Occurrence of Giardia and Cryptosporidium in wild birds in Galicia (Northwest Spain)

Genetic diversity of Cryptosporidium spp., Encephalitozoon spp. and Enterocytozoon bieneusi in feral and captive pigeons in Central Europe

Cryptosporidium spp., Enterocytozoon bieneusi and Encephalitozoon spp. are the most common protistan parasites of vertebrates. The results show that pigeon populations in Central Europe are parasitised by different species of Cryptosporidium and genotypes of microsporidia of the genera Enterocytozoon and Encephalitozoon. A total of 634 and 306 faecal samples of captive and feral pigeons (Columba livia f. domestica) from 44 locations in the Czech Republic, Slovakia and Poland were analysed for the presence of parasites by microscopy and PCR/sequence analysis of small subunit ribosomal RNA (18S rDNA), 60 kDa glycoprotein (gp60) and internal transcribed spacer (ITS) of SSU rDNA. Phylogenetic analyses revealed the presence of C. meleagridis, C. baileyi, C. parvum, C. andersoni, C. muris, C. galli and C. ornithophilus, E. hellem genotype 1A and 2B, E. cuniculi genotype I and II and E. bieneusi genotype Peru 6, CHN-F1, D, Peru 8, Type IV, ZY37, E, CHN4, SCF2 and WR4. Captive pigeons were significantly more frequently parasitised with screened parasite than feral pigeons. Cryptosporidium meleagridis IIIa and a new subtype IIIl have been described, the oocysts of which are not infectious to immunodeficient mice, whereas chickens are susceptible. This investigation demonstrates that pigeons can be hosts to numerous species, genotypes and subtypes of the studied parasites. Consequently, they represent a potential source of infection for both livestock and humans.

The risk of wild birds contaminating source water with zoonotic Cryptosporidium and Giardia is probably overestimated

Cryptosporidium and Giardia are important waterborne protozoan parasites that are resistant to disinfectants commonly used for drinking water. Wild birds, especially wild migratory birds, are often implicated in the contamination of source and wastewater with zoonotic diseases, due to their abundance near water and in urban areas and their ability to spread enteric pathogens over long distances. This review summarises the diversity of Cryptosporidium and Giardia in birds, with a focus on zoonotic species, particularly in wild and migratory birds, which is critical for understanding zoonotic risks. The analysis revealed that both avian-adapted and zoonotic Cryptosporidium species have been identified in birds but that avian-adapted Cryptosporidium species dominate in wild migratory birds. Few studies have examined Giardia species and assemblages in birds, but the non-zoonotic Giardia psittaci and Giardia ardeae are the most commonly reported species. The identification of zoonotic Cryptosporidium and Giardia in birds, particularly C. parvum and G. duodenalis assemblages A and B in wild migratory birds, is likely due to mechanical carriage or spillback from birds co-grazing pastures contaminated with C. parvum from livestock. Therefore, the role of wild migratory birds in the transmission of zoonotic Cryptosporidium and Giardia to source water is likely overestimated. To address knowledge gaps, it is important to conduct more extensive studies on the prevalence of Cryptosporidium and Giardia in a broader range of migratory wild birds. There is also a need to investigate the extent to which zoonotic infections with C. hominis/C. parvum and G. duodenalis assemblages A and B are mechanical and/or transient, and to assess the load and viability of zoonotic oo/cysts shed in avian faeces. Understanding the contribution of birds to zoonoses is essential for effective disease surveillance, prevention, and control.

Zoonotic Cryptosporidium meleagridis in urban invasive monk parakeets

Zoonotic Cryptosporidium meleagridis was identified in invasive monk parakeets (Myiopsitta monachus) from Santiago metropolis in Chile. Oocysts were isolated from nestlings' faeces, and a fragment of 18S ribosomal RNA gene was amplified and sequenced. This finding emphasizes the importance of permanent pathogen monitoring in synanthropic species with wide global distribution.

Molecular Detection and Epidemiology of Potentially Zoonotic Cryptosporidium spp. and Giardia duodenalis in Wild Boar (Sus scrofa) from Eastern Spain

The protozoans Giardia duodenalis and Cryptosporidium spp. are common causes of gastrointestinal disease in humans and animals. While both are commonly documented in domestic animals, few studies have analysed their presence in wildlife. To assess the prevalence of both parasites in wild boar (Sus scrofa) in the Valencian Community (eastern Spain), 498 wild boar faecal samples were collected from 2018 to 2022. Cryptosporidium spp. was detected by performing a nested PCR targeting a 578 bp sequence of the small subunit ribosomal RNA gene (SSU rRNA), followed by sequencing and phylogenetic analysis. For G. duodenalis, a qPCR amplifying a fragment of 62 bp from the SSU rRNA was employed. Positive samples were genotyped for glutamate dehydrogenase and β-giardin genes. Different epidemiological factors were considered potential modulating variables in the transmission of both parasites. G. duodenalis prevalence was 1.20%, while Cryptosporidium spp. prevalence reached 21.7%. Coinfection was observed in 0.2%. Genotyping of G. duodenalis isolates only detected genotype E. Two species of Cryptosporidium spp. were identified: Cryptosporidium scrofarum and Cryptosporidium suis. The results of this study demonstrate that the exposure to Cryptosporidium spp. in wild boars is high, particularly among young individuals belonging to the Typical Mediterranean climate. Moreover, the probability of infection is dependent on both the season and the density of wild boars. On the other side, exposure to G. duodenalis seems scarce and is influenced, in turn, by the climate. Both Cryptosporidium species detected in the present study have been reported in humans. Due to wild boar increasing in number and their colonisation of urban and peri-urban areas, this could represent an inherent health risk for the human population.

Migrating Anatidae as Sources of Environmental Contamination with Zoonotic Giardia, Cryptosporidium, Cyclospora and Microsporidia

Giardia, Cryptosporidium, Cyclospora, and microsporidia are gastrointestinal pathogens that can cause various disease symptoms in both animals and humans. Numerous studies worldwide have confirmed the presence of these eukaryotic pathogens in nesting and migrating wild geese, ducks, and swans. Migration spreads these zoonotic enteric pathogens to distant locations, which could have public health implications. Soils and water bodies (lakes, ponds, rivers and wetlands) in urban and suburban areas have been shown to be vulnerable to contamination by waterfowl droppings. This review addresses the epidemiology of these enteric pathogens in wild migratory bird species (Anatidae) and some consequences of their spread in the environment. To date, both zoonotic pathogens and genotypes restricted to avian hosts have been found in faecal samples from 21 anatid species worldwide. One of the routes of infection for these zoonotic gastrointestinal micropathogens is the indirect route. For example, shared water bodies (e.g., for drinking or recreational purposes) previously contaminated by birds during the migratory season may facilitate infections of humans through water. However, it is unclear how much wild waterfowl contribute to the transmission of giardiasis, cryptosporidiosis, cyclosporosis, and microsporidiosis in many regions through contaminated environmental sources. Comprehensive epidemiological surveillance based on molecular data on gastrointestinal pathogens is crucial to take measures to control infections in the future.

Cryptosporidiosis: From Prevention to Treatment, a Narrative Review

Cryptosporidiosis is a water- and food-borne zoonotic disease caused by the protozoon parasite of the genus Cryptosporidium. C. hominis and C. parvum are the main two species causing infections in humans and animals. The disease can be transmitted by the fecal-oral route as well as the respiratory route. The infective stage (sporulated oocysts) is resistant to different disinfectants including chlorine. Currently, no effective therapeutic drugs or vaccines are available to treat and control Cryptosporidium infection. To prevent cryptosporidiosis in humans and animals, we need to understand better how the disease is spread and transmitted, and how to interrupt its transmission cycle. This review focuses on understanding cryptosporidiosis, including its infective stage, pathogenesis, life cycle, genomics, epidemiology, previous outbreaks, source of the infection, transmission dynamics, host spectrum, risk factors and high-risk groups, the disease in animals and humans, diagnosis, treatment and control, and the prospect of an effective anti-Cryptosporidium vaccine. It also focuses on the role of the One Health approach in managing cryptosporidiosis at the animal-human-environmental interface. The summarized data in this review will help to tackle future Cryptosporidium infections in humans and animals and reduce the disease occurrence.

Cryptosporidium of birds in pet markets in Wuhan city, Hubei, China

Cryptosporidium is a group of protistan parasites of a range of vertebrates including mammals and birds. Stimulated by previous work that revealed “zoonotic” Cryptosporidium meleagridis subtypes (i.e. IIIbA26G1R1b and IIIbA22G1R1c) in diarrhoeic children and domestic chickens in Wuhan city and environs in Hubei Province, China, here we explored whether zoonotic C. meleagridis subtypes might also occur in pet birds in Wuhan city. From 11 bird markets in this city, we collected 322 faecal samples from 48 species of birds (representing six taxonomic orders), isolated genomic DNA and then conducted PCR-based sequencing of genetic markers in the small subunit (SSU) of the nuclear ribosomal RNA and the 60 kDa glycoprotein (gp60) genes of Cryptosporidium. Using SSU, Cryptosporidium was detected in 55 (17%) of the 322 samples. Cryptosporidium avium, C. baileyi, C. meleagridis, C. muris and C. proventriculi were characterised in 18%, 47%, 11%, 2% and 20% of the 55 samples, respectively, and a novel Cryptosporidium galli-like taxon in one sample. Using gp60, only one subtype (IIIeA17G2R1) of C. meleagridis was identified, which had not been detected in a previous study of diarrhoeic children in Wuhan. However, IIIe subtypes have been found in both humans and birds around the world. The relatively high prevalence and genetic diversity of Cryptosporidium recorded here in pet birds raise awareness about possible reservoirs of zoonotic variants of Cryptosporidium in birds in Wuhan, and potentially, other provinces in China.

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A total of 322 faecal samples from 48 species of pet birds were tested for Cryptosporidium.

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Relatively high prevalence and genetic diversity of Cryptosporidium were found.

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A novel Cryptosporidium galli-like genotype was recorded.

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A Cryptosporidium meleagridis subtype with zoonotic potential was detected.

Zoonotic giardiasis: an update

Giardia duodenalis is a common intestinal parasite in various hosts, with the disease giardiasis being a zoonosis. The use of molecular typing tools has improved our understanding of the distribution and zoonotic potential of G. duodenalis genotypes in different animals. The present review summarizes recent data on the distribution of G. duodenalis genotypes in humans and animals in different areas. The dominance of G. duodenalis assemblages A and B in humans and common occurrence of host-adapted assemblages in most domesticated animals suggests that zoonotic giardiasis is probably less common than believed and could be attributed mainly to contact with or contamination from just a few species of animals such as nonhuman primates, equines, rabbits, guinea pigs, chinchillas, and beavers. Future studies should be directed to advanced genetic characterization of isolates from well-designed epidemiological investigations, especially comparative analyses of isolates from humans and animals living in the same household or community. This will likely lead to better understanding of zoonotic transmission of G. duodenalis in different environmental and socioeconomic settings.

Investigation of giardiasis in captive animals in zoological gardens with strain typing of assemblages in China

Giardia duodenalis is a common zoonotic intestinal pathogen. It has been increasingly reported in humans and animals; however, genotyping information for G. duodenalis in captive animals is still limited. This study was conducted to assess the prevalence and multilocus genotyping of G. duodenalis in captive animals in zoological gardens in Shanghai, China. A total of 678 fresh fecal samples were randomly collected from captive animals including non-human primates (NHPs) (n = 190), herbivores (n = 190), carnivores (n = 151), birds (n = 138) and reptiles (n = 9) in a zoo and were examined for the presence of G. duodenalis using nested polymerase chain reaction (nested PCR). All G. duodenalis positive samples were assayed with PCR followed by sequencing at β-giardin (bg), glutamate dehydrogenase (gdh) and triose phosphate isomerase (tpi) genes. In this study, 42 specimens (6.2%) were tested G. duodenalis-positive of the 678 fecal samples examined based on a single locus. A total of 30 (4.4%), 30 (4.4%) and 22 (3.2%) specimens were successfully amplified and sequenced at gdh, tpi and bg loci, respectively. Assemblages A and B were identified with assemblage B dominating in NHPs. Sequence analysis demonstrated that one, two and five new isolates were identified at bg, gdh and tpi loci. DNA sequences and new assemblage-subtypes of zoonotic G. duodenalis assemblages A and B were identified in the current study. Our data indicate the occurrence and molecular diversity of G. duodenalis and the potential zoonotic transmission in captive animals in China.

Wildlife Is a Potential Source of Human Infections of Enterocytozoon bieneusi and Giardia duodenalis in Southeastern China

Wildlife is known to be a source of high-impact pathogens affecting people. However, the distribution, genetic diversity, and zoonotic potential of Cryptosporidium, Enterocytozoon bieneusi, and Giardia duodenalis in wildlife are poorly understood. Here, we conducted the first molecular epidemiological investigation of these three pathogens in wildlife in Zhejiang and Shanghai, China. Genomic DNAs were derived from 182 individual fecal samples from wildlife and then subjected to a nested polymerase chain reaction–based sequencing approach for detection and characterization. Altogether, 3 (1.6%), 21 (11.5%), and 48 (26.4%) specimens tested positive for Cryptosporidium species, E. bieneusi, and G. duodenalis, respectively. Sequence analyses revealed five known (BEB6, D, MJ13, SC02, and type IV) and two novel (designated SH_ch1 and SH_deer1) genotypes of E. bieneusi. Phylogenetically, novel E. bieneusi genotype SH_deer1 fell into group 6, and the other genotypes were assigned to group 1 with zoonotic potential. Three novel Cryptosporidium genotypes (Cryptosporidium avian genotype V-like and C. galli-like 1 and 2) were identified, C. galli-like 1 and 2 formed a clade that was distinct from Cryptosporidium species. The genetic distinctiveness of these two novel genotypes suggests that they represent a new species of Cryptosporidium. Zoonotic assemblage A (n = 36) and host-adapted assemblages C (n = 1) and E (n = 7) of G. duodenalis were characterized. The overall results suggest that wildlife act as host reservoirs carrying zoonotic E. bieneusi and G. duodenalis, potentially enabling transmission from wildlife to humans and other animals.

Survey on the Presence of Bacterial and Parasitic Zoonotic Agents in the Feces of Wild Birds

Wild avifauna may act as fecal source of bacterial and parasitic pathogens for other birds and mammals. Most of these pathogens have a relevant impact on human and livestock health which may cause severe disease and economic loss. In the present study, the fecal samples collected from 121 wild birds belonging to 15 species of the genera Anas, Tadorna, Fulica, Arddea, Larus, Falco, Athene, Accipiter, and Columba were submitted to bacteriological and molecular analyses to detect Brucella spp., Coxiella burnetii, Mycobacterium spp., Salmonella spp., Cryptosporidium spp., Giardia spp., and microsporidia. Four (3.3%) animals were positive for one pathogen: one Anas penelope for C. burnetii, one Larus michahellis for S. enterica serovar Coeln, and two Columba livia for Encephalitozoon hellem. Although the prevalence rates found in the present survey were quite low, the obtained results confirm that wild birds would be the a potential fecal source of bacterial and parasitic zoonotic pathogens which sometimes can also represent a severe threat for farm animals.

Cryptosporidium and cryptosporidiosis in wild birds: A One Health perspective

Cryptosporidium is one of the most important parasitic protozoa that can be transmitted through food and water contamination. With the increasing report of Cryptosporidium infections in wild birds, especially in herbivorous waterfowl, concerns have been raised for oocyst contamination of water and food supplies, which in turn can cause human and domestic animal infections in areas neighboring wild birds' habitats. This review discusses the epidemiology, species, and genotypes distribution of Cryptosporidium in wild birds around the world. The overall prevalence of Cryptosporidium in wild birds was calculated as 3.96% (1945/49129), with 6 Cryptosporidium species (C. andersoni, C. parvum, C. meleagridis, C. avium, C. baileyi, and C. galli) and 5 genotypes (Goose genotype I, Goose genotype II, Avian genotype I, Avian genotype III, and Avian genotype VI) reported. As wild birds mainly live in the wild, control method for the Cryptosporidium infection in wild birds is still lacking, which increases the probability of disease transmission from wild birds to humans. The main purpose of this review is to highlight the Cryptosporidium infection in wild birds and its transmission, associated risk factors, and their prevention, illustrating the necessity of multidisciplinary approaches toward screening and control of Cryptosporidium infections.

Molecular Identification of Cryptosporidium spp., Enterocytozoon bieneusi, and Giardia duodenalis in Captive Pet Birds in Henan Province, Central China

Cryptosporidium spp., Enterocytozoon bieneusi, and Giardia duodenalis are common enteric pathogens that are capable of infecting humans and animals. Total of 1,005 fecal samples from captive pet birds were collected from seven locations in Henan Province, China. The results demonstrated that 9.9% (99/1,005) of the captive birds were infected with one of these three pathogens. Enterocytozoon bieneusi was the most prevalent species among the birds (45/1,005, 4.5%) followed by G. duodenalis (33/1,005, 3.3%) and Cryptosporidium spp. (21/1,005, 2.1%). Five Cryptosporidium species were identified, namely, C. baileyi (10), C. galli (5), C. meleagridis (4), C. andersoni (1), and C. parvum (1). Two known E. bieneusi genotypes were identified: Peru 6 (44) was identified in pigeons (34) and European turtle doves (10); whereas, the genotype PtEb I (1) was only identified in a pigeon. Only G. duodenalis assemblage E (33) was identified in some pet birds. To the best of our knowledge, this study is the first to undertake the molecular identification of G. duodenalis in birds in China. The identification of potentially zoonotic species/genotypes of the pathogens suggests that exposure to the excreta of these birds, either directly or via food and water, may pose a threat to human health.

Epidemiology of Giardia duodenalis assemblages in Brazil: there is still a long way to go

Giardia duodenalis infection is distributed worldwide and can achieve prevalence around 60%, especially in developing countries. This protozoan is divided into eight assemblages, in which A and B have high zoonotic potential, whereas C to H are host-specific. This scenario is changing as molecular studies progress, highlighting that knowledge on host-specificity still has a long way to go. Understanding the players involved in transmission routes enables rational designs of control strategies. Considering the high prevalence of giardiasis, this review aims to gather together the data on available studies on the distribution of G. duodenalis assemblages in Brazil until September 2020.

Occurrence of Cryptosporidium and Giardia in wild birds from Qinghai Lake on the Qinghai-Tibetan Plateau, China

Cryptosporidium and Giardia are important intestinal zoonotic pathogens that can infect various hosts and cause diarrhoeal diseases. There are few reports of the epidemiological prevalence and molecular characterization of Cryptosporidium and Giardia in wild birds around Qinghai Lake and in the surrounding areas on the Qinghai-Tibetan Plateau, Northwest China. Therefore, the aim of this study was to determine the Cryptosporidium spp. and Giardia duodenalis genotypes and their epidemiological prevalence in wild birds by PCR amplification. To our knowledge, this is the first report of a variety of Cryptosporidium spp. and G. duodenalis infections in wild birds from that area, with overall prevalence rates of 8.98% (61/679) and 3.39% (23/679), respectively. Furthermore, PCR sequencing confirmed the presence of Cryptosporidium baileyi (n = 3), Cryptosporidium parvum (n = 58), and G. duodenalis assemblage B (n = 19) and E (n = 4) in wild birds from the areas around Qinghai Lake. The results of the present study demonstrated the wide distribution of Cryptosporidium and Giardia among wild birds, which has potential public health significance. Moreover, the study findings also provided useful molecular epidemiological data for monitoring and investigating the two parasitic protozoa in wild animals and surrounding environments.

Occurrence and Molecular Typing of Giardia psittaci in Parakeets in Germany-A Case Study

A grey-hooded parakeet (Psilopsiagon aymara) and two budgerigars (Melopsittacus undulatus) from different owners presented with decreased activity, vomitus, and diarrhea. A microscopic examination of feces showed trophozoites of the protozoan flagellate Giardia. A commercial immunochromatographic dipstick test for Giardia sp. antigens confirmed the infection. These findings were assured by PCR of the small subunit ribosomal RNA (SSU rRNA) gene and coproantigen ELISA. Sequencing of PCR products of the SSU rRNA (292 bp) and β-giardin genes (511 bp) identified Giardia psittaci as the species involved. Therefore, our results show that a GSA 65-based coproantigen ELISA, which was established for diagnosis of Giardia duodenalis is applicable for the detection of G. psittaci. A treatment with ronidazole was started. Additionally, fecal examination and dissection of the dead birds revealed coinfection with the fungal pathogen Macrorhabdus ornithogaster. One budgerigar survived and repeatedly tested negative after treatment with ronidazole. The described cases indicate that a single infection with G. psittaci has a good prognosis, whereas the prognosis is poor when coinfections occur, especially with M. ornithogaster.

A chicken embryo model for the maintenance and amplification of Cryptosporidium parvum and Cryptosporidium baileyi oocysts

Cryptosporidium is a genus of apicomplexan parasites that inhabit the respiratory and gastrointestinal tracts of vertebrates. Research of these parasites is limited by a lack of model hosts. This study aimed to determine the extent to which infection at the embryo stage can enhance the propagation of Cryptosporidium oocysts in chickens. Nine-day-old chicken embryos and one-day-old chickens were experimentally infected with different doses of Cryptosporidium baileyi and Cryptosporidium parvum oocysts. Post hatching, all chickens had demonstrable infections, and the infection dose had no effect on the course of infection. Chickens infected as embryos shed oocysts immediately after hatching and shed significantly more oocysts over the course of the infection than chickens infected as one-day-olds. In chickens infected as embryos, C. baileyi was found in all organs except the brain whereas, C. parvum was only found in the gastrointestinal tract and trachea. In chickens infected as one-day-olds, C. baileyi was only found in the gastrointestinal tract and trachea. Chickens infected as embryos with C. baileyi died within 16 days of hatching. All other chickens cleared the infection. Infection of chickens as embryos could be used as an effective and simple model for the propagation of C. baileyi and C. parvum.

Generalizability and comparability of prevalence estimates in the wild bird literature: methodological and epidemiological considerations

Wild birds have been the focus of a great deal of research investigating the epidemiology of zoonotic bacteria and antimicrobial resistance in the environment. While enteric pathogens (e.g. Campylobacter, Salmonella, and E. coli O157:H7) and antimicrobial resistant bacteria of public health importance have been isolated from a wide variety of wild bird species, there is a considerable variation in the measured prevalence of a given microorganism from different studies. This variation may often reflect differences in certain ecological and biological factors such as feeding habits and immune status. Variation in prevalence estimates may also reflect differences in sample collection and processing methods, along with a host of epidemiological inputs related to overall study design. Because the generalizability and comparability of prevalence estimates in the wild bird literature are constrained by their methodological and epidemiological underpinnings, understanding them is crucial to the accurate interpretation of prevalence estimates. The main purpose of this review is to examine methodological and epidemiological inputs to prevalence estimates in the wild bird literature that have a major bearing on their generalizability and comparability. The inputs examined here include sample type, microbiological methods, study design, bias, sample size, definitions of prevalence outcomes and parameters, and control of clustering. The issues raised in this review suggest, among other things, that future prevalence studies of wild birds should avoid opportunistic sampling when possible, as this places significant limitations on the generalizability of prevalence data.

First Detection of Cryptosporidium spp. in Migratory Whooper Swans (Cygnus cygnus) in China

Cryptosporidium is an important protozoan parasite that can cause gastrointestinal diseases in humans and that also causes respiratory and gastrointestinal diseases in birds. In this study, we investigated the occurrence of Cryptosporidium species in migratory whooper swans in China. Fecal samples (n = 467) from whooper swans were collected from Sanmenxia Swan Lake National Urban Wetland Park, China. The samples were analyzed for Cryptosporidium species and genotypes with PCR along a sequence analysis of the small subunit rRNA. Cryptosporidium was detected in eight of the 467 (1.7%) samples. The analysis of the small subunit rRNA sequence data revealed two zoonotic species (Cryptosporidium parvum and Cryptosporidium andersoni) and one genotype (Cryptosporidium goose genotype II). These are the first data on the positive rate of Cryptosporidium spp. in whooper swans in China, and they suggest that whooper swans can harbor the zoonotic species C. parvum and C. andersoni in China.

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.

Genotypic Characterization of Cryptosporidium Species in Humans and Peri-Domestic Animals in Ekiti and Oyo States, Nigeria

Cryptosporidiosis is one of the leading causes of diarrhea in humans and several other vertebrate species. Because surveys of Cryptosporidium genotypes from animals and humans living in the same region are rare, our understanding of the importance of zoonotic transmission in the epidemiology of cryptosporidiosis remains superficial. PCR was used to amplify a portion of the Cryptosporidium 18S small subunit ribosomal RNA gene from fecal DNA from humans and livestock living in Ekiti and Oyo states, Nigeria. PCR-positive samples were further analyzed using PCR targeting the heat-shock protein HSP-70, the actin, and the sporozoite glycoprotein gene gp60. A questionnaire was used to collect demographic information. Sixteen of 187 samples collected were Cryptosporidium 18S PCR positive. Of these, 5 samples originating from HIV-positive patients, 5 from otherwise healthy children, 2 from chickens, 3 from goats, and 1 from a dog were positive for at least 1 marker. Sequencing of the 18S rRNA amplicons revealed the presence of Cryptosporidium parvum in 2 HIV positive patients and in a child; the actin sequence confirmed the presence of this species. Two samples of HIV-positive patients amplified Cryptosporidium hominis 18S rRNA, one of them confirmed by the HSP-70, actin, and gp60 sequences. Cryptosporidium meleagridis was found in another HIV patient, while C. hominis was detected in 3 children (of which 2 were confirmed by gp60). Cryptosporidium muris was found in 1 child. In birds, we found C. meleagridis and, significantly, C. parvum, whereas we detected C. parvum and C. muris in 1 goat each. The only dog sampled was positive for Cryptosporidium canis. We conclude that, in the environment we surveyed, humans and animals are a potential part of the same transmission cycle. Measures to prevent zoonotic transmission should therefore be considered to reduce the prevalence of cryptosporidiosis.

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

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

Detection and molecular characterization of Cryptosporidium spp. in captive canaries (Serinus canaria) using different diagnostic methods

This study used several diagnostic methods to examine the occurrence of and molecularly characterize Cryptosporidium spp. in captive canaries (Serinus canaria) in southern and southeastern Brazil. A total of 498 fecal samples were purified by centrifugal-flotation using Sheather's solution. Cryptosporidium spp. diagnosis was performed using three diagnostic methods: malachite green negative staining, nested PCR targeting the 18S rRNA gene, followed by sequencing the amplified fragments, and duplex real-time PCR targeting the 18S rRNA specific to detect Cryptosporidium galli and Cryptosporidium avian genotype III. The overall positivity for Cryptosporidium spp. (total samples positive in at least one protocol) from the microscopic analysis, nested PCR and duplex real-time PCR protocol results was 13.3% (66/498). The positivity rates were 2.0% (10/498) and 4.6% (23/498) for Cryptosporidium spp. by microscopy and nested PCR, respectively. Sequencing of 20 samples amplified by nested PCR identified C. galli (3.0%; 15/498), Cryptosporidium avian genotype I (0.8%; 4/498) and Cryptosporidium avium (0.2%; 1/498). Duplex real-time PCR revealed a positivity of 7.8% (39/498) for C. galli and 2.4% (12/498) for avian genotype III. Malachite green negative staining differed significantly from nested PCR in detecting Cryptosporidium spp. Duplex real-time PCR was more sensitive than nested PCR/sequencing for detecting gastric Cryptosporidium in canaries.

First detection of Cryptosporidium parvum in falcons (Falconiformes): Diagnosis, molecular sequencing, therapeutic trial and epidemiological assessment of a possible emerging disease in captive falcons

Cryptosporidiosis in raptors and falcons is well-known to be caused by Cryptosporidium baileyi and associated mainly with respiratory pathology. This report presents the diagnosis of an atypical cryptosporidiosis event caused by Cryptosporidium parvum, that to the authors' knowledge, is a case observed for the first time in falcons. Two falcons (Gyrfalcon x Peregrine hybrids) were presented for annual check without any clinical signs. Hematology, biochemistry, fecal and crop parasitology, radiographic and endoscopic examinations were performed. Endoscopy revealed microcystic formation of the caudal lung field in the two falcons, adhesions and air sac alterations. Sampling and subsequent cytology revealed fungal spores and acid fast stain organisms (identified as Cryptosporidium spp.). Feces and affected lung tissue was further send for Cryptosporidium spp.-DNA detection. Fecal samples and lung tissue tested positive for Cryptosporidium spp. gp60 gene by PCR. By sequence analysis of the gp60 gene locus, diagnosis of C. parvum was confirmed with 100% homology. Despite the fact that falcons didn't recover after 1 month of therapy, eight months after the initial examination they were clinically healthy and had satisfactory flying performance. No other falcons were observed with C. parvum infections in the facility so far. The possible source, infection route and implications are discussed.

Captive-bred neotropical birds diagnosed with Cryptosporidium Avian genotype III

Currently, there are only three valid species of Cryptosporidium infecting avian hosts, namely, Cryptosporidium meleagridis, Cryptosporidium baileyi, Cryptosporidium galli and Cryptosporidium avium in addition to 12 genotypes of unknown species status. The objectives of this study were to microscopically diagnose the presence of Cryptosporidium in birds from a commercial aviary located in Rio de Janeiro, Brazil; genotypically characterize species and/or genotypes of genus Cryptosporidum; and conduct sequencing and phylogenetic analyses to compare the obtained DNA sequences with those deposited in GenBank. A total of 85 fecal samples were collected from wild captive-bred birds: 48 of family Psittacidae and 37 of family Ramphastidae. Initially, a search for the presence of Cryptosporidium sp. oocysts was conducted using the centrifugal-flotation in saturated sugar solution technique, after that, the collected samples were analyzed microscopically. Cryptosporidium infections were only detected in 24.32% of samples belonging to the family Ramphastidae. DNA was extracted from positive samples and molecular diagnostics was applied targeting the 18S rRNA gene, followed by sequencing and phylogenetic analysis. The Cryptosporidium Avian genotype III was diagnosed in this study more closely related to the gastric species. This is the first record of Cryptosporidium Avian genotype III in order Piciformes and family Ramphastidae, where three host species (Ramphastus toco, Ramphastus tucanus, and Pteroglossus bailloni) were positive for the etiologic agent. Based on the molecular data obtained, these wild birds raised in captivity do not represent a source of human cryptosporidiosis, considering that Cryptosporidium Avian genotype III does not constitute a zoonosis.

Detection and characterization of Cryptosporidium species and genotypes in three chicken production systems in Brazil using different molecular diagnosis protocols

The objective of this study was to determine the occurrence of Cryptosporidium spp. in domestic chickens raised in different chicken production systems in Brazil using three nested PCR protocols. The purification and concentration of oocysts present in 190 fecal samples from chickens raised in extensive, semi-intensive and intensive production systems were accomplished by centrifugal flotation in Sheather's solution and were followed by the extraction of genomic DNA. The detection and molecular characterization of Cryptosporidium species and genotypes were performed using three nested polymerase chain reaction (nested PCR) protocols targeting the 18S rRNA gene followed by sequencing of the amplified fragments. Subgenotyping of C. meleagridis was performed using a nested PCR reaction targeting the gp60 gene. Sample identified as Cryptosporidium sp. genetically similar to Cryptosporidium xiaoi and Cryptosporidium bovis by 18S rRNA gene sequencing were further analyzed by nested PCR targeting the actin gene and subsequent sequencing of the amplified fragment. Positive amplification for Cryptosporidium spp. was observed in 12.6% (24/190) of the samples, including C. baileyi (9.8%; 18/190), C. meleagridis (0.5%, 1/190), C. parvum (2.1%; 4/190) and Cryptosporidium sp. (0.5%; 1/190). Subgenotyping of C. meleagridis revealed the presence of the zoonotic subtype IIIgA23G3R1. Sequencing of the 18S rRNA gene and the actin gene fragments revealed a Cryptosporidium genotype in an extensive poultry system genetically related to C. xiaoi and C. bovis. There was no significant difference in the frequency of positive results obtained by the three nested PCR protocols (p > 0.05); additionally, the agreement obtained by Kappa index ranged from substantial (0.70) to almost perfect (0.9).

Cryptosporidium spp. in caged exotic psittacines from Brazil: Evaluation of diagnostic methods and molecular characterization

The aim of this study was to evaluate the prevalence of and diagnostic methods for Cryptosporidium spp. in caged adult exotic parrots from Southern and Southeastern Brazil. Oocysts were purified from fecal samples from 463 psittacines by centrifugal-flotation in Sheather's sugar solution. Cryptosporidium spp. were detected by malachite green negative staining and nested PCR targeting the 18S rRNA gene. Cryptosporidium species were identified by sequencing nested PCR amplicons. Samples were also tested by duplex real-time PCR targeting the 18S rRNA gene of Cryptosporidium galli and Cryptosporidium avian genotype III. The prevalence rates of Cryptosporidium spp. determined by microscopy and nested PCR were 3.0% (14/463) and 5.0% (23/463), respectively. The nested PCR/sequencing identified avian genotype III (1.7%; 8/463), Cryptosporidium parvum (0.9%; 4/463) and Cryptosporidium canis (0.2%; 1/463). Duplex real-time PCR was positive for gastric Cryptosporidium in 9.5% (44/463) of the samples. Among them, 1.9% (9/463) were positive for C. galli, 5.8% (27/463) were positive for avian genotype III and 1.7% (8/463) showed mixed infections with C. galli and avian genotype III. With regards to the positive detection of Cryptosporidium spp., there was no statistically significant difference between nested PCR and microscopic analysis (p = .1237), and a fair agreement existed between them (Kappa = 0.242). A statistically significant difference (p < .0001) and fair agreement (Kappa = 0.317) were obtained between nested PCR/sequencing and duplex real-time PCR for the detection of gastric Cryptosporidium. We determined that nested PCR and duplex real-time PCR are the best options for the detection of Cryptosporidium spp. and gastric Cryptosporidium, respectively, and that avian genotype III is the most common Cryptosporidium genotype/species in psittacines.

Detection of zoonotic and livestock-specific assemblages of Giardia duodenalis in free-living wild lizards

Giardia duodenalis is a zoonotic parasite that infects the gut of a wide range of vertebrates, including numerous wildlife species. However, little is known about this protozoan parasite in reptiles. Fecal samples from 31 wild lizards were collected in Galicia (northwest Spain) and screened for the presence of Giardia by PCR amplification and sequencing of the ITS1-5.8S-ITS2 region in the ribosomal unit. This allowed detection of the parasite in 5 samples (16.1%), and enabled identification of G. duodenalis assemblage A2 in two samples of Iberian rock lizard (Iberolacerta monticola), G. duodenalis assemblage B in other two samples of I. monticola, and G. duodenalis assemblage E in one sample of Bocage's wall lizard (Podarcis bocagei). The results obtained after PCR amplification and sequencing of the SSU-rDNA gene confirmed the presence of G. duodenalis assemblage A in two samples of I. monticola. This is the first report of G. duodenalis in free-living lizards, although further studies are needed to distinguish between actual infection and mechanical dissemination of cysts. The detection of zoonotic and livestock-specific assemblages of G. duodenalis demonstrates the wide environmental contamination by this parasite, possibly due to human activities.

First description of Cryptosporidium parvum in carrier pigeons (Columba livia)

The carrier pigeon and the domestic pigeon are different breeds of the species Columba livia. Carrier pigeons are used for recreational activities such as bird contests and exhibitions. Due to the close contact with humans, these birds may potentially represent a public health risk, since they can host and disseminate zoonotic parasites, such as those belonging to the genus Cryptosporidium (phylum Apicomplexa). The purpose of this work was the detection by microscopic and molecular techniques of Cryptosporidium spp. oocysts in fecal samples of carrier pigeons, and subsequently to sequence the 18S ribosomal RNA marker of positive samples to identify the species. A total of 100 fecal samples were collected individually in two pigeon breeding facilities from Formiga and Araçatuba, cities located in Minas Gerais state and São Paulo state, Brazil, respectively. The age of the birds ranged from one to 12 years; 56 were females and 44 males. Fecal smears were stained with negative malachite green, whereas the molecular characterization was based on the sequence of a ∼800bp fragment of the 18S rRNA gene. Microscopic examination of fecal smears revealed 4% (4/100) oocyst positivity. On the other hand, 7% (7/100) of positivity were found using nested PCR. Three samples were 99% to 100% similar to Cryptosporidium parvum 18S rDNA type A (Genbank AH006572) and the other three samples had 99% to 100% similarity to C. parvum 18S rDNA type B (Genbank AF308600). To our knowledge, this is the first report of C. parvum oocysts in carrier pigeons.

Occurrence and molecular genotyping of Giardia duodenalis and Cryptosporidium spp. in wild mesocarnivores in Spain

There is a surprisingly scarce amount of epidemiological and molecular data on the prevalence, frequency, and diversity of the intestinal protozoan parasites Giardia duodenalis and Cryptosporidium spp. in wildlife in general and mesocarnivore species in particular. Consequently, the extent of the cyst/oocyst environmental contamination attributable to these wild host species and their potential implications for public veterinary health remain largely unknown. In this molecular epidemiological survey a total of 193 individual faecal samples from badgers (Meles meles, n=70), ferrets (Mustela putorius furo, n=2), genets (Genetta genetta, n=6), Iberian lynxes (Lynx pardinus, n=6), beech martens (Martes foina, n=8), mongooses (Herpestes ichneumon, n=2), otters (Lutra lutra, n=2), polecats (Mustela putorius, n=2), red foxes (Vulpes vulpes, n=87), wildcats (Felis silvestris, n=2), and wolves (Canis lupus, n=6) were obtained from road-killed, hunted, and accidentally found carcasses, and from camera-trap surveys or animals entering rescue shelters, during the period December 2003-April 2016. Investigated specimens were collected in five Spanish autonomous regions including Andalusia (n=1), Asturias (n=69), Basque Country (n=49), Castile-La Mancha (n=38), and Extremadura (n=36). The presence of cysts/oocysts was confirmed by PCR-based methods targeting the small subunit (ssu) ribosomal RNA gene of these parasite species. Genotyping of the obtained isolates were attempted at appropriate markers including the glutamate dehydrogenase (G. duodenalis) and the 60-kDa glycoprotein (C. parvum and C. ubiquitum) loci. Overall, G. duodenalis was detected in 8% (7/87) of red foxes, a single beech marten, and a single wolf, respectively. Cryptosporidium was identified in 3% (2/70) of badgers, 8% (7/87) of red foxes, a single genet, and a single mongoose, respectively. None of the nine G. duodenalis isolates generated could be genotyped at the assemblage/sub-assemblage level. Out of the nine Cryptosporidium isolates successfully characterized, three were identified as C. canis (one in a mongoose and two in red foxes), and three as C. parvum (one in a badger and three in red foxes). The remaining three isolates were assigned to C. felis (in a red fox), C. hominis (in a badger), and C. ubiquitum (in a red fox), respectively. Two additional Cryptosporidium isolates infecting a badger and a genet, respectively, were untypable. The red fox was confirmed as a suitable host of potentially zoonotic Cryptosporidium species, mainly C. parvum and C. ubiquitum. The high mobility and wide home range of red foxes, together with their increasing presence in urban and peri-urban settings, may led to the overlapping of sylvatic and domestic cycles of the parasite, and consequently, to an increased risk of cryptosporidiosis in production animals and humans. The detection of C. hominis oocysts in a badger raises the question of whether this finding represents a true infection or a sporadic event of mechanical passage of C. hominis oocyst of anthroponotic origin.

Molecular identification of Enterocytozoon bieneusi, Cryptosporidium, and Giardia in Brazilian captive birds

A total of 85 fecal samples from captive birds collected from October 2013 to September 2014 in Uberlândia and Belo Horizonte in the state of Minas Gerais (Brazil) were evaluated for the presence of Enterocytozoon bieneusi, Cryptosporidium, and Giardia by PCR. Of these, three birds were found positive for E. bieneusi (3.5%), two for Cryptosporidium (2.3%), and one for Giardia (1.2%). Two genotypes of E. bieneusi were detected by nucleotide sequence analysis of the ITS region, genotypes D and Peru 6 in a swan goose and in two rock pigeons, respectively. For Cryptosporidium and Giardia, nucleotide sequence analysis of the SSU rRNA identified Cryptosporidium baileyi and Duck genotype in a swan goose and a mandarin duck, respectively, and Giardia duodenalis assemblage A in a toco toucon. Our results demonstrate that human-pathogenic E. bieneusi genotypes D and Peru6 and G. duodenalis assemblage A are present in captive birds in Brazil, corroborating their potential role as a source of human infection and environmental contamination.

Identification and genotyping of Giardia spp. and Cryptosporidium spp. isolates in aquatic birds in the Salburua wetlands, Álava, Northern Spain

Aquatic birds are known to be suitable hosts for a number of avian-specific species and genotypes of the enteric protozoan parasites Giardia and Cryptosporidium. Waterbirds have also been reported as sporadic carriers of species of both pathogens from human or domestic animal origin via environmental contamination. Because aquatic birds can shed substantial amounts of infective Giardia and Cryptosporidium (oo)cysts to the environment including surface waters intended for human consumption, this situation may pose a potential risk of waterborne zoonotic disease. A total of 265 waterbird faecal samples were collected from May 2014 to June 2015 at Salburua (Álava), one of the most valued continental wetlands in northern Spain. The detection of Giardia oocyst and Cryptosporidium oocysts was carried out by direct fluorescence microscopy and molecular (PCR and sequence analysis) methods targeting the small subunit ribosomal RNA gene of the parasites. Typing of Giardia duodenalis isolates at the sub-assemblage level was based on the specific amplification and sequencing of a partial fragment of the glutamate dehydrogenase gene. Overall, Giardia cysts and Cryptosporidium oocysts were detected in 22 (8.3%) and 6 (2.3%), respectively, of the 265 faecal samples analysed. The two only Giardia isolates characterized (one novel, one known) were assigned to the sub-assemblage BIV of G. duodenalis, none of them previously reported in Spanish human isolates. This finding raises doubts about the actual origin of the infection and whether waterbirds may serve as potential source of infective Giardia cysts to humans via waterborne transmission or through direct contact. The six Cryptosporidium isolates obtained were characterized as avian genotype III (n=4), duck genotype b (n=1), and goose genotype Id (n=1), all considered avian-specific and therefore of negligible risk of zoonotic infection.

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

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

Cryptosporidium infections in birds - a review

Cryptosporidiosis is one of the main protozoan infections in birds. It manifests as either a respiratory or a digestive illness, and it affects a very large number of avian species across several continents. The aim of this review is to report on the main results of studies on cryptosporidiosis among birds and the importance of these results to veterinary medicine and public health.