Molecular characterization of Balantioides coli in pigs from Shaanxi province, northwestern China

The Phylogenetic Characterization of Balantioides coli Isolated in the Pavlova Culture Medium Supplemented with Coconut Water and Animal Serum

Balantioides coli is a ciliated protist that can cause dysentery in humans, pigs and nonhuman primates and may have the potential for zoonotic transmission. Its diagnosis is routinely performed through conventional parasitological techniques, and few studies have used culturing techniques to isolate it, applying molecular tools for the characterization of this protozoan. Thus, the objective of this study was to confirm B. coli diagnosis using molecular tools and to characterize the genetic variants of this parasite isolated from pigs kept on family farms in Brazil using three different culture media that differed in the serum added. Fecal samples from pigs were inoculated in Pavlova medium plus coconut water (PC), fetal bovine serum (PB) and horse serum (PH). Of the 127 samples positive for forms compatible with the phylum Ciliophora, 31 were selected for isolation. The most successful medium for isolation was PB 19/31 (61.3%), followed by PH 18/31 (58.1%) and PC 11/31 (35.5%). Of the nucleotide sequences generated, 20 were classified as genetic variant type B0, two as A1 and 15 as A0. The results indicated that PC, despite having allowed the isolation of B. coli for a short period, was not an adequate medium for the maintenance of this parasite in vitro, therefore requiring improvement.

Prevalence and sequence diversity of Balantioides coli in pigs in Xinjiang, China

Balantioides coli is a common intestinal parasitic protozoan in pigs. In the present study, 801 fecal samples of pigs from seven farms in Xinjiang were analyzed based on the ITS1-5.8S rRNA-ITS2 gene. The prevalence of B. coli was 4.2% (34/801), with the highest prevalence of 18.9% (18/95) occurring in Alaer, Xinjiang. B. coli was detected in all age groups (pre-weaned pigs, post-weaned pigs, fattening pigs and sows), with the highest rate in fatteners (6.9%, 9/129) and the lowest (1.2%, 2/169) in pre-weaned pigs. Significant differences (P = 0.000) were found among sampling sites but not among age groups (P = 0.084). Sequence analysis indicated that 34 sequence variants, including sequence type A (n = 11) and sequence type B (n = 23), occurred in all age groups. In this study, the existence of sequence type A suggested that B. coli poses a potential threat to human health. More studies are needed to better understand the distributions and public health significance of B. coli in China.

Gastro-intestinal parasites of urban rhesus macaques (Macaca mulatta) in the Kathmandu Valley, Nepal

Intestinal parasitic infections such as amoebiasis, ascariasis, hookworm infection, and trichuriasis are the most common infections among non-human primates (NHPs). There are always the possibilities of transmission these parasites between humans and NHPs. Multiple groups of rhesus macaques (Macaca mulatta) live in the urban area of Kathmandu Valley near human settlements, however the gastrointestinal (GI) parasitic infections in those macaques are understudied. This study aimed to explore the GI parasites in free-ranging macaques from Pashupatinath, Swayambhunath, Tripureshwor, Nilbarahi temples and a group of captive rhesus macaques in the Central Zoo, Kathmandu. Fecal samples were collected from the macaques between October 2021 to September 2022 and assessed for parasites by the both wet mount method and concentration technique. There is high prevalence of GI parasite infection; out of 121 fecal samples examined, 87.6% of samples were positive. Six species of protozoans and eight species of helminths were identified from the fecal samples including the first report of Iodamoeba butschlii in monkeys of Nepal. Among the protozoan parasites, Entamoeba coli (54.71%) showed the highest prevalence followed by Balantioides coli (44.33%), E. histolytica (19.81%), and Iodamoeba butschlii (10%). Among the helminths, Trichuris spp. (31.13%) and Strongyloides spp. (31.13%) showed the highest prevalence followed by Hookworm (24.52%), and Strongyle spp. (23.58%). The likelihood ratio test suggested that the prevalence differed significantly with the seasons for Iodamoeba butschlii, Giardia spp., Strongyles spp., Hookworm, and Trichostrongylus spp. The prevalence of E. histolytica, E. coli, Iodamoeba. butschlii, Trichuris spp., Trichostrongylus spp., and Unknown spp.1 differed with sampling localities. The high prevalence of GI parasites found in the macaques living in the densely urbanized Kathmandu presents a potential threat to humans and warrants further study as well as increased education of the public and management of the human-macaque interface in the urban landscape of the Valley.

Metagenome of Gut Microbiota Provides a Novel Insight into the Pathogenicity of Balantioides coli in Weaned Piglets

Balantioides coli plays an important role in the diarrhea of weaned piglets, but its pathogenic potential and interaction with gut microbes remain unclear. To investigate the impact of B. coli colonization on the gut bacterial structure and function of weaned piglets, a metagenomic analysis based on shotgun sequencing was performed on fresh fecal samples collected from ten B. coli-colonized piglets and eight B. coli-free ones in this study. The results showed that decreasing diversity and shifted composition and function of the bacterial community were detected in the weaned piglets infected by B. coli. In contrast to the B. coli-negative group, the relative abundances of some members of the Firmicutes phylum including Clostridium, Ruminococcus species, and Intestinimonas butyriciproducens, which produce short-chain fatty acids, were significantly reduced in the B. coli-positive group. Notably, some species of the Prevotella genus (such as Prevotella sp. CAG:604 and Prevotella stercorea) were significantly increased in abundance in the B. coli-positive piglets. A functional analysis of the gut microbiota demonstrated that the differential gene sets for the metabolism of carbohydrates and amino acids were abundant in both groups, and the more enriched pathways in B. coli-infected piglets were associated with the sugar-specific phosphotransferase system (PTS) and the two-component regulatory system, as well as lipopolysaccharide (LPS) biosynthesis. Furthermore, several species of Prevotella were significantly positively correlated to the synthesis of lipid A, leading to the exporting of endotoxins and, thereby, inducing inflammation in the intestines of weaned piglets. Taken together, these findings revealed that colonization by B. coli was distinctly associated with the dysbiosis of gut bacterial structure and function in weaned piglets. Lower relative abundances of Clostridiaceae and Ruminococcaceae and higher abundances of Prevotella species were biomarkers of B. coli infection in weaned piglets.

Prevalence of Swine Gastrointestinal Parasites in Two Free-Range Farms from Nord-West Region of Romania

Parasitic diseases cause significant economic losses in swine, including free-range swine farms, the number of which in Romania has increased in the last decades. The current study aimed to identify the parasitic profile of swine raised on two free-range (low-input) farms from Transylvania. Nine hundred sixty samples collected from weaners, fatteners, and sows were investigated by flotation, centrifugal sedimentation, modified Ziehl-Neelsen stained fecal smear, modified Blagg technique, and oocyst/egg cultures. The number of oocysts (OPG), cysts (CPG), and eggs (EPG) were counted per gram of fecal matter. The examination revealed parasitic infections with Balantidium coli, Eimeria spp., Ascaris suum, Trichuris suis, Oesophagostomum spp., Strongyloides ransomi and Cryptosporidium spp. Prevalence (P) and the mean intensity (MI) of the infections varied according to age, swine category, farm, and season. The overall prevalence in both free-range farms according to the age category was 63.2%—Eimeria spp., 70.31%—B. coli, 9.38%—Oesophagostomum spp., 3.75% S. ransomi, and 18.12% Cryptosporidium spp. in weaners. In fatteners Eimeria spp. revealed a prevalence of 50.93%, B. coli—72.5 %, A. suum—63.13%, T. suis—39.06%, and in sows Eimeria spp.—39.06%, B. coli—62.19%, A. suum—34.06%, Oesophagostomum spp.—27.19%, S. ransomi—1.56% and Cryptosporidium spp.—9.38%. The study revealed statistically significant (p < 0.05) differences between age groups, seasons, and farms for all diagnosed parasites. Further research is required to better understand the epidemiology of these infections in swine from Transylvania.

Development and Preliminary Evaluation of a Nanoparticle-Assisted PCR Assay for the Detection of Cryptosporidium parvum in Calves

C. parvum is an important diarrheal pathogen in humans and animals, especially in young hosts. To accurately and rapidly detect C. parvum infection in calves, we established a nano-PCR assay targeting the cgd3_330 gene for the specific detection of C. parvum. This nano-PCR assay was ten times more sensitive than that of the normal PCR assay by applying the same primers and did not cross-react with C. andersoni, C. bovis, C. ryanae, Balantidium coli, Enterocytozoon bieneusi, Giardia lamblia, and Blastocystis sp. To further test the nano-PCR in clinical settings, a total of 20 faecal samples from calves were examined by using the nano-PCR, the normal PCR, and the nested PCR assays. The positive rates were 30% (6/20), 30% (6/20), and 25% (5/20) for the nano-PCR, the normal PCR, and the nested PCR assays, respectively, indicating that the nano-PCR and the normal PCR assays had the same positive rate (30%). Taken together, the present study could provide a candidate method for the specific detection of C. parvum infection in calves in clinical settings.

Identification of Zoonotic Balantioides coli in Pigs by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) and Its Distribution in Korea

Balantioides coli is a zoonotic protozoan parasite whose main reservoir is pigs. Recent studies have shown that B. coli variant A but not B has zoonotic potential. While B. coli infection has been reported in different animals and countries, the prevalence of the zoonotic variant is limited due to a lack of molecular information. Therefore, this study investigated the prevalence of B. coli in domestic pigs in Korea and assessed its zoonotic potential. A total of 188 pig fecal samples were collected from slaughterhouses in Korea. B. coli was identified by microscopy and molecular methods. B. coli was identified in 79 (42.9%) and 174 (94.6%) samples by microscopy and polymerase chain reaction (PCR), respectively. This study also developed a PCR-restriction fragment length polymorphism (PCR-RFLP) method to differentiate B. coli variant A from B without sequence analysis. Using this method, 62 (33.7%) and 160 (87.0%) samples were positive for variants A and B, respectively, and 48 (26.1%) samples were co-infected with both variants. Sequence and phylogenetic analyses showed a high genetic diversity of B. coli in pigs in Korea. To our knowledge, this is the first study to develop a method to differentiate B. coli variants A and B without sequence analysis and to assess the molecular epidemiology of B. coli in pigs. Continuous monitoring of zoonotic B. coli in pigs should be performed as pigs are the main source of human balantidiasis.

Parasitic Intestinal Protists of Zoonotic Relevance Detected in Pigs by Metabarcoding and Real-Time PCR

Several parasite species are shared between humans and pigs. We explored the application of next-generation sequencing-based metabarcoding supplemented with real-time PCR to fecal DNAs from 259 samples from 116 pigs in Denmark to detect and differentiate single-celled intestinal parasites of zoonotic relevance. Enterocytozoon bieneusi, Balantioides coli, and Giardia duodenalis were observed in 34/37 (92%), 148/259 (57%), and 86/259 (33%) samples, respectively. Entamoeba polecki ST1, E. polecki ST3, and Entamoeba hartmanni were detected in 104/259 (40%), 161/259 (62%), and 8/259 (3%) samples, respectively. Metabarcoding and real-time PCR detected Cryptosporidium in 90/259 (35%) and 239/259 (92%) of the samples, respectively, with Cryptosporidium suis and Cryptosporidium scrofarum observed in nearly equal proportions. Blastocystis subtypes 1, 3, 5, and 15 were found in 72 (28%), 6 (2%), 176 (68%), and 36 (14%) of 259 samples, respectively. Iodamoeba was identified in 1/259 samples (<1%), while none of 37 tested samples was positive for Dientamoeba fragilis. Our results illustrate how metabarcoding exemplifies a 'one-fits-many' approach to detecting intestinal single-celled parasites in feces supplemented with real-time PCR for selected parasites. Using metabarcoding with pathogen-specific assays may help detect emerging and previously underdetected pathogens and further elucidate the role of micro-eukaryotic parasites in human and animal health and disease.