Occurrence and molecular characterization of Cryptosporidium spp. in yaks (Bos grunniens) in China

Prevalence of Cryptosporidium spp. in Yaks (Bos grunniens) in China: A Systematic Review and Meta-Analysis

Cryptosporidium spp., the causative agent of cryptosporidiosis, can infect a variety of hosts. So far, there has been limited information regarding Cryptosporidium spp. infection in yaks (Bos grunniens). Here, we performed the first systematic review and meta-analysis for Cryptosporidium spp. infection in yaks in China. To perform the meta-analysis, five databases (Chinese National Knowledge Infrastructure (CNKI), VIP Chinese journal database, WanFang Data, PubMed, and ScienceDirect) were employed to search for studies related to the prevalence of Cryptosporidium spp. in yaks in China. The total number of samples was 8,212, and the pooled Cryptosporidium spp. prevalence in yaks was estimated to be 10.52% (1192/8012). The prevalence of Cryptosporidium spp. in yaks was 13.54% (1029/5277) and 4.49% (148/2132) in northwestern and southwestern China, respectively. In the sampling year subgroups, the prevalence before 2012 (19.79%; 650/2662) was significantly higher than that after 2012 (6.07%; 437/4476). The prevalence of Cryptosporidium spp. in cold seasons (20.55%; 188/794) was higher than that in warm seasons (4.83%; 41/1228). In the age subgroup, the yaks with age < 12 months had a higher prevalence (19.47%; 231/1761) than that in yaks with age ≥12 months (16.63%; 365/2268). Among 12 Cryptosporidium spp. species/genotypes, the C. bovis had the highest prevalence. Moreover, the effects of geography (latitude, longitude, precipitation, temperature, and altitude) and climate on Cryptosporidium spp. infection in yaks were evaluated. Through analyzing the risk factors correlated with the prevalence of Cryptosporidium spp., we recommend that effective management measures should be formulated according to the differences of different geographical factors, in order to prevent cryptosporidiosis and reduce economic losses in yaks in China.

Prevalence and Characterization of Cryptosporidium Species in Tibetan Antelope (Pantholops hodgsonii)

Cryptosporidium is an enteric apicomplexan parasite, which can infect multiple mammals including livestock and wildlife. Tibetan Antelope (Pantholops hodgsonii) is one of the most famous wildlife species, that belongs to the first class protected wild animals in China. However, it has not been known whether Tibetan Antelope is infected with Cryptosporidium so far. The objective of the present study was to determine the prevalence and characterization of Cryptosporidium species infection in Tibetan Antelope and the corresponding species by using molecular biological method. In the current study, a total of 627 fecal samples were randomly collected from Tibetan Antelope in the Tibet Autonomous Region (2019–2020), and were examined by PCR amplification of the small subunit ribosomal RNA (SSU rRNA) gene. Among 627 samples, 19 (3.03%, 19/627) were examined as Cryptosporidium-positive, with 7 (2.33%, 7/300) in females and 12 (3.67%, 12/327) in males. The analysis of SSU rRNA gene sequence suggested that only two Cryptosporidium species, namely, C. xiaoi and C. ubiquitum, were identified in this study. This is the first evidence for an existence of Cryptosporidium in Tibetan Antelope. These findings extend the host range for Cryptosporidium spp. and also provide important data support for prevention and control of Cryptosporidium infection in Tibetan Antelope.

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.

Genotyping and identification of Cryptosporidium spp., Giardia duodenalis and Enterocytozoon bieneusi from free-range Tibetan yellow cattle and cattle-yak in Tibet, China

To assess the prevalence and molecular characteristics of Cryptosporidium spp., Giardia duodenalis and Enterocytozoon bieneusi in natural grazing local breed cattle, 513 fecal samples from Tibetan yellow cattle and cattle-yaks were tested for these pathogens. Cryptosporidium, G. duodenalis and E. bieneusi in Tibetan yellow cattle prevalence were 0.7% (3/442), 3.8% (17/442) and 2.5% (11/442), respectively. Cryptosporidium bovis (n = 3), G. duodenalis assemblages A (n = 2) and E (n = 15) were identified based on sequence analysis. Among three E. bieneusi genotypes, I (n = 7), EbpC (n = 2) and CHC8 (n = 2) detected, EbpC was classified into Group 1, which has a significant zoonotic importance, whereas genotypes I and CHC8 belonged to Group 2. None of these pathogens was identified in cattle-yaks. The presence of zoonotic C. bovis, assemblage A and EbpC indicates Tibetan yellow cattle may be a potential spread source of intestinal pathogens with a zoonotic transmission risk. The relationships between natural free-range mode and the prevalence or genetic diversity of these pathogens need be confirmed in further studies.

Molecular detection of Cryptosporidium spp. and Enterocytozoon bieneusi in Longjiang Wagyu cattle in Northeastern China

Cryptosporidium spp. and Enterocytozoon bieneusi are two important zoonotic pathogens that can cause diarrhea and other gastrointestinal illnesses in humans and animals. However, the prevalence and genotype of the parasites in Longjiang Wagyu cattle in Heilongjiang Province, Northeast China have not been reported. In the present study, a total of 423 fecal samples of Longjiang Wagyu cattle collected from different farms in Heilongjiang Province, Northeast China, were examined for Cryptosporidium spp. and E. bieneusi using nested PCR. The overall infection rates for Cryptosporidium spp. and E. bieneusi were 6.38% (n = 27) and 7.09% (n = 30), respectively. The prevalence in different age groups ranged from 3.80% (95% confidence interval (CI) 1.01-6.59) to 8.36% (95% CI 4.83-11.90) for Cryptosporidium spp. and 5.97% (95% CI 2.52-9.43) to 7.94% (95% CI 4.49-11.40) for E. bieneusi. By analyzing the DNA sequences of the small subunit (SSU) rRNA gene, two Cryptosporidium species were detected in this study, namely C. parvum (n = 25) and C. ryanae (n = 2). The IIdA20G1 subtype was further identified by using the 60-kDa glycoprotein (gp60) gene of C. parvum. E. bieneusi was identified using three known sequences through the analysis of internal transcribed spacer (ITS) sequences: J (n = 23), I (n = 5), and BEB4 (n = 2), and all belonged to group 2. The results indicated that some of the Cryptosporidium species and E. bieneusi genotypes identified in Longjiang Wagyu cattle in the study areas might have zoonotic potential.

Subtyping Cryptosporidium ryanae: A Common Pathogen in Bovine Animals

Cryptosporidium ryanae is one of the most common species for cryptosporidiosis in cattle. However, little is known of the genetic characteristics of C. ryanae due to the lack of subtyping tools. In the present study, the 60-kDa glycoprotein (gp60) gene of C. ryanae was identified in whole genome sequence data and analyzed for sequence characteristics using bioinformatics tools. The protein it encodes had some of the typical characteristics of GP60 proteins, with a signal peptide, a furin cleavage site, and a glycosylphosphatidylinositol anchor at the C terminus of the protein, and numerous O-glycosylation sites. The gene sequence was used in the development of a subtyping tool, which was used in characterizing C. ryanae from 110 specimens from dairy cattle, 2 from beef cattle, 6 from yaks, and 4 from water buffaloes in China. Altogether, 17 subtypes from 8 subtype families were recognized, namely XXIa to XXIh. Possible host adaption was identified within this species, reflected by the unique occurrence of XXIa, XXIc, and XXIh in dairy cattle, yaks, and water buffaloes, respectively. Some geographical differences were detected in the distribution of subtype families in dairy cattle; specimens from southern China showed higher genetic diversity than from northern China, and the XXIa subtype family was only seen in dairy cattle in southern and eastern China. The gp60-based subtyping tool should be useful in molecular epidemiological studies of the transmission of C. ryanae.

Prevalence and molecular characterization of Cryptosporidium spp. in yaks (Bos grunniens) in Naqu, China

The intestinal protozoan specie, Cryptosporidium causes serious diarrheal syndrome in humans and animals worldwide. However, limited knowledge is known about the infection caused by this specie in yaks in Naqu. About 950 serum and 150 fecal samples were collected and assayed by using commercial ELISA kits and nPCR detection methods to find the prevalence and molecular characterization of Cryptosporidium spp. in yaks. Results found that 103 out of 950 (10.8%) serums were uncovered against C. parvum antibodies. In different regions, the prevalence of C. parvum in yaks were in a range from 9.1% to 16.7%, with obvious difference among the three areas (P < 0.001). In male and female yaks, the prevalence of C. parvum was found to be 7.2% and 13.3% respectively (P < 0.001); and a significant difference (P < 0.001) with a range of 9.8%-18.2% was observed among different age groups. Out of 150 fecal samples, only 2 (1.3%) positive samples were detected via nPCR. The positive samples were sequenced and identified to be C. bovis. The two isolates were clustered to cattle and yak clade separately. Our results highlight the prevalence and epidemiological status of Cryptosporidium spp. in yaks which may contribute towards the prevention and control of this zoonotic disease in Naqu, China.

Molecular detection of Cryptosporidium and Enterocytozoon bieneusi in dairy calves and sika deer in four provinces in Northern China

The protistan pathogens Cryptosporidium and Enterocytozoon bieneusi can cause significant intestinal diseases in animals and humans. However, limited information is available regarding prevalence and molecular characterization of Cryptosporidium and E. bieneusi in ruminants in Northern China. In this study, the overall prevalence of Cryptosporidium and E. bieneusi was 19.3% (62/321) and 28.97% (93/321) in dairy calves and 1.10% (9/818) and 13.57% (111/818) in sika deer (Cervus nippon) in four provinces in Northern China, respectively. The prevalence of Cryptosporidium and E. bieneusi in different factor groups was various. Five Cryptosporidium species/genotypes were identified, of which C. parvum, C. ryanae, C. bovis, and C. andersoni were only found in dairy calves, and only Cryptosporidium deer genotype was found in sika deer. Moreover, J, I, and BEB4 ITS genotypes of E. bieneusi were found in dairy calves, and six known genotypes (JLD-III, JLD-IX, JLD-VII, EbpC, BEB6, and I) and ten novel genotypes (namely LND-I and JLD-XV to JLD-XXIII) were found in sika deer in this study. Cryptosporidium parvum and E. bieneusi genotype J were identified as the predominant species/genotypes in dairy calves, whereas the predominance of Cryptosporidium spp. and E. bieneusi in sika deer was Cryptosporidium deer genotype and BEB6, respectively. The present study reported the prevalence and genotypes of Cryptosporidium and E. bieneusi in dairy calves and sika deer in four provinces in northern China. The present findings also suggest that investigated dairy calves and sika deer may play an important role in the transmission of E. bieneusi and Cryptosporidium to humans and other animals, and also in an effort to better understand the epidemiology of these enteric pathogens in China.

Molecular characterization and distribution of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi from yaks in Tibet, China

BACKGROUND

With worldwide distribution and importance for veterinary medicine, Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi have been found in a wide variety of vertebrate hosts. At present, few available molecular data can be used to understand the features of genetic diversity of these pathogens in areas without or less intensive farming. Dominated by grazing, Tibet is a separate geographic unit in China and yaks are in frequent contact with local herdsmen and necessary for their daily life. Therefore, to investigate the distribution of these pathogens in yaks of Tibet, 577 fecal specimens were screened using nested PCR for the presence and genotypes of the three intestinal pathogens.

RESULTS

The overall prevalence of Cryptosporidium spp., G. duodenalis, and E. bieneusi were 1.4% (8/577), 1.7% (10/577), and 5.0% (29/577), respectively. Cryptosporidium andersoni (n = 7) and Cryptosporidium bovis (n = 1) were detected by sequence analysis of the SSU rRNA gene. Genotyping at the SSU rRNA and triosephosphate isomerase genes suggested that all G. duodenalis positive specimens belonged to assemblage E. Sequence analysis of the internal transcribed spacer gene identified six known E. bieneusi genotypes: BEB4 (n = 11), I (n = 6), D (n = 5), J (n = 2), CHC8 (n = 1), and BEB6 (n = 1). One subtype (A5,A4,A2,A1) for C. andersoni and three multilocus genotypes for E. bieneusi were identified by multilocus sequence typing.

CONCLUSIONS

We report for the first time the status of three enteric pathogens infection simultaneously for grazing yaks in Tibet. Yaks in our study are likely to impose a low zoonotic risk for humans. The molecular epidemiology data add to our knowledge of the characteristics of distribution and transmission for these pathogens in Tibet and their zoonotic potential and public health significance.

First genotyping of Blastocystis in yaks from Qinghai Province, northwestern China

Background

Blastocystis is a common protist that can infect domestic and wild animals worldwide. Yak (Bos grunniens), an ancient species which can survive in alpine regions, has supplied necessities to local residents in plateau areas for generations. However, the infections with Blastocystis in yaks has been ignored for a long time. In the present study, the infections and genotypes of Blastocystis spp. in domestic yaks from Qinghai Province (northwestern China) were explored.

Results

Of 1027 faecal samples collected from yaks in seven regions of Qinghai Province, northwestern China, the total prevalence of Blastocystis was 27.07% (278/1027) targeting the small subunit ribosome rRNA (SSU rRNA) gene. This protist was detected in yaks within each examined age group, geographical origin and season. Significant difference in prevalence was found in yaks from different geographical origins. The highest prevalence (48.94%) was observed in animals from Haixi county. Sequence analysis revealed three animal-specific subtypes (ST10, ST12 and ST14) of Blastocystis spp. in these yaks, with ST10 being the predominant subtype widely distributed in all investigated regions, seasons and age groups. Interestingly, this is the first report about subtype ST12 infecting yaks.

Conclusions

To our knowledge, this is the first systematic report on Blastocystis prevalence in yaks from China, and the findings provide fundamental data for establishing effective control measures for this protist in yaks as well as other animals in China.

Diversity of Cryptosporidium in common voles and description of Cryptosporidium alticolis sp. n. and Cryptosporidium microti sp. n. (Apicomplexa: Cryptosporidiidae)

Fecal samples from wild-caught common voles (n = 328) from 16 locations in the Czech Republic were screened for Cryptosporidium by microscopy and PCR/sequencing at loci coding small-subunit rRNA, Cryptosporidium oocyst wall protein, actin and 70 kDa heat shock protein. Cryptosporidium infections were detected in 74 voles (22.6%). Rates of infection did not differ between males and females nor between juveniles and adults. Phylogenetic analysis revealed the presence of eight Cryptosporidium species/genotypes including two new species, C. alticolis and C. microti. These species from wild-caught common voles were able to infect common and meadow voles under experimental conditions, with a prepatent period of 3-5 days post-infection (DPI), but they were not infectious for various other rodents or chickens. Meadow voles lost infection earlier than common voles (11-14 vs 13-16 DPI) and had significantly lower infection intensity. Cryptosporidium alticolis infects the anterior small intestine and has larger oocysts (5.4 × 4.9 µm), whereas C. microti infects the large intestine and has smaller oocysts (4.3 × 4.1 µm). None of the rodents developed clinical signs of infection. Genetic and biological data support the establishment of C. alticolis and C. microti as separate species of the genus Cryptosporidium.

Prevalence and molecular characterization of Cryptosporidium spp. and Giardia duodenalis in 1-2-month-old highland yaks in Qinghai Province, China

Cryptosporidium and Giardia are ubiquitous parasites that infect humans and animals. Few reports are available on the prevalence of these two protozoan parasites in yaks (Bos grunniens). In this study, 344 faecal samples were collected from yaks with diarrhoea in the Chenduo and Nangqian counties of Qinghai Province, China. Cryptosporidium spp. and Giardia duodenalis were detected by light and immunofluorescence microscopy and nested PCR (nPCR). Fifteen samples were positive (4.5%) by Kinyoun staining, 40 (11.6%) samples were positive by immunofluorescence test (IFT), and 39 (11.3%) samples were positive by nPCR for Cryptosporidium spp., Cryptosporidium bovis (11/39, 28.2%) was the most prevalent species, followed by C. ryanae (6/39, 15.4%), C. andersoni (5/39, 12.8%), C. struthionis (5/39, 12.8%), C. parvum (5/39, 12.8%), C. hominis (4/39, 10.3%) and C. canis (3/39, 7.7%). Thirteen out of 344 (3.8%) samples were positive for Giardia by simple microscopy, 20 (5.8%) by IFT and 18 samples (5.2%) yak faecal samples were Giardia positive by nPCR. Two G. duodenalis assemblages (B, E) were detected in this study. Nine positive samples for G. duodenalis assemblage E were from the towns of Xiewu (8/9, 4.9%) and Xiangda (1/9, 1.3%), and nine positive samples (9/9, 8.5%) for G. duodenalis assemblage B were from the town of Zhenqin. This report provides information about infection with Cryptosporidium species and G. duodenalis assemblages in domesticated 1-2-month-old highland yaks living in the Qinghai-Tibet Plateau region of China.

Prevalence and molecular characterization of Cryptosporidium spp. and Giardia duodenalis in deer in Henan and Jilin, China

Background

Little is known about the prevalence and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in deer in China. In this study, 662 fecal samples were collected from 11 farms in Henan and Jilin Provinces between July 2013 and August 2014, and were screened for the presence of Cryptosporidium and G. duodenalis with genotyping and subtyping methods.

Results

Cryptosporidium spp. and G. duodenalis were detected in 6.80% (45/662) and 1.21% (5/662) of samples, respectively. Six Cryptosporidium species/genotypes were identified based on the small subunit ribosomal ribonucleic acid (SSU rRNA) gene: C. parvum (n = 11); C. andersoni (n = 5); C. ubiquitum (n = 3); C. muris (n = 1); C. suis-like (n = 1); and Cryptosporidium deer genotype (n = 24). When five of the 11 C. parvum isolates were subtyped by sequencing the 60 kDa glycoprotein (gp60) gene, zoonotic subtypes IIaA15G2R2 (n = 4) and IIdA19G1 (n = 1) were found. According to a subtype analysis, three C. ubiquitum isolates belonged to XIIa subtype 2. In contrast, only assemblage E was detected in the five Giardia-positive samples with small subunit ribosomal ribonucleic acid (SSU rRNA) gene sequencing.

Conclusions

To our knowledge, this is the first study to report C. andersoni, as well as C. parvum zoonotic subtypes IIaA15G2R2 and IIdA19G1 in cervids. These data, though limited, suggest that cervids may be a source of zoonotic Cryptosporidium and Giardia. Cervids in the present study are likely to be of low zoonotic potential to humans, and more molecular epidemiological studies are required to clarify the prevalence and public health significance of Cryptosporidium and G. duodenalis in cervids throughout China.

Molecular detection and prevalence of Cryptosporidium spp. infections in two types of domestic farm animals in the Qinghai-Tibetan Plateau Area (QTPA) in China

The objective of this study was to determine the prevalence of Cryptosporidium species infections in young cattle and sheep in the north-eastern part of the Qinghai-Tibetan Plateau Area (QTPA), north-western China. A total number of 454 faecal samples (389 from cattle and 65 from sheep) were collected and investigated to determine the prevalence of Cryptosporidium spp. oocysts. Cryptosporidium spp. infections detected in cattle (n = 56 positive samples) and sheep (n = 4 positive samples) were as following: C. andersoni (16/56, 28.6%) was the dominant species, followed by C. canis (9/56, 16.1%), C. bovis (9/56, 16.1%), C. hominis (8/56, 14.3%), C. struthionis (7/56, 12.5%), C. ryanae (5/56, 8.9%), and C. serpentis (2/56, 3.6%). Two Cryptosporidium species were detected in sheep: C. parvum (2/4) and C. canis (2/4). There were no mixed infections. C. hominis, C. struthionis, and C. serpentis are reported in domestic animals for the first time at the QTPA of China and our results indicate an anthropozoonotic transmission of C. hominis. The identification of Cryptosporidium spp. in domestic animals warrants better care of the farm animals in order to avoid contamination in vulnerable animal and human populations.

Molecular investigation of Cryptosporidium and Giardia in pre- and post-weaned calves in Hubei Province, China

Background

The protistan pathogens Cryptosporidium and Giardia can cause significant intestinal diseases in animals and humans. Cattle, particularly calves, carrying these protists can be significant reservoirs for human infections and disease. However, little is known about the genetic make-up of Cryptosporidium and Giardia populations in cattle and other ruminants in some regions of China.

Results

In the present study, PCR-based tools were used to genetically characterise these protists in faecal samples from a total of 339 pre- and post-weaned calves from four distinct locations in Hubei Province using markers in the large (LSU) or small (SSU) subunits of nuclear ribosomal RNA genes. Cryptosporidium andersoni, C. bovis, C. ryanae and Giardia duodenalis assemblage E were detected in 0.6%, 10.9%, 4.1% and 22.6% of calves, respectively.

Conclusions

This study is the first to report the prevalence of Cryptosporidium and Giardia in pre- and post-weaned calves in Hubei Province, and encourages large-scale molecular studies of animals and humans, in an effort to better understand the epidemiology of these enteric pathogens in China.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2463-3) contains supplementary material, which is available to authorized users.

Advances and Perspectives on the Epidemiology of Bovine Cryptosporidium in China in the Past 30 Years

Major progress has been made in understanding the epidemiology of bovine Cryptosporidium in China in the past 30 years. The overall infection rate in that period was 14.50% (5265/36316), with different prevalence being observed among dairy cattle, yaks, beef cattle, and buffalo. The infection rate declined as the animals' ages increased and the lowest prevalence occurred in winter. Ten Cryptosporidium species and two genotypes have been found in cattle, with Cryptosporidium parvum, C. andersoni, C. bovis, and C. ryanae being the commonest species. Cryptosporidium bovis rather than C. parvum predominated in preweaned dairy cattle, and C. parvum IIdA15G1 and IIdA19G1 were the only subtypes detected in dairy cattle. Two subtype families, IIa and IId, were found in yaks. Population genetic analysis detected an epidemic population structure in C. andersoni, which suggested that the prevalence of C. andersoni in China is not attributable to the introduction of dairy cattle. Moreover, C. parvum IId subtypes probably dispersed from western Asia to other geographic regions based on population genetic analysis of isolates from China, Sweden, and Egypt. Therefore, we hypothesize that Cryptosporidium was introduced into China in the past, and different populations formed progressively in various hosts in response to diverse factors, including the transmission dynamics, geographic isolation, host specificity, and large-scale farming. More epidemiological studies are required to test this hypothesis and to clarify the prevalence and transmission of Cryptosporidium species in China.

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.

Epidemiology of Cryptosporidium infection in cattle in China: a review

The present review discusses the findings of cryptosporidiosis research conducted in cattle in China and highlights the currently available information on Cryptosporidium epidemiology, genetic diversity, and distribution in China, which is critical to understanding the economic and public health importance of cryptosporidiosis transmission in cattle. To date, 10 Cryptosporidium species have been detected in cattle in China, with an overall infection rate of 11.9%. The highest rate of infection (19.5%) was observed in preweaned calves, followed by that in juveniles (10.69%), postweaned juveniles (9.0%), and adult cattle (4.94%). The dominant species were C. parvum in preweaned calves and C. andersoni in postweaned, juvenile, and adult cattle. Zoonotic Cryptosporidium species (C. parvum and C. hominis) were found in cattle, indicating the possibility of transmission between humans and cattle. Different cattle breeds had significant differences in the prevalence rate and species of Cryptosporidium. This review demonstrates an age-associated, breed-associated, and geographic-related occurrence of Cryptosporidium and provides references for further understanding of the epidemiological characteristics, and for preventing and controlling the disease.

Prevalence and genetic characterization of Cryptosporidium species and Giardia duodenalis in lambs in Oromia Special Zone, Central Ethiopia

BACKGROUND

Cryptosporidium and Giardia duodenalis are gastro-intestinal parasites that infect human and animals worldwide. Both parasites share a broad host range and are believed to be zoonosis. The aim of this study was to identify the species of Cryptosporidium and assemblages of G. duodenalis in lambs and to elucidate their role in zoonotic transmission.

RESULTS

A total of 389 fecal samples were collected from lambs and screened by microscopy and nested PCR targeting the small-subunit ribosomal RNA for Cryptosporidium; and the small-subunit ribosomal RNA, triose phosphate isomerase, β-giardin, and glutamate dehydrogenase genes for G. duodenalis. The prevalence of Cryptosporidium and G. duodenalis was 2.1% (8/389) and 2.6% (10/389), respectively. The infection rate at the three study sites ranged from 1.3 to 3.1% for Cryptosporidium and 1.6 to 3.9% for G. duodenalis; but variation was not statistically significant (p > 0.05). The finding also showed that there is no sex and age group associated difference in the occurrence of Cryptosporidium and G. duodenalis infections in lambs. Sequence analysis revealed that lambs were mono-infection with C. ubiquitum and G. duodenalis assemblage E. The analysis also indicated the presence of genetic variation within isolates of assemblage E; with 4 of them are novel genotypes at the small-subunit ribosomal RNA, β-giardin, and glutamate dehydrogenase genes.

CONCLUSION

The findings of the current study showed that lambs are capable of harboring C. ubiquitum and G. duodenalis assemblage E. This finding suggests that lambs might be sources for potentially zoonotic Cryptosporidium species. This was first molecular study in lambs and contributes to a better understanding of the epidemiology of Cryptosporidium and G. duodenalis in central Ethiopia.

Molecular identification of the Cryptosporidium deer genotype in the Hokkaido sika deer (Cervus nippon yesoensis) in Hokkaido, Japan

The protozoan Cryptosporidium occurs in a wide range of animal species including many Cervidae species. Fecal samples collected from the Hokkaido sika deer (Cervus nippon yesoensis), a native deer of Hokkaido, in the central, western, and eastern areas of Hokkaido were examined by polymerase chain reaction (PCR) to detect infections with Cryptosporidium and for sequence analyses to reveal the molecular characteristics of the amplified DNA. DNA was extracted from 319 fecal samples and examined with PCR using primers for small-subunit ribosomal RNA (SSU-rRNA), actin, and 70-kDa heat shock protein (HSP70) gene loci. PCR-amplified fragments were sequenced and phylogenetic trees were created. In 319 fecal samples, 25 samples (7.8 %) were positive with SSU-rRNA PCR that were identified as the Cryptosporidium deer genotype. Among Cryptosporidium-positive samples, fawns showed higher prevalence (16.1 %) than yearlings (6.4 %) and adults (4.7 %). The result of Fisher's exact test showed a statistical significance in the prevalence of the Cryptosporidium deer genotype between fawn and other age groups. Sequence analyses with actin and HSP70 gene fragments confirmed the SSU-rRNA result, and there were no sequence diversities observed. The Cryptosporidium deer genotype appears to be the prevalent Cryptosporidium species in the wild sika deer in Hokkaido, Japan.

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.

Distribution of Cryptosporidium species in Tibetan sheep and yaks in Qinghai, China

Few data are available on the distribution of Cryptosporidium species in Tibetan sheep and yaks, which are free-range animals living in a cold, low oxygen, and high ultraviolet radiation habitat. In this study, 904 fecal specimens were collected from 350 Tibetan sheep and 554 yaks in six counties. Cryptosporidium spp. were detected and differentiated by PCR and sequence analyses. Altogether, 43 (12.3%) Tibetan sheep and 158 (28.5%) yaks were positive for Cryptosporidium spp. In Tibetan sheep, Cryptosporidium xiaoi (39/43, 90.7%) was the dominant species, with the remaining cases (4/43, 9.3%) by Cryptosporidium ubiquitum. All C. ubiquitum specimens belonged to the subtype family XIIa. In contrast, Cryptosporidium andersoni (72/158, 45.6%), Cryptosporidium bovis (47/158, 29.7%), Cryptosporidium ryanae cattle type (35/158, 22.2%), C. ryanae buffalo type (2/158, 1.3%), and Cryptosporidium suis-like (2/158, 1.3%) were identified in yaks. Contradictory to previous observations, C. andersoni was one of the dominant Cryptosporidium species in yaks in this study. Despite sharing habitats, Tibetan sheep and yaks are evidently infected with different Cryptosporidium species.

Effect of electrical stimulation and hot boning on the eating quality of Gannan yak longissimus lumborum

The objective of this study was to evaluate the effects of electrical stimulation (ES) versus non-electrical stimulation (NES) and type of boning (hot versus cold) on the eating quality of Gannan yak longissimus lumborum. Eighteen Gannan yak bulls were randomly divided into two groups: ES and NES. Hot boning (HB) and cold boning (CB) were applied to the left and right side of the carcasses, respectively. All of the four treatments missed the "ideal" pH/temperature window. HB reduced the rate of pH decline, decreased meat tenderness and water holding capacity. ES increased the rate of pH decline and improved yak meat tenderness (P<0.05); however, ES explained only 1% of the variation in WBSF. HB and ES had no significant effects on cooking loss, L* or b* values of yak meat. Postmortem aging increased yak meat tenderness and improved meat color parameters. HB had negative effects on yak meat quality, while ES could not reverse these deleterious effects.

Prevalence and molecular characterization of Cryptosporidium spp. in dairy cattle, northwest China

Cryptosporidium spp. cause enteric diseases in a wide range of animals, including dairy cattle. However, limited information is available regarding prevalence and molecular characterization of Cryptosporidium spp. in dairy cattle in Gansu province and Ningxia Hui Autonomous Region (NXHAR), northwest China. A total of 2945 dairy feces samples (1257 from Gansu province and 1688 from NXHAR) were collected between December 2012 and March 2014 and were tested by PCR amplification of the small subunit (SSU) rRNA gene. A total of 150 (5.09 %, 58 from Gansu and 92 from NXHAR) samples were PCR-positive for Cryptosporidium, and the prevalence is associated with the region and age of dairy cattle. Species identification showed Cryptosporidium andersoni in 36 samples (24.00 %, 19 from NXHAR and 17 from Gansu), Cryptosporidium ryanae in 24 samples (16.00 %, 13 from NXHAR and 11 from Gansu), Cryptosporidium bovis in 70 samples (46.67 %, 41 from NXHAR and 29 from Gansu), and Cryptosporidium parvum in 20 samples (13.33 %, 19 from NXHAR and 1 from Gansu). A DNA sequence analysis of the gp60 gene suggested that all the 20 C. parvum isolates represented subtype IIdA15G1. These findings indicated the presence of zoonotic Cryptosporidium in Gansu and NXHAR. This is the first report of four species of Cryptosporidium (C. andersoni, C. ryanae, C. bovis, and C. parvum) infection in dairy cattle in Gansu province. This is also the first report of C. ryanae infection in dairy cattle in NXHAR. Effective control strategies should be implemented to prevent and control Cryptosporidium infection in dairy cattle and humans.

Molecular characterization of Cryptosporidium spp. and Giardia duodenalis from yaks in the central western region of China

BACKGROUND

Cryptosporidium spp. and Giardia duodenalis are important causes of diarrheal diseases in humans and animals worldwide, and there is an increased interest in the role of animals in the mechanical transmission of these protozoa. To examine the role of yaks in this process, we examined the occurrence and genotypes of Cryptosporidium and G. duodenalis in yaks in western China.

RESULTS

A total of 545 fecal specimens were collected from yaks from nine different counties in the central western region of China. The prevalence for Cryptosporidium spp. and G. duodenalis were 4.0 % (22/545) and 6.0 % (16/545), respectively. Mixed infections of Cryptosporidium and G. duodenalis were also detected in four specimens. The prevalence of both protozoa differed significantly between some age groups, with higher rates of infection in animals < 1 year old. Sequence analysis of the small subunit rRNA (SSU rRNA) gene of the Cryptosporidium isolates identified the species as C. parvum (n = 12), C. bovis (n = 6), C. ryanae (n = 3), and C. ubiquitum (n = 1). Genotyping based on 60-kDa glycoprotein (gp60) gene from five C. parvum isolates identified all as IId with three isolates identified as IIdA15G1, one as IIdA18G1, and one as IIdA19G1. One C. ubiquitum isolate was identified as subtype VIIa. Amongst the G. duodenalis isolates, 16 were identified as assemblage E at the SSU rRNA gene. Four novel glutamate dehydrogenase (gdh) subtypes and two triosephosphate isomerase (tpi) subtypes were found amongst the G. duodenalis assemblage E isolates.

CONCLUSIONS

The presence of C. parvum subtype IIdA15G1, IIdA18G1, and IIdA19G1 isolates further confirms the dominance of the C. parvum IId subtypes in China. These findings also indicate that yaks may be a source of zoonotic Cryptosporidium infection, and this is the first report of G. duodenalis in yaks. The data presented here provides the basis for further genotyping or subtyping studies of G. duodenalis in yaks.

Occurrence and molecular characterization of Cryptosporidium spp. and Enterocytozoon bieneusi in dairy cattle, beef cattle and water buffaloes in China

Cryptosporidium spp. and Enterocytozoon bieneusi are important protists in a wide range of vertebrate hosts, causing diarrheal diseases. Cattle are considered potential reservoirs of Cryptosporidium infection in humans, although their role in the transmission of E. bieneusi is not clear. In the present work, 793 fecal specimens from dairy cattle, native beef cattle, and water buffaloes on 11 farms in China were examined for the presence of Cryptosporidium spp. and E. bieneusi using nested PCR targeting the small subunit (SSU) rRNA gene of Cryptosporidium spp. and the internal transcribed spacer (ITS) of E. bieneusi. For Cryptosporidium, 144/446 (32.3%) dairy cattle, 44/166 (26.5%) beef cattle, and 43/181 (23.8%) water buffaloes were PCR-positive. Sequence analysis was successful for 213 of the 231 Cryptosporidium-positive isolates; among them 94 had Cryptosporidium andersoni, 61 had Cryptosporidium bovis, 54 had Cryptosporidium ryanae, 2 had a Cryptosporidium suis-like genotype, and 2 had mixed infections of C. bovis and C. ryanae. In dairy and beef cattle, C. andersoni and C. bovis were the most common species, whereas C. ryanae was the dominant species in water buffaloes. The latter species produced SSU rRNA sequences different between cattle and water buffaloes. For E. bieneusi, the infection rate of E. bieneusi in dairy cattle, beef cattle and water buffaloes was 4.9%, 5.4% and 2.2%, respectively. All 35 E. bieneusi-positive specimens were successfully sequenced, revealing the presence of four genotypes: three Group 2 genotypes previously reported in cattle as well as humans (I, J and BEB4) and one Group 1 genotype recently reported in yaks (CHN11). Genotypes I and J were the most common genotypes in dairy and beef cattle, while genotype CHN11 was the only genotype seen in water buffaloes. Thus, the distribution of Cryptosporidium spp. and E. bieneusi in water buffaloes might be different from in dairy and beef cattle in China. These findings indicate that some of the Cryptosporidium species and all four E. bieneusi genotypes identified in bovine animals in the study areas may have zoonotic potential.

Prevalence and molecular characterization of Cryptosporidium in goats across four provincial level areas in China

This study assessed the prevalence, species and subtypes of Cryptosporidium in goats from Guangdong Province, Hubei Province, Shandong Province, and Shanghai City of China. Six hundred and four fecal samples were collected from twelve goat farms, and the overall infection rate was 11.4% (69/604). Goats infected with Cryptosporidium were found in eleven farms across four provincial areas, and the infection rate ranged from 2.9% (1/35) to 25.0% (9/36). Three Cryptosporidium species were identified. Cryptosporidium xiaoi (45/69, 65.2%) was the dominant species, followed by C. parvum (14/69, 20.3%) and C.ubiquitum (10/69, 14.5%). The infection rate of Cryptosporidium spp. was varied with host age and goat kids were more susceptible to be infected than adult goats. Subtyping C.parvum and C.ubiquitum positive samples revealed C. parvum subtype IIdA19G1 and C. ubiquitum subtype XIIa were the most common subtypes. Other C. parvum subtypes were detected as well, such as IIaA14G2R1, IIaA15G1R1, IIaA15G2R1 and IIaA17G2R1. All of these subtypes have also been detected in humans, suggesting goats may be a potential source of zoonotic cryptosporidiosis. This was the first report of C. parvum subtypes IIaA14G2R1, IIaA15G1R1 and IIaA17G2R1 infecting in goats and the first molecular identification of C.parvum and its subtypes in Chinese goats.