The presence of Giardia intestinalis in donkeys, Equus asinus, in China

Prevalence and Multilocus Genotyping of Giardia duodenalis in Donkeys in Shanxi Province, North China

Giardia duodenalis is a ubiquitous flagellated protozoan, causing significant economic losses to animal husbandry and posing threats to public health. China ranks the world's sixth largest major producer of donkeys, rearing approximately 2.6 million donkeys in 2019, but limited investigation of G. duodenalis prevalence has been conducted in the past, and it is yet to be known whether donkeys in Shanxi Province are infected with G. duodenalis. In the present study, a total of 815 fecal samples collected from donkeys in representative regions of Shanxi Province, North China, were examined for G. duodenalis using nested PCR. Then, the assemblages and multilocus genotypes (MLGs) were examined based on three established loci: namely, β-giardin (bg), triosephosphate isomerase (tpi), and glutamate dehydrogenase (gdh). The overall prevalence of G. duodenalis in donkeys in Shanxi Province was 16.81% (137/815). The region was identified as the main risk factor for the observed difference in G. duodenalis prevalence in donkeys among the three study areas (χ2 = 21.611, p < 0.001). Assemblages A, E, and B were identified, with the latter as the predominant assemblage. Three MLGs (MLG-novel-1 to 3) were formed based on sequence variation among the three loci. The present study reveals the presence of G. duodenalis in donkeys in Shanxi Province, North China, for the first time, which not only enriches the data on the distribution of G. duodenalis in donkeys in China but also provides useful baseline data for planning control strategies against G. duodenalis infection in the sampled areas.

Occurrence and genetic characteristics of Giardia duodenalis in donkeys in Xinjiang, China

Giardia duodenalis is a common enteric parasite in humans and animals. To examine the occurrence and genetic characteristics of Giardia in donkeys in Xinjiang, China, 758 fecal samples from donkeys were collected, and Giardia was screened via PCR at the SSU rRNA gene. A total of 17.0% (129/758) of samples tested positive for Giardia, with the infection rate in large-scale farm and domestic donkeys being 21.4% (124/580) and 2.8% (5/178), respectively; the infection rates in <1-year-old and ≥1-year-old donkeys were 19.3% (72/374) and 12.7% (41/323), respectively. Three Giardia assemblages were identified, with assemblage B (n = 102) as the prevalent assemblage, followed by assemblage A (n = 23) and assemblage E (n = 4). Of the 129 Giardia-positive isolates, 40, 34 and 59 sequences were obtained at the bg, gdh and tpi genes, respectively. Twenty-one isolates successfully allowed multilocus genotyping (MLG), with four novel assemblage A MLGs, named MLG-AI-1 (n = 1), MLG-AI-2 (n = 1), MLG-AI-3 (n = 1), and MLG-AI-4 (n = 1) and three novel assemblage B MLGs, named MLG-B1 (n = 1), MLG-B2 (n = 14), and MLG-B3 (n = 1). Moreover, two isolates formed two MLG-mixed sequences. The results suggest that donkeys are commonly infected with Giardia in Xinjiang, and there is genetic diversity and host adaptability among the isolates.

Epidemiology of giardiasis and assemblages A and B and effects on diarrhea and growth trajectories during the first 8 years of life: Analysis of a birth cohort in a rural district in tropical Ecuador

BACKGROUND

There are limited longitudinal data on the acquisition of Giardia lamblia infections in childhood using molecular assays to detect and type assemblages, and measure effects of infections on diarrhea risk and childhood growth.

METHODS

We analysed stool samples from a surveillance sample within a birth cohort in a rural district in tropical Ecuador. The cohort was followed to 8 years of age for the presence of G. lamblia in stools by quantitative PCR and A and B assemblages by Taqman assay or Sanger sequencing. We explored risk factors associated with infection using generalized estimating equations applied to longitudinal binary outcomes, and longitudinal panel data analysis to estimate effects of infection on diarrhea and growth trajectories.

RESULTS

2,812 stool samples collected between 1 month and 8 years of age from 498 children were analyzed and showed high rates of infection: 79.7% were infected at least once with peak prevalence (53.9%) at 5 years. Assemblage B was accounted for 56.8% of genotyped infections. Risk factors for infection included male sex (P = 0.001), daycare attendance (P<0.001), having a household latrine (P = 0.04), childhood (P<0.001) and maternal soil-transmitted helminth (P = 0.029) infections, and exposures to donkeys (age interaction P = 0.034). G. lamblia was associated with increased risk of diarrhea (per episode, RR 1.03, 95% CI 1.01-1.06, P = 0.011) during the first 3 years of life and a transient impairment of weight (age interaction P = 0.017) and height-for-age (age interaction P = 0.025) trajectories between 1 and 4 years of age. There was no increased risk of either assemblage being associated with outcomes.

CONCLUSION

Our data show a relatively high edemicity of G. lamblia transmission during childhood in coastal Ecuador, and evidence that infection is associated with a transiently increased risk of diarrhea during the first 3 years of life and impairment of weight and height between 1 and 4 years.

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.

Detection of Point Prevalence and Assemblages of Giardia spp. in Dairy Calves and Sika Deer, Northeast China

Giardia lamblia (syn Giardia duodenalis) is an important protozoan parasite that can cause enterocyte damage and loss of brush border of the epithelial cells in the intestine, resulting in shortening of microvilli and altered epithelial barrier function. Many animals have been detected as the hosts of the G. lamblia. However, the information on the epidemiology and molecular detection of G. lamblia in dairy calves and sika deer in northeastern China is limited. To investigate the prevalence and genotypes of dairy calves and sika deer in northeastern China, a total of 321 fecal samples from dairy calves in Heilongjiang Province and 818 fecal samples from sika deer in four provinces (Jilin Province, Heilongjiang Province, Liaoning Province, and Inner Mongolia Autonomous Region) in China were conducted by PCR methods, between September 2017 and April 2018. The overall prevalence of G. lamblia in dairy calves in Heilongjiang Province and sika deer in the four provinces was 4.98% (16/321) and 0.61% (5/818), respectively. In this study, the point prevalence of Giardia spp. in different factor groups was dissimilar. A total of 16 Giardia spp. positive samples in dairy calves were identified as assemblage E based on the triosephosphate isomerase (tpi), β-giardine (bg), and glutamate dehydrogenase (gdh) genes. Furthermore, two positive samples of assemblage A and three positive samples of assemblage E were identified with gdh and bg genes in the sika deer. Assemblage A was zoonotic genotype of G. lamblia, and assemblage E was identified as the predominant assemblage in dairy calves and sika deer. This study reported the prevalence and genotypes of G. lamblia in dairy calves in Heilongjiang Province and sika deer in four provinces in China. These results provided basic information to understand the epidemiology of G. lamblia in dairy calves and sika deer in China.

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.

Zoonotic potential of Enterocytozoon bieneusi and Giardia duodenalis in horses and donkeys in northern China

Limited data are available on infection rates and genetic identity of Enterocytozoon bieneusi and Giardia duodenalis in horses and donkeys. In this study, 865 fecal specimens were collected from donkeys (n = 540) and horses (n = 325) in three provinces and autonomous regions in northern China during 2015-2019. Enterocytozoon bieneusi was detected and genotyped by PCR and sequence analyses of the ribosomal internal transcribed spacer (ITS) and G. duodenalis was detected and genotyped by PCR and sequence analyses of the β-giardin, glutamate dehydrogenase, and triosephosphate isomerase genes. The overall infection rates of E. bieneusi and G. duodenalis were 21.9% (118/540) and 11.5% (62/540) in donkeys, and 7.4% (24/325) and 2.8% (9/325) in horses, respectively. These differences in infection rates of E. bieneusi and G. duodenalis between donkeys and horses were significant (χ² = 30.9, df = 1, P < 0.0001; χ² = 20.4, df = 1, P < 0.0001, respectively). By age, the 28.9% infection rate of E. bieneusi in donkeys under 6 months was significantly higher than that in animals over 6 months (6.0%; χ² = 35.2, df = 1, P < 0.0001). In contrast, donkeys of 6-12 months had higher infection rate (35.9%) of G. duodenalis than donkeys under 6 months (9.9%; χ² = 22.1, df = 1, P < 0.0001) and over 12 months (8.7%; χ² = 17.3, df = 1, P < 0.0001). In horses, animals of > 12 months had significantly higher infection rate (31.1%) of E. bieneusi than horses under 6 months (3.4%; χ² = 29.4, df = 1, P < 0.0001) and 6-12 months (3.8%; χ² = 26.1, df = 1, P < 0.0001). Twenty genotypes of E. bieneusi were detected, including six known ones and 14 new genotypes. Among them, nine genotypes in 45% E. bieneusi-positive specimens belonged to the zoonotic group 1. Similarly, three G. duodenalis assemblages were detected, including A (in 2 horses and 30 donkeys), B (in 6 horses and 29 donkeys), and E (in 1 horse); three donkeys had coinfections of assemblages A and B. The assemblage A isolates identified all belong to the sub-assemblage AI. These results indicate that unlike in other farm animals, there is a common occurrence of zoonotic E. bieneusi and G. duodenalis genotypes in horses and donkeys.

First Molecular Detection and Phylogenetic Analyses of Zoonotic Giardia intestinalis in Horses in Turkey

The goal of our study was to investigate the molecular prevalence of Giardia intestinalis in naturally infected horses in Kayseri, Central Anatolia Region in Turkey, to determine the molecular characterization of the obtained isolates and to exhibit the potential role of horses in zoonotic transmission of G. intestinalis. Fecal samples were randomly collected from totally 150 horses with clinically healthy between March and June of 2018. After the genomic DNA extractions, 25 (16.6%) of the 150 fecal samples, were found positive for G. intestinalis by nested PCR analyses of β-giardin gene. Phylogenetic analysis of the β-giardin gene sequences of G. intestinalis showed that the sequences detected in this study belonged to assemblage A that is regarded as zoonotic. Our study is the first report on the presence of G. intestinalis in horses in Turkey. The findings of the present study indicate that future research studies are required to determine molecular epidemiology and geographical distribution of G. intestinalis infections in horses nationwide. In addition, this study also may be helpful to assess the zoonotic potential for public health of G. intestinalis infections.

Potential Hazards Associated with Raw Donkey Milk Consumption: A Review

Donkey milk can be used as a substitute for infants and children who suffer from cow milk proteins intolerance and multiple food hypersensitivity. Up to date, this is one of the main reasons why donkey milk has become a substantial area for reasearch, with an increase over the the last fifteen years. In donkey milk chain, risk analysis should be the object of particular attention because children are the main consumers of this food. In fact, this process is one of the main tool to achieve a high level of protection of human health and life; thus, the most important safety hazards should be monitored in order to attain this goal. This review focuses on the main hazards possibly present in raw donkey milk, including bacteria, fungal toxins, parasites, and chemical pollutants. Literature data have been considered, including some information that is not provided in the international literature. In the authors' opinion, the current scientific knowledge should be improved, with the aim of allowing a suitable risk assessment along the whole donkey milk chain. However, in the meantime, the competent authorithies must carry out more stringent official controls, with particular attention given to the level of primary production. The issue of a traceability system in donkey milk chain should be considered of paramount importance.

Prevalence and molecular characterization of Giardia intestinalis in racehorses from the Sichuan province of southwestern China

Giardia intestinalis, a cosmopolitan zoonotic parasite, is one of the most common causes of protozoal diarrhea in both humans and animals worldwide. Although G. intestinalis has been detected in many animals, information regarding its prevalence and genotype in Chinese racehorses is scarce. In the present study, we investigated the prevalence of G. intestinalis in racehorses and performed molecular characterization of the pathogen to assess its zoonotic potential. Two hundred and sixty-four racehorse fecal samples from six equestrian clubs located in different regions of the Sichuan province of southwestern China were examined. Nested polymerase chain reaction (PCR) analysis of the gene encoding triose-phosphate isomerase (tpi) showed the prevalence of G. intestinalis to be 8.3% (22/264), and the prevalence in different clubs varied from 3.6% to 13.5%. Three assemblages were identified in the successfully sequenced samples, including the potentially zoonotic assemblages A (n = 5) and B (n = 14), the mouse-specific assemblage G (n = 3), and a mixed A and B assemblage. Sequence analysis of tpi, glutamate dehydrogenase (gdh), and beta giardin (bg) loci revealed that the majority of sequences isolated from assemblage A were identical to the subtype AIV and assemblage B isolates showed variability among the nucleotide sequences of the subtype BIV. Using the nomenclature for the multilocus genotype (MLG) model, one each of multilocus genotypes A (MLG1) and B (MLG2) were identified, with MLG2 being a novel genotype. To the best of our knowledge, this is the first study to investigate G. intestinalis in Chinese racehorses. The presence of both animal and human assemblages of G. intestinalis in racehorses indicated that these animals might constitute a potential zoonotic risk to human beings.

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.