily through mechanical carriage. Similarly, the limited reports of Giardia duodenalis (assemblages A, B and E) in reptiles may also be due to mechanical carriage. Thus, the available evidence indicates minimal zoonotic risk associated with these organisms in wild and captive frogs and reptiles. The exact transmission routes for these infections within reptile populations remain poorly understood, particularly regarding the importance of mechanical carriage. Although the risk appears minimal, continued research and surveillance efforts are necessary to gain a more comprehensive understanding of the transmission dynamics and ultimately improve our ability to safeguard human and animal health.

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.

Detection and Molecular Characterization of Giardia and Cryptosporidium spp. Circulating in Wild Small Mammals from Portugal

Cryptosporidium spp. and Giardia spp. are important diarrhea-causing protozoan parasites worldwide that exhibit broad host ranges. Wild small mammals can harbor host-adapted and potentially zoonotic species of both parasites. The aim of this study was to investigate Cryptosporidium spp. and Giardia spp. in wild rodents and shrews in Portugal, focusing on the protist's occurrence and genetic diversity. Molecular screening by PCR at the small subunit (SSU) rRNA gene locus of 290 fecal samples from wood mice (Apodemus sylvaticus), southwestern water voles (Arvicola sapidus), Cabrera's voles (Microtus cabrerae), Lusitanian pine voles (Microtus lusitanicus), Algerian mice (Mus spretus) and greater white-toothed shrews (Crocidura russula) in Northeast Portugal revealed the low occurrence of Cryptosporidium spp. (1%) and high occurrence of Giardia spp. (32.8%). The analysis revealed that "species" was the only significant factor associated with the increasing probability of Giardia spp. infection, with the highest prevalence reported in southwestern water voles and Lusitanian pine voles. Cryptosporidium and Giardia species determination at the SSU rRNA gene locus revealed C. muris and G. microti as the only circulating species, respectively. Subtyping of the glutamate dehydrogenase (gdh) and beta-giardin (bg) genes provided evidence of the high genetic diversity within the G. microti clade. This study suggests that rodent-adapted G. microti occurs to a large extent in cricetid hosts and supports the limited role of wild rodents and shrews as natural sources of human infections in Northeast Portugal regarding the investigated parasites. Moreover, this is the first record of G. microti in southwestern water voles, Lusitanian pine voles, Algerian mice, wood mice and Cabrera's voles and C. muris in Cabrera's voles. Finally, this study improves the database of sequences relevant for the sequence typing of G. microti strains and provides new insights about the epidemiology of Giardia spp. and Cryptosporidium spp. in wild rodents and shrews, two parasite genera of high importance for public and animal health.

Occurrence, genetic characterization, and zoonotic importance of Giardia duodenalis in various species of rodents (Mus musculus, Rattus norvegicus, and Rattus rattus)

Giardia duodenalis is a well-known flagellated parasite and the causative agent of protozoal diarrhea in animals and humans worldwide. Current study was aimed at determination of G. duodenalis prevalence, genetic variation and zoonotic significance in various species of rodents in Shiraz, southwestern Iran. In brief, 120 fecal specimens were collected from rodents (Rattus rattus, Rattus norvegicus, and Mus musculus) during May up to November 2021 and microscopically examined for Giardia cysts. Further molecular characterization of positive samples was done by nested-PCR, followed by nucleotide sequencing of the triose phosphate isomerase (tpi) gene. A total prevalence of 3.3% (4/120) was observed in rodents, with highest rate in black rats [5% (2/40)]. Regarding brown rats and house mice, only one sample was found to be positive, showing 2.5% and 2.5% prevalence, respectively. It is noteworthy that Giardia B and G assemblages were found in black rats (one case/genotype), whereas the only positive samples from brown rats and house mice were characterized as assemblage G. The major findings of the present study were the presence of both zoonotic and non-zoonotic Giardia assemblages in examined rats in Shiraz and the potential of black rats to harbor Giardia infection to humans. These concerns should be taken seriously in terms of public health. Nevertheless, the true epidemiology and assemblage distribution of Giardia is still open to question.

Detection of zoonotic-borne parasites in Rattus spp. in Klang Valley, Malaysia

Background and Aim:

Rattus spp. are the most common animals capable of adapting to their environment. They can be reservoirs or vectors of diseases that facilitate the transmission of zoonotic-borne parasites to humans. Hence, a study on the detection of parasites in rat populations in urban areas is crucial to prepare for emerging zoonosis. Therefore, this study aims to identify blood parasites, ectoparasites, and helminths in Rattus spp. from wet markets located in Klang Valley, an urban area with a high-density human population.

Materials and Methods:

A total of 32 rats were trapped in several wet markets in Klang Valley, Malaysia. They were anesthetized for morphometric examination followed by exsanguination. Various parasitological techniques such as perianal tape test, simple flotation, direct examination of the intestine, and fecal smear were performed for intestinal parasite detection; hair plucking, skin scraping, and full body combing for ectoparasite identification; and blood smear, microhematocrit centrifugation, and buffy coat techniques for blood parasite detection.

Results:

The rats were identified as Rattus rattus (71.9%) and Rattus norvegicus (28.1%). The only blood protozoan found was Trypanosoma lewisi. The ectoparasites identified belonged to two broad groups, mites (Laelaps spp. and Ornithonyssus spp.) and fleas (Xenopsylla cheopis), known to be parasitic zoonotic disease vectors. The zoonotic intestinal parasites were cestodes (Hymenolepis nana), nematodes (Nippostrongylus brasiliensis, Strongyloides spp., Trichuris spp., Capillaria spp., and Syphacia spp.), and intestinal protozoa (coccidian oocysts and Giardia spp.). Microscopic images showing Giardia spp. are the first report of this organism in rats in Malaysia.

Conclusion:

Rats caught in this urban area of the Klang Valley harbor parasites can pose a potential zoonotic threat to humans, raising public health concerns because of their proximity to densely populated urban areas.

Public health and ecological significance of rodents in Cryptosporidium infections

Cryptosporidium is one of the most important genera of intestinal zoonotic pathogens that cause diarrhea in both humans and animals. Rodents are common and important hosts or carriers of pathogens with public health importance, and rodents play an important role in the ecology of zoonotic transmission. The overall worldwide prevalence of Cryptosporidium spp. in rodents is 19.8% (4589/23142). Twenty-five known Cryptosporidium species and 43 genotypes have been identified, and C. parvum is the dominant species in rodents worldwide. Rodents transfer pathogens to humans by the direct route or by serving as intermediate hosts transmitting the pathogens to other animals. We review the epidemiology, diversity, and transmission routes of Cryptosporidium spp. in rodents. The main purpose of this review is to highlight Cryptosporidium infection in rodents and its transmission, associated risk factors, and prevention; in addition, we assess the public health and ecological significance of Cryptosporidium infections from the One Health perspective.

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Review of the epidemiology and diversity of Cryptosporidium in rodents.

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The overall worldwide prevalence is 19.8% (4589/23142), C. parvum is the dominant species.

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Public health and ecological significance of rodent-borne Cryptosporidium at “One Health” perspective.

Current state of infection and prevalence of giardiasis in Malaysia: a review of 20 years of research

Background

Giardiasis is a neglected parasitic zoonotic disease caused by Giardia duodenalis that is often overlooked despite the damage inflicted upon humans and domestic/wild animals. Lack of surveillance studies, low sensitivity of diagnostic tools, and resistance to giardiasis treatment add to the challenge in managing giardiasis, leaving a gap that continues to render giardiasis a silent threat to public health worldwide. This situation is not much different in Malaysia, where giardiasis remains a public health problem, especially in the indigenous communities. Realizing the existence of gaps in the literature and information on giardiasis in Malaysia, this review aims to revisit and update the situation of giardiasis in Malaysia based on articles published in 20 years from 2000 to 2020, providing estimates on the incidence of giardiasis in humans, animals, and the environment, which may inform efforts to prevent and control the impact of giardiasis in the country.

Methodology

We searched PubMed, Science Direct, and Scopus using MeSH terms and text keywords "Giardia duodenalis OR Giardia intestinalis OR Giardia lamblia OR intestinal protozoa AND Malaysia". Information was collected from all giardiasis reports published between 2000 and 2020.

Results

Giardiasis in Malaysia is more prevalent among the poorest segments of the population, namely the indigenous communities and people living in densely populated areas such as slums and prisons, due to low standard of personal hygiene, unsafe water resources, and improper sanitation. While the prevalence data is hugely dependent on microscopic fecal examination in epidemiological studies of giardiasis, current studies mostly focused on species identification and genotype distribution by multilocus genotyping. Thus far, the outbreak of giardiasis has not been reported in the country, but the disease was found to be significantly associated with stunting, wasting, and malnutrition among children of the indigenous communities. Surveillance studies also discovered the simultaneous presence of Giardia in the animal-environments, including wild animals, ruminants, and treated and untreated water. The data collected here will be a useful addition to the literature body on giardiasis in Malaysia, which can be exploited in efforts to prevent and control the impact of giardiasis in the country.

Conclusions

The last 10 years have shown that the overall mean rate of giardiasis in Malaysia is quite encouraging at 13.7%. While this figure appears to be declining, there has been a slight increase in the prevalence of underweight, stunting, and wasting among rural children in 2019. The fact that giardiasis is linked to long-term childhood developmental problems, indicates that addressing and providing better disease control against giardiasis should be a priority in supporting the national agenda to achieve Malaysia Global Nutrition Targets by 2025.

Cryptosporidium spp. in wild murids (Rodentia) from Corsica, France

Cryptosporidium spp. are worldwide protozoan parasites that can affect to a broad range of vertebrate hosts, including rodents. In the island of Corsica (France), there are no previous data about these protozoa infecting wild rodents. To estimate the distribution and occurrence, a total of 117 wild murine rodents of the species Rattus rattus (84), Mus musculus domesticus (21), Apodemus sylvaticus (11), and Rattus norvegicus (1) were captured in 24 different biotopes. Fecal samples were screened for Cryptosporidium spp. by nested PCR to amplify an 830 bp fragment of the 18S rRNA gene. As general occurrence, 15.4% of the rodents analyzed were positive for Cryptosporidium spp., being detected widely distributed along the island in R. rattus (17.6%) and M. m. domesticus (14.3%). Cryptosporidium viatorum, Cryptosporidium sp. rat genotype II, and Cryptosporidium sp. rat genotype III were successfully identified in R. rattus. The results herein reported provide the first data on Cryptosporidium spp. in wild murine species from a Mediterranean island and constitute the first report of the zoonotic species C. viatorum in R. rattus. Although a low occurrence of Cryptosporidium spp. in murids was obtained and only in one animal the zoonotic species C. viatorum was identified, our results highlight that wild murine rodents from Corsica could mediate in the maintenance and transmission of this protozoan to the environment and other hosts including humans and animals. Further studies are required to better understand the epidemiology of Cryptosporidium spp. in wild rodents from Corsica and their possible public health repercussions.

Zoonotic Cryptosporidium spp. in Wild Rodents and Shrews

There has been a significant increase in the number of reported human cryptosporidiosis cases in recent years. The aim of this study is to estimate the prevalence of Cryptosporidium spp. in wild rodents and shrews, and investigate the species and genotype distribution to assess zoonotic risk. Partial 18S rRNA gene nested-PCR reveals that 36.8, 53.9 and 41.9% of mice, voles and shrews are infected with Cryptosporidium species. The highest prevalence occurred in the Microtus agrestis (field vole) and Myodes glareolus (bank vole). Interestingly, bank voles caught in fields were significantly more often Cryptosporidium-positive compared to those caught in forests. The proportion of infected animals increases from over-wintered (spring and summer) to juveniles (autumn) suggesting acquired immunity in older animals. Based on Sanger sequencing and phylogenetic analyses, Apodemus flavicollis (yellow-necked mouse) is commonly infected with zoonotic C. ditrichi. Voles carry multiple different Cryptosporidium sp. and genotypes, some of which are novel. C. andersoni, another zoonotic species, is identified in the Craseomys rufocanus (grey-sided vole). Shrews carry novel shrew genotypes. In conclusion, this study indicates that Cryptosporidium protozoan are present in mouse, vole and shrew populations around Finland and the highest zoonotic risk is associated with C. ditrichi in Apodemus flavicollis and C. andersoni in Craseomys rufocanus. C. parvum, the most common zoonotic species in human infections, was not detected.

The Role of Peridomestic Rodents as Reservoirs for Zoonotic Foodborne Pathogens

Although rodents are well-known reservoirs and vectors for a number of zoonoses, the functional role that peridomestic rodents serve in the amplification and transmission of foodborne pathogens is likely underappreciated. Clear links have been identified between commensal rodents and outbreaks of foodborne pathogens throughout Europe and Asia; however, comparatively little research has been devoted to studying this relationship in the United States. In particular, regional studies focused on specific rodent species and their foodborne pathogen reservoir status across the diverse agricultural landscapes of the United States are lacking. We posit that both native and invasive species of rodents associated with food-production pipelines are likely sources of seasonal outbreaks of foodborne pathogens throughout the United States. In this study, we review the evidence that identifies peridomestic rodents as reservoirs for foodborne pathogens, and we call for novel research focused on the metagenomic communities residing at the rodent-agriculture interface. Such data will likely result in the identification of new reservoirs for foodborne pathogens and species-specific demographic traits that might underlie seasonal enteric disease outbreaks. Moreover, we anticipate that a One Health metagenomic research approach will result in the discovery of new strains of zoonotic pathogens circulating in peridomestic rodents. Data resulting from such research efforts would directly inform and improve upon biosecurity efforts, ultimately serving to protect our food supply.

Occurrence and Multi-Locus Analysis of Giardia duodenalis in Coypus (Myocastor coypus) in China

Giardia duodenalis is a major gastrointestinal parasite found globally in both humans and animals. This work examined the occurrence of G. duodenalis in coypus (Myocastor coypus) in China. Multi-locus analysis was conducted to evaluate the level of genetic variation and the potential zoonotic role of the isolates. In total, 308 fecal samples were collected from seven farms in China and subjected to PCR screening to reveal G. duodenalis. Notably, G. duodenalis was detected in 38 (12.3%) specimens from assemblages A (n = 2) and B (n = 36). Positive samples were further characterized by PCR and nucleotide sequencing of the triose phosphate isomerase (tpi), beta giardin (bg), and glutamate dehydrogenase (gdh) genes. Multi-locus genotyping yielded 10 novel multi-locus genotypes (MLGs) (one MLG and nine MLGs for assemblages A and B, respectively). Based on the generated phylogenetic tree, AI-novel 1 clustered more closely with MLG AI-2. Furthermore, within the assemblage B phylogenetic analysis, the novel assemblage B MLGs were identified as BIV and clustered in the MLG BIV branch. This is the first report of G. duodenalis in coypus in China. The presence of zoonotic genotypes and subtypes of G. duodenalis in coypus suggests that these animals can transmit human giardiasis.

Molecular characterization of Cryptosporidium isolates from humans in Ontario, Canada

BACKGROUND

Cryptosporidiosis is a gastrointestinal disease with global distribution. It has been a reportable disease in Canada since 2000; however, routine molecular surveillance is not conducted. Therefore, sources of contamination are unknown. The aim of this project was to identify species and subtypes of Cryptosporidium in clinical cases from Ontario, the largest province in Canada, representing one third of the Canadian population, in order to understand transmission patterns.

METHODS

A total of 169 frozen, banked, unpreserved stool specimens that were microscopy positive for Cryptosporidium over the period 2008-2017 were characterized using molecular tools. A subset of the 169 specimens were replicate samples from individual cases. DNA was extracted directly from the stool and nested PCR followed by Sanger sequencing was conducted targeting the small subunit ribosomal RNA (SSU) and glycoprotein 60 (gp60) genes.

RESULTS

Molecular typing data and limited demographic data were obtained for 129 cases of cryptosporidiosis. Of these cases, 91 (70.5 %) were due to Cryptosporidium parvum and 24 (18.6%) were due to Cryptosporidium hominis. Mixed infections of C. parvum and C. hominis occurred in four (3.1%) cases. Five other species observed were Cryptosporidium ubiquitum (n = 5), Cryptosporidium felis (n = 2), Cryptosporidium meleagridis (n = 1), Cryptosporidium cuniculus (n = 1) and Cryptosporidium muris (n = 1). Subtyping the gp60 gene revealed 5 allelic families and 17 subtypes of C. hominis and 3 allelic families and 17 subtypes of C. parvum. The most frequent subtype of C. hominis was IbA10G2 (22.3%) and of C. parvum was IIaA15G2R1 (62.4%).

CONCLUSIONS

The majority of isolates in this study were C. parvum, supporting the notion that zoonotic transmission is the main route of cryptosporidiosis transmission in Ontario. Nonetheless, the observation of C. hominis in about a quarter of cases suggests that anthroponotic transmission is also an important contributor to cryptosporidiosis pathogenesis in Ontario.

Cryptosporidium ratti n. sp. (Apicomplexa: Cryptosporidiidae) and genetic diversity of Cryptosporidium spp. in brown rats (Rattus norvegicus) in the Czech Republic

The diversity and biology of Cryptosporidium that is specific for rats (Rattus spp.) are not well studied. We examined the occurrence and genetic diversity of Cryptosporidium spp. in wild brown rats (Rattus norvegicus) by microscopy and polymerase chain reaction (PCR)/sequencing targeting the small subunit rDNA (SSU), actin and HSP70 genes. Out of 343 faecal samples tested, none were positive by microscopy and 55 were positive by PCR. Sequence analysis of SSU gene revealed the presence of Cryptosporidium muris (n = 4), C. andersoni (n = 3), C. ryanae (n = 1), C. occultus (n = 3), Cryptosporidium rat genotype I (n = 23), Cryptosporidium rat genotype IV (n = 16) and novel Cryptosporidium rat genotype V (n = 5). Spherical oocysts of Cryptosporidium rat genotype I obtained from naturally-infected rats, measuring 4.4-5.4 μm × 4.3-5.1 μm, were infectious to the laboratory rats, but not to the BALB/c mice (Mus musculus) nor Mongolian gerbils (Meriones unguiculatus). The prepatent period was 3 days post infection and the patent period was longer than 30 days. Naturally- and experimentally-infected rats showed no clinical signs of disease. Percentage of nucleotide similarities at the SSU, actin, HSP70 loci between C. ratti n. sp. and the rat derived C. occultus and Cryptosporidium rat genotype II, III, IV, and V ranged from 91.0 to 98.1%. These genetic variations were similar or greater than that observed between closely related species, i.e. C. parvum and C. erinacei (93.2-99.5%). Our morphological, genetic and biological data support the establishment of Cryptosporidium rat genotype I as a new species, Cryptosporidium ratti n. sp.

Co-occurrence of and risk factors for Cryptosporidium and Giardia in brown rats from Buenos Aires, Argentina

A rodent survey was conducted in different landscape units of the city of Buenos Aires (Argentina) to determine the prevalence of Cryptosporidium and Giardia in Rattus norvegicus and to, ultimately, assess the biotic, environmental and meteorological factors that explain the variations of the likelihood of infection for both parasites in an urban environment. The results of this study revealed a ubiquitous presence of Cryptosporidium and Giardia in R. norvegicus within an urban environment with the likelihood of infection depending on environmental and meteorological conditions for both parasites. The overall prevalence was greater for Cryptosporidium (p = 50.4%) than for Giardia (20.3%). The prevalence for both parasites separately was higher in parks compared to shantytowns and scrap metal yards. Generalized Linear Mixed Models revealed that the occurrence of these parasites separately, at an individual level, was positively related with rainfall variables and that the effect of temperature depended on the landscape unit. The similarities in the transmission modes, which are affected by common extrinsic factors, may facilitate the co-occurrence of Cryptosporidium and Giardia in urban rats. Rattus norvegicus is recognized as a good model for epidemiological studies and the results of this work suggest that, from an epidemiological point of view, the probability of contact with infectious oocysts and cysts of these parasites can be modulated through environmental management and healthy behaviour towards risk factors. The information presented here will be useful to improve the understanding of the dynamics of zoonotic diseases within urban environments and to contribute to the decision-making of new and effective prophylactic measures.

Diversity of Cryptosporidium spp. in wild rodents from the Canary Islands, Spain

BACKGROUND

Cryptosporidium spp. are worldwide protozoan parasites which include species that can lead to cryptosporidiosis in humans. Different animal species can serve as reservoirs and sources of dissemination of the disease, such as rodent species due their potential in transmitting zoonotic pathogens to humans and other animals. In the Canary Islands (Spain), Cryptosporidium parvum and Cryptosporidium hominis have been identified in patients with diarrhea. However, the occurrence of Cryptosporidium spp. in possible reservoirs in this archipelago remains unclear. Considering the zoonotic potential of these protozoans, the aim of the present study was to determine the presence of Cryptosporidium spp. in peridomestic wild rodents and the possible role of these mammals as a source of transmission of these protozoans in Canary Islands.

METHODS

A total of 179 rodents belonging to Rattus rattus and Mus musculus domesticus from four Canary Islands, La Palma, El Hierro, Tenerife and Lanzarote, were analyzed. Feces were screened for Cryptosporidium spp. by nested PCR of the 18S ribosomal RNA fragment and the sequences used for phylogenetic analyses.

RESULTS

Cryptosporidium spp. were found widely distributed with an overall prevalence of 12.30% in rodents (13.86% for R. rattus and 10.25% for M. m. domesticus). The overall prevalence by island was 19.60% for Tenerife, 7.14% for La Palma, 5.71% for El Hierro and 0% for Lanzarote. Cryptosporidium tyzzeri, Cryptosporidium meleagridis, Cryptosporidium muris and Cryptosporidium sp. rat genotype I and II/III were successfully identified, in addition to two unidentified Cryptosporidium genotypes.

CONCLUSIONS

This study contributes to the knowledge of the biodiversity and distribution of Cryptosporidium spp. in wild rodents from the Canary Islands, highlighting the presence of three zoonotic species, C. tyzzeri, C. meleagridis and C. muris, being the first detection of these three species in wild rodents in the Canary Islands and the first report of C. meleagridis in R. rattus. Given the results obtained in our study, future studies in non-sampled areas are required to better understand the epidemiology of these protozoans in wild rodents in the archipelago.

Molecular characterization of Cryptosporidium spp. and Giardia duodenalis in experimental rats in China

Cryptosporidium and Giardia are ubiquitous protozoan parasites that infect a broad range of hosts. The presence of Cryptosporidium spp. and G. duodenalis was detected in 355 fecal samples of laboratory experimental rats from four experimental rat rearing facilities in China by PCR amplification of the small subunit (SSU) rRNA gene. The G. duodenalis positive samples were further characterized in the β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes. The overall infection rates of Cryptosporidium spp. and G. duodenalis were 0.6% (2/355) and 9.3% (33/355), respectively, with no co-infection. Among the four facilities, only the rats in Zhengzhou1 were found positive for the two pathogens. Undetermined Cryptosporidium genotype was observed in one sample and C. ubiquitum in another sample. Assemblage G was identified in all the 33 G. duodenalis positive isolates at SSU rRNA gene, out of which 19, 20, and 21 isolates were also subtyped as assemblage G at tpi, gdh and bg gens, respectively. To our knowledge, this is the first report of Cryptosporidium and G. duodenalis infections in laboratory experimental rats in China. The infections of these pathogens in laboratory animals should be monitored routinely since they may interfere the biological experiments in these animals.

Cryptosporidiosis among Hemodialysis Patients in Jordan: First Preliminary Screening Surveillance

Few studies have reported the incidence of cryptosporidiosis among hemodialysis patients worldwide. Currently many molecular and immunological assays have been developed for the sensitive diagnosis of cryptosporidiosis, but still, the microscopic detection of the parasitic infective stage (oocysts) in stool specimens using modified acid stain is regarded as a reliable sensitive technique which is widely used in many clinical labs. In the present study, a total of 133 stool samples were collected from hemodialysis patients and were screened for Cryptosporidium oocyst using formalin-ether concentration and modified acid-fast staining technique. Clinical and demographic data were also collected and analyzed. Cryptosporidium oocysts were recovered in 15/133 (11%) of the investigated hemodialysis patients. The age of patients ranged from 25 to 80 years (mean: 57.84 ± 12.22). Most of the Cryptosporidium-positive cases were recovered from males (73.7%) residing in rural villages in Irbid city (86.6%). The most repeatedly reported symptoms in the Cryptosporidium-positive patients were gastrointestinal symptoms, including diarrhea (15%), nausea (24%), abdominal pain (23%) and bloating (17%), in addition to general fatigue (32%) and weight loss (19%). No statistically significant associations for certain clinical symptoms or risk factors were found. The present study is the first preliminary study in Jordan that provided a brief screening for the incidence of cryptosporidiosis among hemodialysis patients.

Molecular epidemiology of giardiasis from a veterinary perspective

A total of eight Giardia species are accepted. These include: Giardia duodenalis (syn. Giardia intestinalis and Giardia lamblia), which infects humans and animals, Giardia agilis, Giardia ardeae, Giardia psittaci, Giardia muris, Giardia microti, Giardia peramelis and G. cricetidarum, which infect non-human hosts including amphibians, birds, rodents and marsupials. Giardia duodenalis is a species complex consisting of eight assemblages (A-H), with assemblages A and B the dominant assemblages in humans. Molecular studies to date on the zoonotic potential of Giardia in animals are problematic and are hampered by lack of concordance between loci. Livestock (cattle, sheep, goats and pigs) are predominantly infected with G. duodenalis assemblage E, which has recently been shown to be zoonotic, followed by assemblage A. In cats and dogs, assemblages A, B, C, D and F are commonly reported but relatively few studies have conducted molecular typing of humans and their pets and the results are contradictory with some studies support zoonotic transmission but the majority of studies suggesting separate transmission cycles. Giardia also infects a broad range of wildlife hosts and although much less well studied, host-adapted species as well as G. duodenalis assemblages (A-H) have been identified. Fish and other aquatic wildlife represent a source of infection for humans with Giardia via water contamination and/or consumption of undercooked fish and interestingly, assemblage B and A predominated in the two molecular studies conducted to date. Our current knowledge of the transmission dynamics of Giardia is still poor and the development of more discriminatory typing tools such as whole genome sequencing (WGS) of Giardia isolates is therefore essential.