Molecular characterization of Blastocystis sp. in Chinese bamboo rats (Rhizomys sinensis)

High prevalence of Blastocystis sp. in farmed sika deer (Cervus nippon) in Northern China

Introduction

Blastocystis sp. is a widespread intestinal protist, that threatens the health of humans and animals. However, epidemiological data on Blastocystis sp. in sika deer are still scarce in China and globally. This study aimed to reveal the infection rate, and subtype distribution of Blastocystis sp. in farmed sika deer across China.

Methods

A total of 466 fresh fecal samples were collected from farmed sika deer in northern China. A 600 bp fragment of the SSU rRNA was amplified to detect the presence of Blastocystis sp. in samples.

Results

The results revealed an overall infection rate of Blastocystis sp. at 65.02% (303/466). The highest infection rate was found in Shandong (98%, 49/50), followed by Heilongjiang (95.51%, 85/89), while the lowest infection rate was found in Jilin (36.31%, 61/168). Additionally, within the seasonal group, the infection rate was significantly higher in autumn (69.04%) than in summer (43.06%). In the age group, although the infection rate in young animals (68.38%) was higher than in adults (63.90%), no statistical difference was observed. Ten subtypes were identified from 303 Blastocystis sp.-positive samples, including ST1, ST5, ST10, ST14, ST21, ST23, ST24, ST26, ST30 and ST42. Among these, ST10 was the dominant subtype with an infection rate of 43.23% (131/303), and ST1 and ST5 were zoonotic subtypes. Notably, this study is the first to report the presence of ST42 in sika deer.

Discussion

These findings suggest that sika deer may be a potential source of human Blastocystis sp. infection. In addition, this study reveals the high infection rate of Blastocystis sp. in farmed sika deer and reports for the first time the presence of ST42 subtype, providing valuable data for the epidemiological study of Blastocystis sp. in sika deer.

Global Prevalence and Subtype Distribution of Blastocystis sp. in Rodent Populations: A Systematic Review and Meta-Analysis

BACKGROUND

The present systematic review and meta-analysis aimed to gather and analyse global data on the prevalence, subtypes (STs) distribution and zoonotic potential of Blastocystis sp. in rodents.

METHODS

A systematic literature search was performed across multiple databases (PubMed, Scopus, Web of Science and ProQuest) for studies published by 23 July 2024. The analysis included 34 studies/78 datasets, comprising 5661 samples from various rodent species across 15 countries. Statistical analyses were performed using comprehensive meta-analysis (CMA) software, employing a random-effects model to estimate pooled prevalence and 95% confidence intervals (CIs) and the I2 index for assessing heterogeneity.

RESULTS

This review found that 16% (95% CI: 12.6%-20.2%) of rodents worldwide were infected with Blastocystis sp. Voles and squirrels exhibited the highest infection rates at 29.8% (95% CI: 14.7%-51%) and 28.8% (95% CI: 14.4%-49.2%), whereas civets and porcupines had the lowest rates at 9.5% (95% CI: 6.6%-13.6%) and 7.1% (95% CI: 3.3%-14.7%), respectively. The findings indicated that rodents can host various Blastocystis sp. STs (ST1-ST8, ST10, ST13, ST15, ST17), with several (ST1-ST8 and ST10) having zoonotic potential. Globally, ST4, ST5, ST1 and ST3 were the most commonly reported STs in rodents. China and the UK showed the highest ST diversity in rodents, with 10 (ST1-ST7, ST10, ST13, ST17) and 7 (ST1-ST5, ST10, ST15) distinct STs, respectively. ST6, ST7 and ST13 were unique to China, whereas ST15 was found only in the United Kingdom. Squirrels, rats, mice and voles had the highest ST diversity of Blastocystis sp., with 8, 7, 5 and 5 distinct STs, respectively. Notably, ST6 and ST13 were unique to squirrels, ST7 only appeared in rats, and ST15 was found only in voles. Most ST1, ST3-ST5 and ST17 came from Asia. ST6, ST7 and ST13 were also isolated there, whereas ST15 was only found in Europe. ST17 was reported in Africa, ST4 and ST17 in North America, and ST1-ST3 and ST8 in South America.

CONCLUSIONS

This review emphasizes the widespread presence of Blastocystis sp. in rodent populations globally, underscoring the need for continued surveillance and research into its zoonotic potential.

Prevalence and subtypes of Blastocystis in wild rodents from three provinces in China

Introduction

Blastocystis is one of the most critical intestinal protozoans in various hosts, including humans and mice. To determine the status of Blastocystis infection in wild rodents in China.

Methods

A total of 344 faecal samples were collected from seven wild rodent species from three provinces, and the small subunit ribosomal RNA (SSU rRNA) genes of Blastocystis were amplified to determine their prevalence and subtypes.

Results

Of the 344 samples, 54 (15.70%) were detected as Blastocystis-positive. The prevalence of Blastocystis was 26.14% (40/153), 7.95% (7/88), and 6.80% (7/103) in wild rodents from Hunan Province, Yunnan Province, and Guangxi Province, respectively. The prevalence of Blastocystis in different wild rodent species varied from 0.00% (0/13) in Mus musculus to 40.00% (2/5) in Rattus rattus sladeni. The prevalence of Blastocystis in samples from the lake beach area (27.40%, 40/146) was significantly higher than in those from the mountain (6.80%, 7/103) and field regions (7.37%, 7/95). The prevalence in different seasons was 26.14% in summer (40/153), 7.95% in autumn (7/88), and 6.80% in winter (7/103). Moreover, a total of two Blastocystis subtypes were identified in the investigated wild rodents, including ST4 and ST5.

Discussion

The present study discovered the existence of Blastocystis infection in Rattus favipectus, Microtus fortis, Apodemus agrarius, Bandicota indica, Rattus rattus sladeni, and Rattus losea, expanding the host range of this parasite. The findings also demonstrate that wild rodents may be an important potential infection source for Blastocystis infection in humans and other animals.

Molecular prevalence, subtype distribution, and zoonotic potential of Blastocystis sp. in wild rodents and shrews inhabiting Zhejiang province of China

Introduction

Globally, rodents and shrew populations constitute crucial elements of diverse environments and animal communities. It is imperative to study their population dynamics to mitigate any potential negative impact on humans, as they can be involved in the transmission of critical zoonotic agents, such as Blastocystis. Therefore, this study aimed to identify the prevalence and genetic composition of Blastocystis in wild rodents and shrews residing in the Zhejiang provinces of China.

Methods

A total of 652 wild rodents and and shrews were captured from three different regions in Zhejiang Province from April 1st to October 31, 2023. The DNA was isolated by collecting fresh feces from the intestines of each rodent or and shrew. Rodent and shrew species were examined by vertebrate cytochrome b (cytb) analysis and PCR amplification. Blastocystis was also found in all fecal samples using PCR analysis and sequencing of the partial small subunit of ribosomal RNA (SSU rRNA) gene.

Results

Among all the samples, 6.6% (43/652) showed a positive result for Blastocystis. In the results, 6 species of rodent and shrew were identified with Blastocystis, including Apodemus agrarius (n = 36) (2.8%), Niviventer confucianus (n = 75) (17.3%), Rattus losea (n = 18) (5.6%), R. norvegicus (n = 155) (2.6%), R. tanezumi (n = 86) (3.5%), and Suncus murinus (n = 282) (7.4%). The existence of 6 Blastocystis subtypes, ST4 (n = 33), ST1 (4), ST7 (n = 3), ST2 (n = 1), ST3 (n = 1), and ST5 (n = 1), were confirmed by sequence analysis.

Discussion

Based on the molecular data obtained, the wild rodents and shrews under investigation were found to be concurrently infected with zoonotic subtypes of Blastocystis, including ST1 to ST5 and ST7. This suggests that these animals could potentially pose a zoonotic threat to humans and other animals susceptible to Blastocystis infection.

Predominance of the Blastocystis subtype ST5 among free-living sympatric rodents within pig farms in China suggests a novel transmission route from farms

Blastocystis is a parasitic protist that can infect humans and various domestic and wild animals. However, there is limited research on the prevalence of this parasite among rodents, particularly those living in pig farm settings. Therefore, to investigate the occurrence, molecular characterization, and zoonotic potential of Blastocystis among rodents within pig farm environments, we conducted an investigation of 227 rodents and shrews from 34 pig farms located in Henan, Shaanxi, and Shanxi provinces of China using nested PCR of the SSU rRNA gene of Blastocystis. The potential transmission and public health implications were also assessed from a One Health perspective. Blastocystis was detected in 86 (37.9%) fecal samples. The highest infection rate was observed among Ruttus norvegicus (73.7%, 42/58), followed by Ruttus tanezumi (30.1%, 41/136), and Mus musculus (12.0%, 3/25). However, it was not detected among individuals with Apodemus agrarius (n = 1) and Crocidura shantungensis (n = 7). Five known zoonotic Blastocystis subtypes (ST1-ST5) were identified, with ST4 (51.2%, 44/86) and ST5 (40.7%, 35/86) being the predominant ones, followed by ST1 (3.5%, 3/86), ST3 (3.5%, 3/86), and ST2 (1.2%, 1/86). ST4 was prevalent among R. norvegicus (83.3%, 35/42), while ST5 dominated R. tanezumi (70.7%, 29/41). Furthermore, ST5 exhibited the widest distribution at pig farm level, accounting for 65.0% (13/20) of Blastocystis-positive pig farms. This investigation presents the first documented Blastocystis infection in R. tanezumi and M. musculus, highlighting the predominant presence of the zoonotic ST5 subtype in rodents for the first time. The results demonstrate that sympatric rodents can serve as natural reservoirs for Blastocystis and play a role in its transmission. These findings provide information on the dynamics of rodent transmission and emphasize the potential public health threat posed by zoonotic Blastocystis subtypes spillover from pig farms.

Prevalence and distribution of subtypes of Blastocystis in Asiatic brush-tailed porcupines (Atherurus macrourus), bamboo rats (Rhizomys pruinosus), and masked palm civets (Paguma larvata) farmed in Hainan, China

Blastocystis sp. is an important gastrointestinal parasite with global distribution, prevalent in humans, farmed animals, and wildlife. Therefore, this study aimed to investigate the prevalence and genetic diversity of Blastocystis sp. in Asiatic brush-tailed porcupines (Atherurus macrourus), bamboo rats (Rhizomys pruinosus), and masked palm civets (Paguma larvata) in Hainan Province, China. A total of 900 fecal samples were collected from three farmed animal species including 257 porcupines, 360 rats, and 283 civets. Genomic DNA was extracted from each fecal sample and Blastocystis sp. was detected by PCR at the small subunit ribosomal RNA (SSU rRNA) gene. A phylogenetic tree was constructed using the maximum likelihood method. Blastocystis sp. was detected in 47 (5.2%) fecal samples: 12 (4.7%) Asiatic brush-tailed porcupines, 8 (2.2%) bamboo rats, and 27 (9.5%) masked palm civets. Three known Blastocystis sp. subtypes, including ST1, ST4, ST5, and one unnamed subtype (unST), were found in one, 19, 26, and one animal, respectively. Subtypes ST4 and unST were detected in porcupines, ST4 in rats, and ST1 and ST5 in civets. Our results suggest that the three farmed animal species reported in this study could serve as reservoirs for potentially zoonotic Blastocystis sp. subtypes and transmit this parasite to humans, other farmed animals, and wildlife.

Molecular Identification and Genotyping of Cryptosporidium spp. and Blastocystis sp. in Cattle in Representative Areas of Shanxi Province, North China

Both Cryptosporidium spp. and Blastocystis sp. are common intestinal protozoa, which can cause zoonotic diseases and economic losses to livestock industry. To evaluate the prevalence and genetic population structure of Cryptosporidium spp. and Blastocystis sp. in beef and dairy cattle in Shanxi Province, north China, a total of 795 fecal samples were collected from beef and dairy cattle in three representative counties in Shanxi Province, and these fecal samples were examined using molecular approaches based on 18S small-subunit ribosomal RNA (SSU rRNA) of Cryptosporidium spp. and Blastocystis sp., respectively. Among 795 cattle fecal samples, 23 were detected as Cryptosporidium-positive and 103 were detected as Blastocystis-positive, and the overall prevalence of Cryptosporidium spp. and Blastocystis sp. in cattle in Shanxi Province was 2.9% and 13.0%, respectively. For Cryptosporidium spp., DNA sequence analysis indicated that all 23 positive samples were identified as C. andersoni. Furthermore, five known subtypes (ST1, ST10, ST14, ST21 and ST26) and three unknown subtypes of Blastocystis sp. were detected among 103 positive samples using DNA sequence analysis. This study reported the occurrence and prevalence of Cryptosporidium spp. and Blastocystis sp. in cattle in Shanxi Province for the first time, which extends the geographical distribution of these two zoonotic parasites and provides baseline data for the prevention and control of these two important zoonotic parasites in cattle in Shanxi Province.

Prevalence, potential risk factors and genetic diversity of Blastocystis in ruminant livestock animals from Penang, Malaysia

Blastocystis is a unicellular, anaerobic protist inhabiting the intestinal tract of diverse animal hosts, including human. Information regarding Blastocystis in small ruminants, namely goats and sheep, is limited globally; thus, this study was carried out to investigate the distribution and determinants of Blastocystis in ruminant livestock animals from Penang, Malaysia. Fecal samples from 127 cattle, 149 goats, and 100 sheep were examined for Blastocystis by in vitro cultivation using modified Jones' medium, while DNA barcoding was used for subtyping. Overall, 23.1% (87/376) of animals screened were positive for Blastocystis sp. The prevalence of infection was significantly higher in goats than in cattle and sheep, while the female gender, semi-intensive farming system, and the Northeast Penang Island district were identified as potential risk factors for Blastocystis infection. Blastocystis sp. ST5, ST14, and ST25 were identified in cattle; ST5, ST10, ST13, and ST14 in goats; and ST4, ST5, ST14, and ST15 in sheep. ST5 and ST14 were found to be the most abundant and widespread subtypes in the study area. To the best of our knowledge, this is the first report of ST4 from sheep and ST13 from goats, thus serving as an update to the host range of Blastocystis sp. ST4 and ST13. The isolation of ST4 and ST5 in this study suggests that ruminant livestock animals could serve as reservoirs of human infection.

Occurrence and Genotypic Identification of Blastocystis spp., Enterocytozoon bieneusi, and Giardia duodenalis in Leizhou Black Goats in Zhanjiang City, Guangdong Province, China

Blastocystis spp., Enterocytozoon bieneusi, and Giardia duodenalis are three common zoonotic intestinal parasites that cause severe diarrhea and enteric diseases. Leizhou black goats are characterized by a high reproductive rate, fast growth, and good meat quality, making them one of the pre-eminent goat breeds in China. Goats are reportedly common reservoirs of these three intestinal pathogens, but no information on their prevalence or genotypic distributions in black goats in Guangdong Province, China, is available. A total of 226 fecal samples were collected from goats in Zhanjiang city and genomic DNA was extracted from them. The presence of the three pathogens was detected using nested PCR targeting the sequences encoding SSU rRNA (Blastocystis spp.), the internal transcribed spacer of rRNA (ITS; E. bieneusi), as well as beta-giardin, glutamate dehydrogenase, and triosephosphate isomerase (G. duodenalis). All PCR products were sequenced to determine the species and genotypes of the organisms. The total prevalence rates of Blastocystis spp., E. bieneusi, and G. duodenalis were 33.63% (76/226), 17.70% (40/226), and 24.78% (56/226), respectively. Four subtypes of Blastocystis spp. were detected: ST5 (n = 6), ST10 (n = 50), ST14 (n = 14), and ST21 (n = 6). Among them, ST10 was the dominant genotype, accounting for 65.79% of strains, followed by the genotypes ST14 (18.42%), zoonotic ST5 (7.89%), and ST21 (7.89%). Four genotypes of E. bieneusi were detected: CHG3 (n = 32), CM21 (n = 4), CHG1 (n = 2), and ET-L2 (n = 2). Among these, CHG3 was the dominant genotype. Assemblage E (n = 54) and concurrent assemblages A and E (n = 2) were identified in the G. duodenalis-positive goats using multilocus genotyping. Blastocystis spp., E. bieneusi, and G. duodenalis infections were common in Leizhou black goats, all of which have zoonotic genotypes, indicating the potential risk of zoonotic transmission. Our results provide basic data for the prevention and control of these three intestinal pathogens. Further studies are required to better understand their genetic characteristics and zoonotic potential in Guangdong Province.