Toxoplasmosis--a global threat. Correlation of latent toxoplasmosis with specific disease burden in a set of 88 countries

An optimized ROP6 mRNA construct successfully expressed immunogenic Toxoplasma gondii ROP6 protein in cell culture

Toxoplasma gondii is an apicomplexan parasite infecting all mammals including humans and causes toxoplasmosis. There is no vaccine available for humans and thus vaccine development efforts continue using novel antigens and/or vaccine platforms. Since our previous microarray screening study showed that ROP6 is a suitable antigen to be used in vaccine studies, in this study, we aimed to design an optimized mRNA construct encoding the ROP6 protein and then demonstrate its efficiency and immunogenicity using in vitro methods. For this, we constructed a pT7CFE1-Chis/ROP6 vector encoding optimized ROP6 mRNA containing EMCV 5'UTR with IRES and a 20 nucleotides fragment from alpha globin 3' UTR. Then, we generated the optimized ROP6 mRNAs with anti-reverse cap analogue (ARCA) and approximately 150 nucleotide long poly-A tail. Next, HEK293T cells were transfected with the optimized ROP6 mRNAs to show recombinant ROP6 protein expression capability. Moreover, we expressed in vitro recombinant ROP6 protein in HeLa cell lysate using the pT7CFE1-Chis/ROP6 vector to reveal the immunogenicity of recombinant ROP6 protein using sera samples collected from mice infected with PRU strain of T. gondii. The IFA and Western blot results showed that the optimized ROP6 mRNAs successfully expressed the recombinant ROP6 protein in HEK293T cells. Moreover the recombinant ROP6 protein expressed in HeLa cell lysate strongly reacted with sera samples collected from mice. The absorbance difference detected among positive and negative mice serum samples analyzed was statistically significant, indicating that the recombinant ROP6 protein was immunogenic (P = 0.0003). In conclusion, this study demonstrated that the optimized ROP6 mRNAs can be used in the development of mRNA vaccines against toxoplasmosis.

Environmental stressors and zoonoses in the Arctic: Learning from the past to prepare for the future

The risk of zoonotic disease transmission from animals to humans is elevated for people in close contact with domestic and wild animals. About three-quarters of all known human infectious diseases are zoonotic, and potential health impacts of these diseases are higher where infectious disease surveillance and access to health care and public health services are limited. This is especially the case for remote circumarctic regions, where drivers for endemic, emerging, and re-emerging zoonotic diseases include anthropogenic influences, such as pollution by long-range transport of industrial chemicals, climate change, loss of biodiversity and ecosystem alterations. In addition to these, indirect effects including natural changes in food web dynamics, appearance of invasive species and thawing permafrost also affect the risk of zoonotic disease spill-over. In other words, the Arctic represents a changing world where pollution, loss of biodiversity and habitat, and maritime activity are likely driving forward occurrence of infectious diseases. As a broad international consortium with a wide range of expertise, we here describe a selection of case studies highlighting the importance of a One Health approach to zoonoses in the circumarctic, encompassing human health, animal health, and environmental health aspects. The cases highlight critical gaps in monitoring and current knowledge, focusing on environmental stressors and lifestyle factors, and they are examples of current occurrences in the Arctic that inform on critically needed actions to prepare us for the future. Through these presentations, we recommend measures to enhance awareness and management of existing and emerging zoonoses with epidemic and pandemic potential while also focusing on the impacts of various environmental stressors and lifestyle factors on zoonoses in the Arctic.

Assessing the impact of preventative measures to limit the spread of Toxoplasma gondii in wild carnivores of Madagascar

Novel multihost pathogens can threaten endangered wildlife species, as well as humans and domestic animals. The zoonotic protozoan parasite Toxoplasma gondii is transmitted by members of Felidae and can infect a large number of animal species, including humans. This parasite can have significant health consequences for infected intermediate hosts and could further endanger wild carnivore populations of Madagascar. Building on an empirical characterization of the prevalence of the pathogen in local mammals, we used mathematical models of pathogen transmission in a multihost community to compare preventative measures that aim to limit the spread of this parasite in wild carnivores. Specifically, we examined the effect of hypothetical cat vaccination and population control campaigns on reducing the risk of infection by T. gondii in wild Eupleridae. Our model predicted that the prevalence of exposure to T. gondii in cats would be around 72% and that seroprevalence would reach 2% and 43% in rodents and wild carnivores, respectively. Reducing the rodent population in the landscape by half may only decrease the prevalence of T. gondii in carnivores by 10%. Similarly, cat vaccination and reducing the population of definitive hosts had limited impact on the prevalence of T. gondii in wild carnivorans of Madagascar. A significant reduction in prevalence would require extremely high vaccination, low turnover, or both in the cat population. Other potential control methods of T. gondii in endangered Eupleridae include targeted vaccination of wild animals but would require further investigation. Eliminating the threat entirely will be difficult because of the ubiquity of cats and the persistence of the parasite in the environment.

The Prevalence of Toxoplasma gondii in Saudi Arabia (1994-2023): A Systematic Review and Meta-Analysis

Toxoplasmosis is one of the most common parasites affecting humans in diverse populations caused by T. gondii. This study aims to systematically review and analyze the prevalence of T. gondii infection among various population categories in Saudi Arabia. Our search was done in five databases: PubMed, Scopus, Cochrane Library, Embase, and Web of Science to find the relevant studies from inception to November 2023. The pooled prevalence of toxoplasmosis among the total population living in Saudi Arabia was estimated using a random-effect meta-analysis approach, and Comprehensive Meta-Analysis software was utilized for this analysis. Our study included 30 case-control and retrospective studies published from 1994 to 2023 involving 20,699 patients from different regions in the Kingdom of Saudi Arabia. Various cities were included, such as Al-Ahsa, Najran, Riyadh, Arar, Mecca, al Khobar, Mushait, Tabuk, jazan, Hail City, Almadinah Almunawwarah, AL-Ahsa, and Abha; 27 reported outcomes related to IgG seroprevalence, revealing an overall toxoplasmosis prevalence of 27.5% in Saudi Arabia. Fifteen studies that measured IgM seroprevalence found an overall toxoplasmosis prevalence of 2.2%. Specifically for pregnant women, IgG seroprevalence was 28%. Among different age categories, the highest toxoplasmosis prevalence was observed in the group aged 31-45 years, reaching 32.5%, while the lowest prevalence was in the 10-20 years category at 19.3%. Regarding gravidity, the grand multi-gravida group exhibited the highest prevalence at 32.9%, with an upper limit of 47.8%. Furthermore, individuals who consumed freshwater demonstrated a higher incidence than those drinking bottled water, with respective prevalence rates of 33.5% and 29.4%. In conclusion, the prevalence of toxoplasmosis in Saudi Arabia is lower than the global average, with significant variations across different age groups, water sources, and dietary habits. Targeted educational programs and public health interventions are essential to raise awareness and reduce the risk of T. gondii infection. Future research should focus on improving study quality and exploring the broader implications of toxoplasmosis on public health in Saudi Arabia.

Role of inflammasomes in Toxoplasma and Plasmodium infections

BACKGROUND

The detection of pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs) by multimeric protein complexes, known as inflammasomes, triggers an inflammatory response, which is a critical component of the innate immune system. This inflammatory response plays a pivotal role in host resistance against parasitic infections, presenting a significant global health challenge.

METHODS

We systematically searched for relevant articles from the Pubmed and the Web of Science database to summarize current insights into how inflammasomes function in preventing infections caused by the apicomplexan parasites Toxoplasma and Plasmodium.

RESULTS

In vivo and in vitro studies have extensively explored inflammasomes such as the absent in melanoma 2 (AIM2), NLR family pyrin-containing protein 1 (NLRP1), NLRP3, and NLRP12 inflammasomes, alongside noncanonical inflammasomes, with particular emphasis on the NLRP1 and the NLRP3 inflammasome during Toxoplasma gondii infection or the AIM2 and the NLRP3 inflammasome at various stages of Plasmodium infection. Toxoplasma gondii interacts with inflammasomes to activate or inhibit immune responses.

CONCLUSIONS

Inflammasomes control parasite burden and parasite-induced cell death, contribute to immune recognition and inflammatory responses and thus influence apicomplexan parasite-associated pathogenesis and the severity of clinical outcomes. Hence, inflammasomes play crucial roles in the progression and outcomes of toxoplasmosis and malaria. A comprehensive understanding of how parasitic infections modulate inflammasome activity enhances insight into host immune responses against parasites.

TgLaforin, a glucan phosphatase, reveals the dynamic role of storage polysaccharides in Toxoplasma gondii tachyzoites and bradyzoites

The asexual stages of Toxoplasma gondii are defined by the rapidly growing tachyzoite during the acute infection and by the slow growing bradyzoite housed within tissue cysts during the chronic infection. These stages represent unique physiological states, each with distinct glucans reflecting differing metabolic needs. A defining feature of T. gondii bradyzoites is the presence of insoluble storage glucans known as amylopectin granules (AGs), the function of which remains largely unexplored during the chronic infection. The presence of storage glucans has more recently been established in tachyzoites, a finding corroborated by specific labeling with the anti-glycogen antibody IV58B6. The T. gondii genome encodes activities needed for glucan turnover inlcuding: a glucan phosphatase (TgLaforin; TGME49_205290) and a glucan kinase (TgGWD; TGME49_214260) that catalyze a cycle of reversible glucan phosphorylation required for glucan degradation by amylases. Disruption of TgLaforin in tachyzoites had no impact on growth under nutrient-replete conditions. Growth of TgLaforin-KO tachyzoites was however severely stunted when starved of glutamine despite being glucose replete. Loss of TgLaforin attenuated acute virulence in mice and was accompanied by a lower tissue cyst burden, without a direct impact on tissue cyst size. Quantification of relative AG levels using AmyloQuant, an imaging based application, revealed the starch-excess phenotype associated with the loss of TgLaforin is heterogeneous and linked to an emerging AG cycle in bradyzoites. Excessive AG accumulation TgLaforin-KO bradyzoites promoted intra-cyst bradyzoite death implicating reversible glucan phosphorylation as a legitimate target for the development of new drugs against chronic T. gondii infections.

Toxoplasmosis Infection in an HIV-Negative Patient Presenting with Clinical and MRI Findings Similar to those of Multiple Sclerosis

Toxoplasmosis is a parasitic infection that can present in various clinical forms, ranging from asymptomatic to severe neurological manifestations. The primary sources of infection include undercooked meat, unwashed produce and contact with cat faeces. Toxoplasmosis can lead to encephalitis, particularly in immunocompromised patients, and is often misdiagnosed as other neurological conditions such as multiple sclerosis (MS). We report the case of a 44-year-old male from Almaty, Kazakhstan, who presented with neurological symptoms including headaches, dizziness, diplopia, leg weakness and elevated blood pressure. The patient had a history of consuming undercooked meat, but no prior neurological conditions. Initial magnetic resonance imaging (MRI) revealed demyelinating lesions, leading to a diagnosis of MS. However, high levels of IgG antibodies against Toxoplasma gondii were detected, prompting further testing. A polymerase chain reaction test for toxoplasmosis was negative, but the patient was treated empirically with trimethoprim and sulfamethoxazole for six months. A follow-up MRI showed a significant reduction in brain lesions, and the patient's symptoms improved.

LEARNING POINTS

This case aids in the differential diagnosis between multiple sclerosis and cerebral toxoplasmosis. It highlights the necessity of conducting ELISA tests for parasitic infections when multiple sclerosis is suspected.

Trend in serological and molecular diagnostic methods for Toxoplasma gondii infection

BACKGROUND

Toxoplasma gondii, an intracellular parasite, is a significant cause of zoonotic disease, with an estimated one-third of the world's human population believed to be infected. T. gondii is transmitted to humans through the consumption of contaminated water, soil, vegetables, fruits, shellfish or undercooked meat, and can also be passed from human to human through vertical transmission, transplants and blood transfusion. While T. gondii infection typically manifests mild symptoms such as colds among immunocompetent individuals, it can prove lethal for those with weakened immune systems.

METHODS

To summarize the diagnostic methods for Toxoplasma gondii infection, we performed a literature search on PubMed from 1948 to 2023 using the keywords "T. gondii serological diagnosis" or "T. gondii molecular diagnosis".

RESULTS

Rapid and accurate diagnosis of T. gondii infection is imperative. Although a diagnostic kit is currently commercially available, there are a number of disadvantages to the validation principles applied to each diagnostic kit. Consequently, multiple diagnostic methods are concurrently employed to offset these limitations. Serological methods for diagnosing T. gondii infection include the Dye Test (DT), Agglutination Test (AT), Modified Agglutination Test (MAT), Latex Agglutination Test (LAT), Enzyme-Linked Immunosorbent Assay (ELISA), and Western Blot. Meanwhile, molecular methods such as polymerase chain reaction (PCR), nested PCR, real-time PCR, loop-mediated isothermal amplification (LAMP), multiplex PCR, and PCR-restriction fragment length polymorphism (PCR-RFLP) are also utilized. Each of these methods possess its own set of advantages and disadvantages.

CONCLUSIONS

By summarizing the advantages and disadvantages of different diagnostic techniques, it is hoped that the epidemiology, prevention, and control of toxoplasmosis will be improved in the future through the use of appropriate technologies.

Ganoderma lucidum triterpenoids investigating their role in medicinal applications and genomic protection

OBJECTIVES

Ganoderma lucidum (GL) is a white rot fungus widely used for its pharmacological properties and health benefits. GL consists of several biological components, including polysaccharides, sterols, and triterpenoids. Triterpenoids are often found in GL in the form of lanostane-type triterpenoids with quadrilateral carbon structures.

KEY FINDINGS

The study revealed that triterpenoids have diverse biological properties and can be categorized based on their functional groups. Triterpenoids derived from GL have shown potential medicinal applications. They can disrupt the cell cycle by inhibiting β-catenin or protein kinase C activity, leading to anti-cancer, anti-inflammatory, and anti-diabetic effects. They can also reduce the production of inflammatory cytokines, thus mitigating inflammation. Additionally, triterpenoids have been found to enhance the immune system's defenses against various health conditions. They possess antioxidant, antiparasitic, anti-hyperlipidemic, and antimicrobial activities, making them suitable for pharmaceutical applications. Furthermore, triterpenoids are believed to afford radioprotection to DNA, protecting it from radiation damage.

SUMMARY

This review focuses on the types of triterpenoids isolated from GL, their synthesis pathways, and their chemical structures. Additionally, it highlights the pharmacological characteristics of triterpenoids derived from GL, emphasizing their significant role in various therapeutic applications and health benefits for both humans and animals.

Ocular Toxoplasmosis: Advances in Toxoplasma gondii Biology, Clinical Manifestations, Diagnostics, and Therapy

Toxoplasma gondii, an obligate intracellular parasite, is a globally prevalent pathogen capable of infecting a wide range of warm-blooded animals, including humans. Ocular toxoplasmosis (OT), a severe manifestation of T. gondii infection, can lead to potentially blinding complications. This comprehensive review delves into the current understanding of T. gondii biology, exploring its complex life cycle, diverse transmission routes, and strain diversity. This article provides an in-depth analysis of the clinical manifestations of OT, which can result from both congenital and acquired infections, presenting a spectrum of signs and symptoms. The review examines various diagnostic strategies employed for OT, including clinical examination, multimodal imaging techniques such as fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), optical coherence tomography (OCT), and optical coherence tomography angiography (OCTA), as well as laboratory tests including serology and molecular methods. Despite extensive research, the specific mechanisms underlying ocular involvement in T. gondii infection remain elusive, and current diagnostic options have limitations. Moreover, the treatment of active and recurrent OT remains a challenge. While existing therapies, such as antimicrobial agents and immunosuppressants, can control active infections, they do not offer a definitive cure or completely prevent recurrence. The clinical endpoints for the management of active and recurrent OT are also not yet well-established, and the available treatment methods carry the potential for adverse effects. This article highlights the need for future research to elucidate the pathogenesis of OT, investigate genetic factors influencing susceptibility to infection, and develop more sensitive and specific diagnostic tools. Enhancing global surveillance, implementing robust prevention strategies, and fostering multidisciplinary collaborations will be crucial in reducing the burden of OT and improving patient outcomes. This comprehensive review aims to provide a valuable resource for clinicians, researchers, and policymakers, contributing to a better understanding of T. gondii infection and its impact on ocular health.

Malate dehydrogenase in parasitic protozoans: roles in metabolism and potential therapeutic applications

The role of malate dehydrogenase (MDH) in the metabolism of various medically significant protozoan parasites is reviewed. MDH is an NADH-dependent oxidoreductase that catalyzes interconversion between oxaloacetate and malate, provides metabolic intermediates for both catabolic and anabolic pathways, and can contribute to NAD+/NADH balance in multiple cellular compartments. MDH is present in nearly all organisms; isoforms of MDH from apicomplexans (Plasmodium falciparum, Toxoplasma gondii, Cryptosporidium spp.), trypanosomatids (Trypanosoma brucei, T. cruzi) and anaerobic protozoans (Trichomonas vaginalis, Giardia duodenalis) are presented here. Many parasitic species have complex life cycles and depend on the environment of their hosts for carbon sources and other nutrients. Metabolic plasticity is crucial to parasite transition between host environments; thus, the regulation of metabolic processes is an important area to explore for therapeutic intervention. Common themes in protozoan parasite metabolism include emphasis on glycolytic catabolism, substrate-level phosphorylation, non-traditional uses of common pathways like tricarboxylic acid cycle and adapted or reduced mitochondria-like organelles. We describe the roles of MDH isoforms in these pathways, discuss unusual structural or functional features of these isoforms relevant to activity or drug targeting, and review current studies exploring the therapeutic potential of MDH and related genes. These studies show that MDH activity has important roles in many metabolic pathways, and thus in the metabolic transitions of protozoan parasites needed for success as pathogens.

Complement-dependent loss of inhibitory synapses on pyramidal neurons following Toxoplasma gondii infection

The apicomplexan parasite Toxoplasma gondii has developed mechanisms to establish a central nervous system infection in virtually all warm-blooded animals. Acute T. gondii infection can cause neuroinflammation, encephalitis, and seizures. Meanwhile, studies in humans, nonhuman primates, and rodents have linked chronic T. gondii infection with altered behavior and increased risk for neuropsychiatric disorders, including schizophrenia. These observations and associations raise questions about how this parasitic infection may alter neural circuits. We previously demonstrated that T. gondii infection triggers the loss of inhibitory perisomatic synapses, a type of synapse whose dysfunction or loss has been linked to neurological and neuropsychiatric disorders. We showed that phagocytic cells (including microglia and infiltrating monocytes) contribute to the loss of these inhibitory synapses. Here, we show that these phagocytic cells specifically ensheath excitatory pyramidal neurons, leading to the preferential loss of perisomatic synapses on these neurons and not those on cortical interneurons. Moreover, we show that infection induces an increased expression of the complement C3 gene, including by populations of these excitatory neurons. Infecting C3-deficient mice with T. gondii revealed that C3 is required for the loss of perisomatic inhibitory synapses. Interestingly, loss of C1q did not prevent the loss of perisomatic synapses following infection. Together, these findings provide evidence that T. gondii induces changes in excitatory pyramidal neurons that trigger the selective removal of inhibitory perisomatic synapses and provide a role for a nonclassical complement pathway in the remodeling of inhibitory circuits in the infected brain.

Emerging Infectious Diseases and the Eye: Ophthalmic Manifestations, Pathogenesis, and One Health Perspectives

Infectious diseases may lead to ocular complications including uveitis, an ocular inflammatory condition with potentially sight-threatening sequelae, and conjunctivitis, inflammation of the conjunctiva. Emerging infectious pathogens with known ocular findings include Ebola virus, Zika virus, Avian influenza virus, Nipah virus, severe acute respiratory syndrome coronaviruses, and Dengue virus. Re-emerging pathogens with ocular findings include Toxoplasma gondii and Plasmodium species that lead to malaria. The concept of One Health involves a collaborative and interdisciplinary approach to achieve optimal health outcomes by combining human, animal, and environmental health factors. This approach examines the interconnected and often complex human-pathogen-intermediate host interactions in infectious diseases that may also result in ocular disease, including uveitis and conjunctivitis. Through a comprehensive review of the literature, we review the ophthalmic findings of emerging infectious diseases, pathogenesis, and One Health perspectives that provide further insight into the disease state. While eye care providers and vision researchers may often focus on key local aspects of disease process and management, additional perspective on host-pathogen-reservoir life cycles and transmission considerations, including environmental factors, may offer greater insight to improve outcomes for affected individuals and stakeholders.

The quality and characteristics of bovine sperm are compromised by Toxoplasma gondii antigens, impacting in in vitro bull fertility

Studies in various species have demonstrated different results on the effects of T. gondii infection on sperm quality. It has also been demonstrated that in some stages of the disease, there is elimination of cellular debris or even the intact parasite in the semen. The present work aimed to evaluate the in vitro effects of the presence of soluble T. gondii antigens in bovine semen on sperm integrity. The spermatozoa were treated with T. gondii antigens in double serial dilutions classified as high, medium and low doses (8, 4, 2 µg/ml) in "TALP-Sperm" and "TALP-Fert" media. The results showed that T. gondii antigens affect sperm motility and mitochondrial activity, and cause changes in sperm chromatin integrity, as well as damage to the sperm membrane and acrosome. Finally, spermatozoa treated with T. gondii antigens were evaluated in the in vitro production of embryos (IVEP). The use of semen contaminated with antigens in IVEP routines did not lead to a decrease in the fertilization of oocytes, as sperm undergo selection before in vitro fertilization, which eliminates the most altered sperm. However, early embryonic development was affected, probably by structural changes that were not eliminated in the selection process. The results demonstrated that the presence of soluble T. gondii antigens in bovine semen alters sperm integrity and vital characteristics for the fertilization process and embryonic development and therefore causes fertility problems in males.

Motility-dependent processes in Toxoplasma gondii tachyzoites and bradyzoites: same same but different

The tachyzoite stage of the apicomplexan parasite Toxoplasma gondii utilizes motility for multiple purposes during its lytic cycle, including host cell invasion, egress from infected cells, and migration to new uninfected host cells to repeat the process. Bradyzoite stage parasites, which establish a new infection in a naïve host, must also use motility to escape from the cysts that are ingested by the new host and then migrate to the gut wall, where they either invade cells of the intestinal epithelium or squeeze between these cells to infect the underlying connective tissue. We know very little about the motility of bradyzoites, which we analyze in detail here and compare to the well-characterized motility and motility-dependent processes of tachyzoites. Unexpectedly, bradyzoites were found to be as motile as tachyzoites in a 3D model extracellular matrix, and they showed increased invasion into and transmigration across certain cell types, consistent with their need to establish the infection in the gut. The motility of the two stages was inhibited to the same extent by cytochalasin D and KNX-002, compounds known to target the parasite's actomyosin-based motor. In contrast, other compounds that impact tachyzoite motility (tachyplegin and enhancer 5) have less of an effect on bradyzoites, and rapid bradyzoite egress from infected cells is not triggered by treatment with calcium ionophores, as it is with tachyzoites. The similarities and differences between these two life cycle stages highlight the need to characterize both tachyzoites and bradyzoites for a more complete understanding of the role of motility in the parasite life cycle and the effect that potential therapeutics targeting parasite motility will have on disease establishment and progression.

Associations between Fetal Symptoms during Pregnancy and Neonatal Clinical Complications with Toxoplasmosis

INTRODUCTION

Toxoplasmosis is a parasitism transmitted by Toxoplasma gondii, part of the TORCH complex, the most prevalent parasitism worldwide. It is asymptomatic in immunocompetent individuals but causes severe infections and developmental abnormalities in pregnant women, mainly affecting the central nervous system and the gastrointestinal system.

METHODS

In our prospective study, we analyzed cases of recent maternal Toxoplasma infections confirmed by serological testing between 1996 and 2020 at the Department of Obstetrics and Gynecology, Semmelweis University. Amniocentesis, followed by PCR, was performed in cases of recent infection confirmed by serological testing during pregnancy. After birth, a neonatological, microbiological, pediatric neurological and ophthalmological examination and a follow-up was carried out.

RESULTS

During the study period, a total of 238 cases of amniotic fluid Toxoplasma PCR testing due to Toxoplasma recent infection were performed. In terms of pregnancies, there were 219 deliveries and seven abortions. Twelve cases had no data available on the outcome of the pregnancy. In total, 133 cases of ultrasound abnormalities were detected during pregnancy, while in 105 cases, no abnormalities were detected on ultrasound examination. During amniocentesis, eight cases of Toxoplasma infection were revealed in amniotic fluid samples by PCR, and in 230 cases, the result was negative. Neonatal follow-up was performed in 139 cases, with no abnormalities during follow-up in 117 cases, and in 22 cases, there was a detectable complication that was likely to be related to Toxoplasma infection. In all 22 cases, amniotic fluid PCR Toxoplasma testing was negative.

CONCLUSIONS

The most common ultrasound abnormalities involve the nervous system and the gastrointestinal system. In cases of suspicion, it is recommended to perform amniocentesis Toxoplasma PCR testing besides the indirect methods to help the pregnant woman decide whether to carry the pregnancy to term. During follow-up, a multidisciplinary team experienced in pregnancies complicated by toxoplasmosis must carry out the follow-up, care and subsequent development.

Anti-Toxoplasma gondii effects of XYP1-derived peptides and regulatory mechanisms of XYP1

BACKGROUND

Toxoplasmosis, caused by Toxoplasma gondii , poses serious health issues for humans and animals. Individuals with impaired immune systems are more susceptible to severe toxoplasmosis. Pregnant women infected by T. gondii can face the possibility of birth defects and miscarriages. While pyrimethamine and sulfadiazine are commonly used drugs in clinical practice, concerns over their side effects and resistance are on the rise. A spider peptide XYP1 isolated from Lycosa coelestis had potent anti-T. gondii effects, but it had a high synthesis cost and strong cytotoxicity.

METHODS

This study intended to modify XYP1 for producing derived peptides via amino acid truncation and substitution. The anti-T. gondii effect was evaluated by trypan blue staining assay and killing experiment of RH strain tachyzoites. The CCK8 and hemolysis assays were used to compare their safeties. The morphological changes of T. gondii were observed by scanning electron microscope and transmission electron microscope. In addition, the mechanism of XYP1 against T. gondii through RNA-sequencing was further explored.

RESULTS

In vivo and in vitro experiments revealed that XYP1-18 and XYP1-18-1 had excellent anti-T. gondii activity with lower cytotoxicity and hemolysis activity than XYP1. XYP1, XYP1-18, and XYP1-18-1 were able to disrupt the surface membrane integrity of T. gondii tachyzoites, forming pores and causing the disruption of organelles. Furthermore, RNA-sequencing analysis indicated that XYP1 could stimulate the host immune response to effectively eliminate T. gondii and lessen the host's inflammatory reaction.

CONCLUSIONS

XYP1-18 had lower cytotoxicity and hemolysis activity than XYP1, as well as significantly extending the survival time of the mice. XYP1 played a role in host inflammation and immune responses, revealing its potential mechanism. Our research provided valuable insights into the development and application of peptide-based drugs, offering novel strategies and directions for treating toxoplasmosis.

Prevalence of Human Toxoplasmosis in Spain Throughout the Three Last Decades (1993-2023): A Systematic Review and Meta-analysis

Humans are infected by Toxoplasma gondii worldwide and its consequences may seriously affect an immune deprived population such as HIV and transplanted patients or pregnant women and foetuses. A deep knowledge of toxoplasmosis seroprevalence in Spain is needed in order to better shape health policies and educational programs. We present the results of the first systematic review and meta-analysis on the human prevalence for this disease in Spain. Databases (PubMed, Web of Science, SCOPUS and Teseo) were searched for relevant studies that were published between January 1993 and December 2023 and all population-based cross-sectional and longitudinal studies reporting the human seroprevalence in Spain were revised. Within the population analysed, our targeted groups were immunocompetent population, pregnant women and immunocompromised patients. Among 572 studies and 35 doctoral theses retrieved, 15 studies and three doctoral theses were included in the meta-analysis. A random effects model was used for the meta-analyses due to the high heterogeneity found between studies (I2: 99.97), since it is a statistically conservative model, in addition to allowing better external validity. The global pooled seroprevalence was 32.3% (95% CI 28.7-36.2%). Most of the studies carried out were in pregnant women and the meta-analysis reported that the pooled seroprevalence of toxoplasmosis in pregnant women in Spain was 24.4% (24,737/85,703, 95% CI 21.2-28.0%), based on the random effects model. It is recommended to continue monitoring the seroprevalence status of T. gondii in order to obtain essential guidelines for the prevention and control of the infection in the population.

IgG seroprevalence of Toxoplasma gondii and Leishmania infantum in leprosy patients: Implications for screening and management of co-infections

Parasitic co-infections are common in developing countries and can interfere with leprosy treatment, leading to an increased risk of inflammatory leprosy reactions. This study assessed serum immunoglobulin G (IgG) levels against Toxoplasma gondii and Visceral Leishmaniasis (VL) antigens in 270 leprosy patients from Brazilian states. Regarding the respective cut-offs, the prevalence of IgG seropositivity for T. gondii and VL were 21.05 % and 47.36 % in the leprosy-negative group, and 77.7 % and 52.6 % in the leprosy-positive group. Of the 270 leprosy patients, 158 (58.5 %) presented with inflammatory leprosy reactions. Of those, 72 (59.5 %) had neuritis, 35 (48.6 %) had reverse reactions, and 28 (38.9 %) had ENL in both Brazilian states. Leprosy patients with anti-Leishmania IgG seropositivity were 3.25 times more likely to develop neuritis (95 % C.I.: 1.187 - 9.154; p = 0.019). These findings are particularly relevant for clinical settings where both leprosy and parasitic diseases are prevalent and could provide essential guidance for detecting and addressing complications arising from parasitic co-infections in leprosy patients, thereby improving clinical management strategies.

Assessment of nebivolol efficacy in experimental models of toxoplasmosis: insights into parasite burden reduction and neuronal protection

This study investigates the efficacy of nebivolol (NBV) in experimental models of toxoplasmosis, focusing on parasite burden reduction and neuronal protection. In the acute model of experimental toxoplasmosis, Swiss mice infected with RH strain tachyzoites received oral NBV chlorhydrate doses of 2 mg/kg/day and 4 mg/kg/day for 8 days. Treatment with NBV significantly reduced parasite burden compared to vehicle and standard drug (PYR) groups. In the chronic model of experimental toxoplasmosis, C57/BL6 mice infected with the ME49 strain received NBV chlorhydrate 41 days post-infection and were evaluated after 10 days of treatment. NBV chlorhydrate effectively reduced cyst number and area, as well as bradyzoite burden compared to controls. Histological analysis demonstrated that NBV chlorhydrate preserved neuronal count, with the 4 mg/kg/day dose yielding counts similar to non-infected mice. Statistical analysis confirmed significant differences compared to control groups. Furthermore, immunohistochemical analysis revealed a significant reduction in iNOS labeling in the brains of mice treated with NBV chlorhydrate, indicating a decrease in nitric oxide production compared to control groups. These findings suggest NBV's potential as a promising candidate for toxoplasmosis treatment, highlighting its ability to reduce parasite burden and protect neuronal integrity. Further research is warranted to elucidate NBV's mechanisms of action and its clinical application in managing toxoplasmosis.

In vitro and in vivo activities of a trithiolato-diRuthenium complex conjugated with sulfadoxine against the apicomplexan parasite Toxoplasma gondii

Organometallic compounds, including Ruthenium complexes, have been widely developed as anti-cancer chemotherapeutics, but have also attracted much interest as potential anti-parasitic drugs. Recently hybrid drugs composed of organometallic Ruthenium moieties that were complexed to different antimicrobial agents were synthesized. One of these compounds, a trithiolato-diRuthenium complex (RU) conjugated to sulfadoxine (SDX), inhibited proliferation of Toxoplasma gondii tachyzoites grown in human foreskin fibroblast (HFF) monolayers with an IC50 < 150 nM, while SDX and the non-modified RU complex applied either individually or as an equimolar mixture were much less potent. In addition, conjugation of SDX to RU lead to decreased HFF cytotoxicity. RU-SDX did not impair the in vitro proliferation of murine splenocytes at concentrations ranging from 0.1 to 0.5 μM but had an impact at 2 μM, and induced zebrafish embryotoxicity at 20 μM, but not at 2 or 0.2 μM. RU-SDX acted parasitostatic but not parasiticidal, and induced transient ultrastructural changes in the mitochondrial matrix of tachyzoites early during treatment. While other compounds that target the mitochondrion such as the uncouplers FCCP and CCCP and another trithiolato-Ruthenium complex conjugated to adenine affected the mitochondrial membrane potential, no such effect was detected for RU-SDX. Evaluation of the in vivo efficacy of RU-SDX in a murine T. gondii oocyst infection model comprised of non-pregnant outbred CD1 mice showed no effects on the cerebral parasite burden, but reduced parasite load in the eyes and in heart tissue.

A Review of Immunological and Neuropsychobehavioral Effects of Latent Toxoplasmosis on Humans

Toxoplasmosis as a zoonotic disease has a worldwide distribution and can infect a wide range of animal hosts, as well as at least one third of the world's human population. The disease is usually mild or asymptomatic in immunocompetent individuals, but dormant tissue cysts survive especially in the brain for the host lifespan, known as latent toxoplasmosis (LT). Recent studies suggest that LT can have certain neurological, immunological psychological and behavioural effects on human including schizophrenia, bipolar disorder, Alzheimer's disease, depression, suicide anxiety and sleeping disorders. LT effects are controversial, and their exact mechanisms of action is not yet fully understood. This review aims to provide an overview of the potential effects, their basic mechanisms including alteration of neurotransmitter levels, immune activation in the central nervous system and induction of oxidative stress. Additionally, beneficial effects of LT, and an explanation of the effects within the framework of manipulation hypothesis, and finally, the challenges and limitations of the current research are discussed.

Identification of novel biomarkers for anti-Toxoplasma gondii IgM detection and the potential application in rapid diagnostic fluorescent tests

Toxoplasmosis, while often asymptomatic and prevalent as a foodborne disease, poses a considerable mortality risk for immunocompromised individuals during pregnancy. Point-of-care serological tests that detect specific IgG and IgM in patient sera are critical for disease management under limited resources. Despite many efforts to replace the T. gondii total lysate antigens (TLAs) by recombinant antigens (rAgs) in commercial kits, while IgG detection provides significant specificity and sensitivity, IgM detection remains comparatively low in sensitivity. In this study, we attempted to identify novel antigens targeting IgM in early infection, thereby establishing an IgM on-site detection kit. Using two-dimensional gel electrophoresis (2DE) and mouse serum immunoblotting, three novel antigens, including EF1γ, PGKI, and GAP50, were indicated to target T. gondii IgM. However, rAg EF1γ was undetectable by IgM of mice sera in Western blotting verification experiments, and ELISA coated with PGKI did not eliminate cross-reactivity, in contrast to GAP50. Subsequently, the lateral flow reaction employing a strip coated with 0.3 mg/mL purified rAg GAP50 and exhibited remarkable sensitivity compared with the conventional ELISA based on tachyzoite TLA, which successfully identified IgM in mouse sera infected with tachyzoites, ranging from 103 to 104 at 5 dpi and 104 at 7 dpi, respectively. Furthermore, by using standard T. gondii-infected human sera from WHO, the limit of detection (LOD) for the rapid fluorescence immunochromatographic test (FICT) using GAP50 was observed at 0.65 IU (international unit). These findings underline the particular immunoreactivity of GAP50, suggesting its potential as a specific biomarker for increasing the sensitivity of the FICT in IgM detection.

MicroRNA mmu-miR-511-5p: A promising Diagnostic Biomarker in Experimental Toxoplasmosis Using Different Strains and Infective Doses in Mice with Different Immune States Before and After Treatment

PURPOSE

Searching for a novel early diagnostic biomarker for toxoplasmosis, real-time-PCR was currently used to measure the serum mmu-miR-511-5p level in male Swiss-albino mice infected with either; ME49 or RH Toxoplasma gondii (T. gondii) strains.

METHODS

Three mice groups were used; (GI) constituted the non-infected control group, while (GII) and (GIII) were experimentally infected with ME49 or RH strains, respectively. GII mice were orally infected using 10 or 20 ME49 cysts (ME-10 and ME-20), both were subdivided into; non-treated (ME-10-NT and ME-20-NT) and were further subdivided into; immunocompetent (ME-10-IC and ME-20-IC) [euthanized 3-days, 1, 2, 6 or 8-weeks post-infection (PI)], and immunosuppressed using two Endoxan® injections (ME-10-IS and ME-20-IS) [euthanized 6- or 8-weeks PI], and spiramycin-treated (ME-10-SP and ME-20-SP) that received daily spiramycin, for one-week before euthanasia. GIII mice individually received 2500 intraperitoneal RH strain tachyzoites, then, were subdivided into; non-treated (RH-NT) [euthanized 3 or 5-days PI], and spiramycin-treated (RH-SP) that were euthanized 5 or 10-days PI (refer to the graphical abstract).

RESULTS

Revealed significant upregulation of mmu-miR-511-5p in GII, one-week PI, with gradually increased expression, reaching its maximum 8-weeks PI, especially in ME-20-NT group that received the higher infective dose. Immunosuppression increased the upregulation. Contrarily, treatment caused significant downregulation. GIII recorded significant upregulation 3-days PI, yet, treatment significantly decreased this expression.

CONCLUSION

Serum mmu-miR-511-5p is a sensitive biomarker for early diagnosis of ME49 and RH infection (as early as one-week and 3-days, respectively), and its expression varies according to T. gondii infective dose, duration of infection, spiramycin-treatment and host immune status.

Oral Sex as a Potential Route for Toxoplasma Gondii Transmission: Experiment with Human Semen and Laboratory Mice Model

PURPOSE

Toxoplasma gondii is one of the most widespread parasites in the human population globally. Several modes of its transmission have been proposed: some are well-researched and confirmed, others remain unconfirmed. One unconfirmed hypothesis pertains to potential transmission of Toxoplasma gondii via oral sex (fellatio) in humans. A recent study found tissue cysts in the semen of men with latent toxoplasmosis. Therefore, we aimed to test the hypothesis of Toxoplasma gondii transmission through oral sex experimentally.

METHODS

Eighty-two laboratory mice were orally administered semen samples from 41 men with latent toxoplasmosis. These semen samples were examined for the presence of Toxoplasma gondii DNA using PCR.

RESULTS

We detected Toxoplasma gondii DNA in three of the 41 semen samples from men with latent toxoplasmosis. Oral administration of semen samples to laboratory mice did not result in parasite transmission.

CONCLUSION

We have not demonstrated the transmission of Toxoplasma to mice by oral exposure to semen from infected men. While this does not conclusively rule out the possibility of such transmission in humans, the results suggest that, if it does occur, this mode of transmission is likely infrequent.

Cognitive Effects of Toxoplasma and CMV Infections: A Cross-Sectional Study of 557 Young Adults Considering Modulation by Sex and Rh Factor

One-third of humanity harbors a lifelong infection with Toxoplasma gondii, and probably about 80% are infected with human cytomegalovirus (CMV). This study aims to delineate the associations between toxoplasmosis and cognitive abilities and compare these to the associations with CMV. We evaluated the cognitive performance of 557 students, who had been examined for Toxoplasma and CMV infections, using intelligence, memory, and psychomotor tests. The results indicated cognitive impairments in seropositive individuals for both pathogens, with variations in cognitive impact related to sex and the Rh factor. Specifically, Toxoplasma infection was associated with lower IQ in men, whereas CMV was predominantly associated with worse performance by women when testing memory and reaction speeds. Analysis of the antibody concentrations indicated that certain Toxoplasma-associated cognitive detrimental effects may wane (impaired intelligence) or worsen (impaired reaction times) over time following infection. The findings imply that the cognitive impairments caused by both neurotropic pathogens are likely due to pathological changes in the brain rather than from direct manipulative action by the parasites.

Effect of concurrent infection of Helicobacter pylori with Toxoplasma gondii infection on gastric pathology

BACKGROUND

Toxoplasma gondii (T. gondii) and Helicobacter pylori (H. pylori) are among the most prevalent foodborne parasitic and bacterial infections worldwide. However, the concurrent impact of coinfection on gastric pathology has yet to be studied in depth. The effect of coinfection generally either adds a synergetic or antagonistic impact; we aimed in the current work to assess the impact of T. gondii coinfection on the progression of H. pylori-associated gastric pathology and reporting H. pylori virulent strains. The study was conducted on 82 patients complaining of persistent gastrointestinal symptoms with failed treatment response and prone to endoscopy. They were subjected to stool examination to detect H. pylori antigen, serological screening for latent toxoplasmosis, endoscopy, histopathological examination, and molecular detection of H. pylori virulence strains in gastric biopsies. Out of the 82 patients, 62 patients were positive for H. pylori antigen in stool and 55 patients confirmed positivity by histopathology; out of them, 37 patients had isolated Vac As1 variants, 11 patients had combined Vac As1 and Cag A variants, and 7 patients had combined Vac As1, Cag A and VacAs2 variants. Patients with the combined two or three variances showed significantly deteriorated histopathological features than patients with a single Vac As1 variant (P < 0.05). Latent toxoplasmosis was positive among 35/82 patients. Combined H. pylori and Toxoplasma gondii infection had significantly marked inflammation than patients with isolated infection (P < 0.05).

CONCLUSION

Screening for toxoplasmosis among H. pylori-infected patients is recommended as it is considered a potential risk factor for gastric inflammation severity. H. pylori gastric inflammation may be heightened by Toxoplasma coinfection.

Toxoplasma gondii Infection in Humans: A Comprehensive Approach Involving the General Population, HIV-Infected Patients and Intermediate-Duration Fever in the Canary Islands, Spain

A prior investigation in 1993 identified a high seroprevalence of toxoplasmosis (63%) in the Canary Islands. This study aims to assess the current prevalence of the disease in diverse population groups. The study was based on a population-scale screening involving 273 residents utilizing T. gondii IgG ELISA and a 20 year retrospective study (1998-2018). This included AIDS/HIV outpatients (1357, of which 324 were residents), AIDS/HIV hospitalized patients (741) and patients with fever of intermediate duration (158). The seroprevalence in the resident population was 37%, with significant differences between islands. Among resident outpatients with AIDS/HIV, 14.2% had specific anti-T. gondii IgG, and three had anti-T. gondii IgM; however, IgG avidity testing indicated non-active infection. In patients hospitalized for AIDS/HIV, T. gondii causing encephalitis was detected in 2%. Among patients with fever of intermediate duration, 28.5% were positive for T. gondii IgG, and four also showed IgM positivity, although the infection was non-active. The study reveals a decrease in human toxoplasmosis over the past 30 years. However, the current seroprevalence, which stands at 37%, together with the substantial risk that T. gondii represents for immunocompromised individuals, highlights the need to implement preventive and control strategies to control the threat that this infection can pose to public health in the Canary Islands population.

Toxoplasma gondii infection and testosterone alteration: A systematic review and meta-analyses

BACKGROUND

Toxoplasma gondii (T. gondii) is a worldwide distributed protozoan parasite which has infected a wide range of warm-blooded animals and humans. The most common form of T. gondii infection is asymptomatic (latent); nevertheless, latent toxoplasmosis can induce various alterations of sex hormones, especially testosterone, in infected humans and animals. On the other hand, testosterone is involved in behavioral traits and reproductive functions in both sexes. Hence, the purpose of this systematic review is to summarize the available evidence regarding the association between T. gondii infection and testosterone alteration.

METHODS

In the setting of a systematic review, an electronic search (any date to 10 January 2023) without language restrictions was performed using Science Direct, Web of Science, PubMed, Scopus, and Google Scholar. The PRISMA guidelines were followed. Following the initial search, a total of 12,306 titles and abstracts were screened initially; 12,281 were excluded due to the lack of eligibility criteria or duplication. Finally, 24 articles met the included criteria. A mean±standard deviation (SD) was calculated to assess the difference of testosterone between T. gondii positive and T. gondii negative humans. The possibility of publication bias was assessed using Egger's regression. P-value < 0.05 was considered statistically significant.

RESULTS

This systematic review identified 24 articles (18 studies in humans and six studies in animals). Most human studies (13 out of 19) reported an increased level of testosterone following latent toxoplasmosis in males, while three studies reported decreased levels and two studies reported an insignificant change. Eleven articles (seven datasets in males and seven datasets in females) were eligible to be included in the data synthesis. Based on the random-effects model, the pooled mean± SD of testosterone in T. gondii positive than T. gondii negative was increased by 0.73 and 0.55 units in males and females, respectively. The Egger's regression did not detect a statistically significant publication bias in males and females (p = value = 0.95 and 0.71), respectively. Three studies in male animals (rats, mice, and spotted hyenas) and two studies in female animals (mice and spotted hyenas) reported a decline in testosterone in infected compared with non-infected animals. While, one study in female rats reported no significant changes of testosterone in infected than non-infected animals. Moreover, two studies in male rats reported an increased level of testosterone in infected than non-infected animals.

CONCLUSIONS

This study provides new insights about the association between T. gondii infection and testosterone alteration and identifies relevant data gaps that can inform and encourage further studies. The consequence of increased testosterone levels following T. gondii infection could partly be associated with increased sexual behavior and sexual transmission of the parasite. On the other hand, declining testosterone levels following T. gondii infection may be associated with male reproductive impairments, which were observed in T. gondii-infected humans and animals. Furthermore, these findings suggest the great need for more epidemiological and experimental investigations in depth to understand the relationship between T. gondii infection and testosterone alteration alongside with future consequences of testosterone alteration.

Advancing Toxoplasma gondii multiplex serology

Toxoplasma gondii is a highly prevalent pathogen causing zoonotic infections with significant public health implications. Yet, our understanding of long-term consequences, associated risk factors, and the potential role of co-infections is still limited. Seroepidemiological studies are a valuable approach to address open questions and enhance our insights into T. gondii across human populations. Here, we present substantial advancements to our previously developed T. gondii multiplex serology assay, which is based on the immunodominant antigens SAG1 and P22. While our previous bead-based assay quantified antibody levels against multiple targets in a high-throughput fashion requiring only a small sample volume, impaired assay characteristics emerged in sample dilutions beyond 1:100 and when being transferred to magnetic beads. Both are now critical for inclusion in large-scale seroprevalence studies. Using the truncated versions, SAG1D1 and P22trunc, significantly enhanced signal-to-noise ratios were achieved with almost perfect concordance with the gold-standard Sabin-Feldman dye test. In sample dilutions of 1:100, the diagnostic accuracy of SAG1D1 and P22trunc reached sensitivities (true positive rates) of 98% and 94% and specificities (true negative rates) of 93% and 95%, respectively. Importantly, performance metrics were reproducible in a 1:1,000 sample dilution, using both magnetic and nonmagnetic beads. Thresholds for seropositivity were derived from finite mixture models and performed equally well as thresholds by receiver operating characteristic analysis. Our improved multiplex serology assay is therefore able to generate robust and reproducible performance metrics under various assay conditions. Inclusion of T. gondii antibody measurements with other pathogens, in multiplex serology panels will allow for large-scale seroepidemiological research.

IMPORTANCE

Toxoplasma gondii is a pathogen of significant public health concern due to its widespread prevalence and zoonotic potential. However, our understanding of key aspects, such as risk factors for infection and disease, potential outcomes, and their trends, remains limited. Seroepidemiological studies in large cohorts are invaluable for addressing these questions but remain scarce. Our revised multiplex serology assay equips researchers with a powerful tool capable of delivering T. gondii serum antibody measurements with high sensitivity and specificity under diverse assay conditions. This advancement paves the way for the integration of T. gondii antibody measurements into multi-pathogen multiplex serology panels, promising valuable insights into public health and pathogen interactions.

Home range size and habitat selection of owned outdoor domestic cats (Felis catus) in urban southwestern Ontario

Domestic cats (Felis catus) play a dual role in society as both companion animals and predators. When provided with unsupervised outdoor access, cats can negatively impact native wildlife and create public health and animal welfare challenges. The effective implementation of management strategies, such as buffer zones or curfews, requires an understanding of home range size, the factors that influence their movement, and the types of habitats they use. Here, we used a community/citizen scientist approach to collect movement and habitat use data using GPS collars on owned outdoor cats in the Kitchener-Waterloo-Cambridge-Guelph region, southwestern Ontario, Canada. Mean (± SD) 100% minimum convex polygon home range size was 8 ± 8 ha (range: 0.34-38 ha) and was positively associated with road density but not with intrinsic factors such as boldness, sex, or age. With regards to habitat selection, cats used greenspaces, roads, and agricultural land less often than predicted but strongly selected for impervious surfaces (urban areas other than greenspaces or roads). Our results suggest that wildlife near buildings and residential areas are likely at the greatest risk of cat predation and that a buffer size of 840 m would be needed to restrict cats from entering areas of conservation concern.

Revealing the Prevalence of Toxoplasma in Sierra Morena's Wild Boar: An ELISA-Based Study Using Meat Juice

This research work focused on the prevalence of Toxoplasma gondii in wild boar from the Sierra Morena region. We conducted an ELISA analysis using meat juice samples. A total of 892 samples from six hunting seasons (2013-2019) were collected from the provinces that constitute the Sierra Morena Mountain range. These samples were analyzed using the Pigtype® ELISA kit, specifically developed for detecting T. gondii in meat juice. The overall prevalence of T. gondii in Sierra Morena was 23.2%. The highest prevalences were observed in Córdoba (31.6%) and Jaén (25.9%). These provinces exhibit the highest density of wild boar as well as the greatest presence of the Iberian lynx (Lynx pardinus). Further in-depth studies are necessary, but it appears that the presence of wild felids and scavenger behavior may be associated with this observation.

Positive Toxoplasma IgG Serology Is Associated with Increased Overall Mortality - A Propensity Score-Matched Analysis

Toxoplasma gondii is a prevalent parasitic disease with significant morbidity and mortality in immunocompromised populations. We lack long-term outcomes for latent infections. We aimed to elucidate the relationship between latent T. gondii infection and mortality risk. We queried TriNetX, a international multicenter network, to validate mortality risk differences among patients with positive or negative toxoplasma IgG through propensity score matching (PSM). We excluded patients with toxoplasmosis disease by International Classification of Diseases codes or polymerase chain reaction testing. We found 28,138 patients with available toxoplasma IgG serology. Seropositive patients were older and had a male preponderance. More seropositive patients identified as Hispanic, Latino, or Black persons. Patients who were positive for T. gondii IgG serology were slightly more likely to have underlying heart failure, a transplanted organ or tissue, malignant neoplasms of lymphoid or hematopoietic tissues, and diseases of the nervous system than seronegative controls. After PSM of patients with positive (N = 6,475) and negative (N = 6,475) toxoplasma IgG serologies, toxoplasmosis-positive patients were more likely to have long-term drug use but less likely to suffer from behavioral disorders. The overall PSM 1- and 5-year mortality was higher among patients with a positive toxoplasma IgG serology. The risk of schizophrenia was increased at 5 years. We found a prevalence of toxoplasma IgG positivity of 0.03% during the last 3 years. Latent T. gondii associates with a higher overall mortality risk. The study of social determinants of health and follow-up studies are necessary to corroborate the findings and find possible causal mechanisms.

Beyond the acute phase: a comprehensive literature review of long-term sequelae resulting from infectious diseases

Infectious diseases have consistently served as pivotal influences on numerous civilizations, inducing morbidity, mortality, and consequently redirecting the course of history. Their impact extends far beyond the acute phase, characterized by the majority of symptom presentations, to a multitude of adverse events and sequelae that follow viral, parasitic, fungal, or bacterial infections. In this context, myriad sequelae related to various infectious diseases have been identified, spanning short to long-term durations. Although these sequelae are known to affect thousands of individuals individually, a comprehensive evaluation of all potential long-term effects of infectious diseases has yet to be undertaken. We present a comprehensive literature review delineating the primary sequelae attributable to major infectious diseases, categorized by systems, symptoms, and duration. This compilation serves as a crucial resource, illuminating the long-term ramifications of infectious diseases for healthcare professionals worldwide. Moreover, this review highlights the substantial burden that these sequelae impose on global health and economies, a facet often overshadowed by the predominant focus on the acute phase. Patients are frequently discharged following the resolution of the acute phase, with minimal long-term follow-up to comprehend and address potential sequelae. This emphasizes the pressing need for sustained vigilance, thorough patient monitoring, strategic health management, and rigorous research to understand and mitigate the lasting economic and health impacts of infectious diseases more fully.

Drivers of infection with Toxoplasma gondii genotype type II in Eurasian red squirrels (Sciurus vulgaris)

BACKGROUND

In September 2014, there was sudden upsurge in the number of Eurasian red squirrels (Sciurus vulgaris) found dead in the Netherlands. High infection levels with the parasite Toxoplasma gondii were demonstrated, but it was unclear what had caused this increase in cases of fatal toxoplasmosis. In the present study, we aimed to gain more knowledge on the pathology and prevalence of T. gondii infections in Eurasian red squirrels in the Netherlands, on the T. gondii genotypes present, and on the determinants of the spatiotemporal variability in these T. gondii infections. The presence of the closely related parasite Hammondia hammondi was also determined.

METHODS

Eurasian red squirrels that were found dead in the wild or that had died in wildlife rescue centres in the Netherlands over a period of seven years (2014-2020) were examined. Quantitative real-time polymerase chain reaction was conducted to analyse tissue samples for the presence of T. gondii and H. hammondi DNA. Toxoplasma gondii-positive samples were subjected to microsatellite typing and cluster analysis. A mixed logistic regression was used to identify climatic and other environmental predictors of T. gondii infection in the squirrels.

RESULTS

A total of 178 squirrels were examined (49/178 T. gondii positive, 5/178 H. hammondi positive). Inflammation of multiple organs was the cause of death in 29 squirrels, of which 24 were also T. gondii polymerase chain reaction positive. Toxoplasma gondii infection was positively associated with pneumonia and hepatitis. Microsatellite typing revealed only T. gondii type II alleles. Toxoplasma gondii infection rates showed a positive correlation with the number of days of heavy rainfall in the previous 12 months. Conversely, they showed a negative association with the number of hot days within the 2-week period preceding the sampling date, as well as with the percentage of deciduous forest cover at the sampling site.

CONCLUSIONS

Toxoplasma gondii infection in the squirrels appeared to pose a significant risk of acute mortality. The T. gondii genotype detected in this study is commonly found across Europe. The reasons for the unusually high infection rates and severe symptoms of these squirrels from the Netherlands remain unclear. The prevalence of T. gondii in the deceased squirrels was linked to specific environmental factors. However, whether the increase in the number of dead squirrels indicated a higher environmental contamination with T. gondii oocysts has yet to be established.

Pre-Transplant Seroprevalence, Associated Factors, and Post-Transplant Incidence of Toxoplasma gondii Infection Among Heart Transplant Recipients in Japan

BACKGROUND

Among solid organ transplant (SOT) recipients, heart transplant (HT) recipients are at a higher risk of Toxoplasma gondii infection. As Toxoplasma seroprevalence varies by geographic location, updated local epidemiology is essential to guide preventive and therapeutic strategies. However, the Toxoplasma seroprevalence and incidence of post-transplant toxoplasmosis among SOT recipients in Japan are unknown.

METHODS

We performed a single-center retrospective observational study at an HT center in Tokyo, Japan. All HT recipients aged ≥18 years between 2006 and April 2019 were included. We reviewed patient charts and conducted a questionnaire survey to investigate the risk factors for infection.

RESULTS

Among 105 recipients included in the study, 11 (10.5%) were seropositive before transplant. Ninety-five recipients (90.5%), including all pre-transplant seropositive recipients, answered the questionnaire. The recipients who had lived in Okinawa (odds ratio [OR] 7.5 [95% CI 1.42-39.61]; P = .032) and who reported raw-meat eating habits (OR 4.64 [95% CI 1.04-23.3]; P = .021) were more likely to be seropositive. None of the patients developed symptoms of toxoplasmosis. The post-transplant incidence of other major adverse outcomes was not significantly different according to the pre-transplant serostatus.

CONCLUSIONS

About 10% of HT recipients at an HT center in Tokyo were seropositive for Toxoplasma pre-transplant, and none developed symptomatic toxoplasmosis post-transplant on trimethoprim-sulfamethoxazole. The history of raw meat consumption was associated with seropositivity; therefore, avoiding it might be recommended for HT recipient candidates.

The role of species ecology in predicting Toxoplasma gondii prevalence in wild and domesticated mammals globally

Macroecological approaches can provide valuable insight into the epidemiology of globally distributed, multi-host pathogens. Toxoplasma gondii is a protozoan that infects any warm-blooded animal, including humans, in almost every habitat worldwide. Toxoplasma gondii infects its hosts through oocysts in the environment, carnivory of tissue cysts within intermediate host prey and vertical transmission. These routes of infection enable specific predictions regarding the ecological and life history traits that should predispose specific taxa to higher exposure and, thus infection rates of T. gondii. Using T. gondii prevalence data compiled from 485 studies representing 533 free-ranging wild mammalian species, we examined how ecological (habitat type, trophic level) and life history (longevity, vagility, gestation duration and torpor) traits influence T. gondii infection globally. We also compared T. gondii prevalence between wild and domesticated species from the same taxonomic families using data compiled from 540 studies of domestic cattle, sheep, and pigs. Across free-ranging wildlife, we found the average T. gondii prevalence was 22%, which is comparable to the global human estimate. Among ecological guilds, terrestrial species had lower T. gondii prevalence than aquatic species, with freshwater aquatic taxa having an increased prevalence compared to marine aquatic species. Dietary niches were also influential, with carnivores having an increased risk compared to other trophic feeding groups that have reduced tissue cyst exposure in their diet. With respect to influential life history traits, we found that more vagile wildlife species had higher T. gondii infection rates, perhaps because of the higher cumulative risk of infection during movement through areas with varying T. gondii environmental loads. Domestic farmed species had a higher T. gondii prevalence compared to free-ranging confamilial wildlife species. Through a macroecological approach, we determined the relative significance of transmission routes of a generalist pathogen, demonstrating an increased infection risk for aquatic and carnivorous species and highlighting the importance of preventing pathogen pollution into aquatic environments. Toxoplasma gondii is increasingly understood to be primarily an anthropogenically-associated pathogen whose dissemination is enhanced by ecosystem degradation and human subsidisation of free-roaming domestic cats. Adopting an ecosystem restoration approach to reduce one of the world's most common parasites would synergistically contribute to other initiatives in conservation, feline and wildlife welfare, climate change, food security and public health.

Enhancement of apoptosis in Caco-2, Hep-G2, and HT29 cancer cell lines following exposure to Toxoplasma gondii peptides

Objective

Cancer or neoplasm is a cosmopolitan catastrophe that results in more than 20 million new cases and 10 million deaths every year. Some factors lead to carcinogenesis like infectious diseases. Parasites like Toxoplasma gondii, by its components, could modulate the cancer system by inducing apoptosis. The objective of this investigation is to assess the potential of peptides derived from T. gondii in combating cancer by examining their effects on Caco-2, Hep-G2, and HT29 cell lines.

Materials and methods

Candidate peptide by its similarity to anticancer compounds was predicted through the computer-based analysis/platform. The impact of the peptide on cell viability, cell proliferation, and gene expression was evaluated through the utilization of MTT assay, flow cytometry, and real-time polymerase chain reaction (PCR) methodologies.

Results

The cell viability rate exhibited a significant decrease (p < 0.001) across all cell lines when exposed to a concentration of ≤160 μg. Within the 48-hour timeframe, the half maximal inhibitory concentration (IC50) for HT29 and Hep-G2 cell lines was determined to be 107.2 and 140.6 μg/mL, respectively. Notably, a marked decrease in the expression levels of Bcl2 and APAF1 genes was observed in both the Hep-G2 and HT29 cell lines.

Conclusion

These findings indicate that the T. gondii peptide affected cancer cell mortality and led to changes in the expression of genes associated with apoptosis.

Genetic diversity of Toxoplasma gondii in South America: occurrence, immunity, and fate of infection

Toxoplasma gondii is an intracellular parasite with a worldwide distribution. Toxoplasma gondii infections are of great concern for public health, and their impact is usually most severe in pregnant women and their foetuses, and in immunocompromised individuals. Displaying considerable genetic diversity, T. gondii strains differ widely according to geographical location, with archetypal strains predominantly found in the Northern Hemisphere and non-archetypal (atypical) strains, with highly diverse genotypes, found mainly in South America. In this review, we present an overview of the identification and distribution of non-archetypal strains of T. gondii. Special attention is paid to the strains that have been isolated in Brazil, their interaction with the host immunological response, and their impact on disease outcomes. The genetic differences among the strains are pivotal to the distinct immunological responses that they elicit. These differences arise from polymorphisms of key proteins released by the parasite, which represent important virulence factors. Infection with divergent non-archetypal strains can lead to unusual manifestations of the disease, even in immunocompetent individuals.

Anti-Toxoplasma gondii Antibodies in European Residents: A Systematic Review and Meta-Analysis of Studies Published between 2000 and 2020

Toxoplasmosis has a major impact on animal and public health. Information regarding the seroprevalence of human Toxoplasma gondii infections from a European perspective has not yet been compiled to date. Thus, the present review summarized available resident data from the period 2000-2020. The overall seroprevalence of anti-T. gondii IgG was 32.1%, with great variability between countries (n = 30). The subgroup analysis identified different pooled prevalence data depending on the geographic area (p < 0.0001), target population (p = 0.0147), and serological diagnosis assays used (p = 0.0059). A high heterogeneity (I2 = 100%, p < 0.001; Q = 3.5e+05, d.f. = 135, p < 0.001) and degree of publication bias (Egger's test = 6.14, p < 0.001) were observed among the 134 studies considered. The occurrence of anti-T. gondii IgM, which was reported in 64.7% of studies, reached a pooled seroprevalence of 0.6%. In addition, among the eight main risk factors identified, "contact with soil", "consumption of undercooked beef", and "intake of unwashed vegetables" were the most significantly associated with infections. The fact that one-third of the European population has been exposed to T. gondii justifies extra efforts to harmonize surveillance systems and develop additional risk-factor analyses based on detailed source attribution assessment.

Antibacterial and anti-Toxoplasma activities of Aspergillus niger endophytic fungus isolated from Ficus retusa: in vitro and in vivo approach

Emergent records propose that Aspergillus niger endophytic fungus is a vital source for various bioactive molecules possessing many biological properties. The current study was designed to inspect the antibacterial and anti-Toxoplasma potentials of Ficus retusa-derived endophytic fungi. After isolation and identification (using 18S rRNA gene sequencing) of A. niger endophytic fungus, LC/MS was utilized for identification and authentication of the chemical profile of the A. niger endophyte extract. Then, the fungal extract was assessed for its antibacterial and antibiofilm activities against Klebsiella pneumoniae clinical isolates. Additionally, its efficacy against Toxoplasma gondii was elucidated in vivo. The fungal extract displayed antibacterial activity against K. pneumoniae isolates with minimum inhibitory concentration values of 64-512 µg/mL. It also possessed a membrane potential dissipating effect using flow cytometry. Moreover, it formed distorted cells with rough surfaces and deformed shapes using a scanning electron microscope (SEM). Regarding its antibiofilm activity, it resulted in a dysregulation of the genes encoding biofilm formation (fimH, mrkA and mrkD) using qRT-PCR in nine K. pneumoniae isolates. The in vivo anti-Toxoplasma potential was demonstrated by decreasing the mortality rate of mice and reducing the tachyzoites' count in the peritoneal fluids and liver impression smears of mice. In addition, the deformities of the parasite decreased, as revealed by SEM and the inflammation in tissues diminished. Thus, A. niger endophytic fungi could be a valuable source of antibacterial and anti-Toxoplasma compounds.

Bat-associated microbes: Opportunities and perils, an overview

The potential biotechnological uses of bat-associated bacteria are discussed briefly, indicating avenues for biotechnological applications of bat-associated microbes. The uniqueness of bats in terms of their lifestyle, genomes and molecular immunology may predispose bats to act as disease reservoirs. Molecular phylogenetic analysis has shown several instances of bats harbouring the ancestral lineages of bacterial (Bartonella), protozoal (Plasmodium, Trypanosoma cruzi) and viral (SARS-CoV2) pathogens infecting humans. Along with the transmission of viruses from bats, we also discuss the potential roles of bat-associated bacteria, fungi, and protozoan parasites in emerging diseases. Current evidence suggests that environmental changes and interactions between wildlife, livestock, and humans contribute to the spill-over of infectious agents from bats to other hosts. Domestic animals including livestock may act as intermediate amplifying hosts for bat-origin pathogens to transmit to humans. An increasing number of studies investigating bat pathogen diversity and infection dynamics have been published. However, whether or how these infectious agents are transmitted both within bat populations and to other hosts, including humans, often remains unknown. Metagenomic approaches are uncovering the dynamics and distribution of potential pathogens in bat microbiomes, which might improve the understanding of disease emergence and transmission. Here, we summarize the current knowledge on bat zoonoses of public health concern and flag the gaps in the knowledge to enable further research and allocation of resources for tackling future outbreaks.

Parasitic manipulation or side effects? The effects of past Toxoplasma gondii and Borrelia spp. infections on human personality and cognitive performance are not mediated by impaired health

Bacteria Borrelia burgdorferi s. l. and even more the protist Toxoplasma gondii Nicolle et Manceaux, 1908, are known to affect the behaviour and mental health of their animal and human hosts. Both pathogens infect a significant fraction of human population, both are neurotropic and survive in the host's body for a long time. While latent infections were thought to be clinically asymptomatic, recent studies suggest otherwise, revealing adverse effects on human health. It was hypothesised that the specific behavioural effects of these pathogens may be side effects of general health impairments in infected individuals. This hypothesis was tested using about one hour-long survey consisting of questionnaires and performance tests on a cohort of 7,762 members of the internet population. Results showed that individuals infected with T. gondii reported worse physical and mental health, and those infected with Borrelia spp. reported worse physical health than uninfected controls. Furthermore, infected and noninfected individuals differed in several personality traits, including conscientiousness, pathogen disgust, injury disgust, Machiavellianism, narcissism, tribalism, anti-authoritarianism, intelligence, reaction time, and precision. While the majority of behavioural effects associated with Borrelia infection were similar to those associated with Toxoplasma infection, some differences were observed, such as performance in the Stroop test. Path analyses and nonparametric partial Kendall correlation tests showed that these effects were not mediated by impaired health in infected individuals, contradicting the side effects hypothesis.

Modular Approach for the Synthesis and Bioactivity Profiling of 8,8'-Biflavones

In this work, we report the scalable and modular synthesis of a library of 55 monomeric and dimeric flavonoids including 14 8,8'-biflavones. The sterically demanding tetra-ortho-substituted axis of an acetophenone dimer key intermediate was constructed in a regioselective manner using Fe-mediated oxidative coupling. This step was systematically optimized and performed on up to multigram scale. The biological activities of this compound library were evaluated, including cytotoxicity against healthy and malignant human cell lines, antimicrobial activity against the apicomplexan parasite Toxoplasma gondii, and antioxidant capacity. A marked increase in activity for the 8,8'-dimeric structures compared to that of their monomeric counterparts was observed. Several biflavones were identified with high selectivity indices (low cytotoxicity and high antiprotozoal activity), showing that this class of natural products may serve as lead structures for further investigations.

A Toxoplasma gondii lipoxygenase-like enzyme is necessary for virulence and changes localization associated with the host immune response

IMPORTANCE

Lipoxygenases (LOXs) are enzymes that catalyze the deoxygenation of polyunsaturated fatty acids such as linoleic and arachidonic acid. These modifications create signaling molecules that are best characterized for modulating the immune response. Deletion of the first lipoxygenase-like enzyme characterized for Toxoplasma gondii (TgLOXL1) generated a less virulent strain, and infected mice showed a decreased immune response. This virulence defect was dependent on the mouse cytokine interferon gamma IFNγ. TgLOXL1 changes location from inside the parasite in tissue culture conditions to vesicular structures within the host immune cells during mouse infection. These results suggest that TgLOXL1 plays a role in the modification of the host immune response in mice.

Antiprotozoal activity of auranofin on Trypanosoma cruzi, Leishmania tropica and Toxoplasma gondii: in vitro and ex vivo study

BACKGROUND

Three obligate intracellular protozoan parasite species, which are responsible for significant morbidity and mortality and settle in macrophage cells, affect more than one-half of the world's population, namely, Trypanosoma cruzi, Leishmania tropica and Toxoplasma gondii, which are causative agents of Chagas disease, leishmaniasis and toxoplasmosis, respectively. In the current study, it was aimed to investigate the in vitro and ex vivo antiprotozoal activity of auranofin on T. cruzi, L. tropica and T. gondii.

METHODS

The in vitro drug efficacy (IC50) of auranofin was investigated by haemocytometry and the CellTiter-Glo assay methods and the ex vivo drug efficacy (IC50) by light microscopic examination of Giemsa-stained slides. Also, the cytotoxic activity (CC50) of auranofin was examined by the CellTiter-Glo assay. The selectivity index (SI) was calculated for auranofin.

RESULTS

According to IC50, CC50 and SI data, auranofin did not exhibit cytotoxic activity on Vero cells, but exhibited antiprotozoal activity on epimastigotes and intracellular amastigotes of T. cruzi, promastigotes and intracellular amastigotes of L. tropica and intracellular tachyzoites of T. gondii (p<0.05).

CONCLUSIONS

The detection antiprotozoal activity of auranofin on T. cruzi, L. tropica and T. gondii according to the IC50, CC50 and SI values is considered an important and promising development. This is significant because auranofin may be an effective alternative treatment for Chagas disease, leishmaniasis and toxoplasmosis in the future.

A preliminary study to develop a lateral flow assay using recombinant GRA1 protein for the diagnosis of toxoplasmosis in stray cats

Toxoplasma gondii is a protozoan parasite that may infect many mammals including humans. Cats are one of the main sources of infection for humans. Therefore, routine screening of cats with tests that are inexpensive, rapid, and do not require sophisticated laboratory equipment is important. In this study, a lateral flow assay (LFA) was designed to rapidly diagnose toxoplasmosis in cats. For this purpose, we selected GRA1 protein of T. gondii due to its high antigenicity in diagnostic and vaccine studies. We further analyzed the immunological properties of GRA1 protein using in silico tools. Then, we expressed and purified recombinant GRA1 (rGRA1) protein and used it during the development of LFA to detect toxoplasmosis in serum samples (n = 40) of cats. According to the results, rGRA1 protein has negative GRAVY value, high aliphatic index, alpha helix, random coil and 12 B cell epitopes. The in silico data supported the high antigenic properties of rGRA1 protein and showed that it can be a good antigen candidate for LFA. Among 30 cat positive serum samples, 27 were found positive by the LFA while seronegative sera (n = 10) were negative by the LFA. The preliminary data showed that the LFA has high sensitivity (90 %) and specificity (100 %). When we used high responsive cat sera (i.e. sera that have optical density > 0.5 with ELISA) the sensitivity value reached 100 %. These results showed that rGRA1 protein is a good candidate to develop a LFA for rapid diagnosis of toxoplasmosis in cats.

Rottlerin impairs early and late steps of Toxoplasma gondii infection in human trophoblast cells and villous explants

Congenital toxoplasmosis, caused by the opportunistic protozoan parasite T. gondii, can cause stillbirths, miscarriages and fetal abnormalities, as well as encephalitis and chorioretinitis in newborns. Available treatment options rely on antiparasitic drugs that have been linked to serious side effects, high toxicity and the development of drug-resistant parasites. The search for alternative therapeutics to treat this disease without acute toxicity for the mother and child is essential for the advancement of current therapeutic procedures. The present study aimed to unravel the mode of the anti-T. gondii action of Rottlerin, a natural polyphenol with multiple pharmacological properties described. Herein, we further assessed the antiparasitic activity of Rottlerin against T. gondii infection on the human trophoblastic cells (BeWo cells) and, for the first time, on human villous explants. We found that non-cytotoxic doses of Rottlerin impaired early and late steps of parasite infection with an irreversible manner in BeWo cells. Rottlerin caused parasite cell cycle arrest in G1 phase and compromised the ability of tachyzoites to infect new cells, thus highlighting the possible direct action on parasites. An additional and non-exclusive mechanism of action of Rottlerin involves the modulation of host cell components, by affecting lipid droplet formation, mitochondrial function and upregulation of the IL-6 and MIF levels in BeWo cells. Supporting our findings, Rottlerin also controlled T. gondii proliferation in villous explants with low toxicity and reduced the IL-10 levels, a cytokine associated with parasite susceptibility. Collectively, our results highlighted the potential use of Rottlerin as a promising tool to prevent and/or treat congenital toxoplasmosis.

Toxoplasmosis lymphadenopathy-A series of 8 cases diagnosed in a 2-year timeframe: Is it a needle in a haystack?

Toxoplasmosis is a zoonosis caused by Toxoplasma gondii, an obligate intracellular parasite. Clinical presentation of infection depends on the age and immune status of the patient. In immunocompetent patient, it may present as a non-specific lymphadenopathy and self- limiting illness. In contrast, in immunocompromised patients it can be a life-threatening infection. We present a series of 8 cases of toxoplasma lymphadenitis diagnosed in our institute in last two years. Lymphadenopathy raises a suspicion of malignancy; however, diagnosis of reactive lymphadenitis often marks the end of diagnostic evaluation. Careful morphological evaluation, the classic triad, often can direct at a conclusive diagnosis. We are presenting a case series to draw attention to this entity as majority of the published literature is in the form of case report and serological surveys and very occasional study showing both the histopathology and serology in tandem.

Toxoplasma gondii inhibits the expression of autophagy-related genes through AKT-dependent inactivation of the transcription factor FOXO3a

The intracellular parasite Toxoplasma gondii induces host AKT activation to prevent autophagy-mediated clearance; however, the molecular underpinnings are not fully understood. Autophagy can be negatively regulated through AKT-sensitive phosphorylation and nuclear export of the transcription factor Forkhead box O3a (FOXO3a). Using a combination of pharmacological and genetic approaches, herein we investigated whether T. gondii hinders host autophagy through AKT-dependent inactivation of FOXO3a. We found that infection by type I and II strains of T. gondii promotes gradual and sustained AKT-dependent phosphorylation of FOXO3a at residues S253 and T32 in human foreskin fibroblasts (HFF) and murine 3T3 fibroblasts. Mechanistically, AKT-sensitive phosphorylation of FOXO3a by T. gondii required live infection and the activity of PI3K but was independent of the plasma membrane receptor EGFR and the kinase PKCα. Phosphorylation of FOXO3a at AKT-sensitive residues was paralleled by its nuclear exclusion in T. gondii-infected HFF. Importantly, the parasite was unable to drive cytoplasmic localization of FOXO3a upon pharmacological blockade of AKT or overexpression of an AKT-insensitive mutant form of FOXO3a. Transcription of a subset of bona fide autophagy-related targets of FOXO3a was reduced during T. gondii infection in an AKT-dependent fashion. However, parasite-directed repression of autophagy-related genes was AKT-resistant in cells deficient in FOXO3a. Consistent with this, T. gondii failed to inhibit the recruitment of acidic organelles and LC3, an autophagy marker, to the parasitophorous vacuole upon chemically or genetically induced nuclear retention of FOXO3a. In all, we provide evidence that T. gondii suppresses FOXO3a-regulated transcriptional programs to prevent autophagy-mediated killing. IMPORTANCE The parasite Toxoplasma gondii is the etiological agent of toxoplasmosis, an opportunistic infection commonly transmitted by ingestion of contaminated food or water. To date, no effective vaccines in humans have been developed and no promising drugs are available to treat chronic infection or prevent congenital infection. T. gondii targets numerous host cell processes to establish a favorable replicative niche. Of note, T. gondii activates the host AKT signaling pathway to prevent autophagy-mediated killing. Herein, we report that T. gondii inhibits FOXO3a, a transcription factor that regulates the expression of autophagy-related genes, through AKT-dependent phosphorylation. The parasite's ability to block the recruitment of the autophagy machinery to the parasitophorous vacuole is impeded upon pharmacological inhibition of AKT or overexpression of an AKT-insensitive form of FOXO3a. Thus, our study provides greater granularity in the role of FOXO3a during infection and reinforces the potential of targeting autophagy as a therapeutic strategy against T. gondii.