Prevalence and burden of Toxoplasma gondii infection in HIV-infected people: a systematic review and meta-analysis

Investigation of Toxoplasma gondii Infection in Yunnan Semi-fine Wool Sheep (Ovis aries) and wild Rodents in Yunnan, China

BACKGROUND

Toxoplasma gondii, a globally distributed zoonotic obligate intracellular parasite, infects a wide array of mammals, including humans, sheep, and birds. As a unique sheep breed in southwestern China, Yunnan semi-fine wool sheep occupies an important position in animal husbandry in Zhaotong due to its strong adaptability, high reproductive rate, and excellent wool quality. Lambs infected with T. gondii are prone to neurological symptoms and growth retardation, while T. gondii infection in ewes can cause abortions, stillbirths, and deformities, thus affecting sheep reproduction and sheep product quality. Meanwhile, mutton and dairy products contaminated with T. gondii can become potential sources of human infection, potentially threatening public health and safety.

METHOD

To understand the T. gondii infection in semi-fine wool sheep in Zhaotong, Yunnan Province, 586 blood samples were collected and subjected to indirect hemagglutination assay (IHA) for T. gondii antibodies, and the infection-related factors were analyzed through cross-sectional analysis. In the meantime, nested PCR was conducted on a total of 217 samples collected from 31 rodents caught in and around the sheep breeding ground to test the T. gondii B1 gene in rodent tissues.

RESULTS

A total of 94 sera tested positive for T. gondii antibodies, with a total positive rate of 16.04% (94/586) (95% CI: 14.77-20.89). Cross-sectional statistical analysis on factors related to semi-fine wool sheep infection rate, including sampling season, sex, age, and weight, suggested that age (< 6 months: 23.81%; 6-12 months: 11.74%; > 12 months: 15.83%) was a significant factor explaining the infection rate differences (P = 0.003 < 0.05, χ2 = 11.62, df = 2). Thus, age was considered a key risk factor for T. gondii infection in this study (odds ratio, OR = 2.35, 95% CI: 1.42-3.87). Nested PCR analysis on 217 (heart, liver, spleen, lung, kidney, brain, and muscle) tissues from the 31 rodents indicated that 11 tested positive. The total infection rate of rodents in and around the breeding ground was 35.48% (11/31), and 14 samples tested positive, with a positive infection rate of 6.45% (14/217).

CONCLUSION

The T. gondii infection rates of semi-fine wool sheep and rodents from their breeding environment in Zhaotong, Yunnan Province, were high, necessitating enhanced prevention, control, and treatment measures to ensure the healthy breeding of semi-fine wool sheep and veterinary public health and safety.

Prevalence of Ocular Toxoplasmosis in the General Population and Uveitis Patients: A Systematic Review and Meta-Analysis

PURPOSE

The present study aimed to estimate the global prevalence of ocular toxoplasmosis in the general population and patients with uveitis.

METHODS

Four electronic databases were searched and 130 studies for evaluating the prevalence of OT among the general population and uveitis patients were included.

RESULTS

The pooled prevalence of OT among the general population was estimated at 2% (95% CI, 2-3%; 762/486 051). The highest prevalence rate was observed in America 6% (95% CI, 1-11%). In uveitis patients, a prevalence rate of 9% (95% CI, 8-10%; 5668/88 006) was reported. The countries with a lower middle income had higher prevalence rates. The prevalence of OT in posterior uveitis 33% (95%CI, 24-42%) was substantially higher than in panuveitis 7% (95% CI, 5-8%).

CONCLUSION

Our results provide a new perspective on the prevalence of OT. Knowledge of international and regional patterns of disease is essential for the establishment of precise diagnostic protocols and control programs.

Cerebral toxoplasmosis mimicking stroke in a woman living with undiagnosed HIV

Toxoplasma gondii is an opportunistic pathogen that can intrude into the blood-brain barrier and reside in the brain only with low inflammatory reaction. When infected with HIV, the immune system becomes severely compromised and leads to the reactivation of latent toxoplasmosis infection, which can mimic the clinical manifestation of stroke. We report a case of a 65-year-old female patient who presented with sudden right limb weakness, walking difficulty, and numbness without other typical symptoms, raising suspicion of acute ischemic stroke. The HIV serology returned positive, which expedited the diagnostic workup for opportunistic infection. Combining imageological examination and metagenomics next-generation sequencing of cerebrospinal fluid, HIV-associated cerebral toxoplasmosis was confirmed. The patient underwent treatment for toxoplasmosis and HIV. Six months after onset, the patient can walk independently but still exhibits weakness in the right upper limb. In HIV-infected patients, cerebral toxoplasmosis, particularly presenting as isolated stroke-like episodes, poses a more significant challenge, emphasizing the need for more thorough investigations to reduce the potential for misdiagnosis.

Cross-sectional study to investigate the seroprevalence and risk factors of Toxoplasma gondii among women attending the antenatal clinic in Namwala, Zambia

BACKGROUND

Toxoplasmosis is a zoonotic parasitic disease caused by Toxoplasma gondii (T. gondii). It has a wide host range and is capable of vertical transmission in pregnant women, which may lead to undesirable pregnancy outcomes such as congenital malformations, miscarriage, premature birth and stillbirth. This study investigated the seroprevalence of T. gondii infection among pregnant women attending the antenatal clinic at Namwala District Hospital in Southern Zambia.

METHODS

This was a cross-sectional study where blood was collected, and the serum was tested for Toxoplasma IgG and IgM. A questionnaire was administered to participants on demographic characteristics and risk factors. Data were entered in Microsoft Excel and exported to STATA version 14 for analysis.

RESULTS

A total of 401 women were enrolled in the study from 3 March to 5 August 2021. The seroprevalence of Toxoplasma IgG was 4.2% (n=17), while the seroprevalence of Toxoplasma IgM was 0.7% (n=3). The median age was 27 (IQR: 24-30) years, and a larger proportion had primary-level education (n=223, 55.6%). The majority (81.6%) of the women were married. None of the risk factors investigated in this study were significant for T. gondii infection.

CONCLUSION

There was a low seroprevalence of T. gondii infection among pregnant women in the Namwala district of Southern Province, Zambia, and regular screening may not be warranted in this population. Continued research on toxoplasmosis is recommended to understand its epidemiology across Zambia.

Protective function and differentiation cues of brain-resident CD8+ T cells during surveillance of latent Toxoplasma gondii infection

Chronic Toxoplasma gondii infection induces brain-resident CD8+ T cells (bTr), but the protective functions and differentiation cues of these cells remain undefined. Here, we used a mouse model of latent infection by T. gondii leading to effective CD8+ T cell-mediated parasite control. Thanks to antibody depletion approaches, we found that peripheral circulating CD8+ T cells are dispensable for brain parasite control during chronic stage, indicating that CD8+ bTr are able to prevent brain parasite reactivation. We observed that the retention markers CD69, CD49a, and CD103 are sequentially acquired by brain parasite-specific CD8+ T cells throughout infection and that a majority of CD69/CD49a/CD103 triple-positive (TP) CD8+ T cells also express Hobit, a transcription factor associated with tissue residency. This TP subset develops in a CD4+ T cell-dependent manner and is associated with effective parasite control during chronic stage. Conditional invalidation of Transporter associated with Antigen Processing (TAP)-mediated major histocompatibility complex (MHC) class I presentation showed that presentation of parasite antigens by glutamatergic neurons and microglia regulates the differentiation of CD8+ bTr into TP cells. Single-cell transcriptomic analyses revealed that resistance to encephalitis is associated with the expansion of stem-like subsets of CD8+ bTr. In summary, parasite-specific brain-resident CD8+ T cells are a functionally heterogeneous compartment which autonomously ensure parasite control during T. gondii latent infection and which differentiation is shaped by neuronal and microglial MHC I presentation. A more detailed understanding of local T cell-mediated immune surveillance of this common parasite is needed for harnessing brain-resident CD8+ T cells in order to enhance control of chronic brain infections.

N-acetylglucosamine supplementation fails to bypass the critical acetylation of glucosamine-6-phosphate required for Toxoplasma gondii replication and invasion

The cell surface of Toxoplasma gondii is rich in glycoconjugates which hold diverse and vital functions in the lytic cycle of this obligate intracellular parasite. Additionally, the cyst wall of bradyzoites, that shields the persistent form responsible for chronic infection from the immune system, is heavily glycosylated. Formation of glycoconjugates relies on activated sugar nucleotides, such as uridine diphosphate N-acetylglucosamine (UDP-GlcNAc). The glucosamine-phosphate-N-acetyltransferase (GNA1) generates N-acetylglucosamine-6-phosphate critical to produce UDP-GlcNAc. Here, we demonstrate that downregulation of T. gondii GNA1 results in a severe reduction of UDP-GlcNAc and a concomitant drop in glycosylphosphatidylinositols (GPIs), leading to impairment of the parasite's ability to invade and replicate in the host cell. Surprisingly, attempts to rescue this defect through exogenous GlcNAc supplementation fail to completely restore these vital functions. In depth metabolomic analyses elucidate diverse causes underlying the failed rescue: utilization of GlcNAc is inefficient under glucose-replete conditions and fails to restore UDP-GlcNAc levels in GNA1-depleted parasites. In contrast, GlcNAc-supplementation under glucose-deplete conditions fully restores UDP-GlcNAc levels but fails to rescue the defects associated with GNA1 depletion. Our results underscore the importance of glucosamine-6-phosphate acetylation in governing T. gondii replication and invasion and highlight the potential of the evolutionary divergent GNA1 in Apicomplexa as a target for the development of much-needed new therapeutic strategies.

Prevalence of coccidia in lagomorphs in China between 1981 and 2023: A systematic review and meta-analysis

Lagomorpha coccidiosis, caused by coccidia, is a prevalent disease affecting rabbits, hares and pikas. This meta-analysis aimed to estimate the pooled prevalence of coccidia infection in lagomorphs and identify potential risk factors. A systematic search of six databases yielded 102 studies published between 1981 and 2023. The pooled prevalence of Eimeriidae, Sarcocystidae and Cryptosporidiidae in lagomorphs was 76.4%, 6.2% and 3.9%, respectively. Rabbits had the highest prevalence of Eimeriidae (76.8%) and Sarcocystidae (7.4%), while pikas had the highest prevalence of Cryptosporidiidae (6.2%). Juvenile rabbits exhibited the highest prevalence of Eimeriidae (84.6%) and Cryptosporidiidae (9.9%). Northwest China had the highest prevalence of Eimeriidae (87.8%). Over time, the prevalence of Eimeriidae declined (Coefficient: -0.0062; P<0.05), but remained high (65.0%) in the past five years. Our findings highlight the prevalence of Eimeriidae infection in lagomorphs and the need for further research on Sarcocystidae and Cryptosporidiidae infections. We emphasize the importance of developing lagomorpha coccidia vaccines and implementing vaccination schedules for juvenile rabbits to mitigate coccidia infections.

The Toxoplasma gondii F-Box Protein L2 Functions as a Repressor of Stage Specific Gene Expression

Toxoplasma gondii is a foodborne pathogen that can cause severe and life-threatening infections in fetuses and immunocompromised patients. Felids are its only definitive hosts, and a wide range of animals, including humans, serve as intermediate hosts. When the transmissible bradyzoite stage is orally ingested by felids, they transform into merozoites that expand asexually, ultimately generating millions of gametes for the parasite sexual cycle. However, bradyzoites in intermediate hosts differentiate exclusively to disease-causing tachyzoites, which rapidly disseminate throughout the host. Though tachyzoites are well-studied, the molecular mechanisms governing transitioning between developmental stages are poorly understood. Each parasite stage can be distinguished by a characteristic transcriptional signature, with one signature being repressed during the other stages. Switching between stages require substantial changes in the proteome, which is achieved in part by ubiquitination. F-box proteins mediate protein poly-ubiquitination by recruiting substrates to SKP1, Cullin-1, F-Box protein E3 ubiquitin ligase (SCF-E3) complexes. We have identified an F-box protein named Toxoplasma gondii F-Box Protein L2 (TgFBXL2), which localizes to distinct perinucleolar sites. TgFBXL2 is stably engaged in an SCF-E3 complex that is surprisingly also associated with a COP9 signalosome complex that negatively regulates SCF-E3 function. At the cellular level, TgFBXL2-depleted parasites are severely defective in centrosome replication and daughter cell development. Most remarkable, RNAseq data show that TgFBXL2 conditional depletion induces the expression of stage-specific genes including a large cohort of genes necessary for sexual commitment. Together, these data suggest that TgFBXL2 is a latent guardian of stage specific gene expression in Toxoplasma and poised to remove conflicting proteins in response to an unknown trigger of development.

Seroprevalence of Toxoplasma gondii among HIV Positive Patients under Surveillance in Greek Infectious Disease Units: A Screening Study with Comparative Evaluation of Serological Methods

This study aims to screen for IgG antibodies against Toxoplasma gondii (T. gondii) in the sera of 155 newly diagnosed Human Immunodeficiency Virus (HIV) positive patients under surveillance in Greek Infectious Disease Units. Additionally, risk factors based on patient demographics were examined, and a comparative evaluation of commercially available serological methods was conducted. Three methods were employed to detect IgG antibodies against T. gondii: Enzyme-Linked Immunosorbent Assay (ELISA), Indirect Immunofluorescence Antibody Test (IFAT), and Western Blot (WB), which was used as a reference here. Forty-nine sera samples were true-positive for IgG antibodies against T. gondii, resulting in a 31.61% positivity rate, and the immunoassay test statistical reliability analysis resulted in higher IFAT accuracy (90.97%) compared to ELISA (76.26%). Furthermore, statistical analysis of demographic and immunological data included in the study placed female and foreign/non-Greek individuals at 2.24 (p = 0.0009) and 2.34 (p = 0.0006) times higher risk of positive T. gondii IgG testing compared to their male and Greek counterparts, respectively. Our findings on positivity rates and comparative serology underscore the importance of early and suitable screening measures for newly diagnosed HIV+ patients to mitigate the life-threatening outcomes that may arise from a potential subsequent T. gondii activation.

RPA-CRISPR/Cas9-based method for the detection of Toxoplasma gondii: A proof of concept

Toxoplasma gondii is a widespread and specialized intracellular protozoan pathogen that affects one third of the world' s population, posing a great threat to public health. As the definitive host, cats excrete oocysts and play a crucial role in the transmission of toxoplasmosis. The current diagnostic tools usually require bulky equipment and expertize, which hinders the efficient diagnosis and intervention of Toxoplasma infection in cats. In this study, we combined (RPA) with clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 technique to establish an easier method for the detection of T. gondii oocysts in cat fecal samples. The sensitivity, specificity, and practicability of the established RPA-CRISPR/Cas9 method were evaluated using a lateral flow strip, with the limitation of detection determined at 10 plasmid copies/μL (corresponding to about one oocyst), cross reactivity to none of Giardia lamblia, Cryptosporidium sp., Microsporidium biberi and Blastocystis hominis that also commonly found in cats, and comparable performance in detecting T. gondii in clinical samples to conventional PCR amplification. This RPA-CRISPR/Cas9 method provides an alternative to conventional molecular tools used in the clinical diagnosis of Toxoplasma infection in cats and other animals.

A Blast From the Past: Toxoplasmic Encephalitis As the Initial Presentation of HIV/AIDS

Many opportunistic infections (OIs) seen early in the human immunodeficiency virus (HIV) epidemic receded in prevalence with the advent of antiretroviral therapy (ART). Despite the availability of early detection and treatment of HIV as well as guidelines for near-universal screening, there remains a sizable population of individuals living with HIV who are not yet aware of their HIV status. These individuals are at risk for OIs such as toxoplasmosis, which would otherwise be preventable with ART and appropriate prophylaxis. Toxoplasmic encephalitis (TE) usually occurs in the late stages of HIV with acquired immunodeficiency syndrome (AIDS), but we present a case of a 38-year-old female with TE as the initial presentation of HIV/AIDS. Testing for the presence of an immunocompromising condition such as HIV is important in patients presenting with focal brain lesions as the differential diagnosis will change, and proper workup may spare invasive procedures such as a brain biopsy.

Prevalence of ocular toxoplasmosis among people living with HIV: a systematic review and meta-analysis

Aim: To determine the prevalence of ocular toxoplasmosis among people living with HIV through a systematic review and meta-analysis. Materials & methods: A literature search was conducted, estimating pooled prevalence and performing quality assessment, outlier, influential and meta-regression analyses. Results: Twenty-nine studies were included in the analysis, revealing that the rate of ocular toxoplasmosis among people living with HIV was 0.37% (95% CI: 0.2-0.6). Substantial heterogeneity was observed among the studies. Despite analyzing continuous variables, including year of publication, proportion of males, mean age and proportion of patients receiving antiretroviral therapy, no statistically significant associations were found. Conclusion: This study provides an overview of the prevalence of ocular toxoplasmosis in people living with HIV, emphasizing the need for further research to uncover factors contributing to its development.

Global prevalence of poor sleep quality in cancer patients: A systematic review and meta-analysis

OBJECTIVE

Poor sleep quality is common in patients with cancer, but the prevalence rates varied widely across studies. This systematic review and meta-analysis examined the pooled prevalence of poor sleep quality among patients with cancer.

METHODS

Systematic literature searches were independently conducted in the major databases (Web of Science, PubMed, EMBASE and PsycINFO). Studies that reported the prevalence of poor sleep quality in patients with cancer were analyzed using a random effects model. Funnel plots and Egger's tests were used to assess publication bias. Statistical analyses were performed using R software.

RESULTS

A total of 59 epidemiological studies involving 16,223 patients were included. The pooled prevalence of poor sleep quality in patients with cancer was 57.4% [95% confidence interval (CI): 53.3% - 61.6%]. Additionally, three comparative studies with 372 patients and 412 healthy controls were included. Compared to healthy controls, patients with cancer had a significantly higher risk for poor sleep quality [odd ratio (OR) = 3.0; 95%CI: 1.2-7.2; P < 0.05]. Subgroup analyses of the studies revealed that studies from Middle East & North Africa region and low income countries, and on gynecological cancer as well as those with a lower cut-off value of sleep quality (all P < 0.01) reported a higher prevalence of poor sleep quality. Meta-regression analyses showed that higher prevalence of poor sleep quality was associated with higher prevalence of comorbid depression (P < 0.05) and anxiety (P < 0.01), but was associated with a lower education level (P < 0.05) and alcohol use ratio (P < 0.05).

CONCLUSION

Poor sleep quality is common among patients with cancer. Considering the overall high prevalence rate and negative impact of poor sleep quality, appropriate measures to identify and improve poor sleep quality are needed to enhance the clinical outcomes in this group.

Toxoplasma gondii surface antigen 1 (SAG1) interacts in vitro with host cell receptor for activated C kinase 1 (RACK1)

Toxoplasma gondii (T. gondii) surface antigen 1 (SAG1) is crucial for tachyzoite invasion into host cells. However, the role of SAG1 in interaction with host cells remains unknown. The primary objective of this study was to analyze and validate the interaction between SAG1 and host cells. RACK1, an intracellular multifunctional protein, was identified as a SAG1 binding partner in host cells. Furthermore, the expression of RACK1 is manipulated by SAG1, and depletion of RACK1 negatively regulated host cell viability. These results imply that through interaction with RACK1, SAG1 preserves the viability of host cells to satisfy the survival needs of T. gondii. Our findings suggest a novel role for SAG1 in intracellular parasitism.

The diagnosis of central nervous system infections in resource-limited settings and the use of novel and molecular diagnostic platforms to improve diagnosis

INTRODUCTION

Central nervous system infections (CNSI) disproportionately affect individuals in low-resource settings where diagnosis is challenging; large proportions of patients never receive a confirmed microbiological diagnosis resulting in inadequate management and high mortality. The epidemiology of CNSI varies globally and conventional diagnostics deployed in resource-limited settings have significant limitations, with an urgent need for improved diagnostic strategies.

AREAS COVERED

This review describes molecular platforms and other novel diagnostics used in the diagnosis of CNSI that are applicable to resource-limited settings. An extensive literature search of Medline and PubMed was performed. The emphasis is on investigations targeting infections of relevance to resource-limited settings either due to variation in regional CNSI epidemiology or due to increased prevalence in patients with immunosuppression. This includes commercially available multiplex PCR platforms, mycobacterial PCR platforms, and rapid diagnostics tests. To offer a framework for the optimal implementation in clinical settings, existing evidence highlighting the advantages and limitations of available platforms is reviewed.

EXPERT OPINION

The implementation of molecular platforms and other novel diagnostics has the potential to transform CNSI diagnosis in resource-limited settings, with several examples of successful rollout of novel diagnostics such as Xpert MTB/RIF Ultra and cryptococcal antigen testing.

Toxoplasma gondii actin filaments are tuned for rapid disassembly and turnover

The cytoskeletal protein actin plays a critical role in the pathogenicity of the intracellular parasite, Toxoplasma gondii, mediating invasion and egress, cargo transport, and organelle inheritance. Advances in live cell imaging have revealed extensive filamentous actin networks in the Apicomplexan parasite, but there are conflicting data regarding the biochemical and biophysical properties of Toxoplasma actin. Here, we imaged the in vitro assembly of individual Toxoplasma actin filaments in real time, showing that native, unstabilized filaments grow tens of microns in length. Unlike skeletal muscle actin, Toxoplasma filaments intrinsically undergo rapid treadmilling due to a high critical concentration, fast monomer dissociation, and rapid nucleotide exchange. Cryo-EM structures of jasplakinolide-stabilized and native (i.e. unstabilized) filaments show an architecture like skeletal actin, with differences in assembly contacts in the D-loop that explain the dynamic nature of the filament, likely a conserved feature of Apicomplexan actin. This work demonstrates that evolutionary changes at assembly interfaces can tune the dynamic properties of actin filaments without disrupting their conserved structure.

Prevalence of Mycobacterium bovis in deer in mainland China: a systematic review and meta-analysis

Background

Deer tuberculosis is a chronic zoonotic infectious disease, despite the existence of socio-economic and zoonotic risk factors, but at present, there has been no systematic review of deer tuberculosis prevalence in mainland China. The aim of this meta-analysis was to estimate the overall prevalence of deer TB in mainland China and to assess possible associations between potential risk factors and the prevalence of deer tuberculosis.

Methodology

This study was searched in six databases in Chinese and English, respectively (1981 to December 2023). Four authors independently reviewed the titles and abstracts of all retrieved articles to establish the inclusion exclusion criteria. Using the meta-analysis package estimated the combined effects. Cochran's Q-statistic was used to analyze heterogeneity. Funnel plots (symmetry) and used the Egger's test identifying publication bias. Trim-and-fill analysis methods were used for validation and sensitivity analysis. we also performed subgroup and meta-regression analyses.

Results

In this study, we obtained 4,400 studies, 20 cross-sectional studies were screened and conducted a systematic review and meta-analysis. Results show: The overall prevalence of tuberculosis in deer in mainland China was 16.1% (95% confidence interval (CI):10.5 24.6; (Deer tuberculosis infected 5,367 out of 22,215 deer in mainland China) 5,367/22215; 1981 to 2023). The prevalence in Central China was the highest 17.5% (95% CI:14.0-21.9; 63/362), and among provinces, the prevalence in Heilongjiang was the highest at 26.5% (95% CI:13.2-53.0; 1557/4291). Elaphurus davidianus was the most commonly infected species, with a prevalence of 35.3% (95% CI:18.5-67.2; 6/17). We also assessed the association between geographic risk factors and the incidence of deer tuberculosis.

Conclusion

Deer tuberculosis is still present in some areas of China. Assessing the association between risk factors and the prevalence of deer tuberculosis showed that reasonable and scientific-based breeding methods, a suitable breeding environment, and rapid and accurate detection methods could effectively reduce the prevalence of deer tuberculosis. In addition, in the management and operation of the breeding base, improving the scientific feed nutrition standards and establishing comprehensive standards for disease prevention, immunization, quarantine, treatment, and disinfection according to the breeding varieties and scale, are suggested as ways to reduce the prevalence of deer tuberculosis.

Toxoplasma gondii molecular detection and phylogenetic analysis in hemodialysis patients from Khuzestan, Southwest Iran

BACKGROUND

The diagnosis and genetic characterization of Toxoplasma gondii (T. gondii) infection can make a significant influence to the prevention of the dangerous consequences of toxoplasmosis, particularly in immunocompromised people.

OBJECTIVE

The aim of this investigation was to assess the frequency and genotyping of T. gondii in blood samples of patients with hemodialysis.

MATERIALS AND METHODS

In the current investigation, a total of 379 blood samples were taken from subjects with hemodialysis who were referred to teaching hospital of Ahvaz in the southwest of Iran. The samples were evaluated using the Nested PCR by targeting the B1 gene, and then, sequencing and phylogenetic tree were constructed.

RESULTS

T. gondii DNA was found in 112 (29.55%) of the blood samples by Nested PCR. Amplicons from T. gondii revealed high identity with GenBank sequences. The phylogenetic analysis revealed that all sequences were closely related to Type I of T. gondii.

CONCLUSION

Because of the high incidence of toxoplasmosis with type I prevalent in hemodialysis patients, we recommend a systematic screening for toxoplasmosis to carry out for monitoring the possible dissemination of toxoplasmosis during hemodialysis.

Anti-Toxoplasma gondii effect of tylosin in vitro and in vivo

BACKGROUND

Toxoplasma gondii is an important protozoan pathogen with medical and veterinary importance worldwide. Drugs currently used for treatment of toxoplasmosis are less effective and sometimes cause serious side effects. There is an urgent need for the development of more effective drugs with relatively low toxicity.

METHODS

The effect of tylosin on the viability of host cells was measured using CCK8 assays. To assess the inhibition of tylosin on T. gondii proliferation, a real-time PCR targeting the B1 gene was developed for T. gondii detection and quantification. Total RNA was extracted from parasites treated with tylosin and then subjected to transcriptome analysis by RNA sequencing (RNA-seq). Finally, murine infection models of toxoplasmosis were used to evaluate the protective efficacy of tylosin against T. gondii virulent RH strain or avirulent ME49 strain.

RESULTS

We found that tylosin displayed low host toxicity, and its 50% inhibitory concentration was 175.3 μM. Tylsoin also inhibited intracellular T. gondii tachyzoite proliferation, with a 50% effective concentration of 9.759 μM. Transcriptome analysis showed that tylosin remarkably perturbed the gene expression of T. gondii, and genes involved in "ribosome biogenesis (GO:0042254)" and "ribosome (GO:0005840)" were significantly dys-regulated. In a murine model, tylosin treatment alone (100 mg/kg, i.p.) or in combination with sulfadiazine sodium (200 mg/kg, i.g.) significantly prolonged the survival time and raised the survival rate of animals infected with T. gondii virulent RH or avirulent ME49 strain. Meanwhile, treatment with tylosin significantly decreased the parasite burdens in multiple organs and decreased the spleen index of mice with acute toxoplasmosis.

CONCLUSIONS

Our findings suggest that tylosin exhibited potency against T. gondii both in vitro and in vivo, which offers promise for treatment of human toxoplasmosis.

A newly characterized dense granule protein (GRA76) is important for the growth and virulence of Toxoplasma gondii

Pathogenicity of the zoonotic pathogen Toxoplasma gondii largely depends on the secretion of effector proteins into the extracellular milieu and host cell cytosol, including the dense granule proteins (GRAs). The protein-encoding gene TGME49_299780 was previously identified as a contributor to parasite fitness. However, its involvement in parasite growth, virulence and infectivity in vitro and in vivo remains unknown. Here, we comprehensively examined the role of this new protein, termed GRA76, in parasite pathogenicity. Subcellular localization revealed high expression of GRA76 in tachyzoites inside the parasitophorous vacuole (PV). However, its expression was significantly decreased in bradyzoites. A CRISPR-Cas9 approach was used to knock out the gra76 gene in the T. gondii type I RH strain and type II Pru strain. The in vitro plaque assays and intracellular replication showed the involvement of GRA76 in replication of RH and Pru strains. Deletion of the gra76 gene significantly decreased parasite virulence, and reduced the brain cyst burden in mice. Using RNA sequencing, we detected a significant increase in the expression of bradyzoite-associated genes such as BAG1 and LDH2 in the PruΔgra76 strain compared with the wild-type Pru strain. Using an in vitro bradyzoite differentiation assay, we showed that loss of GRA76 significantly increased the propensity for parasites to form bradyzoites. Immunization with PruΔgra76 conferred partial protection against acute and chronic infection in mice. These findings show the important role of GRA76 in the pathogenesis of T. gondii and highlight the potential of PruΔgra76 as a candidate for a live-attenuated vaccine.

Poor sleep quality in schizophrenia patients: A systematic review and meta-analyses of epidemiological and case-control studies

OBJECTIVE

Poor sleep quality is common in patients with schizophrenia but estimated prevalence rates in this population have been mixed. This systematic review and meta-analysis examined the prevalence of poor sleep quality in schizophrenia samples and moderators of prevalence from epidemiological studies as well as the risk of poor sleep quality in schizophrenia patients based on case-control studies.

METHODS

Both international (PubMed, Web of Science, PsycINFO, EMBASE) and Chinese databases [Chinese Nation knowledge Infrastructure (CNKI) and WANFANG] were systematically searched. Studies that estimated the prevalence of poor sleep quality in schizophrenia were analyzed using a random effects model. Funnel plots and Egger's tests were used to assess publication bias. Statistical analyses were performed using R software.

RESULTS

In total, 23 epidemiological studies and nine case-control studies were included. Based on the epidemiological studies, the pooled overall prevalence of poor sleep quality was 63.4 % [95 % confidence interval (CI): 57.0 %-69.9 %]. Additionally, based on the nine case-control studies, schizophrenia patients had a significantly higher risk for poor sleep quality compared to healthy controls [odd ratio (OR) = 4.5; 95%CI: 2.4-8.3; P < 0.0001].

CONCLUSION

Poor sleep quality is common among schizophrenia patients. Considering negative outcomes caused by poor sleep quality, regular screening on poor sleep quality should be conducted and effective interventions should be provided to those in need.

The Global and Regional Prevalence of Hospital-Acquired Carbapenem-Resistant Klebsiella pneumoniae Infection: A Systematic Review and Meta-analysis

Background

Due to scarce therapeutic options, hospital-acquired infections caused by Klebsiella pneumoniae (KP), particularly carbapenem-resistant KP (CRKP), pose enormous threat to patients' health worldwide. This study aimed to characterize the epidemiology and risk factors of CRKP among nosocomial KP infections.

Method

MEDLINE, Embase, PubMed, and Google Scholar were searched for studies reporting CRKP prevalence from inception to 30 March 2023. Data from eligible publications were extracted and subjected to meta-analysis to obtain global, regional, and country-specific estimates. To determine the cause of heterogeneity among the selected studies, prespecified subgroup analyses and meta-regression were also performed. Odds ratios of CRKP-associated risk factors were pooled by a DerSimonian and Laird random-effects method.

Results

We retained 61 articles across 14 countries and territories. The global prevalence of CRKP among patients with KP infections was 28.69% (95% CI, 26.53%-30.86%). South Asia had the highest CRKP prevalence at 66.04% (95% CI, 54.22%-77.85%), while high-income North America had the lowest prevalence at 14.29% (95% CI, 6.50%-22.0%). In the country/territory level, Greece had the highest prevalence at 70.61% (95% CI, 56.77%-84.45%), followed by India at 67.62% (95% CI, 53.74%-81.79%) and Taiwan at 67.54% (95% CI, 58.65%-76.14%). Hospital-acquired CRKP infections were associated with the following factors: hematologic malignancies, corticosteroid therapies, intensive care unit stays, mechanical ventilations, central venous catheter implantations, previous hospitalization, and antibiotic-related exposures (antifungals, carbapenems, quinolones, and cephalosporins).

Conclusions

Study findings highlight the importance of routine surveillance to control carbapenem resistance and suggest that patients with nosocomial KP infection have a very high prevalence of CRKP.

Immunization with Live-Attenuated RHΔhad2a Strain Confers Partial Protective Immunity against Acute and Chronic Infection of Toxoplasma gondii in Mice

Toxoplasmosis caused by Toxoplasma gondii is an important zoonosis of human and animal health significance. Current chemical therapeutics have side effects, and no commercially available vaccine is licensed for the prevention of toxoplasmosis in humans and most animals. Developing a safe and effective vaccine with long-term protection against T. gondii infection is necessary to control toxoplasmosis. HAD2a is a key member of the haloacid dehalogenase (HAD) phosphatase family, which is essential for T. gondii daughter budding. However, the role of HAD2a in T. gondii virulence remains unknown. In this study, we successfully constructed the had2a gene knockout strain in the T. gondii-type I RH strain (RHΔhad2a) and determined its role in virulence and vaccination. These results demonstrate that HAD2a played an important role in parasite daughter budding and in vitro replication. Knockout of the had2a gene attenuated the virulence of the T. gondii-type I RH strain. Vaccination with RHΔhad2a tachyzoites induced a Th1-biased immune response, provided partial protection against acute T. gondii infection in mice by highly virulent tachyzoites of RH and PYS (ToxoDB#9, Chinese I) strains, and conferred strong protection against challenge infection by cysts and oocysts of the less virulent type II Pru strain. These results demonstrate that T. gondii had2a is important for its in vitro proliferation and virulence in mice and that RHΔhad2a may be used as a candidate strain to generate a multiple gene knockout live-attenuated strain or be collaboratively applied with other live-attenuated strains to confer more effective protection against T. gondii infection.

Molecular diagnosis of opportunistic infections in the central nervous system of HIV-infected adults in Manaus, Amazonas

Background

Opportunistic infections in the central nervous system (CNS) of people with HIV/AIDS (PLWHA) remain significant contributors to morbidity and mortality, especially in resource-limited scenarios. Diagnosing these infections can be challenging, as brain imaging is non-specific and expensive. Therefore, molecular analysis of cerebrospinal fluid (CSF) may offer a more accurate and affordable method for diagnosing pathogens.

Methods

We conducted extensive real-time PCR testing (qPCR) on CSF to evaluate etiological agents in PLWHA with neurological manifestations. Primers targeting DNA from specific pathogens, including cytomegalovirus (CMV), herpes simplex virus (HSV), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), John Cunningham virus (JCV), Toxoplasma gondii, and human T-lymphotropic virus types 1 and 2 (HTLV-1 and HTLV-2), were used.

Results

Cerebrospinal fluid samples revealed 90 pathogens (36.7%). Toxoplasma gondii was the most frequently detected pathogen, found in 22 samples (30.5%). Other pathogens included Cryptococcus sp. (7.7%), EBV (5.3%), CMV, VZV, and JCV (4.0% each).

Conclusion

Despite antiretroviral therapy and medical follow-up, opportunistic central nervous system infections remain frequent in PLWHA. Herpesviruses are commonly detected, but T. gondii is the most prevalent opportunistic pathogen in our study population. Therefore, molecular diagnosis is a crucial tool for identifying opportunistic infections, even in patients undergoing treatment.

Neurological Complications Caused by Human Immunodeficiency Virus (HIV) and Associated Opportunistic Co-infections: A Review on their Diagnosis and Therapeutic Insights

Neurocognitive disorders associated with human immunodeficiency virus (HIV) infected individuals increase the risk of mortality and morbidity that remain a prevalent clinical complication even in the antiretroviral therapy era. It is estimated that a considerable number of people in the HIV community are developing neurological complications at their early stages of infection. The daily lives of people with chronic HIV infections are greatly affected by cognitive declines such as loss of attention, learning, and executive functions, and other adverse conditions like neuronal injury and dementia. It has been found that the entry of HIV into the brain and subsequently crossing the blood-brain barrier (BBB) causes brain cell damage, which is the prerequisite for the development of neurocognitive disorders. Besides the HIV replication in the central nervous system and the adverse effects of antiretroviral therapy on the BBB, a range of opportunistic infections, including viral, bacterial, and parasitic agents, augment the neurological complications in people living with HIV (PLHIV). Given the immuno-compromised state of PLHIV, these co-infections can present a wide range of clinical syndromes with atypical manifestations that pose challenges in diagnosis and clinical management, representing a substantial burden for the public health system. Therefore, the present review narrates the neurological complications triggered by HIV and their diagnosis and treatment options. Moreover, coinfections that are known to cause neurological disorders in HIV infected individuals are highlighted.

Association of polymorphism of IL-17A, IL-17F, and IL-6 with Toxoplasma gondii infection susceptibility in HIV/AIDS patients in Shiraz, southern Iran

INTRODUCTION

Toxoplasma gondii infection is considered as one of the most important opportunistic infections and cause of death in HIV patients.

METHODS

In this cross-sectional study, 334 HIV positive patients were included. The molecular test was performed by the restriction fragment length polymorphism-polymerase chain reaction method. Allelic frequency, haplotype analyses, and linkage disequilibrium were calculated. The odds ratio was calculated. The linear regression model was used to analysis of interleukin (IL)-17A, IL-17F, and IL-6 single-nucleotide polymorphism genotypes in HIV patients with and without toxoplasmosis.

RESULTS

In total, 95 tested'patients (28.4%) were positive for toxoplasmosis. The risk of toxoplasma infection in the current study did not correlate with IL-17 and IL-6 polymorphism and the risk of contracting toxoplasma was also not significantly correlated in this study. There was no association between the frequency of alleles and the risk of toxoplasma infection in IL-17 haplotype analysis.

CONCLUSION

The findings of this study revealed that there were significant differences in the serum levels of IL-6 and IL-17A, but not IL-17F, between the case and control groups in various genetic models. However, these polymorphisms did not show a significant relationship with toxoplasma infection in HIV-positive patients. This study represents the first investigation in Iran to explore the role of IL-6 and IL-17 polymorphisms in toxoplasma infection among HIV-positive patients.

Toxoplasma gondii F-Box Protein L2 Silences Feline-Restricted Genes Necessary for Sexual Commitment

Toxoplasma gondii is a foodborne pathogen that can cause severe and life-threatening infections in fetuses and immunocompromised patients. Felids are its only definitive hosts, and a wide range of animals, including humans, serve as intermediate hosts. When the transmissible bradyzoite stage is orally ingested by felids, they transform into merozoites that expand asexually, ultimately generating millions of gametes for the parasite sexual cycle. However, bradyzoites in intermediate hosts differentiate exclusively to disease-causing tachyzoites, which rapidly disseminate throughout the host. Though tachyzoites are well-studied, the molecular mechanisms governing transitioning between developmental stages are poorly understood. Each parasite stage can be distinguished by a characteristic transcriptional signature, with one signature being repressed during the other stages. Switching between stages requires substantial changes in the proteome, which is achieved in part by ubiquitination. F-box proteins mediate protein poly-ubiquitination by recruiting substrates to SKP1, Cullin-1, F-Box protein E3 ubiquitin ligase (SCF-E3) complexes. We have identified an F-box protein named Toxoplasma gondii F-Box Protein L2 (TgFBXL2), which localizes to distinct nuclear sites. TgFBXL2 is stably engaged in an SCF-E3 complex that is surprisingly also associated with a COP9 signalosome complex that negatively regulates SCF-E3 function. At the cellular level, TgFBXL2-depleted parasites are severely defective in centrosome replication and daughter cell development. Most remarkable, RNA seq data show that TgFBXL2 conditional depletion induces the expression of genes necessary for sexual commitment. We suggest that TgFBXL2 is a latent guardian of sexual stage development in Toxoplasma and poised to remove conflicting proteins in response to an unknown trigger of sexual development.

Ongoing Healthcare Disparities in neuroHIV: Addressing Gaps in the Care Continuum

PURPOSE OF REVIEW

We aim to review the neurological complications of HIV and the social, cultural, and economic inequalities that contribute to disparities in neuroHIV care.

RECENT FINDINGS

Disparities in diagnostics and care of patients with neurological infections and non-infectious conditions associated with HIV in both high-income and low-to-middle-income countries (LMIC) are common. The COVID-19 pandemic has exacerbated these disparities. Factors, such as HIV-related stigma, may deter people from accessing HIV treatment. First-line recommended treatments for neurological infections are not available in many LMICs, leading to inadequate treatment and exposure to agents with more harmful side effect profiles. Access-related factors, such as lack of transportation, lack of health insurance, and inadequate telehealth access, may increase the risk of HIV-related neurological complications. Further research is needed to increase awareness of neurological complications among providers and PWH, and regional guidelines should be considered to better address these complications.

Health and sociodemographic factors associated with low muscle strength, muscle mass, and physical performance among people living with HIV

ABSTRACTThis study examined the factors associated with low muscle strength, muscle mass, and physical performance in 331 people living with HIV. Participants completed handgrip as a strength measure, appendicular skeletal muscle mass using bioimpedance analysis, and chair rise was a physical performance measure. Multivariate logistic regression was used to analyze the association between low values on these measures with sociodemographic, HIV-related factors, and comorbidities. Higher body mass index (BMI) (OR = 0.91; CI = 0.86-0.97) and higher CD4/CD8 ratio (OR = 0.38; 95% CI = 0.18-0.82) were associated with decreased likelihood of low handgrip strength. Being non-employed (OR = 2.08; 95% CI = 1.07-4.06), having hypertension (OR = 2.27; 95% CI = 1.13-4.54) and rheumatism (OR = 5.46; 95% CI = 1.68-17.74) increased the chance of low handgrip strength. Higher BMI (OR = 0.43; 95% CI = 0.34-0.56), CD4/CD8 ratio (OR = 0.29; 95% CI = 0.09-0.93), and bioimpedance phase angle (OR = 0.22; 95% CI = 0.12-0.40) were associated with decreased likelihood of low muscle mass. Lastly, having less than eight years of education (OR = 1.87; 95% CI = 1.02-3.41) and being non-employed (OR = 8.18; 95% CI = 3.09-21.61) increased the chance of low chair stand performance. In addition, higher CD4 + lymphocytes count (OR = 0.99; 95% CI = 0.99-0.99) was associated with a decreased likelihood of low chair stand performance. In conclusion, specific and non-specific HIV-related factors are associated with low handgrip strength, low muscle mass, and/or low chair stand performance.

Boosting Mouse Defense against Lethal Toxoplasma gondii Infection with Full-Length and Soluble SAG1 Recombinant Protein

Toxoplasmosis is a major worldwide protozoan zoonosis. The surface antigen 1 (SAG1) of Toxoplasma gondii (T. gondii) has always been recognized as an ideal vaccine candidate antigen. However, the intact and soluble SAG1 protein is usually difficult to acquire in vitro, which is unfavorable for employing the recombinant protein as a vaccine candidate antigen. In the present study, we obtained the full-length SAG1 recombinant protein in soluble form by Escherichia coli Transetta (DE3) cells under optimized expression conditions. The immunogenicity and protective ability of this recombinant protein against T. gondii acute infection were evaluated in a mouse model. Monitoring changes in serum antibody levels and types, the presence of cytokines, and the rate of lymphocyte proliferation in vaccinated mice were used to assess humoral and cellular immune responses. Additional assessments were performed to determine the protective potency of the recombinant protein in combating T. gondii RH tachyzoites. It was found that the titers of both IgG2a and IgG2b were considerably greater in the immunized mice compared to the titers of IgG1 and IgG3. The levels of Th1-type cytokines (IFN-γ, IL-12p70, IL-2, and TNF-α) and Th2-type cytokines (IL-10) significantly increased when splenocytes from immunological group mice were treated with T. gondii lysate antigen. Compared to the control group, a recombinant protein substantially increased the longevity of infected mice, with an average death time prolonged by 14.50 ± 0.34 days (p < 0.0001). These findings suggest that the full-length and soluble SAG1 recombinant protein produced potent immune responses in mice and could be a preferred subunit vaccine candidate for T. gondii, offering a feasible option for vaccination against acute toxoplasmosis.

Immune system roles in pathogenesis, prognosis, control, and treatment of Toxoplasma gondii infection

Toxoplasma gondii is the protozoan causative agent of toxoplasmosis in humans and warm-blooded animals. Recent studies have illustrated that the immune system plays a pivotal role in the pathogenesis of toxoplasmosis by triggering immune cytokines like IL-12, TNF-α, and IFN-γ and immune cells like DCs, Th1, and Th17. On the other hand, some immune components can serve as prognosis markers of toxoplasmosis. In healthy people, the disease is often asymptomatic, but immunocompromised people and newborns may suffer severe symptoms and complications. Therefore, the immune prognostic markers may provide tools to measure the disease progress and help patients to avoid further complications. Immunotherapies using monoclonal antibody, cytokines, immune cells, exosomes, novel vaccines, and anti-inflammatory molecules open new horizon for toxoplasmosis treatment. In this review article, we discussed the immunopathogenesis, prognosis, and immunotherapy of Toxoplasma gondii infection.

Emerging and Re-Emerging Parasitic Infections of the Central Nervous System (CNS) in Europe

In a rapidly evolving global landscape characterized by increased international travel, migration, and ecological shifts, this study sheds light on the emergence of protozoal and helminthic infections targeting the central nervous system (CNS) within Europe. Despite being traditionally associated with tropical regions, these infections are progressively becoming more prevalent in non-endemic areas. By scrutinizing the inherent risks, potential outcomes, and attendant challenges, this study underscores the intricate interplay between diagnostic limitations, susceptibility of specific population subsets, and the profound influence of climate fluctuations. The contemporary interconnectedness of societies serves as a conduit for introducing and establishing these infections, warranting comprehensive assessment. This study emphasizes the pivotal role of heightened clinician vigilance, judicious public health interventions, and synergistic research collaborations to mitigate the potential consequences of these infections. Though rare, their profound impact on morbidity and mortality underscores the collective urgency required to safeguard the neurological well-being of the European populace. Through this multifaceted approach, Europe can effectively navigate the complex terrain posed with these emergent infections.

CD4+ T Cell Responses to Toxoplasma gondii Are a Double-Edged Sword

CD4+ T cells have been found to play critical roles in the control of both acute and chronic Toxoplasma infection. Previous studies identified a protective role for the Toxoplasma CD4+ T cell-eliciting peptide AS15 (AVEIHRPVPGTAPPS) in C57BL/6J mice. Herein, we found that immunizing mice with AS15 combined with GLA-SE, a TLR-4 agonist in emulsion adjuvant, can be either helpful in protecting male and female mice at early stages against Type I and Type II Toxoplasma parasites or harmful (lethal with intestinal, hepatic, and spleen pathology associated with a storm of IL6). Introducing the universal CD4+ T cell epitope PADRE abrogates the harmful phenotype of AS15. Our findings demonstrate quantitative and qualitative features of an effective Toxoplasma-specific CD4+ T cell response that should be considered in testing next-generation vaccines against toxoplasmosis. Our results also are cautionary that individual vaccine constituents can cause severe harm depending on the company they keep.

Toxoplasma gondii actin filaments are tuned for rapid disassembly and turnover

The cytoskeletal protein actin plays a critical role in the pathogenicity of Toxoplasma gondii, mediating invasion and egress, cargo transport, and organelle inheritance. Advances in live cell imaging have revealed extensive filamentous actin networks in the Apicomplexan parasite, but there is conflicting data regarding the biochemical and biophysical properties of Toxoplasma actin. Here, we imaged the in vitro assembly of individual Toxoplasma actin filaments in real time, showing that native, unstabilized filaments grow tens of microns in length. Unlike skeletal muscle actin, Toxoplasma filaments intrinsically undergo rapid treadmilling due to a high critical concentration, fast monomer dissociation, and rapid nucleotide exchange. Cryo-EM structures of stabilized and unstabilized filaments show an architecture like skeletal actin, with differences in assembly contacts in the D-loop that explain the dynamic nature of the filament, likely a conserved feature of Apicomplexan actin. This work demonstrates that evolutionary changes at assembly interfaces can tune dynamic properties of actin filaments without disrupting their conserved structure.

Prevalence of soil-transmitted helminth infections in HIV patients: a systematic review and meta-analysis

Soil-transmitted Helminth (STH) infections have been found associated with people living with human immunodeficiency virus (HIV) but little is known about the overall burden of STH coinfection in HIV patients. We aimed to assess the burden of STH infections among HIV patients. Relevant databases were systematically searched for studies reporting the prevalence of soil-transmitted helminthic pathogens in HIV patients. Pooled estimates of each helminthic infection were calculated. The odds ratio was also determined as a measure of the association between STH infection and the HIV status of the patients. Sixty-one studies were finally included in the meta-analysis, consisting of 16,203 human subjects from all over the world. The prevalence of Ascaris lumbricoides infection in HIV patients was found to be 8% (95% CI 0.06, 0.09), the prevalence of Trichuris trichiura infection in HIV patients was found to be 5% (95% CI 0.04, 0.06), the prevalence of hookworm infection in HIV patients was found to be 5% (95% CI 0.04, 0.06), and prevalence of Strongyloides stercoralis infection in HIV patients was found to be 5% (95% CI 0.04, 0.05). Countries from Sub-Saharan Africa, Latin America & Caribbean and Asia were identified with the highest burden of STH-HIV coinfection. Our analysis indicated that people living with HIV have a higher chance of developing Strongyloides stercoralis infections and decreased odds of developing hookworm infections. Our findings suggest a moderate level of prevalence of STH infections among people living with HIV. The endemicity of STH infections and HIV status both are partially responsible for the burden of STH-HIV coinfections.

A case report of a successful alternative regiment therapy for toxoplasma encephalitis in AIDS patients

Introduction

AIDS patients are more susceptible to opportunistic diseases, such as toxoplasma encephalitis, because of weakened immune systems. Toxoplasma encephalitis manifests as a severe neurological crisis in HIV patients. The standard initial treatments are sulfadiazine and pyrimethamine. This case presents an HIV patient treated with an alternative regimen for toxoplasma encephalitis.

Case description

A young Acehnese man, 32 years old, arrived at the emergency unit after complaining of a general seizure 2 hours before arrival. He has a history of a two-week fever and white patches on his tongue and oral cavity. The result of the HIV test was positive, and after a thorough examination, he was diagnosed with toxoplasma encephalitis. The patient was given cotrimoxazole 960 mg twice daily and clindamycin 600 mg four times daily as an alternative treatment. Clinical improvement was reported after six weeks of therapy.

Conclusion

A case of toxoplasma encephalitis was reported. The first-line treatment for toxoplasma encephalitis is pyrimethamine and sulfadiazine; however, the patient was treated with cotrimoxazole and clindamycin as an alternative treatment. Clinical improvement was used to assess the success of therapy. Cotrimoxazole and clindamycin can be utilized as alternative regiment therapy if the first-line treatment option is unavailable.

PP2Acα-B'/PR61 Holoenzyme of Toxoplasma gondii Is Required for the Amylopectin Metabolism and Proliferation of Tachyzoites

Here, we report that the inhibition of the PP2A subfamily by okadaic acid results in an accumulation of polysaccharides in the acute infection stage (tachyzoites) of Toxoplasma gondii, which is a protozoan of global zoonotic importance and a model for the apicomplexan parasites. The loss of the catalytic subunit α of PP2A (ΔPP2Acα) in RHΔku80 leads to the polysaccharide accumulation phenotype in the base of tachyzoites as well as residual bodies and significantly compromises the intracellular growth in vitro and the virulence in vivo. A metabolomic analysis revealed that the accumulated polysaccharides in ΔPP2Acα are derived from interrupted glucose metabolism, which affects the production of ATP and energy homeostasis in the T. gondii knockout. The assembly of the PP2Acα holoenzyme complex involved in the amylopectin metabolism in tachyzoites is possibly not regulated by LCMT1 or PME1, and this finding contributes to the identification of the regulatory B subunit (B'/PR61). The loss of B'/PR61 results in the accumulation of polysaccharide granules in the tachyzoites as well as reduced plaque formation ability, exactly the same as ΔPP2Acα. Taken together, we have identified a PP2Acα-B'/PR61 holoenzyme complex that plays a crucial role in the carbohydrate metabolism and viability in T. gondii, and its deficiency in function remarkably suppresses the growth and virulence of this important zoonotic parasite both in vitro and in vivo. Hence, rendering the PP2Acα-B'/PR61 holoenzyme functionless should be a promising strategy for the intervention of Toxoplasma acute infection and toxoplasmosis. IMPORTANCE Toxoplasma gondii switches back and forth between acute and chronic infections, mainly in response to host immunologic status, which is characterized by flexible but specific energy metabolism. Polysaccharide granules are accumulated in the acute infection stage of T. gondii that have been exposed to a chemical inhibitor of the PP2A subfamily. The genetic depletion of the catalytic subunit α of PP2A leads to this phenotype and significantly affects the cell metabolism, energy production, and viability. Further, a regulatory B subunit PR61 is necessary for the PP2A holoenzyme to function in glucose metabolism and in the intracellular growth of T. gondii tachyzoites. A deficiency of this PP2A holoenzyme complex (PP2Acα-B'/PR61) in T. gondii knockouts results in the abnormal accumulation of polysaccharides and the disruption of energy metabolism, suppressing their growth and virulence. These findings provide novel insights into cell metabolism and identify a potential target for an intervention against a T. gondii acute infection.

A live attenuated RHΔompdcΔuprt mutant of Toxoplasma gondii induces strong protective immunity against toxoplasmosis in mice and cats

BACKGROUND

Toxoplasma gondii is an obligate intracellular apicomplexan parasite and is responsible for zoonotic toxoplasmosis. It is essential to develop an effective anti-T. gondii vaccine for the control of toxoplasmosis, and this study is to explore the immunoprotective effects of a live attenuated vaccine in mice and cats.

METHODS

First, the ompdc and uprt genes of T. gondii were deleted through the CRISPR-Cas9 system. Then, the intracellular proliferation and virulence of this mutant strain were evaluated. Subsequently, the immune responses induced by this mutant in mice and cats were detected, including antibody titers, cytokine levels, and subsets of T lymphocytes. Finally, the immunoprotective effects were evaluated by challenge with tachyzoites of different strains in mice or cysts of the ME49 strain in cats. Furthermore, to discover the effective immune element against toxoplasmosis, passive immunizations were carried out. GraphPad Prism software was used to conduct the log-rank (Mantel-Cox) test, Student's t test and one-way ANOVA.

RESULTS

The RHΔompdcΔuprt were constructed by the CRISPR-Cas9 system. Compared with the wild-type strain, the mutant notably reduced proliferation (P < 0.05). In addition, the mutant exhibited virulence attenuation in both murine (BALB/c and BALB/c-nu) and cat models. Notably, limited pathological changes were found in tissues from RHΔompdcΔuprt-injected mice. Furthermore, compared with nonimmunized group, high levels of IgG (IgG1 and IgG2a) antibodies and cytokines (IFN-γ, IL-4, IL-10, IL-2 and IL-12) in mice were detected by the mutant (P < 0.05). Remarkably, all RHΔompdcΔuprt-vaccinated mice survived a lethal challenge with RHΔku80 and ME49 and WH6 strains. The immunized sera and splenocytes, especially CD8⁺ T cells, could significantly extend (P < 0.05) the survival time of mice challenged with the RHΔku80 strain compared with naïve mice. In addition, compared with nonimmunized cats, cats immunized with the mutant produced high levels of antibodies and cytokines (P < 0.05), and notably decreased the shedding numbers of oocysts in feces (95.3%).

CONCLUSIONS

The avirulent RHΔompdcΔuprt strain can provide strong anti-T. gondii immune responses, and is a promising candidate for developing a safe and effective live attenuated vaccine.

Prevalence and Risk Factors of Ovine and Caprine Fasciolosis in the Last 20 Years in China: A Systematic Review and Meta-Analysis

Fasciolosis is a significant zoonotic and common parasitic disease for animals and humans, creating public health concerns worldwide. This study retrieved articles related to the occurrence of Fasciola hepatica and Fasciola gigantica in sheep and goats in China by searching five databases: PubMed, ScienceDirect, the Chinese National Knowledge Infrastructure (CNKI), Wanfang Data, and the VIP Chinese Journal Database. A total of 60 valid articles were captured. The pooled prevalence of ovine and caprine fasciolosis was 26.00%. It was also found to be higher in the subgroups of Northwest China and Shaanxi Province, as well as in areas with a high altitude, rainfall of ≥800 mm, and temperature ranging between 10 °C and 20 °C. Analysis of the type of season and sampling years showed significant (p < 0.05) difference. In other subgroups, sheep (34.74%), hosts aged over 2 years (32.26%), females (48.33%) and free-range animals (26.83%) showed a higher disease prevalence. These results indicated that ovine and caprine fasciolosis was widely distributed, especially in Northwest China. The sampling years and the type of season are risk factors for the prevalence of ovine and caprine fasciolosis. Therefore, strategies for ovine and caprine fasciolosis control should be developed based on these epidemic risk factors, which will reduce the prevalence of fasciolosis in China.

Influenza A Virus Weakens the Immune Response of Mice to Toxoplasma gondii, Thereby Aggravating T. gondii Infection

This study aimed to investigate the relationship between the T. gondii type II strain (Pru) and respiratory viral infections, specifically focusing on the co-infection with PR8 (influenza A/Puerto Rico/8/34). In this study, we found that the number of T. gondii (Pru) in the lungs of co-infected mice was significantly higher and lesions were more severe than those in the group infected with T. gondii (Pru) alone, whereas IAV (influenza A virus) copy numbers of co-infected and PR8 alone infected groups were negligible, suggesting that infection with IAV increased the pathogenicity of T. gondii (Pru) in mice. The invasion and proliferation assays demonstrated no significant effect of co-infection on T. gondii (Pru) infection or replication in vitro. To further explore the factors causing the altered pathogenicity of T. gondii (Pru) caused by co-infection, we found that decreased expression levels of IL-1β, IL-6, and IL-12 in the co-infected group were associated with the early immune responses against T. gondii (Pru), which affected the division of T. gondii (Pru). Moreover, the significant decrease in the CD4⁺/CD8⁺ ratio indicated a weakened long-term immune killing ability of the host against T. gondii (Pru) following IAV infection. In conclusion, a T. gondii type II strain (Pru) could not be properly cleared by the host immune system after IAV infection, resulting in toxoplasmosis and even death in mice.

Prevalence of Senecavirus A in pigs from 2014 to 2020: a global systematic review and meta-analysis

BACKGROUND

Senecavirus A (SVA), a member of the family Picornaviridae, is newly discovered, which causes vesicular lesions, lameness in swine, and even death in neonatal piglets. SVA has rapidly spread worldwide in recent years, especially in Asia.

OBJECTIVES

We conducted a global meta-analysis and systematic review to determine the status of SVA infection in pigs.

METHODS

Through PubMed, VIP Chinese Journals Database, China National Knowledge Infrastructure, and Wanfang Data search data from 2014 to July 26, 2020, a total of 34 articles were included in this analysis based on our inclusion criteria. We estimated the pooled prevalence of SVA in pigs by the random effects model. A risk of bias assessment of the studies and subgroup analysis to explain heterogeneity was undertaken.

RESULTS

We estimated the SVA prevalence to be 15.90% (1,564/9,839; 95% confidence interval [CI], 44.75-65.89) globally. The prevalence decreased to 11.06% (945/8,542; 95% CI, 28.25-50.64) after 2016. The highest SVA prevalence with the VP1-based RT-PCR and immunohistochemistry assay was 58.52% (594/1,015; 95% CI, 59.90-83.96) and 85.54% (71/83; 95% CI, 76.68-100.00), respectively. Besides, the SVA prevalence in piglet herds was the highest at 71.69% (119/166; 95% CI, 68.61-98.43) (p < 0.05). Moreover, our analysis confirmed that the subgroups, including country, sampling year, sampling position, detected gene, detection method, season, age, and climate, could be the heterogeneous factors associated with SVA prevalence.

CONCLUSIONS

The results indicated that SVA widely exists in various countries currently. Therefore, more prevention and control policies should be proposed to enhance the management of pig farms and improve breeding conditions and the environment to reduce the spread of SVA.

Prevalence and potential risk factors of PDCoV in pigs based on publications during 2015-2021 in China: Comprehensive literature review and meta-analysis

Porcine deltacoronavirus (PDCoV), a novel coronavirus which infects pigs, spreading around the world and causing huge economic losses. In recent years, there have also been human cases of PDCoV infection, which poses a potential threat to public health. Therefore, we conducted a systematic review and meta-analysis to assess the prevalence of PDCoV in pigs in China between 2015 and 2021. The prevalence of PDCoV in China was searched from five databases (CNKI, VIP, WanFang, PubMed and ScienceDirect) and 65 articles met the inclusion criteria, with a total of 25,977 samples, including 3828 positive cases. The overall prevalence of PDCoV was 13.61% (3828/25,977), with the highest prevalence in northern China (19.18%) and the lowest prevalence in southwest China (7.19%). We also analyzed other subgroup information, such as sampling years, test methods, age and geographic factors. The results show that PDCoV is endemic in China and climate may be a potential risk factor for PDCoV infection. It is suggested that appropriate measures should be taken in different climatic areas to reduce local PDCoV infection.

Immunological evaluation of a recombinant vaccine delivered with an analogous hyaluronic acid chitosan nanoparticle-hydrogel against Toxoplasma gondii in mice

BACKGROUND

Toxoplasma gondii (T. gondii) is not only a threat to the public health but it also poses adverse impacts on the livestock industry. This study aimed to develop a recombinant vaccine composed of T. gondii microneme protein 6 (TgMIC6) and T. gondii rhoptry protein 18 (TgROP18).The vaccine was delivered with a novel vector, named analogous hyaluronic acid chitosan nanoparticle-hydrogel (AHACNP-HG) and its immune protection was evaluated.

METHODS

The recombinant MIC6 and ROP18 proteins were obtained by affinity chromatography and loaded onto AHACNP-HG by magnetic stirring. The characterizations of AHACNP-HG were investigated, including its structure, rheological property, nanoparticle size and zeta potential, its ability to release protein in vitro and toxicology in vivo. The immunological and anti-infection effects of AHACNP-HG/rMIC6/rROP18 were examined in the mice model.

RESULTS

AHACNP-HG presented a characteristic of composite system and possessed biosecurity with excellent protein control-release property. AHACNP-HG/rMIC6/rROP18 vaccine enhanced a mixed Th1/Th2 cellular immune response accompanied by an increased level of the cytokines, IFN-γ and IL-10. It also provoked a stronger humoral immune response. Additionally, after challenge with T. gondii tachyzoite, AHACNP-HG/rMIC6/rROP18 inoculation prolonged the survival time of mice.

CONCLUSION

Our data indicated that mixed rMIC6 and rROP18 induced strong immune response and played a certain protective role in controlling T. gondii infection, and the novel adjuvant AHACNP-HG improved modestly some immunogenicity properties in mouse model, which indicated that it can be used as a novel delivery system in vaccine development.

Nanoparticles as a Delivery System of Antigens for the Development of an Effective Vaccine against Toxoplasma gondii

Nanoparticles include particles ranging in size from nanometers to micrometers, whose physicochemical characteristics are optimized to make them appropriate delivery vehicles for drugs or immunogens important in the fight and/or prevention of infectious diseases. There has been a rise in the use of nanoparticles in preventive vaccine formulations as immunostimulatory adjuvants, and as vehicles for immunogen delivery to target immune cells. Toxoplasma is important worldwide, and may cause human toxoplasmosis. In immunocompetent hosts, infection is usually asymptomatic, but in immunocompromised patients it can cause serious neurological and ocular consequences, such as encephalitis and retinochoroiditis. Primary infection during pregnancy may cause abortion or congenital toxoplasmosis. Currently, there is no effective human vaccine against this disease. Evidence has emerged from several experimental studies testing nanovaccines showing them to be promising tools in the prevention of experimental toxoplasmosis. For the present study, a literature review was carried out on articles published over the last 10 years through the PubMed database, pertaining to in vivo experimental models of T. gondii infection where nanovaccines were tested and protection and immune responses evaluated. This review aims to highlight the way forward in the search for an effective vaccine for toxoplasmosis.

Estimations of the number people with mental diseases associated with toxoplasmosis and identification of risk factors by continent

Strong evidence exists based on metanalysis of the relationship between toxoplasmosis and many psychiatric diseases: schizophrenia, bipolar disorder, and suicidal behavior. Herein, we estimate the number of cases based on the attributable fraction due to toxoplasmosis on these diseases. The population attributable fraction of mental disease associated with toxoplasmosis was 20,4% for schizophrenia; 27,3% for bipolar disorder; and 0,29% for suicidal behavior (self-harm). The lower and upper estimated number of people with mental disease associated with toxoplasmosis was 4'816.491 and 5'564.407 for schizophrenia; 6'348.946 and 7'510.118,82 for bipolar disorder; and 24.310 and 28.151 for self-harm; for a global total lower estimated number of 11'189.748 and global total upper estimated number of 13'102.678 people with mental disease associated with toxoplasmosis for the year 2019. According to the prediction through the Bayesian model of risk factors for toxoplasmosis associated with mental disease, these varied in importance geographically; thus, in Africa, the most important risk factor was water contamination and in the European region, the cooking conditions of meats. Toxoplasmosis and mental health should be a research priority given the enormous potential impact of reducing this parasite in the general population.

Toxoplasma gondii, HBV, and HCV co-infection and their correlation with CD4 cells among Iranian HIV-positive patients

INTRODUCTION

Human immunodeficiency virus (HIV/AIDS) infected patients have a higher risk of opportunistic infections (OIs) depending on their immunological status, especially CD4 + cell count. Toxoplasma gondii, hepatitis C virus (HCV), and hepatitis B virus (HBV) are important OIs among Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS) patients. However, little is known about co-infection of these pathogens among HIV-infected individuals and their correlation with the patient's CD4 + cell count. Hence, this study aimed to investigate the serological and molecular status of T. gondii infection among HIV-infected individuals who had co-infection with HBV and HCV infections.

METHODS

A total of 100 HIV/AIDS patients in two cities in the southwest of Iran was tested for T. gondii Immunoglobulin G (IgG) and Immunoglobulin M (IgM) antibodies as well as DNA detection by polymerase chain reaction (PCR) targeting the RE gene. HBV and HCV were detected by hepatitis B surface antigen (HBsAg) test, hepatitis C antibody (HCV Ab) test, and Real-Time PCR. The number of CD4 + cell counts was determined by Flow cytometry.

RESULTS

Anti-T. gondii IgG was positive in 22% of the patients, but anti-T. gondii IgM and PCR were negative in all samples. HBV and HCV were positive in 8% and 33% of the patients, respectively. Co-infections were as followed: HIV + HCV (16%), HIV + HCV + T. gondii (11%), HIV + T. gondii (5%), HIV + HBV (1%), HIV + HBV + T. gondii (1%), HIV + HBV + HCV (1%), and HIV + HBV + HCV + T. gondii (5%). A significant decline in CD4 + cell counts was found in such co-infection groups (HIV + T. gondii, HIV + HCV + T. gondii, and HIV + HBV + HCV + T. gondii) compared with the HIV mono-infection group.

CONCLUSIONS

Our study showed that co-infections of T. gondii, HCV, and HBV were common among HIV-infected patients and co-infections had a negative correlation with CD4 + cell counts of the patients.

Functional Characterization of 15 Novel Dense Granule Proteins in Toxoplasma gondii Using the CRISPR-Cas9 System

The analysis of the subcellular localization and function of dense granule proteins (GRAs) is of central importance for the understanding of host-parasite interaction and pathogenesis of Toxoplasma gondii infection. Here, we identified 15 novel GRAs and used C-terminal endogenous gene tagging to determine their localization at the intravacuolar network (IVN), parasitophorous vacuole (PV), or PV membrane (PVM) in the tachyzoites and at the periphery of the bradyzoites-containing cysts. The functions of the 15 gra genes were examined in type I RH strain and 5 of these gra genes were also evaluated in the cyst-forming type II Pru strain. The 15 novel gra genes were successfully disrupted by using CRISPR-Cas9 mediated homologous recombination and the results showed that 13 gra genes were not individually essential for T. gondii replication in vitro or virulence in mice during acute and chronic infection. Intriguingly, deletion of TGME49_266410 and TGME49_315910 in both RH and Pru strains decreased the parasite replication in vitro and attenuated its virulence, and also reduced the cyst-forming ability of the Pru strain in mice during chronic infection. Comparison of the transcriptomic profiles of the 15 gra genes suggests that they may play roles in other life cycle stages and genotypes of T. gondii. Taken together, our findings improve the understanding of T. gondii pathogenesis and demonstrate the involvement of two novel GRAs, TGME49_266410 and TGME49_315910, in the parasite replication and virulence. IMPORTANCE Dense granule proteins (GRAs) play important roles in Toxoplasma gondii pathogenicity. However, the functions of many putative GRAs have not been elucidated. Here, we found that 15 novel GRAs are secreted into intravacuolar network (IVN), parasitophorous vacuole (PV), or PV membrane (PVM) in tachyzoites and are located at the periphery of the bradyzoite-containing cysts. TGME49_266410 and TGME49_315910 were crucial to the growth of RH and Pru strains in vitro. Deletion of TGME49_266410 and TGME49_315910 attenuated the parasite virulence in mice. However, disruption of other 13 gra genes did not have a significant impact on the proliferation and pathogenicity of T. gondii in vitro or in vivo. The marked effects of the two novel GRAs (TGME49_266410 and TGME49_315910) on the in vitro growth and virulence of T. gondii are notable and warrant further elucidation of the temporal and spatial dynamics of translocation of these two novel GRAs and how do they interfere with host cell functions.

Effect of deleting four Toxoplasma gondii calcium-binding EGF domain-containing proteins on parasite replication and virulence

Several calcium-binding proteins including calcium-dependent protein kinases play important roles in several facets of the intracellular infection cycle of the apicomplexan protozoan parasite Toxoplasma gondii. However, the role of the calcium-binding epidermal growth factor (EGF) domain-containing proteins (CBDPs) remains poorly understood. In this study, we examined the functions of four CBDP genes in T. gondii RH strain of type I by generating knock-out strains using CRISPR-Cas9 system. We investigated the ability of mutant strains deficient in CBDP1, CBDP2, CBDP3, or CBDP4 to form plaques, replicate intracellularly, and egress from the host cells. The results showed that no definite differences between any of these four CBDP mutant strains and the wild-type strain in terms of their ability to form plaques, intracellular replication, and egress. Additionally, CBDP mutants did not exhibit any significant attenuated virulence compared to the wild-type strain in mice. The expression profiles of CBDP2-4 genes were conserved among T. gondii strains of different genotypes, life cycle stages, and developmental forms. Whether other CBDP genes play any roles in the pathogenicity of T. gondii strains of different genotypes remains to be elucidated.

Advances in research on schistosomiasis and toxoplasmosis in China: A bibliometric analysis of Chinese academic journals published from 1980 to 2021

BACKGROUND

The scale-up of zoonoses prevention control and eradication in China, coupled with numerous academic articles in Chinese journals has led to the development of new tools and strategies aimed at further consolidating parasite control goals. As a result, there is a growing need for an up-to-date understanding of the research progress and prevention and control experience of parasitic diseases in China.

METHODS

To understand the research status of schistosomiasis and toxoplasmosis in China, academic articles published in Chinese journals from 1980 to 2021 were retrieved from China National Knowledge Infrastructure (CNKI) and Wanfang databases. The Bibliographic Items Co-occurrence Matrix Builder (BICOMB) software was used to extract and analyze the keyword frequencies. The 'K/A ratio' as the frequency of a keyword that occurred in all the articles within a certain time stage was calculated to compare the popularity of the same keyword in different time stages. Keyword co-occurrence network maps were constructed by VOSviewer software.

RESULTS

A total of 18,508 articles in the research field of Schistosoma and 13,289 articles in the field of Toxoplasma gondii were included. Results in both fields showed some similarities: the annual number of articles presented an increasing trend before entering the 21^st century and decreased rapidly in recent years. Two opposite changing trends of keyword frequency could be observed in the K/A ratio analysis: the K/A ratios of 'Surveillance' and 'Infection' continuously increased over time, while those of 'Schistosoma mansoni' and 'Mesenteric lymph nodes' decreased. The diversification of keyword co-occurrence networks could be observed in the co-occurrence network maps.

CONCLUSIONS

This bibliometric analysis reveals trends in research themes in the fields of Schistosoma and Toxoplasma gondii from 1980 to 2021, presenting China's experience such as a high degree of government involvement and multidisciplinary participation in schistosomiasis and toxoplasmosis control and elimination.

Cerebral toxoplasmosis in HIV-infected patients: a review

Toxoplasma gondii infection in the central nervous system commonly occurs among immunodeficient patients. Its prevalence is high in countries with a high burden of HIV and low coverage of antiretroviral drugs. The brain is one of the predilections for T. gondii infection due to its low inflammatory reaction, and cerebral toxoplasmosis occurs solely due to the reactivation of a latent infection rather than a new infection. Several immune elements have recently been recognized to have an essential role in the immunopathogenesis of cerebral toxoplasmosis. Although real-time isothermal amplification, next-generation sequencing, and enzyme-linked aptamer assays from blood samples have been the recommended diagnostic tools in some in-vivo studies, a combination of clinical symptoms, serology examination, and neuroimaging are still the daily standard for the presumptive diagnosis of cerebral toxoplasmosis and early anti-toxoplasma administration. Clinical trials are needed to find a new therapy that is less likely to affect folate synthesis, have neuroprotective properties, or cure the latent phase of infection. The development of a vaccine is being extensively tested in animals, but its efficacy and safety for humans are still not proven.