Multilocus typing of Cryptosporidium spp. and Giardia duodenalis from non-human primates in China

Molecular characterization and zoonotic risk assessment of Cryptosporidium spp. in children and calves in Bangladesh

Cryptosporidium is a gastro-intestinal protozoan parasite that has been found to infect both humans and livestock. This study investigated the parasite in 998 fecal samples from Bangladeshi children (n = 299) and calves (n = 699) to determine its prevalence, genetic variation, and zoonotic importance. The nested PCR and sequencing of the SSU rRNA gene in the samples showed a Cryptosporidium infection rate of 2.3% (7/299) in children and 15.7% (110/699) in calves. Statistical analysis revealed insignificant variations in Cryptosporidium infections among children across age, gender, and study area, while in calves, the infection rate significantly differed based on location and breed. Genotyping of seven human isolates of Cryptosporidium confirmed C. hominis (n = 5) and C. parvum (n = 2). After characterizing 110 Cryptosporidium isolates from calves, C. andersoni (n = 55), C. ryanae (n = 29), C. bovis (n = 14), C. parvum (n = 10), C. ubiquitum (n = 1), and C. occultus (n = 1) were identified. Cryptosporidium hominis and C. parvum-positive samples were further subjected to nested PCR and sequencing of the glycoprotein 60 (gp60) gene for subtyping. Four C. hominis subtypes (IaA19R3, IaA23R3, IbA9G3, and IdA15G1) and one C. parvum subtype (IIdA15G1) were observed. In conclusion, Cryptosporidium was prevalent in calves but less common in children in the study locations, and the presence of zoonotic Cryptosporidium species and subtypes in calves raises concerns regarding zoonotic transmission to humans.

Molecular characterization and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in humans and domestic animals in Heilongjiang Province, China

BACKGROUND

Cryptosporidiosis and giardiasis are significant parasitic diseases shared between humans and domestic animals. Due to the close contact between humans and domestic animals in rural areas, it is important to consider the potential transmission of zoonotic parasites from infected domestic animals to humans. This investigation aimed to determine the prevalence and molecular characteristics of Cryptosporidium spp. and Giardia duodenalis in domestic animals and villagers.

METHODS

A total of 116 fecal samples from villagers and 686 fecal samples from domestic animals in Heilongjiang Province, China, were analyzed for two parasites using nested polymerase chain reaction (PCR) targeting various genetic loci and DNA sequence analysis of the PCR products.

RESULTS

By sequence analysis of the SSU rRNA gene, the prevalence of Cryptosporidium in humans was 0.9% (1/116), with one species of C. parvum (n = 1) detected; among domestic animals, the prevalence was 2.6% (18/686), with five species identified: C. suis (n = 7) and C. scrofarum (n = 7) in pigs, C. meleagridis (n = 1) in chickens, C. andersoni (n = 1) in cattle, and C. canis (n = 2) in foxes. C. parvum and C. canis were further subtyped as IIdA19G1 and XXa4 on the basis of gp60 gene. Regarding G. duodenalis, based on the SSU rRNA, bg, gdh, and tpi genes, the prevalence in domestic animals was 5.1% (31/608), with three assemblages identified: A (n = 1) in pigs, D (n = 1) in foxes, and E (n = 27) in geese, cattle, pigs, ducks, and sheep, along with mixed infection of A + E (n = 1) in one pig and B + E (n = 1) in one sheep. No G. duodenalis was detected in humans (0/116).

CONCLUSIONS

The present results show that no overlap of subtypes between animals and villagers was found in Cryptosporidium spp. and G. duodenalis, indicating a minor role of domestic animals in infecting humans in this population. However, the presence of zoonotic protozoa in domestic animals highlights the need for special attention to high-risk individuals during close contact with domestic animals.

Subtyping of Nonhuman Primate-Adapted Cryptosporidium hominis in Macaca Fascicularis and Macaca mulatta in Yunnan Province, Southwestern China

Background: Cryptosporidium spp. are a type of protozoan parasite responsible for causing diarrheal illness worldwide. They infect a broad range of vertebrate hosts, including both non-human primates (NHPs) and humans. In fact, zoonotic transmission of cryptosporidiosis from NHPs to humans is frequently facilitated by direct contact between the two groups. However, there is a need to enhance the information available on the subtyping of Cryptosporidium spp. in NHPs in the Yunnan province of China. Materials and Methods: Thus, the study investigated the molecular prevalence and species of Cryptosporidium spp. from 392 stool samples of Macaca fascicularis (n = 335) and Macaca mulatta (n = 57) by using nested PCR targeting the large subunit of nuclear ribosomal RNA (LSU) gene. Of the 392 samples, 42 (10.71%) were tested Cryptosporidium-positive. Results: All the samples were identified as Cryptosporidium hominis. Further, the statistical analysis revealed that age is a risk factor for the infection of C. hominis. The probability of detecting C. hominis was found to be higher (odds ratio = 6.23, 95% confidence interval 1.73-22.38) in NHPs aged between 2 and 3 years, as compared with those younger than 2 years. Sequence analysis of the 60 kDa glycoprotein (gp60) identified six (IbA9 n = 4, IiA17 n = 5, InA23 n = 1, InA24 n = 2, InA25 n = 3, and InA26 n = 18) C. hominis subtypes with "TCA" repeats. Among these subtypes, it has been previously reported that the Ib family subtypes are also capable of infecting humans. Conclusion: The findings of this study highlight the genetic diversity of C. hominis infection among M. fascicularis and M. mulatta in Yunnan province. Further, the results confirm that both these NHPs are susceptible to C. hominis infection, posing a potential threat to humans.

Mammal-related Cryptosporidium infections in endemic reptiles of New Zealand

New Zealand's endemic reptile fauna is highly threatened and pathogens causing infectious diseases may be a significant risk to already endangered species. Here, we investigate Cryptosporidium infection in captive endemic New Zealand reptiles. We found two mammal-related Cryptosporidium species (C. hominis and C. parvum) and six subtypes from three gp60 families (Ib, Ig and IIa) in 12 individuals of captive endemic Tuatara, Otago and Grand skinks, and Jewelled and Rough geckos. Cryptosporidium serpentis was identified in two Jewelled geckos using 18S. In New Zealand, C. hominis and C. parvum are associated with infections in humans and introduced domestic animals but have also been recently found in wildlife. Our finding of Cryptosporidium infection in endemic reptiles can help inform strategies to monitor the conservation of species and manage potential introductions of pathogens to in-situ and ex-situ populations.

Potential Zoonotic Transmission of Giardia duodenalis between Children and Calves in Bangladesh

Giardia duodenalis is a zoonotic protozoan parasite that causes gastrointestinal illness in humans and livestock. We studied the genetic diversity of G. duodenalis in children and calves from Bangladesh to determine its zoonotic potential. Fecal samples collected from children (299) and calves (699) were screened with nested PCR with primers targeting the ssu rRNA gene for G. duodenalis. Positive samples were further multilocus genotyped using the β-giardin (bg), glutamate dehydrogenase (gdh), and triose phosphate isomerase (tpi) genes. The overall infection rate of G. duodenalis was 21.1% (63/299) in children and 5.7% (40/699) in calves. There were no significant differences in infection with G. duodenalis among age groups, sex, and study areas in children and calves. Multilocus genotyping (MLG) of human G. duodenalis identified zoonotic assemblages A (34.0%, 18/53) and B (50.9%, 27/53) and a so-called ruminant-specific assemblage E (11.3%, 6/53), as well as two mixed assemblages, B/D (1/53) and B/E (1/53). Assemblage E predominated in calves (82.3%, 28/34), followed by assemblages A (11.8%, 4/34) and B (5.9%, 2/34). Overall, zoonotic assemblages A, B, and E were found in 6.0% (18/299), 9.0% (27/299), and 2.0% (6/299) of the children’s stool samples, respectively, and 0.6% (4/699), 0.3% (2/699), and 4.0% (28/699) of the calf fecal samples, respectively. Although there was a difference in the distribution of subassemblages in humans (mostly AII) and calves (mostly AI), the zoonotic assemblages A, B, and E present in both children and calves suggest the potential for zoonotic transmission of G. duodenalis. This molecular study highlights the fact that G. duodenalis infections were common in the study areas, with potential zoonotic transmission between children and calves, implying that cattle might play a role in G. duodenalis zoonotic transmission.

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

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

Genetic diversity of Cryptosporidium spp. in non-human primates in rural and urban areas of Ethiopia

Non-Human Primates (NHPs) harbor Cryptosporidium genotypes that can infect humans and vice versa. NHPs Chlorocebus aethiops and Colobus guereza and humans have overlapping territories in some regions of Ethiopia, which may increase the risk of zoonotic transmission of Cryptosporidium. This cross-sectional study examined the molecular prevalence and subtypes of Cryptosporidium spp. from 185 fecal samples of Chlorocebus aethiops and Colobus guereza in rural and urban areas in Ethiopia. Samples were tested for Cryptosporidium infection using nested polymerase chain reaction (PCR), and subtypes were determined by sequencing a fragment of the 60-kDa glycoprotein gene (gp60). Of the 185 samples, fifty-one (27.56%) tested positive for Cryptosporidium infection. The species detected were C. parvum (n = 34), C. hominis (n = 12), and C. cuniculus (n = 3). Mixed infection with C. parvum and C. hominis were detected in 2 samples. Four C. hominis family subtypes (Ia, Ib, Id, and Ie) and one C. parvum family subtype (IIa) were identified. C. hominis IaA20 (n = 7) and C. parvum IIaA17G1R1 (n = 6) were the most prevalent subtypes detected. These results confirm that Chlorocebus aethiops and Colobus guereza can be infected with diverse C. parvum and C. hominis subtypes that can also potentially infect humans. Additional studies could help to understand the role of NHPs in the zoonotic transmission of Cryptosporidium in Ethiopia.

High zoonotic potential of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi in wild nonhuman primates from Yunnan Province, China

Background

Cryptosporidium spp., Giardia duodenalis and Enterocytozoon bieneusi are important zoonotic protists in humans and animals around the world, including nonhuman primates (NHPs). However, the prevalence, genetic identity and zoonotic potential of these pathogens in wild NHPs remain largely unclear.

Methods

A total of 348 fecal samples were collected from wild NHPs at four locations in Yunnan, southwestern China, and analyzed for these pathogens using nested PCR targeting various genetic loci and DNA sequence analysis of the PCR products. The zoonotic potential of the pathogens was assessed by comparing the genetic identity of the pathogens in these animals with that previously reported in humans.

Results

Altogether, two (0.6%), 25 (7.2%) and 30 (8.6%) samples were positive for Cryptosporidium sp., G. duodenalis and E. bieneusi, respectively. The Cryptosporidium sp. identified belonged to C. parvum subtype IIdA20G1. Both assemblages A (n = 3) and B (n = 22) were identified among G. duodenalis-positive animals. Five genotypes in zoonotic Group 1 were identified within E. bieneusi, including Type IV (n = 13), D (n = 7), Peru8 (n = 6), MMR86 (n = 2) and HNFS01 (n = 2). All genotypes and subtypes identified are known human pathogens or phylogenetically related to them.

Conclusions

Data from this study suggest a common occurrence of zoonotic genotypes of G. duodenalis and E. bieneusi in wild NHPs in southwestern China.

Graphical Abstract

Risk Evaluation of Pathogenic Intestinal Protozoa Infection Among Laboratory Macaques, Animal Facility Workers, and Nearby Villagers From One Health Perspective

Background: Previous epidemiological studies have confirmed non-human primates (NHPs) as reservoirs for Cryptosporidium spp. , Giardia intestinalis, and Enterocytozoon bieneusi. It highlights the possibility of interspecies transmission between humans and macaques in laboratory animal facilities. This study aimed to investigate the prevalence of pathogenic intestinal protozoan infections in macaques and humans and to determine the risk of cross-species transmission from One Health view.

Materials and Methods: A total of 360 fecal samples, including 310 from the four Macaca mulatta groups, 25 from the facility workers in a laboratory animal facility, and 25 from the villagers nearby in Yongfu country, southeast China, were collected. Nested PCR assays were done for detecting protozoan pathogens from all the specimens. Furthermore, potential risk factors (gender, age, and direct contact) on the occurrence of intestinal protozoa infection among different sub-groups were evaluated. A phylogenetic and haplotype network analysis was conducted to examine the genetic structure and shared patterns of E. bieneusi and Cyclospora cayetanensis.

Results: The pathogenic intestinal protozoa were detected in both human and macaque fecal samples. A total of 134 (37.2%) samples were tested positive, which included 113 (36.4%) macaques, 14 (56.0%) facility workers, and 7 (28.0%) villagers, respectively. There was no significant difference in four intestinal protozoa infections between facility workers and villagers (χ² = 2.4, P > 0.05). However, the positive rate of pathogenic intestinal protozoa in the facility workers, who had direct contact with macaques, was significantly higher [odds ratio (OR) = 0.31, 95% confidence interval (CI): 0.09–1.00, P < 0.05).Thirty-three ITS genotypes of E. bieneusi were identified, including five known genotypes (PigEBITS7, Peru8, Henan V, D, and CM1) and six novel genotypes (MEB1–6). Seven haplotypes were identified in the network analysis from C. cayetanensis-positive samples. Meanwhile, a phylogenetic and haplotype analysis confirmed the presence of zoonotic subtypes in NHPs and humans.

Conclusion: The data collected from this study confirmed a high prevalence of intestinal protozoan infection in humans and macaques. These results warrant workers of such facilities and residents to limit contact with infected animals in order to minimize related health risks. The need for comprehensive strategies to mitigate the risk of zoonotic transmission, especially from a One Health perspective, is recommended.

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.

Occurrence and molecular characterization of Cryptosporidium spp. and Giardia duodenalis among captive mammals in the Bangladesh National Zoo

Cryptosporidium and Giardia are protozoan parasites capable of causing gastrointestinal illness in humans and animals. The purpose of this research was to determine the occurrence, genetic characteristics, and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in captive mammals at the Bangladesh National Zoo. A total of 200 fresh fecal samples from 32 mammalian species were collected and examined for Cryptosporidium spp. using nested polymerase chain reaction (PCR) targeting the small subunit (SSU) rRNA gene and G. duodenalis targeting the β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes. The overall infection rates of Cryptosporidium and G. duodenalis among captive mammals in the zoo were 3.5% (7/200) and 5.5% (11/200), respectively. Five species/genotypes of Cryptosporidium (C. hominis, C. andersoni, C. muris, C. felis, and Cryptosporidium deer genotype) were identified. C. hominis was subtyped as IbA12G3 by sequence analysis of the glycoprotein 60 (gp60) gene. Multilocus genotyping of G. duodenalis revealed assemblages A, B, and D. Mixed infections of assemblages B and D and A and B were found in an Asiatic jackal and a Nilgiri langur, respectively. To our knowledge, this is the first report on the occurrence and genetic identity of the two parasites among zoo animals in Bangladesh. The results suggest that zoonotic Cryptosporidium spp. and G. duodenalis are maintained in and transmitted between captive mammals. Therefore, washing, cleaning, and disinfection measures should be implemented to reduce the spread of Cryptosporidium and G. duodenalis infections.

Molecular analysis of cryptosporidiosis cases in Western Australia in 2019 and 2020 supports the occurrence of two swimming pool associated outbreaks and reveals the emergence of a rare C. hominis IbA12G3 subtype

Cryptosporidium is an important protozoan parasite and due to its resistance to chlorine is a major cause of swimming pool-associated gastroenteritis outbreaks. The present study combined contact tracing and molecular techniques to analyse cryptosporidiosis cases and outbreaks in Western Australia in 2019 and 2020. In the 2019 outbreak, subtyping at the 60 kDa glycoprotein (gp60) gene identified 89.0% (16/18) of samples were caused by the C. hominis IdA15G1 subtype. Amplicon next generation sequencing (NGS) at the gp60 locus identified five C. hominis IdA15G1 subtype samples that also had C. hominis IdA14 subtype DNA, while multi locus sequence typing (MLST) analysis on a subset (n = 14) of C. hominis samples identified three IdA15G1 samples with a 6 bp insertion at the end of the trinucleotide repeat region of the cp47 gene. In 2020, 88.0% (73/83) of samples typed were caused by the relatively rare C. hominis subtype IbA12G3. Four mixed infections were observed by NGS with three IdA15G1/ IdA14 mixtures and one C. parvum IIaA18G3R1 sample mixed with IIaA16G3R1. No genetic diversity using MLST was detected. Epidemiological and molecular data indicates that the outbreaks in 2019 and 2020 were each potentially from swimming pool point sources and a new C. hominis subtype IbA12G3 is emerging in Australia. The findings of the present study are important for understanding the introduction and transmission of rare Cryptosporidium subtypes to vulnerable populations.

Zoonotic parasites in farmed exotic animals in China: Implications to public health

Several species of wild mammals are farmed in China as part of the rural development and poverty alleviation, including fur animals, bamboo rats, and macaque monkeys. Concerns have been raised on the potential dispersal of pathogens to humans and other farm animals brought in from native habitats. Numerous studies have been conducted on the genetic identity and public health potential of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi in these newly farmed exotic animals. The data generated have shown a high prevalence of the pathogens in farmed wildlife, probably due to the stress from the short captivity and congregation of large numbers of susceptible animals. Host adaptation at species/genotype and subtype levels has reduced the potential for cross-species and zoonotic transmission of pathogens, but the farm environment appears to favor the transmission of some species, genotypes, and subtypes, with reduced pathogen diversity compared with their wild relatives. Most genotypes and subtypes of the pathogens detected appear to be brought in from their native habitats. A few of the subtypes have emerged as human pathogens. One Health measures should be developed to slow the dispersal of indigenous pathogens among farmed exotic animals and prevent their spillover to other farm animals and humans.

Biodiversity of the Coccidia (Apicomplexa: Conoidasida) in vertebrates: what we know, what we do not know, and what needs to be done

Over the last two decades my colleagues and I have assembled the literature on a good percentage of most of the coccidians (Conoidasida) known, to date, to parasitise: Amphibia, four major lineages of Reptilia (Amphisbaenia, Chelonia, Crocodylia, Serpentes), and seven major orders in the Mammalia (Carnivora, Chiroptera, Lagomorpha, Insectivora, Marsupialia, Primates, Scandentia). These vertebrates, combined, comprise about 15,225 species; only about 899 (5.8%) of them have been surveyed for coccidia and 1,946 apicomplexan valid species names or other forms are recorded in the literature. Based on these compilations and other factors, I extrapolated that there yet may be an additional 31,381 new apicomplexans still to be discovered in just these 12 vertebrate groups. Extending the concept to all of the other extant vertebrates on Earth; i.e. lizards (6,300 spp.), rodents plus 12 minor orders of mammals (3,180 spp.), birds (10,000 spp.), and fishes (33,000 spp.) and, conservatively assuming only two unique apicomplexan species per each vertebrate host species, I extrapolate and extend my prediction that we may eventually find 135,000 new apicomplexans that still need discovery and to be described in and from those vertebrates that have not yet been examined for them! Even doubling that number is a significant underestimation in my opinion.

Zoonotic assemblages of Giardia duodenalis in captive non-human primates from the largest zoo in Slovakia

Only a few studies based on multilocus characterization have been conducted on the molecular epidemiology of Giardia duodenalis in captive nonhuman primates (NHPs). The present article provides the first report on the occurrence of G. duodenalis in the ring-tailed lemur (Lemur catta) and barbary macaque (Macaca sylvanus) kept in the zoo in Košice, Slovakia. All samples were examined by flotation technique, with total prevalence of 17.4% (4/23). The microscopically positive samples were assayed by nested PCR and consecutively sequenced at β-giardin (bg), glutamate dehydrogenase (gdh) and triosephosphate isomerase (tpi) genes. Positive isolates were recognized as assemblage B and sub-assemblage BIV and subtype WB8 were confirmed. The identification and genotyping of this parasite in Slovakia, may help to better understand the epidemiological situation in Europe about the circulation of G. duodenalis zoonotic assemblages in NHPs.

Molecular characterization and zoonotic potential of Enterocytozoon bieneusi, Giardia duodenalis and Cryptosporidium sp. in farmed masked palm civets (Paguma larvata) in southern China

BACKGROUND

Masked palm civets are known to play an important role in the transmission of some zoonotic pathogens. However, the distribution and zoonotic potential of Enterocytozoon bieneusi, Giardia duodenalis and Cryptosporidium spp. in these animals remain unclear.

METHODS

A total of 889 fecal specimens were collected in this study from farmed masked palm civets in Hainan, Guangdong, Jiangxi and Chongqing, southern China, and analyzed for these pathogens by nested PCR and DNA sequencing.

RESULTS

Altogether, 474 (53.3%), 34 (3.8%) and 1 (0.1%) specimens were positive for E. bieneusi, G. duodenalis and Cryptosporidium sp., respectively. Sequence analysis revealed the presence of 11 novel E. bieneusi genotypes named as PL1-PL11 and two known genotypes Peru8 and J, with PL1 and PL2 accounting for 90% of E. bieneusi infections. Phylogenetically, PL4, PL5, PL9, PL10 and PL11 were clustered into Group 1, while PL1, PL2, PL3, PL6, PL7 and PL8 were clustered into Group 2. Assemblage B (n = 33) and concurrence of B and D (n = 1) were identified among G. duodenalis-positive animals. Further multilocus genotyping of assemblage B has revealed that all 13 multilocus genotypes in civets formed a cluster related to those from humans. The Cryptosporidium isolate from one civet was identified to be genetically related to the Cryptosporidium bamboo rat genotype II.

CONCLUSIONS

To the best of our knowledge, this first report of enteric protists in farmed masked palm civets suggests that these animals might be potential reservoirs of zoonotic E. bieneusi and G. duodenalis genotypes.

Cryptosporidium hominis infections in non-human animal species: revisiting the concept of host specificity

Parasites in the genus Cryptosporidium, phylum Apicomplexa, are found worldwide in the intestinal tract of many vertebrate species and in the environment. Driven by sensitive PCR methods, and the availability of abundant sequence data and reference genomes, the taxonomic complexity of the genus has steadily increased; 38 species have been named to date. Due to its public health importance, Cryptosporidium hominis has long attracted the interest of the research community. This species was initially described as infectious to humans only. This perception has persisted in spite of an increasing number of observations of natural and experimental infections of animals with this species. Here we summarize and discuss this literature published since 2000 and conclude that the host range of C. hominis is broader than originally described. The evolving definition of the C. hominis host range raises interesting questions about host specificity and the evolution of Cryptosporidium parasites.

Occurrence and multilocus genotyping of Giardia duodenalis in captive non-human primates from 12 zoos in China

Giardia duodenalis is a common enteric protozoan that infects a range of hosts including humans and other mammals. Multilocus genotyping of G. duodenalis in captive non-human primates (NHPs) from zoos in China is limited. In this study, we evaluated 302 NHP fecal samples collected from 32 different NHP species. The primates were from 12 zoos distributed across eight provinces and two municipalities (Chongqing and Beijing) of China. The overall infection rate was 8.3% (25/302). The six G. duodenalis-positive zoos and their infection rates were: Suzhou Zoo (40.0%, 4/10), Yangzhou Zoo (22.2%, 2/9), Dalian Zoo (16.7%, 4/24), Chengdu Zoo (12.8%, 6/47), Guiyang Forest Wildlife Zoo (12.1%, 7/58), and Changsha Zoo (4.7%, 2/43). Molecular analysis of three loci, beta-giardin (bg), triose phosphate isomerase (tpi), and glutamate dehydrogenase (gdh), showed high genetic heterogeneity, and seven novel subtypes (BIII-1, MB10-1, WB8-1, B14-1, MB9-1, DN7-1, and BIV-1) were detected within assemblage B. Additional analysis revealed 12 different assemblage B multilocus genotypes (MLGs), one known MLG and 11 novel MLGs. Based on phylogenetic analysis, 12 assemblage B MLGs formed two main clades, MLG-SW (10-12, 18) and MLG-SW (13, 14, 16, 17), the other four MLG-SW (15, 19, 20, 21) were scattered throughout the phylogenetic tree in this study. Using multilocus genotyping, this study expands our understanding of the occurrence of Giardia infection and genetic variation in Giardia in captive non-human primates from zoos in China.

Prevalence and multilocus analysis of Giardia duodenalis in racehorses in China

Giardia duodenalis is a zoonotic intestinal parasite infecting humans and mammals worldwide. In this study, we evaluated the prevalence of G. duodenalis in racehorses in China and genetically characterized it. In total, 621 fecal samples were collected from racehorses at 17 equestrian clubs in 15 cities in China. Forty-eight (7.7%) animals from 11 equestrian clubs were positive for G. duodenalis of assemblages A (n = 10), B (n = 36), and E (n = 2), based on the small subunit ribosomal RNA (SSU rRNA) gene. Statistically significant differences in the prevalence of this parasite were detected among the different equestrian clubs (χ² = 49.55, df = 16, p < 0.01), whereas no significant differences were detected according to age (χ² = 0.64, df = 1, p > 0.05) or sex (χ² = 1.41, df = 2, p > 0.05). The G. duodenalis-positive samples were further subtyped based on three other genes, which identified 5, 4, and 4 genotypes at the triose phosphate isomerase (tpi), glutamate dehydrogenase (gdh), and β-giardin (bg) loci, respectively. Subassemblage BIV was the predominant genotype. A phylogenetic analysis of the concatenated sequences of subassemblage BIV showed that the multilocus genotypes from the horses were genetically different from those of humans and nonhuman primates, indicating the evolution of host separation in G. duodenalis subassemblage BIV. Our study extends our understanding of the transmission of G. duodenalis between animals and humans.

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.

Cryptosporidium parvum and Cryptosporidium hominis subtypes in crab-eating macaques

BACKGROUND

Non-human primates are often infected with human-pathogenic Cryptosporidium hominis subtypes, but rarely with Cryptosporidium parvum. In this study, 1452 fecal specimens were collected from farmed crab-eating macaques (Macaca fascicularis) in Hainan, China during the period April 2016 to January 2018. These specimens were analyzed for Cryptosporidium species and subtypes by using PCR and sequence analysis of the 18S rRNA and 60 kDa glycoprotein (gp60) genes, respectively.

RESULTS

Altogether, Cryptosporidium was detected using 18S rRNA-based PCR in 132 (9.1%) sampled animals, with significantly higher prevalence in females (12.5% or 75/599 versus 6.1% or 43/706), younger animals (10.7% or 118/1102 in monkeys 1-3-years-old versus 4.0% or 14/350 in those over 3-years-old) and animals with diarrhea (12.6% or 46/365 versus 7.9% or 86/1087). Four Cryptosporidium species were identified, namely C. hominis, C. parvum, Cryptosporidium muris and Cryptosporidium ubiquitum in 86, 30, 15 and 1 animal, respectively. The identified C. parvum, C. hominis and C. ubiquitum were further subtyped by using gp60 PCR. Among them, C. parvum belonged to subtypes in two known subtype families, namely IIoA14G1 (in 18 animals) and IIdA19G1 (in 2 animals). In contrast, C. hominis mostly belonged to two new subtype families Im and In, which are genetically related to Ia and Id, respectively. The C. hominis subtypes identified included ImA18 (in 38 animals), InA14 (in six animals), InA26 (in six animals), InA17 (in one animal) and IiA17 (in three animals). The C. ubiquitum isolates belonged to subtype family XIId. By subtype, ImA18 and IIoA14G1 were detected in animals with diarrhea whereas the remaining ones were mostly found in asymptomatic animals. Compared with C. parvum and C. muris, higher oocyst shedding intensity was observed in animals infected with C. hominis, especially those infected with the Im subtype family.

CONCLUSIONS

Data from the study suggest that crab-eating macaques are infected with diverse C. parvum and C. hominis subtypes. The C. parvum IIo subtype family previously seen in rodents in China has apparently expanded its host range.

Genotypes and public health potential of Enterocytozoon bieneusi and Giardia duodenalis in crab-eating macaques

BACKGROUND

Enterocytozoon bieneusi and Giardia duodenalis are common human and animal pathogens. Studies have increasingly shown that non-human primates (NHPs) are common hosts of these two zoonotic parasites. However, few studies have explored the genetic diversity and public health potential of these pathogens in laboratory monkeys. In this study, we examined the genetic diversity of the two pathogens in crab-eating macaques (Macaca fascicularis) in a commercial facility in Hainan, China.

RESULTS

Enterocytozoon bieneusi and G. duodenalis were detected by PCR analysis in 461/1452 (31.7%) and 469/1452 (32.3%) fecal specimens from the animals, respectively. Significantly higher detection rates of E. bieneusi were detected in males (36.5%, 258/706) than in females (26.7%, 160/599; χ2 = 14.391, P = 0.0001), in animals with loose stools (41.4%, 151/365) than those with normal stool (28.5%, 310/1087; χ2 = 20.83, P < 0.0001), and in animals of over 3 years of age (38.6%, 135/350) than those of 1-3 years (29.6%, 326/1,102; χ2 = 9.90, P = 0.0016). For G. duodenalis, the detection rate in males (33.4%, 236/706) was higher than in females but not statistically significant (30.2%, 181/599; χ2 = 1.54, P = 0.2152), in monkeys with loose stools (41.1%, 150/365) than those with normal stools (29.3%, 319/1087; χ2 = 17.25, P < 0.0001), and in monkeys of 1-3 years of age (36.6%, 403/1102) than those over 3 years (18.9%, 66/350; χ2 = 38.11, P < 0.0001). Nine E. bieneusi genotypes were detected in this study by DNA sequence analysis of the internal transcribed spacer of the rRNA gene, namely Type IV (236/461), Peru8 (42/461), Pongo2 (27/461), Peru11 (12/461), D (4/461) and PigEbITS7 (1/461) previously seen in NHPs as well as humans, and CM1 (119/461), CM2 (17/461) and CM3 (3/461) that had been only detected in NHPs. DNA sequence analyses of the tpi, gdh and bg loci identified all G. duodenalis specimens as having assemblage B. Altogether, eight (4 known and 4 new), seven (6 known and 1 new) and seven (4 known and 3 new) subtypes were seen at the tpi, gdh and bg loci, leading to the detection of 53 multi-locus genotypes (MLG-B-hn01 to MLG-B-hn53). Most of them were genetically related to those previously seen in common Old-World monkeys.

CONCLUSIONS

Data from this study indicate a common occurrence of zoonotic genotypes of E. bieneusi and assemblage B of G. duodenalis in farmed crab-eating macaques in Hainan, China.

Molecular prevalence and subtyping of Cryptosporidium hominis among captive long-tailed macaques (Macaca fascicularis) and rhesus macaques (Macaca mulatta) from Hainan Island, southern China

BACKGROUND

Cryptosporidium is an important zoonotic parasite that is commonly found in non-human primates (NHPs). Consequently, there is the potential for transmission of this pathogen from NHPs to humans. However, molecular characterization of the isolates of Cryptosporidium from NHPs remains relatively poor. The aim of the present work was to (i) determine the prevalence; and (ii) perform a genetic characterization of the Cryptosporidium isolated from captive Macaca fascicularis and M. mulatta on Hainan Island in southern China.

METHODS

A total of 223 fresh fecal samples were collected from captive M. fascicularis (n = 193) and M. mulatta (n = 30). The fecal specimens were examined for the presence of Cryptosporidium spp. by polymerase chain reaction (PCR) and sequencing of the partial small subunit (SSU) rRNA gene. The Cryptosporidium-positive specimens were subtyped by analyzing the 60-kDa glycoprotein (gp60) gene sequence.

RESULTS

Cryptosporidium spp. were detected in 5.7% (11/193) of M. fascicularis. All of the 11 Cryptosporidium isolates were identified as C. hominis. Subtyping of nine of these isolates identified four unique gp60 subtypes of C. hominis. These included IaA20R3a (n = 1), IoA17a (n = 1), IoA17b (n = 1), and IiA17 (n = 6). Notably, subtypes IaA20R3a, IoA17a, and IoA17b were novel subtypes which have not been reported previously.

CONCLUSIONS

To our knowledge, this is the first reported detection of Cryptosporidium in captive M. fascicularis from Hainan Island. The molecular characteristics and subtypes of the isolates here provide novel insights into the genotypic variation in C. hominis.

Intestinal Parasites and the Occurrence of Zoonotic Giardia duodenalis Genotype in Captive Gibbons at Krabokkoo Wildlife Breeding Center, Thailand

Intestinal parasitic infections can have an impact on health and growth of wildlife. The current study aims were to determine the prevalence of intestinal parasites and to molecular characterize Giardia duodenalis and Cryptosporidium spp. in captive gibbons at Krabokkoo Wildlife Breeding Center, Thailand. Fifty-five gibbons, 2 agile- (Hylobates agilis), 38 lar- (Hylobates lar) and 15 pileated gibbons (Hylobates pileatus) were included in this study. Fecal samples were collected individually at Krabokkoo Wildlife Breeding Center, Chachoengsao province, eastern Thailand, in November 2013. Intestinal parasitic infections were examined by zinc sulfate centrifugation flotation and by a commercially available immunofluorescent assay (IFA) for detection of G. duodenalis and Cryptosporidium spp.. Polymerase chain reaction targeting the Giardia glutamate dehydrogenase (gdh), beta- giardin (bg), triose phosphate isomerase (tpi) genes, and the Cryptosporidium small subunit-rRNA and heat-shock protein (hsp70) following by DNA sequencing were performed on the IFA positive samples. The overall prevalence of intestinal parasitic infection in gibbons at Krabokkoo Wildlife Breeding Center was 12.7% (95%CI: 5.3–24.5), Strongyloides spp. eggs or larvae were present in all positive samples. Co-infections with G. duodenalis were detected in 1.8% (95%CI: 0.1–9.7) of the samples. Based on the sequencing results of the three genes, the IFA Giardia positive isolate typed as the zoonotic genotype B. Since the data reveals the occurrence of zoonotic Giardia genotype, good hygiene management is suggested to prevent the transmission of this pathogen from gibbon to human, and vice versa.

Cryptosporidium spp. in wild rats (Rattus spp.) from the Hainan Province, China: Molecular detection, species/genotype identification and implications for public health

Wild rats (Rattus spp.) carry many zoonotic pathogens including Cryptosporidium. Due to the close proximity of rats to humans in urban environments, the potential for disease transmission is high. Cryptosporidium is a protozoan parasite which when ingested causes serious human illness. Despite its importance, genetic characterization of Cryptosporidium in wild rats in the Hainan province of China has not been performed. In this study, we analyzed the occurrence and genetics of Cryptosporidium in wild rats from Hainan, China. From December 2017 to October 2018, 150 wild rats were captured and fresh fecal material was collected from intestinal sections. Rat species were identified by PCR-based amplification and analysis of the vertebrate cytochrome b (cytb) gene. Cryptosporidium was examined by PCR amplification of the partial small subunit of ribosomal DNA (SSU rDNA). C. viatorum were subtyped by PCR analysis of the gp60 gene. A total of four rat species were identified including Asian house rats (Rattus tanezumi) (n = 46), brown rats (Rattus norvegicus) (n = 56), Edward's long-tailed rats (Leopoldamys edwardsi) (n = 38) and muridae (Niviventer fulvescens) (n = 10), with Cryptosporidium positive rates of 73.9%, 28.6%, 55.3% and 40.0%, respectively (average infection rate: 50.0%, 75/150. Sequence analysis confirmed the presence of four Cryptosporidium species and two genotypes including C. viatorum (n = 11); C. occultus (n = 2); C. muris (n = 1); and C. erinacei (n = 1); rat genotypes III (n = 13) and IV (n = 47). Three novel subtypes of C. viatorum were identified in 6 of the 11 infected Edward's long-tailed rats: XVcA2G1a (n = 4), XVcA2G1b (n = 1) and XVdA3 (n = 1). The identification of human pathogenic C. viatorum and zoonotic C. occultus, C. muris and C. erinacei, suggested that wild rats infected with Cryptosporidium pose a threat to human health. Taken together, these findings highlight the need to control the rat population in Hainan, China. The need to improve the public awareness of the risk of disease transmission from wild rats to humans is also highlighted.

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This is the first report of the identification of Cryptosporidium in wild rats in Hainan Province, China.

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A total of 75 out of 150 (50.0%) specimens were PCR-positive for Cryptosporidium.

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Six known species or genotypes and three novel subtypes of C. viatorum were identified.

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The possibility of transmission of Cryptosporidium between wild rats and humans was suggested.

Molecular characterization and epidemiological investigation of Cryptosporidium hominis IkA18G1 and C. hominis monkey genotype IiA17, two unusual subtypes diagnosed in Swedish patients

Cryptosporidium hominis is considered a strictly human-adapted species, and it is only occasionally diagnosed in animals. However, two variants, C. hominis monkey genotype and C. hominis Ik, were originally described in non-human hosts, monkeys and horses, respectively. During a Swedish national Cryptosporidium study, where all samples were analyzed at the small subunit rRNA and the 60 kDa (gp60) glycoprotein loci, we identified two patients infected with C. hominis monkey genotype (subtype IiA17) and two infected with C. hominis subtype IkA18G1. The isolates were further analyzed at the actin and the 70 kDa heat shock protein loci, and these analyses showed that these two subtype families are closely related to each other and to human-adapted C. hominis as well as to Cryptosporidium cuniculus. The two patients with C. hominis monkey genotype infection (a father and son) had visited a monkey farm in Thailand prior to infection, while the two cases with C. hominis Ik were unrelated, both probably infected in Sweden. This is the first time that a monkey genotype infection in humans has been related to contact with monkeys and where the gp60 subtype was identified. It is also the first time that human infection caused by C. hominis subtype Ik is described. Even though we were not able to detect any parasites in the animal samples, zoonotic transmission cannot be ruled out in any of these cases because both subtype families are regarded as animal adapted.

Giardia duodenalis Infections in Humans and Other Animals in China

Giardia duodenalis is an important zoonotic pathogen in both public and veterinary health, and has been genotyped into at least eight assemblages (A-H), each with a distinct host range. In recent years, this intestinal protozoan parasite has been identified widely in humans and various other animals, and has even been recorded in environmental contaminants. Along with whole genome sequencing of G. duodenalis, multilocus sequence typing is increasingly being used to characterize G. duodenalis isolates. Here, we review the epidemiology, genotyping, and subtyping of G. duodenalis from humans and a wide range of other animals, as well as from wastewater, in China.

Multilocus genotyping of Giardia duodenalis in captive non-human primates in Sichuan and Guizhou provinces, Southwestern China

Giardia duodenalis is a common human and animal pathogen. It has been increasingly reported in wild and captive non-human primates (NHPs) in recent years. However, multilocus genotyping information for G. duodenalis infecting NHPs in southwestern China is limited. In the present study, the prevalence and multilocus genotypes (MLGs) of G. duodenalis in captive NHPs in southwestern China were determined. We examined 207 fecal samples from NHPs in Sichuan and Guizhou provinces, and 16 specimens were positive for G. duodenalis. The overall infection rate was 7.7%, and only assemblage B was identified. G. duodenalis was detect positive in northern white-cheeked gibbon (14/36, 38.9%), crab-eating macaque (1/60, 1.7%) and rhesus macaques (1/101, 0.9%). Multilocus sequence typing based on beta-giardin (bg), triose phosphate isomerase (tpi) and glutamate dehydrogenase (gdh) revealed nine different assemblage B MLGs (five known genotypes and four novel genotypes). Based on a phylogenetic analysis, one potentially zoonotic genotype of MLG SW7 was identified in a northern white-cheeked gibbon. A high degree of genetic diversity within assemblage B was observed in captive northern white-cheeked gibbons in Southwestern China, including a potentially zoonotic genotype, MLG SW7. To the best of our knowledge, this is the first report using a MLGs approach to identify G. duodenalis in captive NHPs in Southwestern China.

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

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

Molecular Epidemiology of Cryptosporidiosis in China

Molecular epidemiology of cryptosporidiosis is an active research area in China. The use of genotyping and subtyping tools in prevalence studies has led to the identification of unique characteristics of Cryptosporidium infections in humans and animals. Human cryptosporidiosis in China is exemplified by the high diversity of Cryptosporidium spp. at species and subtype levels, with dominant C. hominis and C. parvum subtypes being rarely detected in other countries. Similarly, preweaned dairy calves, lambs, and goat kids are mostly infected with non-pathogenic Cryptosporidium species (C. bovis in calves and C. xiaoi in lambs and goat kids), with C. parvum starting to appear in dairy calves as a consequence of concentrated animal feeding operations. The latter Cryptosporidium species is dominated by IId subtypes, with IIa subtypes largely absent from the country. Unlike elsewhere, rodents in China appear to be commonly infected with C. parvum IId subtypes, with identical subtypes being found in these animals, calves, other livestock, and humans. In addition to cattle, pigs and chickens appear to be significant contributors to Cryptosporidium contamination in drinking water sources, as reflected by the frequent detection of C. suis, C. baileyi, and C. meleagridis in water samples. Chinese scientists have also made significant contributions to the development of new molecular epidemiological tools for Cryptosporidium spp. and improvements in our understanding of the mechanism involved in the emergence of hyper-transmissible and virulent C. hominis and C. parvum subtypes. Despite this progress, coordinated research efforts should be made to address changes in Cryptosporidium transmission because of rapid economic development in China and to prevent the introduction and spread of virulent and zoonotic Cryptosporidium species and subtypes in farm animals.

Molecular epidemiologic tools for waterborne pathogens Cryptosporidium spp. and Giardia duodenalis

Molecular diagnostic tools have played an important role in improving our understanding of the transmission of Cryptosporidium spp. and Giardia duodenalis, which are two of the most important waterborne parasites in industrialized nations. Genotyping tools are frequently used in the identification of host-adapted Cryptosporidium species and G. duodenalis assemblages, allowing the assessment of infection sources in humans and public health potential of parasites found in animals and the environment. In contrast, subtyping tools are more often used in case linkages, advanced tracking of infections sources, and assessment of disease burdens attributable to anthroponotic and zoonotic transmission. More recently, multilocus typing tools have been developed for population genetic characterizations of transmission dynamics and delineation of mechanisms for the emergence of virulent subtypes. With the recent development in next generation sequencing techniques, whole genome sequencing and comparative genomic analysis are increasingly used in characterizing Cryptosporidium spp. and G. duodenalis. The use of these tools in epidemiologic studies has identified significant differences in the transmission of Cryptosporidium spp. in humans between developing countries and industrialized nations, especially the role of zoonotic transmission in human infection. Geographic differences are also present in the distribution of G. duodenalis assemblages A and B in humans. In contrast, there is little evidence for widespread zoonotic transmission of giardiasis in both developing and industrialized countries. Differences in virulence have been identified among Cryptosporidium species and subtypes, and possibly between G. duodenalis assemblages A and B, and genetic recombination has been identified as one mechanism for the emergence of virulent C. hominis subtypes. These recent advances are providing insight into the epidemiology of waterborne protozoan parasites in both developing and developed countries.

Environmental Transport of Emerging Human-Pathogenic Cryptosporidium Species and Subtypes through Combined Sewer Overflow and Wastewater

The environmental transport of Cryptosporidium spp. through combined sewer overflow (CSO) and the occurrence of several emerging human-pathogenic Cryptosporidium species in developing countries remain unclear. In this study, we collected 40 CSO samples and 40 raw wastewater samples from Shanghai, China, and examined them by PCR and DNA sequencing for Cryptosporidium species (targeting the small subunit rRNA gene) and Giardia duodenalis (targeting the triosephosphate isomerase, β-giardin, and glutamate dehydrogenase genes) and Enterocytozoon bieneusi (targeting the ribosomal internal transcribed spacer) genotypes. Human-pathogenic Cryptosporidium species were further subtyped by sequence analysis of the 60-kDa glycoprotein gene, with additional multilocus sequence typing on the emerging zoonotic pathogen Cryptosporidium ubiquitum. Cryptosporidium spp., G. duodenalis, and E. bieneusi were detected in 12 and 15, 33 and 32, and 37 and 40 CSO and wastewater samples, respectively, including 10 Cryptosporidium species, 3 G. duodenalis assemblages, and 8 E. bieneusi genotypes. In addition to Cryptosporidium hominis and Cryptosporidium parvum, two new pathogens identified in industrialized nations, C. ubiquitum and Cryptosporidium viatorum, were frequently detected. The two novel C. ubiquitum subtype families identified appeared to be genetic recombinants of known subtype families. Similarly, the dominant group 1 E. bieneusi genotypes and G. duodenalis subassemblage AII are known human pathogens. The similar distribution of human-pathogenic Cryptosporidium species and E. bieneusi and G. duodenalis genotypes between wastewater and CSO samples reaffirms that storm overflow is potentially a significant contamination source of pathogens in surface water. The frequent identification of C. ubiquitum and C. viatorum in urban wastewater suggests that these newly identified human pathogens may be endemic in China.IMPORTANCECryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi are major waterborne pathogens. Their transport into surface water through combined sewer overflow, which remains largely untreated in developing countries, has not been examined. In addition, the identification of these pathogens to genotypes and subtypes in urban storm overflow and wastewater is necessary for rapid and accurate assessment of pathogen transmission in humans and transport in the environment. Data from this study suggest that, like untreated urban wastewater, combined sewer overflow is commonly contaminated with human-pathogenic Cryptosporidium, G. duodenalis, and E. bieneusi genotypes and subtypes, and urban storm overflow potentially plays a significant role in the contamination of drinking source water and recreational water with human pathogens. They also indicate that Cryptosporidium ubiquitum and Cryptosporidium viatorum, two newly identified human pathogens, may be common in China, and genetic recombination can lead to the emergence of novel C. ubiquitum subtype families.

High genetic diversity of Giardia duodenalis assemblage E in pre-weaned dairy calves in Shanghai, China, revealed by multilocus genotyping

Giardia duodenalis is a common parasitic protozoan in human and animals. Epidemiological and molecular data are available from dairy cattle in many industrialized countries, but information on genetic diversity at multiple genetic loci is limited, especially in pre-weaned dairy calves. In this study, 818 fecal specimens were collected from five dairy cattle farms located in suburbs of Shanghai, China, with two to five samplings per farm. G. duodenalis assemblages and subtypes were determined using multilocus genotyping (MLG) at the β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) loci. The overall prevalence was 60.1% (492/818) combining data from the three genetic loci. Three G. duodenalis assemblages were detected, including E (n = 482), A (n = 5), and B (n = 1), with the concurrence of A and E in a few animals (n = 4). Intra-genotypic sequence diversity was high for assemblage E, showing 12, 13, and 17 subtypes at the bg, gdh, and tpi loci, including four, six, and eight new subtypes, respectively. All dominant subtypes (E3, E2, and E8 at the bg locus; E1 and E3 at the gdh locus; and E11 and E3 at the tpi locus) were detected on all farms at most sampling occasions, and only limited differences in subtype distribution were observed among five farms. Altogether, 58 assemblage E MLGs were identified, all of which had not been reported before, and seven (MLG-E1-MLG-E7) were each seen on multiple farms. These results indicate a high occurrence of G. duodenalis in dairy calves, the existence of high genetic heterogeneity of assemblage E on five farms, and frequent exchange of parasite populations among farms within a small geographic area. The clinical and epidemiologic significance of these observations warrants further investigations.

An investigation of parasitic infections and review of molecular characterization of the intestinal protozoa in nonhuman primates in China from 2009 to 2015

Parasites are a well-known threat to nonhuman primate (NHP) populations, and potentially cause zoonotic diseases in humans. In this study, the basic data was provided of the parasites in NHPs and the molecular characterization of the Enterocytozoon bieneusi, Giardia duodenalis, Cryptosporidium spp., and Entamoeba spp. were reviewed, which were found in these samples. A total of 3349 fecal samples were collected from 34 species reared at 17 districts in zoos, farms, free-range, or research laboratories, and examined microscopically. Eleven genera of intestinal parasites were detected: five genera of protozoans (Isospora spp., Entamoeba spp., Giardia sp., Cryptosporidium spp., and Cyclospora spp.) and six genera of helminths (Trichuris spp., Strongyloides spp., Ascaris spp., Physaloptera spp., Ancylostoma spp., and Enterobius spp.). The overall sample prevalence of parasitic infection was 54.1% (1811/3349). Entamoeba spp. was the most prevalent (36.4%, 1218/3349). The infection rate was the highest in free-range animals (73.0%, 670/918) (P < 0.01) and Guangxi Zhuang autonomous region (64.8%, 566/873). Mixed infections were mostly detected for Entamoeba spp., Trichuris spp., and Strongyloides spp.. Molecular characterization was reviewed of Enterocytozoon bieneusi, Giardia duodenalis, Cryptosporidium spp., and Entamoeba spp., as these are zoonotic species or genotypes. This parasitological data for NHPs in China, provides important information for veterinarians and public health authorities for the elimination of such parasites and monitor the potential transmission of zoonotic infections from NHPs.

Occurrence and multilocus genotyping of Giardia intestinalis assemblage C and D in farmed raccoon dogs, Nyctereutes procyonoides, in China

Background

Giardia intestinalis, the only causative agent of human giardiasis, can infect a wide range of animals. As no information concerning the prevalence and genotyping of G. intestinalis in raccoon dogs in China is available, examination of 305 faecal samples from raccoon dogs in Jilin Province (n = 110), Heilongjiang Province (n = 40), Liaoning Province (n = 72), Hebei Province (n = 54) and Shandong Province (n = 29) was conducted to estimate the prevalence of G. intestinalis in raccoon dogs in northern China and identify their genotypes using a genetic approach.

Findings

Of 305 faecal samples from farmed raccoon dogs, 22 (7.21 %) were detected G. intestinalis-positive by nested PCR amplification of the triosephosphate isomerase (tpi) gene. The prevalence of G. intestinalis was strongly related to the region and season of sampling. All 22 samples were analysed at the tpi, the glutamate dehydrogenase (gdh) and the beta giardin (bg) gene loci, showing 13, 3, 2 subtypes, respectively. The results also demonstrated that two raccoon dogs harboured mixed infections of assemblage C and assemblage D (or mixed C/D), whereas only assemblage C was detected in the remaining 20 samples. Moreover, five new multilocus genotypes, named as MLGs C1-C5, were observed in the assemblage C in the present study.

Conclusions

This is the first report of G. intestinalis infection in raccoon dogs in China. DNA sequence analysis of the tpi, gdh and bg gene indicated that 13, 3, 2 subtypes were found at these loci, respectively. Furthermore, this is also the first report of five new multilocus genotypes (MLGs C1-C5) in farmed raccoon dogs, which provides baseline data for further studies of the distribution of G. duodenalis in different hosts.

Prevalence of Cryptosporidium spp., Enterocytozoon bieneusi, Encephalitozoon spp. and Giardia intestinalis in Wild, Semi-Wild and Captive Orangutans (Pongo abelii and Pongo pygmaeus) on Sumatra and Borneo, Indonesia

Background

Orangutans are critically endangered primarily due to loss and fragmentation of their natural habitat. This could bring them into closer contact with humans and increase the risk of zoonotic pathogen transmission.

Aims

To describe the prevalence and diversity of Cryptosporidium spp., microsporidia and Giardia intestinalis in orangutans at seven sites on Sumatra and Kalimantan, and to evaluate the impact of orangutans’ habituation and location on the occurrence of these zoonotic protists.

Result

The overall prevalence of parasites in 298 examined animals was 11.1%. The most prevalent microsporidia was Encephalitozoon cuniculi genotype II, found in 21 animals (7.0%). Enterocytozoon bieneusi genotype D (n = 5) and novel genotype Pongo 2 were detected only in six individuals (2.0%). To the best of our knowledge, this is the first report of these parasites in orangutans. Eight animals were positive for Cryptosporidium spp. (2.7%), including C. parvum (n = 2) and C. muris (n = 6). Giardia intestinalis assemblage B, subtype MB6, was identified in a single individual. While no significant differences between the different human contact level groups (p = 0.479–0.670) or between the different islands (p = 0.992) were reported in case of E. bieneusi or E. cuniculi, Cryptosporidium spp. was significantly less frequently detected in wild individuals (p < 2×10⁻¹⁶) and was significantly more prevalent in orangutans on Kalimantan than on Sumatra (p < 2×10⁻¹⁶).

Conclusion

Our results revealed that wild orangutans are significantly less frequently infected by Cryptosporidium spp. than captive and semi-wild animals. In addition, this parasite was more frequently detected at localities on Kalimantan. In contrast, we did not detect any significant difference in the prevalence of microsporidia between the studied groups of animals. The sources and transmission modes of infections were not determined, as this would require repeated sampling of individuals, examination of water sources, and sampling of humans and animals sharing the habitat with orangutans.

Molecular detection and prevalence of Giardia duodenalis and Cryptosporidium spp. among long-tailed macaques (Macaca fascicularis) in Thailand

Giardia duodenalis and Cryptosporidium spp. are divergent protozoal intestinal parasites that infect human beings and other animals, including non-human primates. Although long-tailed macaques (Macaca fascicularis) reside in human communities in Thailand, the prevalence of Giardia spp. and Cryptosporidium spp. in these primates has not been previously investigated. The objective of this study was to evaluate long-tailed macaques living near human communities as possible hosts of these intestinal parasites. In 2014, 200 fecal samples were randomly collected from long-tailed macaques living in different areas of Lopburi province, Thailand, and tested with a panel of PCR assays for Giardia spp. and Cryptosporidium spp. G. duodenalis assemblage B was most frequently detected (6%), while assemblage A and an inconclusive assemblage were detected in single samples, for a total G. duodenalis infection rate of 7%. Two samples (1%) tested positive for Cryptosporidium spp., which were both classified as monkey genotypes. No significant associations were found between G. duodenalis infection and sex or location of macaques. This study indicates that long-tailed macaques can carry G. duodenalis and, to a lesser extent, Cryptosporidium spp. monkey genotype. These results warrant education of residents and tourists to limit contact with long-tailed macaques and to take hygienic precautions to mitigate risk of zoonotic and anthroponotic transmission of these parasites between people and macaques.

Cryptosporidium proliferans n. sp. (Apicomplexa: Cryptosporidiidae): Molecular and Biological Evidence of Cryptic Species within Gastric Cryptosporidium of Mammals

The morphological, biological, and molecular characteristics of Cryptosporidium muris strain TS03 are described, and the species name Cryptosporidium proliferans n. sp. is proposed. Cryptosporidium proliferans obtained from a naturally infected East African mole rat (Tachyoryctes splendens) in Kenya was propagated under laboratory conditions in rodents (SCID mice and southern multimammate mice, Mastomys coucha) and used in experiments to examine oocyst morphology and transmission. DNA from the propagated C. proliferans isolate, and C. proliferans DNA isolated from the feces of an African buffalo (Syncerus caffer) in Central African Republic, a donkey (Equus africanus) in Algeria, and a domestic horse (Equus caballus) in the Czech Republic were used for phylogenetic analyses. Oocysts of C. proliferans are morphologically distinguishable from C. parvum and C. muris HZ206, measuring 6.8–8.8 (mean = 7.7 μm) × 4.8–6.2 μm (mean = 5.3) with a length to width ratio of 1.48 (n = 100). Experimental studies using an isolate originated from T. splendens have shown that the course of C. proliferans infection in rodent hosts differs from that of C. muris and C. andersoni. The prepatent period of 18–21 days post infection (DPI) for C. proliferans in southern multimammate mice (Mastomys coucha) was similar to that of C. andersoni and longer than the 6–8 DPI prepatent period for C. muris RN66 and HZ206 in the same host. Histopatologicaly, stomach glands of southern multimammate mice infected with C. proliferans were markedly dilated and filled with necrotic material, mucus, and numerous Cryptosporidium developmental stages. Epithelial cells of infected glands were atrophic, exhibited cuboidal or squamous metaplasia, and significantly proliferated into the lumen of the stomach, forming papillary structures. The epithelial height and stomach weight were six-fold greater than in non-infected controls. Phylogenetic analyses based on small subunit rRNA, Cryptosporidium oocyst wall protein, thrombospondin-related adhesive protein of Cryptosporidium-1, heat shock protein 70, actin, heat shock protein 90 (MS2), MS1, MS3, and M16 gene sequences revealed that C. proliferans is genetically distinct from C. muris and other previously described Cryptosporidium species.

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.

Emergence of Cryptosporidium hominis Monkey Genotype II and Novel Subtype Family Ik in the Squirrel Monkey (Saimiri sciureus) in China

A single Cryptosporidium isolate from a squirrel monkey with no clinical symptoms was obtained from a zoo in Ya'an city, China, and was genotyped by PCR amplification and DNA sequencing of the small-subunit ribosomal RNA (SSU rRNA), 70-kDa heat shock protein (HSP70), Cryptosporidium oocyst wall protein, and actin genes. This multilocus genetic characterization determined that the isolate was Cryptosporidium hominis, but carried 2, 10, and 6 nucleotide differences in the SSU rRNA, HSP70, and actin loci, respectively, which is comparable to the variations at these loci between C. hominis and the previously reported monkey genotype (2, 3, and 3 nucleotide differences). Phylogenetic studies, based on neighbor-joining and maximum likelihood methods, showed that the isolate identified in the current study had a distinctly discordant taxonomic status, distinct from known C. hominis and also from the monkey genotype, with respect to the three loci. Restriction fragment length polymorphisms of the SSU rRNA gene obtained from this study were similar to those of known C. hominis but clearly differentiated from the monkey genotype. Further subtyping was performed by sequence analysis of the gene encoding the 60-kDa glycoprotein (gp60). Maximum homology of only 88.3% to C. hominis subtype IdA10G4 was observed for the current isolate, and phylogenetic analysis demonstrated that this particular isolate belonged to a novel C. hominis subtype family, IkA7G4. This study is the first to report C. hominis infection in the squirrel monkey and, based on the observed genetic characteristics, confirms a new C. hominis genotype, monkey genotype II. Thus, these results provide novel insights into genotypic variation in C. hominis.

Cryptosporidium spp., Giardia intestinalis, and Enterocytozoon bieneusi in Captive Non-Human Primates in Qinling Mountains

Non-human primates (NHPs) are confirmed as reservoirs of Cryptosporidium spp., Giardia intestinalis, and Enterocytozoon bieneusi. In this study, 197 fresh fecal samples from 8 NHP species in Qinling Mountains, northwestern China, were collected and examined using multilocus sequence typing (MLST) method. The results showed that 35 (17.8%) samples were positive for tested parasites, including Cryptosporidium spp. (3.0%), G. intestinalis (2.0%), and E. bieneusi (12.7%). Cryptosporidium spp. were detected in 6 fecal samples of Macaca mulatta, and were identified as C. parvum (n=1) and C. andersoni (n=5). Subtyping analysis showed Cryptosporidium spp. belonged to the C. andersoni MLST subtype (A4, A4, A4, and A1) and C. parvum 60 kDa glycoprotein (gp60) subtype IId A15G2R1. G. intestinalis assemblage E was detected in 3 M. mulatta and 1 Saimiri sciureus. Intra-variations were observed at the triose phosphate isomerase (tpi), beta giardin (bg), and glutamate dehydrogenase (gdh) loci, with 3, 1, and 2 new subtypes found in respective locus. E. bieneusi was found in Cercopithecus neglectus (25.0%), Papio hamadrayas (16.7%), M. mulatta (16.3%), S. sciureus (10%), and Rhinopithecus roxellana (9.5%), with 5 ribosomal internal transcribed spacer (ITS) genotypes: 2 known genotypes (D and BEB6) and 3 novel genotypes (MH, XH, and BSH). These findings indicated the presence of zoonotic potential of Cryptosporidium spp. and E. bieneusi in NHPs in Qinling Mountains. This is the first report of C. andersoni in NHPs. The present study provided basic information for control of cryptosporidiosis, giardiasis, and microsporidiosis in human and animals in this area.

First report of zoonotic Cryptosporidium spp., Giardia intestinalis and Enterocytozoon bieneusi in golden takins (Budorcas taxicolor bedfordi)

Genetic study of Cryptosporidium spp., Giardia intestinalis and Enterocytozoon bieneusi at species/assemblage/genotype/subtype level facilitates understanding their mechanical transmissions and underpins their control. A total of 191 fresh faecal samples were collected from golden takins in China and examined using multilocus sequence typing (MLST). Cryptosporidium spp. was detected in 15 faecal samples (7.9%), including Cryptosporidium parvum (2/15) and Cryptosporidium andersoni (13/15). MLST tool identified C. andersoni subtypes (A1, A4, A4, A1) and (A4, A4, A4, A1), and C. parvum gp60 gene subtype IId A19G1. The prevalence of G. intestinalis infection was 8.9% (17/191) and assemblage analysis identified 14 assemblage E and three assemblage B. Intra-variations were observed at triose phosphate isomerase (tpi), beta giardin (bg) and glutamate dehydrogenase (gdh) loci within the assemblage E, showing seven, three and three new subtypes in respective locus. Ten and one multilocus genotypes (MLGs) were present in assemblages E and B, respectively. E. bieneusi infection was positive in 14.7% (28/191) of the examined specimens, with three genotypes known (BEB6, D and I) and four novel internal transcribed spacer (ITS) genotypes (TEB1-TEB4). The present study revealed, for the first time, the presence of zoonotic C. parvum IId A19G1, G. intestinalis assemblage B and E. bieneusi genotype D and four novel genotypes in golden takins in China. These findings expand the host range of three zoonotic pathogens and have important implications for controlling cryptosporidiosis, giardiasis and microsporidiosis in humans and animals.

Multi-locus analysis of Giardia duodenalis from nonhuman primates kept in zoos in China: geographical segregation and host-adaptation of assemblage B isolates

Only a few studies based on single locus characterization have been conducted on the molecular epidemiology of Giardia duodenalis in nonhuman primates (NHPs). The present study was conducted to examine the occurrence and genotype identity of G. duodenalis in NHPs based on multi-locus analysis of the small-subunit ribosomal RNA (SSU rRNA), triose phosphate isomerase (tpi), glutamate dehydrogenase (gdh), and beta-giardin (bg) genes. Fecal specimens were collected from 496 animals of 36 NHP species kept in seven zoos in China and screened for G. duodenalis by tpi-based PCR. G. duodenalis was detected in 92 (18.6%) specimens from 18 NHP species, belonging to assemblage A (n=4) and B (n=88). In positive NHP species, the infection rates ranged from 4.8% to 100%. In tpi sequence analysis, the assemblage A included subtypes A1, A2 and one novel subtype. Multi-locus analysis of the tpi, gdh, and bg genes detected 11 (8 known and 3 new), 6 (3 known and 3 new) and 9 (2 known and 7 new) subtypes in 88, 47 and 35 isolates in assemblage B, respectively. Thirty-two assemblage B isolates with data at all three loci yielded 15 multi-locus genotypes (MLGs), including 2 known and 13 new MLGs. Phylogenetic analysis of concatenated sequences of assemblage B showed that MLGs found here were genetically different from those of humans, NHPs, rabbit and guinea pig in Italy and Sweden. It further indicated that assemblage B isolates in ring-tailed lemurs and squirrel monkeys might be genetically different from those in other NHPs. These data suggest that NHPs are mainly infected with G. duodenalis assemblage B and there might be geographical segregation and host-adaptation in assemblage B in NHPs.