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.

Background: The proliferative stage (tachyzoite) ofToxoplasma gondii(T. gondii) is critical for its transmission and pathogenesis, and a proto-oncogene eukaryotic translation initiation factor (eIF-5A) plays an important role in various cellular processes such as cell multiplication.Methods: We performed a proteomic study to evaluate the specific roles of eIF-5A involved in invasion and replication ofT. gondii, and both in vivo and in vitro trials using eIF-5A-interfered and wild tachyzoites were performed to verify the proteomic results.Results: The results of our study showed thatT. gondiieIF-5A affected tachyzoite growth and also participated in the synthesis of proteins through regulation of both ribosomal and splicing pathways. Inhibition of eIF-5A inT. gondiiresulted in the downregulated expression of soluble adhesions, such as microneme protein 1 (MIC1) and MIC4, which in turn decreased the parasite population that adhered to the surface of host cells. The reduced attachment, combined with lower expression of some rhoptry proteins (ROPs) and dense granule antigens (GRAs) involved in different stages of T. gondiiinvasion such as ROP4 and GRA3, ultimately reduce the invasion efficiency. These processes regulated by eIF-5A eventually affect the replication of tachyzoites.Conclusions: Our findings showed that eIF-5A influenced tachyzoite survival and was also involved in the process of parasite invasion and replication. These results will provide new clues for further development of targeted drugs to controlT. gondiiinfection.Graphical

Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan that can elicit a robust immune response during infection. Macrophage cells have been shown to play an important role in the immune response against T. gondii. In our previous study, the eukaryotic translation initiation factor 5A (eIF-5A) gene of T. gondii was found to influence the invasion and replication of tachyzoites. In this study, the recombinant protein of T. gondii eIF-5A (rTgeIF-5A) was incubated with murine macrophages, and the regulatory effect of TgeIF-5A on macrophages was characterized. Immunofluorescence assay showed that TgeIF-5A was able to bind to macrophages and partially be internalized. The Toll-like receptor 4 (TLR4) level and chemotaxis of macrophages stimulated with TgeIF-5A were reduced. However, the phagocytosis and apoptosis of macrophages were amplified by TgeIF-5A. Meanwhile, the cell viability experiment indicated that TgeIF-5A can promote the viability of macrophages, and in the secretion assays, TgeIF-5A can induce the secretion of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and nitric oxide (NO) from macrophages. These findings demonstrate that eIF-5A of T. gondii can modulate the immune response of murine macrophages in vitro, which may provide a reference for further research on developing T. gondii vaccines.

Ascaridia galli infection causes significant economic losses in poultry, with no available vaccine. This study aimed to develop and evaluate a novel nanovaccine by encapsulating A. galli excretory-secretory antigens (ESAs) in poly(lactic-co-glycolic acid) (PLGA) and chitosan (CS) nanoparticles (NPs), comparing their efficacy to antigens delivered with Freund's adjuvant (FA). One-day-old chicks were randomly allocated into five groups. Three treatment groups were immunized intramuscularly on days 7 and 14 with 200 μg of A. galli ESAs delivered via PLGA NPs, CS NPs, or FA. An infected control group and an uninfected blank control group were also included. All groups except the blank control were challenged with 500 infective A. galli larvae on day 21. On day 77, chickens were euthanized for assessment of worm burden, growth performance, antibody responses (systemic and mucosal), and cytokine profiles. Immunization with ESAs-PLGA NPs induced the most significant reduction in total worm burden (34.38%), which was particularly effective against male worms. This group, along with the ESAs-CS NPs group, also showed a significant improvement in average daily weight gain compared to the infected control. Serologically, both NP groups elicited significantly higher and more sustained levels of serum total IgG and ESAs-specific IgG than the FA group. Crucially, only the ESAs-PLGA NPs significantly enhanced IgG levels in the jejunal mucosa. Furthermore, the ESAs-PLGA NP vaccine consistently promoted the strongest Th2-type immune response, characterized by the highest secretion of IL-4 and IL-13. A. galli ESAs are effective vaccine antigens that confer protection by stimulating IgG antibodies and a Th2-skewed immune response. Encapsulation of ESAs in PLGA NPs significantly enhances this immunoprotective efficacy, superior to both CS NPs and traditional FA, by potentiating systemic and mucosal humoral immunity and amplifying Th2-cell responses. The ESAs-PLGA NP formulation represents a promising vaccine candidate for controlling A. galli in poultry.