Search Results (484)

We aimed to assess the seroprevalence of anti-Neospora caninum and anti-Toxoplasma gondii antibodies in cattle intended for human consumption in Paraíba, Brazil, and the associated risk factors. A total of 110 serum samples from slaughtered cattle were analyzed using the Indirect Fluorescence Antibody Test (IFAT), with cut-off points of 1:200 for N. caninum and 1:64 for T. gondii. Seroprevalence was 8.2% (9/110) for N. caninum (titers 1:200–1:6400) and 18.2% (20/110) for T. gondii (titers 1:64–1:512). Risk factor analysis revealed that the variable female sex (cows) and the extensive farming system were statistically significantly associated with seroprevalence for N. caninum. Whereas for T. gondii, extensive farming, frequent animal purchase, and the lack of separation between calves and adult cattle were statistically significant. These findings demonstrate the circulation of these parasites in herds, with implications for animal and public health, indicating a potential risk of transmission to definitive hosts and humans through the consumption of raw or undercooked infected meat. Full article

A systematic review of toxoplasmosis cases in patients receiving targeted immunotherapy with biologics or small molecules was performed. This systematic review searched for case reports, case series and observational studies in PubMed; last search was on 19 July 2025. The review identified 46 toxoplasmosis cases among patients receiving biologics (including CAR T-Cell Therapies) or small molecules for diverse autoimmune, oncologic and transplant conditions. These cases were reported from 18 countries, including the United States and several European countries. Most patients developed severe disease. Fifty percent (23/46) presented with cerebral toxoplasmosis, 33% (15/46) with ocular toxoplasmosis, 7% (3/46) with lymphadenopathy, 4% (2/46) with disseminated disease, 2% (1/46) with both cerebral and ocular disease, 2% (1/46) with pneumonic toxoplasmosis, and 2% (1/46) with severe fetal congenital toxoplasmosis. Among those were also four cases with fatal outcomes due to toxoplasmosis and eight cases with permanent ocular or neurological deficits. In addition, there was a case of fetal congenital toxoplasmosis that occurred despite maternal discontinuation of adalimumab five months before conception, resulting in elective pregnancy termination due to severe fetal cerebral disease. Overall, 44% (20/46) of cases were due to reactivation of chronic latent Toxoplasma infections and 39% (18/46) due to acute primary infections; 17% did not report this information. One case of disseminated acute toxoplasmosis was also identified after eating wild boar sausages, and two cases of severe acute ocular toxoplasmosis after eating undercooked venison meat, and undercooked unspecified type of meat respectively, while on small molecules or biologics. Details on the clinical presentations, management and clinical outcomes of these cases were reported. Recommendations for the management of toxoplasmosis in patients with targeted immunotherapies were also provided. Health care providers should consider toxoplasmosis in patients on biologics or small molecules who present with compatible clinical syndromes. Prompt diagnosis and treatment can be lifesaving. Full article

Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan parasite responsible for toxoplasmosis, a disease with significant health implications for humans and animals. The surface antigen 1 (SAG1) of T. gondii is a major immunodominant protein that facilitates host cell invasion, making it an ideal target for diagnostic and therapeutic interventions. Immunoglobulin Y (IgY), the primary antibody in avian species, offers unique advantages over mammalian IgG, including easier animal care, lower costs, high-yield production, and potential passive immunization. Objectives: This study aimed to induce, purify, and characterize IgY antibodies targeting T. gondii SAG1 from hen egg yolks. Methods: The coding region of the mature portion of T. gondii SAG1 was amplified by PCR, cloned into the pET32a(+) vector for heterologous expression in E. coli. The recombinant SAG1 (rSAG1) was purified by affinity chromatography and used to immunize hens. IgY was extracted from egg yolks using PEG. SDS-PAGE and spectrophotometry were used to evaluate purity and concentration. By ELISA, Western blot, and flow cytometry, the specificity of IgY was assessed against recombinant and endogenous, native, and denatured SAG1. Results: Purified IgY demonstrated strong recognition of both recombinant and native SAG1 in ELISA and Western blot, and against T. gondii tachyzoites by flow cytometry. Conclusions: SAG1-specific IgY was produced in a pure form; it could be helpful in research, diagnosis, and treatment at low costs on a larger production scale, with minimal animal harm. Full article

Toxoplasmosis is a relevant parasitic infection in sheep, with ovine meat an important source of human exposure. Accurate detection of the early immune response to Toxoplasma gondii is essential for preventing reproductive losses and improving diagnostic strategies. This study evaluated the kinetics of the acute immune response in eighteen sheep experimentally exposed to live tachyzoites or immunized with parasite-derived glycoconjugates (GlyC). Animals were divided into three groups and injected with saline solution, tachyzoites, or glycoconjugates combined with an adjuvant. Infected sheep developed specific IgM antibodies against both lysate and glycoconjugate antigens from day 4, and IgG against glycoconjugates from day 12 post-infection. Glycoconjugate-immunized sheep produced IgM against lysate antigens from day 4, and IgG against both antigens from day 12. Flow cytometry revealed a significant increase in circulating CD8+ T cells and a reduction in MHC class II+ cells on day 60 in the infected group. These findings demonstrate the early humoral and cellular immune response profiles following infection or GlyC immunization. This supports their future application in diagnostic tests or as vaccine candidates against toxoplasmosis in sheep. Full article

Toxoplasma gondii is a widely distributed intracellular parasite that disrupts host immune and metabolic homeostasis. Although accumulating evidence highlights the role of gut microbiota in parasitic infections, the effects of acute T. gondii infection on host gut microbial ecology remain poorly understood. In this study, metagenomic sequencing technology was used to systematically analyze the composition and functional alterations of the ileal microbiota in BALB/c mice on day 10 post-infection. Compared to uninfected controls, T. gondii infected mice exhibited a significant reduction in microbial diversity and a pronounced shift in community structure. Notably, there was an expansion of Proteobacteria, particularly the Enterobacteriaceae family, alongside a marked decline in beneficial taxa such as Actinobacteria and Bacillota. Functional annotation using the KEGG and CAZy databases revealed enrichment of metabolic pathways related to glycolysis/gluconeogenesis, O-antigen nucleotide sugar biosynthesis, bacterial secretion systems, and biofilm formation-Escherichia coli in the infected microbiota. These findings provide novel insights into the dysbiosis of gut microbiota and host-microbe interactions during acute T. gondii infection. Full article

Toxoplasma gondii is a globally prevalent parasite capable of establishing lifelong infections, which can have severe consequences in immunocompromised individuals and developing fetuses. GRAs are essential secretory effectors that facilitate nutrient acquisition, modulate host immune responses, and support intracellular survival. In this study, we characterized four putative GRAs (GRA85–88) that co-localize with GRA12 in both tachyzoite and bradyzoite stages. Using CRISPR-Cas9-mediated homologous recombination, we successfully generated knockout strains in both type I RH and type II Pru backgrounds. Phenotypic analysis revealed that GRA85, GRA87, and GRA88 were not individually required for parasite replication, invasion, or virulence. However, deletion of gra86 (PruΔgra86) resulted in a significant reduction in virulence and fewer brain cysts in chronically infected mice, although in vitro growth remained unaffected. Transcriptomic profiling of PruΔgra86 revealed downregulation of bradyzoite–related genes and upregulation of GRAs involved in host interaction. Additionally, in vitro differentiation assays showed impaired bradyzoite development in the absence of GRA86. These findings from murine models and in vitro phenotypic assays highlight GRA86 as a regulator of chronic infection and stage conversion, positioning it as an important player in T. gondii pathogenesis and a promising target for therapeutic intervention. Full article

The conversion from fast-growing tachyzoites to slow-growing bradyzoites is the key factor in establishing the chronic infection and long-term persistence of Toxoplasma gondii. Environmental stressors, such as amino acid starvation and alkaline medium, can trigger the transformation of tachyzoites into bradyzoites. Under such stress conditions, ribosomes slow down, potentially leading to stalling, and ribosomal collisions typically activate ribosome-associated quality control (RQC) pathways. In this study, we investigated the role of T. gondii ribosome quality control complex subunit 2 (TgRqc2), which contains both NFACT and coiled-coil domains, in the parasite’s survival and stage conversion. NFACT represents the “domain” found in the central players involved in RQC, human NEMF and its orthologs FbpA (known as RqcH), Caliban, and Tae2 (known as Rqc2). Phylogenetic analyses revealed that TgRqc2 formed a distinct clade with its orthologs in apicomplexan parasites. The deletion of TgRqc2 impaired T. gondii’s invasion and replication. The Rqc2-knockout strain showed defects in plaque formation and bradyzoite development. Our findings demonstrate that TgRqc2 is essential for T. gondii’s lytic cycle and the conversion of tachyzoites into bradyzoites. RNA-seq analysis further showed that the depletion of TgRqc2 significantly disrupted global transcriptional activity. However, the detailed molecular mechanisms involved remain to be elucidated. In conclusion, our results proved valuable insights that may aid in the development of therapeutic strategies to prevent chronic infection. Full article

Background/Objectives: Toxoplasma gondii is a major cause of zoonotic infections in both humans and animals, resulting in significant mortality in susceptible species, such as New World primates and marsupials. Toxoplasmosis is particularly concerning in zoos and wildlife reserves, where outbreaks threaten conservation efforts for endangered species. In the absence of a commercially available vaccine against toxoplasmosis for humans and captive wild animals, current prevention strategies are limited to restricting the access of cats to enclosures, controlling rodent populations, and maintaining strict food hygiene. Recent research has shown promising results with an intranasal vaccine (VXN-Toxo) composed of maltodextrin nanoparticles conjugated with a purified, inactivated T. gondii parasite. This experimental vaccine does not pose a risk of causing disease and offers advantages such as better stability compared with live pathogen-based vaccines. Methods: This study presents a large-scale evaluation of the effect of VXN-Toxo administered to captive wildlife across 20 zoos in Europe and the Americas between 2017 and 2025. Seven hundred and eighty-four animals, representing over 58 species (including primates, marsupials, rodents, and felids), were vaccinated without any adverse events reported. Results: Retrospective mortality data from 20 participating zoological institutions revealed an overall 96.7% reduction—and, in many cases, a complete elimination—of toxoplasmosis-associated deaths post vaccination. Conclusions: These results demonstrate, for the first time, consistent and broad-spectrum protection against T. gondii of different strains in a wide array of captive wildlife species. This universal vaccine represents a promising tool for toxoplasmosis prevention in zoological collections, with significant implications for animal health and conservation strategies. Full article

Although trap-neuter-return (TNR) is a popular method for managing free-roaming domestic cat populations, a common criticism is that sterilization fails to mitigate the public health risks posed by free-roaming cats. One of these risks is the environmental contamination of Toxoplasma gondii, a parasite that can be spread in the feces of actively infected felids (both domestic and wild). In healthy humans, toxoplasmosis tends to be mild or asymptomatic; however, the disease can have severe consequences (e.g., for pregnant women) and even be fatal in immunocompromised individuals. Previous research has examined the extent to which free-roaming domestic cats might contaminate sites frequented by young children (e.g., schools and parks). However, the model used included several assumptions that are not reflective of sterilized cats in an urban setting (e.g., smaller home range). By properly accounting for several key factors (e.g., reproductive status, home range), our modeling revealed considerably lower rates of potential incursions by sterilized free-roaming cats than those reported previously. More importantly, our results show that sterilization contributes to a considerable reduction in the risk of environmental contamination; TNR therefore appears to be a valuable harm reduction strategy in mitigating the risks of T. gondii infection. Full article

Background/Objectives: Toxoplasma gondii, an obligate intracellular parasite, poses a major global health concern owing to its potential for congenital transmission, particularly during pregnancy. Current pharmacological treatments, including spiramycin and pyrimethamine, exhibit limitations in both efficacy and safety, underscoring the need for novel therapeutic strategies. In this study, we investigated the antiparasitic potential of BthTX-II, an Asp49 phospholipase A₂ (PLA₂) isolated from Bothrops jararacussu venom, in human trophoblast cells (BeWo) and third-trimester human placental explants infected with T. gondii. Methods: In vitro assays were performed using BeWo cells infected with T. gondii tachyzoites and treated with non-cytotoxic concentrations of BthTX-II (3.125, 1.56, and 0.78 µg/mL). An ex vivo model employing third-trimester human placental villous explants was used under similar conditions. Parasite proliferation, adhesion, and invasion were assessed alongside host immune response modulation. Results: Our findings demonstrate that BthTX-II reduces T. gondii proliferation in BeWo cells at all tested non-cytotoxic concentrations. The toxin also significantly impaired parasite adhesion and invasion while modulating host immune response by upregulating interleukin (IL)-6, IL-8, and macrophage migration inhibitory factor (MIF), and downregulating vascular endothelial growth factor—potentially disrupting parasite proliferation. In placental villous explants, BthTX-II (1.56 μg/mL) reduced T. gondii proliferation and modulated IL-8, MIF, and tumour necrosis factor-alpha levels without compromising tissue viability. Conclusions: These findings highlight BthTX-II as a potential candidate in toxoplasmosis treatment. Further investigation should focus on its dual role in limiting parasite development and modulating immune responses at the maternal–fetal interface. Full article

Background/Objectives: Toxoplasmosis, a zoonotic disease caused by Toxoplasma gondii, typically is asymptomatic in immunocompetent individuals but causes severe complications in immunocompromised subjects and during pregnancy. Current treatments such as pyrimethamine and sulfadiazine are effective for acute infections but cannot eliminate encysted bradyzoites and have significant side effects. The antimicrobial killer peptide (KP) has interesting therapeutic potential, but its intracellular delivery is challenging; hyaluronate-based nanoparticles loaded with KP (KP-NPs) were evaluated to target T. gondii-infected cells that overexpress CD44. Methods: KP-NPs made of chitosan and hyaluronate were produced by microfluidics and were characterized for size, surface charge, encapsulation efficiency, and stability under stress conditions. After excluding their toxicity, their activity was tested in vitro against Candida albicans and T. gondii as free tachyzoite or in infected human foreskin fibroblasts (HFFs). Results: KP was efficiently encapsulated in nanoparticles and protected from harsh acidic conditions at high temperature. Preliminary in vitro testing against C. albicans showed that, at the lowest candidacidal concentration of KP (2.5 μg/mL), KP-NPs killed 90.97% of yeast cells. KP itself proved to be non-toxic for HFFs as host cells and effective against T. gondii. Comparable results were obtained for KP-NPs and blank nanoparticles (BLK-NPs), with no observed toxicity to host cells, confirming that encapsulation did not alter peptide efficacy. The parasiticidal effect of KP alone, as well as KP-NPs at 250 µg/mL and BLK-NPs, was confirmed through tests on free T. gondii tachyzoites. Reduction rates for the number of infected cells ranged from 66% to 90% with respect to control, while the reduction in the number of intracellular tachyzoites ranged from 66% to 80%. Interestingly, KP alone was not effective against intracellular tachyzoite, while KP-NPs maintained an efficacy comparable to the extracellular model, suggesting that particles helped the internalization of the peptide. Conclusions: Encapsulation of KP into hyaluronate/chitosan nanoparticles does not alter its activity and improves its efficacy against the intracellular parasite. Notably, BLK-NPs appeared to exhibit efficacy against the parasite on its own, without the presence of KP. Full article

Toxoplasma gondii is a globally distributed protozoan parasite and a major cause of congenital infections, particularly in South America. Current therapies for congenital toxoplasmosis are limited by toxicity, long treatment regimens, and suboptimal efficacy, highlighting the urgent need for safer and more effective alternatives. In this study, we evaluated the antiparasitic effects of crude ethanolic extract of Brazilian Red Propolis (BRP) and its isolated compounds, focusing on 7-O-methylvestitol, in human trophoblast (BeWo) cells and third-trimester placental explants. Both BRP and 7-O-methylvestitol significantly reduced T. gondii adhesion, invasion, and intracellular replication, without compromising host cell viability. Ultrastructural analyses revealed irreversible parasite damage, and cytokine profiling demonstrated immunomodulatory effects, with enhanced production of interleukin (IL)-6, IL-8, and macrophage migration inhibitory factor (MIF) in BeWo cells and downregulation of IL-6, MIF, and tumor Necrosis Factor (TNF) in infected placental villi. Notably, 7-O-methylvestitol reproduced and, in some assays, surpassed the antiparasitic activity of BRP, suggesting it as a key bioactive constituent responsible for the therapeutic potential of the extract. These findings support the identification of 7-O-methylvestitol as a promising lead compound for structure-based drug design and repositioning strategies, advancing the development of novel, safe, and targeted therapies against congenital toxoplasmosis. Full article

Toxoplasma gondii is responsible for the disease toxoplasmosis and has the broadest host range among apicomplexan parasites, as it infects virtually all warm-blooded vertebrates. Toxoplasmosis is a zoonotic and emerging public health concern with considerable morbidity and mortality, especially in the developing world, affecting approximately one-third of the world’s human population. Clinical presentation varies among species, and the infection establishes lifelong chronicity in hosts. Most of the host species (including healthy humans) are asymptomatic on the one hand, it is fatal to marsupials, neotropical primates and some marine mammals on the other hand. In immunocompetent humans, infection is typically asymptomatic, whereas immunocompromised individuals may develop disseminated disease affecting virtually any organ system—most commonly reproductive, cerebral, and ocular systems. Toxoplasmosis spreads by ingestion of food or water contaminated with T. gondii oocysts, consumption of undercooked/raw meat containing tissue cysts, transplacental transmission from mother to fetus, or by receiving infected organ/blood from the infected individual. Toxoplasmosis is mainly diagnosed by serologic tests and polymerase chain reaction (PCR). It is treated with pyrimethamine combined with sulfadiazine or clindamycin, often supplemented with leucovorin, atovaquone, and dexamethasone. Despite having many potent anti-T. gondii antigenic candidates, there is no commercially available vaccine for humans due to many factors, including the complex life cycle of the parasite and its evasion strategies. To date, the only commercially available anti-T. gondii vaccine is for sheep, licensed for veterinary use to prevent ovine abortions. In this review, we have summarized the current understanding of toxoplasmosis. Full article

Background: Toxoplasma gondii (T. gondii) infection causes serious diseases in immunocompromised patients and causes congenital toxoplasmosis in infants. T. gondii microneme protein 8 (MIC8) and apical membrane antigen 1 (AMA1) are essential proteins involved in parasitic invasion. Methods: In this study, we generated virus-like particles (VLPs) and recombinant vaccinia virus (rVV) containing MIC8 or AMA1 proteins. Vaccine efficacy was evaluated in mice (BALB/c) upon challenge infection with T. gondii ME49. Results: Intramuscular immunization with heterologous vaccines (rVV + VLPs; rVV for prime and VLPs for boost) elicited T. gondii-specific IgG antibody responses in mice. Four weeks after the boost, all mice were orally challenged with T. gondii ME49, and protective immunity was assessed. The responses of antibody-secreting cells for IgG2a and IgG2b and those of memory B cells and CD4+ and CD8+ T cells were higher in the rVV + VLP group than in the VLP + VLP group. The rVV + VLP group exhibited a significant reduction in cyst count in the brain. Conclusions: These findings indicate that heterologous vaccination with vaccinia viruses and VLPs improves vaccine efficacy. Full article

Foodborne pathogens represent a class of pathogenic microorganisms capable of causing food poisoning or serving as foodborne vectors, constituting a major source of food safety concerns. With increasing demands for rapid diagnostics, conventional culture-based methods and PCR assays face limitations due to prolonged turnaround times and specialized facility requirements. While CRISPR-based detection has emerged as a promising rapid diagnostic platform, its inherent inability to detect low-abundance targets necessitates coupling with isothermal amplification, thereby increasing operational complexity. In this study, we preliminarily developed a novel amplification-free Cascade-CRISPR detection system utilizing a hairpin DNA amplifier. This method achieves detection sensitivity as low as 10 fM (82 parasites/μL) for DNA targets within 30 min without requiring pre-amplification, with background signal suppression achieved through optimized NaCl concentration. Validation using artificially contaminated food samples demonstrated the platform’s robust performance for both Toxoplasma gondii (T. gondii) and Listeria monocytogenes (L. monocytogenes) detection, confirming broad applicability. In summary, this study preliminarily establishes an amplification-free Cascade-CRISPR detection platform that achieves high sensitivity and rapid turnaround, demonstrating strong potential for on-site screening of foodborne pathogens. Full article