Feeding sites promoting wildlife-related tourism might highly expose the endangered Yunnan snub-nosed monkey (Rhinopithecus bieti) to parasite transmission

Epidemiological investigation of Entamoeba in wild rhesus macaques in China: A novel ribosomal lineage and genetic differentiation of Entamoeba nuttalli

Wild rhesus macaques are a potential source of zoonotic parasites for humans, and Entamoeba spp. are common intestinal parasites. To investigate the prevalence of Entamoeba in wild rhesus macaques in China and explore the genetic differentiation of the potentially pathogenic species Entamoeba nuttalli, a total of 276 fecal samples from five populations at high altitudes (HAG, 2,800-4,100 m above sea level) and four populations at low altitudes (LAG, 5-1,000 m above sea level) were collected. PCR methods based on the ssrRNA gene were used to detect Entamoeba infection. Genotyping of E. nuttalli was performed based on six tRNA-linked short tandem repeat (STR) loci for further genetic analyses. The results revealed that Entamoeba infection (69.2%) was common in wild rhesus macaques in China, especially in LAG which had a significantly higher prevalence rate than that in HAG (P < 0.001). Three zoonotic species were identified: Entamoeba chattoni (60.9%) was the most prevalent species and distributed in all the populations, followed by Entamoeba coli (33.3%) and Entamoeba nuttalli (17.4%). In addition, a novel Entamoeba ribosomal lineage named RL13 (22.8%) was identified, and phylogenetic analysis revealed a close genetic relationship between RL13 and Entamoeba. hartmanni. Genotyping of E. nuttalli obtained 24 genotypes from five populations and further analysis showed E. nuttalli had a high degree of genetic differentiation (FST > 0.25, Nm < 1) between the host populations. The result of analysis of molecular variance (AMOVA) revealed that observed genetic differences mainly originate from differences among populations (FST = 0.91). Meanwhile, the phylogenetic tree showed that these genotypes of E. nuttalli were clustered according to geographical populations, indicating a significant phylogeographic distribution pattern. Considering the potential pathogenicity of E. nuttalli, attention should be paid to its risk of zoonotic transmission.

Molecular characterization of Blastocystis and Entamoeba of muskoxen and sheep in Greenland

Molecular characterisation of endobionts that are shared among human and non-human hosts can help shed light on the epidemiology and inform studies that aim to unravel the role of these organisms in health and disease. Two of the most common of shared endobionts include the single-celled intestinal protists Blastocystis and Entamoeba. Here, we present the first known data on genetic diversity and host specificity of these two genera in Greenland. Faecal DNA samples from 243 muskoxen and 44 sheep were submitted to metabarcoding of nuclear small subunit ribosomal DNA. Entamoeba- and Blastocystis-specific sequences were clustered, and consensus sequences were subjected to taxonomic query. Using MinION-based sequencing, near-complete nuclear small subunit ribosomal DNA sequences were obtained from four faecal samples. Of the 243 muskox samples, 180 (74%) and 19 (8%) were positive for Blastocystis and Entamoeba, respectively. Forty (91%) and six (14%) of the 44 sheep samples were positive for Blastocystis and Entamoeba, respectively. Blastocystis subtypes (ST) 10, 14, 21, 24-26, and a novel subtype (ST40) were identified. Colonisation by more than one subtype was common. ST40 was common in muskoxen but limited to Northeast Greenland. Entamoeba bovis and the E. bovis-associated ribosomal lineages (RL) 1 and 8 were found, and three conditional lineages (CL) 3, 4, and 10 were confirmed; CL10 was promoted to RL12. Several novel lineages were identified, all of which were linked to the E. bovis complex. In conclusion, Blastocystis was far more common than Entamoeba and found in approximately three of every four animals; both can be considered common colonisers of large herbivorous mammals in Greenland. Multiple subtypes/lineages of both genera were commonly observed, some of which were novel, but most of which are seen in many other parts of the world.

Extensive prevalence and significant genetic differentiation of Blastocystis in high- and low-altitude populations of wild rhesus macaques in China

BACKGROUND

Blastocystis is a common intestinal protist with a wide range of hosts. Thus far, 38 subtypes have been identified. In recent years, wild animals have been confronted with habitat fragmentation as well as an increasing risk of zoonotic disease transmission due to human disturbance. Only limited data are available on Blastocystis infection and subtype distribution in wild rhesus macaques in China. The aim of the present study was to investigate the prevalence and genetic diversity of Blastocystis in nine wild rhesus macaque populations in China.

METHODS

A total of 276 faecal samples were collected from five high-altitude populations (high-altitude group [HAG]; 2800-4100 m a.s.l.) and four low-altitude populations (low-altitude group [LAG]; 5-1000 m a.s.l) of rhesus macaques. PCR-based analysis, using a new primer pair for the amplification of a 1690-bp sequence of the small subunit ribosomal RNA (SSU rRNA) gene, was used for prevalence and genetic diversity analysis.

RESULT

Analysis of faecal samples revealed that Blastocystis infection was common in rhesus macaques, with an infection positivity rate of 80.1% (n = 221/276 samples). There was no significant difference (P = 0.121) in positivity rate between the LAG (84.3%) and HAG (76.8%). Overall, 33 haplotypes were obtained and classified into four subtypes (STs), of which three were potentially zoonotic subtypes (ST1, 29.7%; ST2, 16.7%; ST3, 31.9%) and one that was first identified in this study and named ST39 (12.0%). The STs were distributed differently among the rhesus macaque populations, except for ST3, which was found in all populations. Phylogenetic analyses revealed two major divergent clades of ST3 for the HAG and LAG. Genetic diversity analysis showed a high genetic diversity of ST3 (haplotype diversity: 0.846; nucleotide diversity: 0.014) in the rhesus macaques, but a high genetic differentiation (F_ST > 0.25) and a low gene flow (Nm = 0.09) between the HAG and LAG.

CONCLUSION

Our study, which is the first investigation on Blastocystis infection in multiple wild rhesus macaque populations in China, indicates a potential risk of zoonotic transmission of Blastocystis in the study areas. Blastocystis ST3 showed high genetic diversity in wild rhesus macaques and significant genetic differentiation between the HAG and LAG. Our results provide fundamental information on the genetic diversity and prevalence of Blastocystis in wild rhesus macaque populations.

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