Prevalence, molecular epidemiology, and zoonotic potential of Entamoeba spp. in nonhuman primates in China

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.

Occurrence of gastrointestinal parasites in dogs in a rural area of Santa Catarina, Brazil

We investigated the occurrence of gastrointestinal parasites in dogs in rural areas of the municipality of Painel, Santa Catarina, Brazil. For this, 91 canine feces samples were collected from 82 farms between August, 2017 and January, 2018. These fecal materials were processed using the techniques of spontaneous sedimentation, centrifugation-floatation in zinc sulfate and Ziehl-Neelsen staining. A questionnaire in the form of an interview was administered to the dogs' owner and information about the farm and the main care provided for the dogs was obtained. Among 91 sampled dogs, 27 (29.7%) were positive for at least one parasite species. Ancylostoma was the most prevalent genus (16.5%), followed by Giardia duodenalis (14.3%), Trichuris vulpis (6.6%), Toxocara canis (5.5%), Entamoeba spp. (4.8%), Cryptosporidium spp. (3.3%) and Taeniidae (1.1%). Most dogs do not receive veterinarian care and rarely received antiparasitic treatment. They were free to roam and had free access to animal remains and garbage, which was reflected in the significant associations with the occurrence of parasites that were found. We conclude that rural dogs harbor gastrointestinal parasites, but that their owners are unaware of the risks that these parasites can bring to human health.

Prevalence and molecular characterization of Entamoeba moshkovskii in diarrheal patients from Eastern India

BACKGROUND

Importance of the amphizoic amoeba Entamoeba moshkovskii is increasing in the study of amoebiasis as a common human pathogen in some settings. Limited studies are found on the genetic and phylogenetic characterization of E. moshkovskii from India; hence remain largely unknown. In this study, we determined the prevalence and characterized the E. moshkovskii isolates in eastern India.

METHODS

A three-year systemic surveillance study among a total of 6051 diarrhoeal patients from ID Hospital and BC Roy Hospital, Kolkata was conducted for E. moshkovskii detection via a nested PCR system targeting 18S rRNA locus. The outer primer set detected the genus Entamoeba and the inner primer pair identified the E. moshkovskii species. The 18S rRNA locus of the positive samples was sequenced. Genetic and phylogenetic structures were determined using DnaSP.v5 and MEGA-X. GraphPad Prism (v.8.4.2), CA, USA was used to analyze the statistical data.

RESULT

4.84% (95%CI = 0.0433-0.0541) samples were positive for Entamoeba spp and 3.12% (95%CI = 0.027-0.036) were infected with E. moshkovskii. E. moshkovskii infection was significantly associated with age groups (X2 = 26.01, P<0.0001) but not with gender (Fisher's exact test = 0.2548, P<0.05). A unique seasonal pattern was found for E. moshkovskii infection. Additionally, 46.56% (95%CI = 0.396-0.537) were sole E. moshkovskii infections and significantly associated with diarrheal incidence (X2 = 335.5,df = 9; P<0.0001). Sequencing revealed that the local E. moshkovskii strains were 99.59%-100% identical to the prototype (GenBank: KP722605.1). The study found certain SNPs that showed a correlation with clinical features, but it is not necessarily indicative of direct control over pathogenicity. However, SNPs in the 18S rRNA gene could impact the biology of the amoeba and serve as a useful phylogenetic marker for identifying pathogenic E. moshkovskii isolates. Neutrality tests of different coinfected subgroups indicated deviations from neutrality and implied population expansion after a bottleneck event or a selective sweep and/or purifying selection in co-infected subgroups. The majority of FST values of different coinfected subgroups were <0.25, indicating low to moderate genetic differentiation within the subgroups of this geographical area.

CONCLUSION

The findings reveal the epidemiological significance of E. moshkovskii infection in Eastern India as the first report in this geographical area and expose this species as a possible emerging enteric pathogen in India. Our findings provide useful knowledge for further research and the development of future control strategies against E. moshkovskii.

Prevalence Estimation, Antimicrobial Susceptibility, and Serotyping of Salmonella enterica Recovered from New World Non-Human Primates (Platyrrhini), Feed, and Environmental Surfaces from Wildlife Centers in Costa Rica

Concern about zoonoses and wildlife has increased. Few studies described the role of wild mammals and environments in the epidemiology of Salmonella. Antimicrobial resistance is a growing problem associated with Salmonella that threatens global health, food security, the economy, and development in the 21st century. The aim of this study is to estimate the prevalence and identify antibiotic susceptibility profiles and serotypes of non-typhoidal Salmonella enterica recovered from non-human primate feces, feed offered, and surfaces in wildlife centers in Costa Rica. A total of 180 fecal samples, 133 environmental, and 43 feed samples from 10 wildlife centers were evaluated. We recovered Salmonella from 13.9% of feces samples, 11.3% of environmental, and 2.3% of feed samples. Non-susceptibility profiles included six isolates from feces (14.6%): four non-susceptible isolates (9.8%) to ciprofloxacin, one (2.4%) to nitrofurantoin, and one to both ciprofloxacin and nitrofurantoin (2.4%). Regarding the environmental samples, one profile was non-susceptible to ciprofloxacin (2.4%) and two to nitrofurantoin (4.8%). The serotypes identified included Typhimurium/I4,[5],12:i:-, S. Braenderup/Ohio, S. Newport, S. Anatum/Saintpaul, and S. Westhampton. The epidemiological surveillance of Salmonella and antimicrobial resistance can serve in the creation of strategies for the prevention of the disease and its dissemination throughout the One Health approach.

Prevalence and Molecular Identification of Entamoeba spp. in Non-human Primates in a Zoological Garden in Nanjing, China

Objective

Entamoeba spp. are globally distributed zoonotic parasites that infect various hosts, among which non-human primates (NHPs) have been identified as one of the most common hosts of these parasites. Consequently, the infections of Entamoeba spp. in captive NHPs from Nanjing Hongshan Forest Zoo in China were investigated in order to assess their zoonotic potential.

Methods

A total of 120 fresh fecal samples, including 19 species of NHPs, were collected from four breeding bases of the zoo from May to June 2019. The infections of six species of Entamoeba spp. were detected by PCR using the 16S or 18S rDNA-specific primers, and the positive samples were sequenced and analyzed.

Results

Entamoeba spp. were detected as positive in 59 NHPs fecal samples (49.17%), including five Entamoeba species: Entamoeba histolytica (7.50%), E. dispar (22.50%), E. coli (22.50%), E. chattoni (10.00%) and E. nuttalli (1.67%). Infection with one Entamoeba species was more common (35%) than co-infections (13.33%) or infections with three Entamoeba species (0.83%). There was a significantly higher prevalence rate of Entamoeba spp. in the species Pongo pygmaeus and Macaca mulatta than in Papio sp., Mandrillus sphinx, and Saimiri sciureus.

Conclusion

Entamoeba spp. are highly prevalent in the NHPs raised in Nanjing Hongshan Forest Zoo. Therefore, attention should be paid to the development of containment strategies of Entamoeba spp. in this zoological garden.

Environmental and biological drivers of prevalence and number of eggs and oocysts of intestinal parasites in red howler monkeys from Central Amazonia

Host-parasite relationships can be directly affected by host’s biological aspects and environmental factors, which influence both the survival of infective forms and the incidence of parasites. However, logistical difficulties in accessing biological samples for parasitological studies makes the Amazon Forest into a poorly known region in relation to the dynamic of parasites of wild animals. Here, using 34 red howler monkeys’ biological samples donated by local subsistence hunters from two Amazon habitat types (white-water flooded forest and upland forest) as an opportune alternative, we detected four intestinal parasite taxa infecting this species (two nematodes – Trypanoxyuris sp. and Strongyloides sp., one protozoan – Entamoeba sp. –, and one not-identified trematode, the last just found for white-water flooded forest). Trypanoxyuris was the most prevalent intestinal parasite (56.5% at flooded forest and 54.5% at upland forest). There was no difference between habitat types or individual sex regarding the prevalence for any parasite taxa. On the other hand, we found a strong influence of seasonality, with increasing prevalence of all parasite taxa as the river water level increased. In terms of egg and cyst counts, we found a difference between sexes (females > males, p = 0.002) and habitat types (upland forest > white-water flooded forest, p = 0.02), and a positive relationship with river water level (p = 0.002). Although some of these parasite taxa can be shared between humans and howlers, further investigations are necessary to study the parasites taxonomy thoroughly and to assess the potential zoonotic cross-transmission of these pathogens to local people living in the Amazon. In this study, we unveiled a seasonal effect for howler monkeys’ intestinal parasites, that also might occur in other non-human primates of the Amazon. In addition, our results on periods of high risk of intestinal parasite infection are useful to estimate future impacts of climate change on host-parasite dynamics.

Identification of Mamu-DRB1 gene as a susceptibility factor for Entamoeba nuttalli infection in Chinese Macaca mulatta

Entamoeba nuttalli infection is highly prevalent in captive and wild macaques. A recent study suggested that the genetic factor of host macaques was correlated with the genotypes of E. nuttalli isolates. This study focused on the correlation between the rhesus macaque host major histocompatibility complex gene and E. nuttalli infection. Thirty-nine stool samples were obtained from Mount Qing-ling (Guizhou Province, China). Polymerase chain reaction analysis detected the infection rate of E. nuttalli, Entamoeba coli, and Entamoeba chattoni as 69.23%, 69.23%, and 87.18%, respectively. A new Serine-rich Protein genotype was detected, and the rRNA of E. nuttalli isolates from Mount Qian-ling was completely identical to the GY4 strain. In the distance-based neighbor-joining tree, Mamu-DRB1, not Mamu-DPB or Mamu-B gene, was related to E. nuttalli infection. Mamu-DRB1 genes of rhesus macaques in Mounts Qian-ling and Long-hu were highly polymorphic, and the rhesus macaques with two major types of Mamu-DRB1 showed susceptibility to E. nuttalli infection. The Mamu-DRB1 gene analysis in this study indicated that the Mamu-DRB1 gene is an important factor that influences the susceptibility of E. nuttalli infection in Chinese Macaca mulatta. This study contributes to a better understanding of host susceptibility to Entamoeba.

Review of zoonotic amebiasis: Epidemiology, clinical signs, diagnosis, treatment, prevention and control

Amebiasis is a disease caused by the protozoan parasite Entamoeba histolytica, which mainly shows symptoms of acute diarrhea, dysentery, amebic colitis, and amebic liver abscesses. As the fourth leading parasitic cause of human mortality, E. histolytica mainly infect children in developing countries, transmitted by food and water contamination. In the majority of infected individuals, Entamoeba sp. asymptomatically colonizes the large intestine and self-limiting, while in others, the parasite breaches the mucosal epithelial barrier to cause amebic colitis and can disseminate to soft organs to cause abscesses. Metronidazole (MTZ) is the recommended and most widely used drug for treating the invasive amebiasis. No amebiasis vaccine has been approved for human clinical trials to date, but many recent vaccine development studies hold promise. For the prevention and control of amebiasis, improvement of water purification systems and hygiene practices could decrease disease incidence. In this review, we focus on the epidemiology, transmission, clinical signs, pathogenesis, diagnosis, treatment, prevention and control of the zoonotic amebiasis.

Prevalence, molecular epidemiology and zoonotic risk of Entamoeba spp. from experimental macaques in Yunnan Province, southwestern China

Amebiasis is a worldwide parasitic zoonosis, with symptoms of abdominal discomfort, indigestion, diarrhea, and even death. However, limited information about the prevalence of Entamoeba spp. in experimental nonhuman primates (NHPs) in southwestern China is available. The objective of the current study was to investigate the frequency and species identity of Entamoeba to evaluate potential zoonotic risk factors for Entamoeba spp. infection in experimental NHPs. A total of 505 fecal samples were collected from NHPs (macaques) and analyzed by PCR analysis the small subunit rRNA (SSU rRNA) gene of Entamoeba spp. Forty-seven specimens were positive for Entamoeba spp., and the prevalence of Entamoeba spp. was 9.31% (47/505). Significant differences in the prevalence rates among the three breeds (P = 0.002 < 0.01, df = 2, χ² = 12.33) and feed types (P = 0.001 < 0.01, df = 1, χ² = 10.12) were observed. Altogether, four Entamoeba species, including E. dispar (57.44%), E. chattoni (29.78%), E. histolytica (6.38%), and E. coli (6.38%), were identified by DNA sequence analysis. The results suggested a low prevalence but high diversity of Entamoeba species in experimental NHPs in Yunnan Province, southwestern China. Results of this study contribute to the knowledge of the genetic characteristics of Entamoeba spp. in NHPs.

Prevalence and Genetic Identification of Three Entamoeba Species in Pigs in Southeastern China

Parasitic Entamoeba spp. can infect many classes of vertebrates including humans and pigs. Entamoeba suis and zoonotic Entamoeba polecki have been identified in pigs, and swine are implicated as potential reservoirs for Entamoeba histolytica. However, the prevalence of Entamoeba spp. in pigs in southeastern China has not been reported. In this study, 668 fecal samples collected from 6 different regions in Fujian Province, southeastern China, were analyzed to identify three Entamoeba species by nested PCR and sequencing analysis. The overall prevalence of Entamoeba spp. was 55.4% (370/668; 95% CI 51.6% to 59.2%), and the infection rate of E. polecki ST1 was the highest (302/668; 45.2%, 95% CI 41.4% to 49.0%), followed by E. polecki ST3 (228/668; 34.1%, 95% CI 30.5% to 37.7%) and E. suis (87/668; 13.0%, 95% CI 10.5% to 15.6%). E. histolytica was not detected in any samples. Moreover, the coinfection rate of E. polecki ST1 and ST3 was 25.1% (168/668; 95% CI 21.9% to 28.4%), the coinfection rate of E. polecki ST1 and E. suis was 3.7% (25/668; 95% CI 2.3% to 5.2%), the coinfection rate of E. polecki ST3 and E. suis was 0.3% (2/668), and the coinfection rate of E. polecki ST1, E. polecki ST3, and E. suis was 4.0% (27/668; 95% CI 2.5% to 5.5%). A representative sequence (MK347346) was identical to the sequence of E. suis (DQ286372). Two subtype-specific sequences (MK357717 and MK347347) were almost identical to the sequences of E. polecki ST1 (FR686383) and ST3 (AJ566411), respectively. This is the first study to survey the occurrence and to conduct molecular identification of three Entamoeba species in southeastern China. This is the first report regarding mixed infections with E. suis, E. polecki ST1, and E. polecki ST3 in China. More research studies are needed to better understand the transmission and zoonotic potential of Entamoeba spp.

Molecular epidemiology, evolution, and phylogeny of Entamoeba spp

Entamoeba histolytica is a protozoan parasite and the causative agent of amoebiasis in humans. The estimations of the worldwide burden of amoebiasis by the WHO indicated that approximately 500 million people were infected with the parasite and 10% of these individuals had invasive amoebiasis. However, our understanding of the disease burden and epidemiology of human amebiasis has undergone dramatic changes over the last two decades based on molecular analyses. The development of Entamoeba genomics has also provided some interesting and valuable information on the evolution and population structure of this parasite. In addition, the use of a number of molecular markers has greatly expanded our understanding of Entamoeba host range and genetic diversity. In this review, we re-assessed Entamoeba prevalence and species in humans, non-human primates, other animals, and the environment in the context of molecular data. Some issues regarding the evolution and phylogeny of different Entamoeba species lineages are also discussed.

Molecular Characterization of Entamoeba spp. in Wild Taihangshan Macaques (Macaca mulatta tcheliensis) in China

BACKGROUND

Entamoeba spp. is one of the most common enteric parasites of humans and animals.

PURPOSE

However, little information is available regarding prevalence and genotypes of Entamoeba spp. in wild Taihangshan macaques (Macaca mulatta tcheliensis).

METHODS

In the present study, a total of 458 fecal samples from wild rhesus macaque in Taihangshan mountains area between September 2015 and November 2016, were collected and examined for the presence of six Entamoeba species by PCR amplification of the SSU rRNA gene.

RESULTS

The overall prevalence of Entamoeba spp. infection was 89.96% (412/458). Four species of Entamoeba detected in our survey were E. chattoni (88.43%), E. hartmanni (79.91%), E. coil (69.87%) and E. dispar (58.30%), and among these, 398 (84.93%) were mixed infections. Phylogenetic analysis revealed that isolates were clustered into four known genotypes.

CONCLUSION

The present study firstly provides important information about the prevalence and diversity of Entamoeba species infecting wild Taihangshan macaques in China. Enough attention should be paid to monitor the potential interspecies transmission in the region.

Occurrence of Selected Zoonotic Fecal Pathogens and First Molecular Identification of Hafnia paralvei in Wild Taihangshan Macaques (Macaca mulatta tcheliensis) in China

Rhesus macaques (Macaca mulatta) are hosts to a range of zoonotic and potentially zoonotic pathogens. The present study firstly provides a broader investigation of the presence and prevalence of zoonotic fecal pathogens in wild Taihangshan macaques, a subspecies of rhesus macaque in China. A total of 458 fecal samples were collected between September 2015 and November 2016. Fourteen genera of intestinal parasites (four genera of protozoans and ten genera of helminths) and twelve genera of bacteria were tested for using PCR amplification. The overall samples prevalence of parasitic infection was 98.25%. Entamoeba spp. (89.96%), Balantidium coli (70.09%), and Isospora spp. (28.38%) were the most prevalent protozoa, whereas the predominant prevalent helminths were Trichuris sp. (93.23%), Strongyloides spp. (73.36%), and Oesophagostomum sp. (31.66%). Ten genera of intestinal bacteria were detected in samples of rhesus macaques, including Shigella (31.66%), Escherichia coli (29.91%), Klebsiella pneumoniae (28.38%), Leptospira (26.64%), Campylobacter jejuni (18.34%), Salmonella (13.32%), etc. Eight samples (1.75%) were tested Hafnia-positive based on sequences analysis of 16S rRNA and ampC gene. This is the first molecular characterization of Hafnia infection in NHPs. Our cross-sectional prevalence study provides important information for monitoring the potential transmission of zoonotic infections from wild rhesus macaques.

First report on the occurance of intestinal Entamoeba spp. In pigs In China

Three Entamoeba spp. including E. suis, zoonotic E. polecki, and E. histolytica, have been described in pigs to date. However, little is known about the molecular epidemiology of these neglected parasites in pigs globally. In this study we surveyed the occurrence and molecular epidemiology of porcine Entamoeba spp. in pigs in eastern China and evaluated their zoonotic potential. Five hundred fresh fecal samples, collected from seven pig farms in Anhui province, eastern China,were examined for the presence of E. histolytica, E. suis, and E. polecki ST1 and ST3 infections by a combination of nested PCR targeting the small subunit ribosomal DNA gene and subsequent sequencing.The overall occurrence of Entamoeba spp. was 45.8% (229/500). Infection with E. polecki ST1 (38.2%; 191/500) was the most common, followed by E. polecki ST3 (10.0%; 50/500), and E. suis (0.8%; 4/500). No E. histolytica infection was detected. Double infections with E. polecki ST1 and E. suis, and with E. polecki ST1 and ST3 were found in two (0.4%) and 14 (2.8%) samples, respectively. No age predisposition to infection with Entamoeba spp. was observed. PCR and subsequent sequencing confirmed the validity and feasibility of the nested PCR method used in this study in identifying species/subtypes of porcine Entamoeba spp.This is the first report to describe the occurrence and molecular epidemiology of Entamoeba species in pigs in China. The presence of two zoonotic E. polecki subtypes implies that pigs can be reservoirs for human E. polecki infections. More studiess are needed to better understand the transmission and public health significance of porcine Entamoeba spp.

Correlation of genetic diversity between hosts and parasites in Entamoeba nuttalli isolates from Tibetan and rhesus macaques in China

Entamoeba nuttalli infection is prevalent in captive and wild macaques. Recent studies have suggested that genotypes of E. nuttalli isolates are correlated with the geographical distribution of host macaques. Correlation of amoebic genotypes with genetic diversity of host macaques was analyzed in present study. Sixty fresh stool samples were obtained from wild Tibetan macaques living in Mount Huang (HS) of the An-hui Province in China. PCR analysis revealed that the most prevalent Entamoeba species was E. chattoni (E. polecki ST2) (86.7%) followed by E. nuttalli (58.3%) and E. coli (25%). Six E. nuttalli HS isolates were successfully cultured. The tRNA-linked short tandem repeat (STR) loci and serine-rich protein gene of E. nuttalli isolates from four different regions of China (Mount Long-hu, Gui-yang, Mount E-mei, and HS, the former three isolates were obtained in previous studies) were studied and high numbers of polymorphisms were detected. When genetic diversity of different populations of E. nuttalli isolates was compared with geographical distance, an r² value of 0.919 was assigned by a Mantel test based on the tRNA-STR loci. In host macaques, the mtDNA HVS-I gene was also highly polymorphic in each of the genomes. Multiple regression analysis using E. nuttalli tRNA-STR loci genetic, macaque mtDNA HVS-I gene, and geographic distances showed an r² value of 0.943, indicating that a higher relevance was demonstrated when geographic and host gene factors were considered. Analysis of genetic factor of host would benefit for better understanding of the evolution of E. nuttalli.

Novel Entamoeba Findings in Nonhuman Primates

In addition to well-known human-infecting species, Entamoeba species not found in humans have been identified recently in nonhuman primates (NHPs). Importantly, it has become clear that the organism identified as Entamoeba histolytica in NHPs is usually a distinct species, Entamoeba nuttalli. Many DNA-based stool surveys use species-specific detection methods and so may miss the full range of Entamoeba species present. In addition, authors may be using the same species name to describe distinct organisms. These various shortcomings may not be obvious to readers. In this review, we clarify the relationships between Entamoeba species' names based on morphological and molecular data, and highlight gaps in recently published data on Entamoeba species in wild NHPs resulting from the use of variable methodology.