Lei Ma

Blastocystis sp. is a zoonotic protozoan with a broad host range, and its pathogenicity in humans has remained controversial. In this study, we observed neurocognitive impairments in mice following Blastocystis sp. infection, prompting us to investigate the mechanisms underlying these changes. Transcriptomic analysis of brain tissue revealed significant changes in the expression of several Neurocognitive Deficits -associated genes, most notably a marked downregulation of the nuclear receptor NR4A1. These findings were validated and confirmed using Western blot, immunofluorescence, and immunohistochemical analyses. While in vitro infection of BV2 microglial cells with Blastocystis sp. revealed activation of the IL-17-p38 MAPK-NR4A1 signaling axis, in vivo administration of a p38 inhibitor in infected mice ameliorated motor and cognitive deficits, demonstrating that this signaling cascade mediates neuropathology in mouse brain following the parasite infection. This finding indicates that Blastocystis sp. infection induces IL-17 overexpression in both the gut and brain, resulting in the activation of the p38 MAPK pathway. This subsequently leads to significant NR4A1 downregulation and, ultimately, results in Neurocognitive Impairment behavioral phenotypes in mice. This study reveals a novel mechanism whereby Blastocystis sp. infection induces cognitive and motor deficits through activation of the p38 MAPK-NR4A1 pathway in brain tissue, offering a potential therapeutic target for future interventions.

Purpose Entamoeba spp. are common zoonotic intestinal protozoa with a broad host range, posing a potential threat to public health. The purpose of this study was to investigate the prevalence, conduct genotyping, and evaluate the genetic diversity of Entamoeba spp. in cattle within Hebei Province, China. This research aims to enhance our understanding of the infection dynamics and associated risk factors. Methods A total of 2746 fecal samples were collected from cattle across 11 cities in Hebei Province. PCR amplification and sequencing of the 18S rRNA gene were performed, and subtype identification, sequence characterization, genetic distance, and diversity index analyses were conducted using MEGA, PhyloSuite, and PopART software. Results The overall prevalence of Entamoeba spp. in cattle was 51.06% (1402/2746). Infection rates were significantly influenced by geographical location (OR = 0.009, P < 0.0001, breed (OR = 0.255, P < 0.01), feeding practices (OR = 11.811, P < 0.0001), and age (OR = 0.295, P < 0.0001). The prevalence in southern Hebei (97.39%) was markedly higher than that in northern Hebei (24.48%), and higher infection rates were observed in older cattle (59.31%), intensively farmed cattle (56.83%), and dairy cattle (65.68%) compared with under one year of age (30.06%), free-range cattle (10.03%), and beef cattle (10.03%), respectively. Five species were identified in the cattle population: Entamoeba bovis (E. bovis), Entamoeba moshkovskii (E. moshkovskii), Entamoeba spp. RL4, Entamoeba spp. RL2, and Entamoeba spp. MG107/BEL. The overall nucleotide diversity index (π) was 0.077, and the haplotype diversity index (Hd) was 0.986. Both indices indicated high genetic diversity among Entamoeba spp. species, with E. bovis exhibiting the highest level of intraspecific diversity. Conclusion In conclusion, the conclusions of this regional study from Hebei Province should be interpreted within its inherent limitations, including its sample size, single-region focus, and cross-sectional nature. Entamoeba spp. are not only widely distributed in cattle but also display considerable host and genetic diversity. These findings enhance our understanding of the infection status and potential impacts on cattle health, and provide valuable data for the assessment of public health significance.

Highlights 1. Blastocystis sp. is an important pathogenic microorganism that causes a variety of intestinal diseases. 2. Blastocystis sp. causes symptomatic or asymptomatic infection, resulting in mucosal shedding, increased goblet cell mucin, and decreased intestinal permeability. 3. The host immune response to Blastocystis sp. is regulated by inducing apoptosis of host cells, modulating the inflammatory pathway, and altering the microbial composition.

Purpose As an important component of ecosystems, wildlife plays a crucial role in maintaining ecological balance. However, wild animals are also natural hosts of pathogens. In this study, fecal samples from three of wild animals were collected from Hebei Xiaowutai Mountain National Nature Reserve in Zhangjiakou City, Hebei Province, China. Species identification of these samples was performed, and the infection status of common zoonotic protozoa in these three wild animal species was detected. Methods Common zoonotic protozoa were detected after species identification by PCR. Results The results of species identification showed that the fecal samples were from red fox (Vulpes vulpes), leopard cat (Prionailurus bengalensis), and wild boar (Sus scrofa). Colpodella spp. was detected in red fox, with the closest phylogenetic relationship being to Colpodella spp. from Lake Luxembourg (NCBI accession number: GU067926.1); Giardia intestinalis (G. intestinalis) was detected in leopard cat, with the closest phylogenetic relationship to G. intestinalis assemblage F (NCBI accession number: LC341258.1). Conclusions The results showed that wild animals are affected by intestinal protozoan infection and that there is a risk of parasite transmission. The prevention and control of parasitic diseases in wild animals is not only conducive to the protection of animal welfare but also to public health.

Purpose This study aimed to identify and analyze the role of Ferric reductase inBlastocystis sp. subtype 2 (ST2) and explore the relationship between the parasite and iron metabolism. Methods The location of Ferric reductase in Blastocystis sp. was determined using the indirect immunofluorescence assay (IFA). Transmission electron microscopy was employed to reveal the effect of iron ions on the cell membrane of Blastocystis sp.. For the first time, RNA interference technology was used to explore the relationship between Ferric reductase and iron ions. Results Ferric reductase was distributed in the membrane and cytoplasm of the parasite. Iron reduces the thickness of the Blastocystis sp.'s cell membrane. After silencing the Ferric reductase gene, there was no significant difference in the morphology of the parasite strain compared with the control group. The expression level of the Ferric reductase gene does not play a decisive role in maintaining the morphology of the parasite, but the deletion of the Ferric reductase gene reduces the ability of the parasite to absorb iron ions. Conclusions This study fills the gap in the research field of iron metabolism inBlastocystis sp. among parasites, lays a foundation for the research on the gene function of Blastocystis sp., and provides new candidate factors for the development of Blastocystis sp. vaccines.

Purpose Enterocytozoon bieneusi (E. bieneusi) is a microsporidium that causes intestinal disease in animals and humans, and transmits person to person and/or animals to people. A survey was conducted to determine the prevalence and genetic diversity E. bieneusi infection in cattle in Hebei Province, China. Methods A total of 2,746 cattle fecal samples were collected from 11 cities in Hebei Province. PCR amplification targeting the ITS gene of E. bieneusi was performed to detect infections. The subtypes, sequence signatures, pairwise genetic distances, and genetic diversity indices were analyzed using MEGA, PhyloSuite, and PopART. Results The overall prevalence of E. bieneusi in cattle was 4.70% (129/2746). The infection rate varied significantly by region, age, breeding mode, and cattle type: higher in southern Hebei, cattle under one year old, intensively raised cattle, and dairy cattle. Six genotypes were identified (CHG3, SX1, BEB4, BEB6, BEB8, and J), with BEB6 being the dominant genotype. Sequence analysis revealed 260 polymorphic and conserved sites, including 41 variable sites (15.77% of total nucleotides). The nucleotide diversity index (Pi) was 0.06472, and the haplotype diversity index (Hd) was 1.000. Conclusion This study provides the first comprehensive epidemiological data on E. bieneusi infection in cattle in Hebei Province and highlights its rich genetic diversity. These findings offer insights into the potential risk of zoonotic transmission and serve as a reference for further control and prevention strategies.