Toxoplasmosis in Pregnant Women and HIV/AIDS Patients in Ethiopia: A Systematic Review and Meta-Analysis

The antioxidant protein glutaredoxin 1 is essential for oxidative stress response and pathogenicity of Toxoplasma gondii

Glutaredoxins (Grxs) are ubiquitous antioxidant proteins involved in many molecular processes to protect cells against oxidative damage. Here, we study the roles of Grxs in the pathogenicity of Toxoplasma gondii. We show that Grxs are localized in the mitochondria (Grx1), cytoplasm (Grx2), and apicoplast (Grx3, Grx4), while Grx5 had an undetectable level of expression. We generated Δgrx1-5 mutants of T. gondii type I RH and type II Pru strains using CRISPR-Cas9 system. No significant differences in the infectivity were detected between four Δgrx (grx2-grx5) strains and their respective wild-type (WT) strains in vitro or in vivo. Additionally, no differences were detected in the production of reactive oxygen species, total antioxidant capacity, superoxide dismutase activity, and sensitivity to external oxidative stimuli. Interestingly, RHΔgrx1 or PruΔgrx1 exhibited significant differences in all the investigated aspects compared to the other grx2-grx5 mutant and WT strains. Transcriptome analysis suggests that deletion of grx1 altered the expression of genes involved in transport and metabolic pathways, signal transduction, translation, and obsolete oxidation-reduction process. The data support the conclusion that grx1 supports T. gondii resistance to oxidative killing and is essential for the parasite growth in cultured cells and pathogenicity in mice and that the active site CGFS motif was necessary for Grx1 activity.

The strategies of NLRP3 inflammasome to combat Toxoplasma gondii

Infection with the protozoan parasite Toxoplasma gondii (T. gondii) results in the activation of nucleotide-binding domain leucine-rich repeat containing receptors (NLRs), which in turn leads to inflammasome assembly and the subsequent activation of caspase-1, secretion of proinflammatory cytokines, and pyroptotic cell death. Several recent studies have addressed the role of the NLRP3 inflammasome in T. gondii infection without reaching a consensus on its roles. Moreover, the mechanisms of NLRP3 inflammasome activation in different cell types remain unknown. Here we review current research on the activation and specific role of the NLRP3 inflammasome in T. gondii infection.

Serological Evaluation of Toxoplasmosis and Related Risk Factors Among HIV+/AIDS Patients in Northern Iran

PURPOSE

Toxoplasma gondii is an important opportunistic intracellular protozoan parasite that can cause severe sequelae and even death in immunodeficient patients. This study aimed to evaluate the seroprevalence and risk factors of toxoplasmosis among HIV⁺/AIDS patients of the study area.

METHODS

A cross-sectional study was carried out on 121 registered HIV⁺/AIDS patients of behavioral diseases consultation center (BDCC) in Guilan province, north of Iran. Anti-Toxoplasma IgG and IgM antibodies were measured by ELISA technique in the serum samples. IgG avidity was measured for IgG- plus IgM-positive cases. Also, the relationship between T. gondii infection and related demographic and clinical characteristics were investigated.

RESULTS

Anti-T. gondii IgG and IgM antibodies were detected in 60.3 and 4.9% of patients, respectively. One case of acute toxoplasmosis (0.83%) was detected using an IgG avidity test. A significant correlation was observed between toxoplasmosis with age and marital status in these patients. The mean CD4⁺count of HIV⁺/AIDS patients was 549 ± 27 cells/µl. Viral load in 69.7% of the HIV patients was less than1000 copies/ml.

CONCLUSION

None of the T. gondii IgM-positive HIV patients received anti-Toxoplasma prophylaxis. This finding highlights the importance of T. gondii infection surveillance in HIV patients. Regarding the high prevalence of toxoplasmosis in the study population, educational efforts are recommended to prevent reactivation or acquiring primary infection and developing severe cases of toxoplasmosis in immunocompromised HIV⁺/AIDS patients.

Functional Characterization of Two Thioredoxin Proteins of Toxoplasma gondii Using the CRISPR-Cas9 System

Toxoplasmosis caused by infection with Toxoplasma gondii is an important parasitic zoonosis with a worldwide distribution. In this study, we examined the functions of two thioredoxins (namely CTrp26 and CTrx1) of T. gondii tachyzoites by generation of HA tag strains or gene deficient parasites in Type I RH strain (ToxoDB#10). Immunofluorescence analysis (IFA) was used to investigate the subcellular localization of the thioredoxins (Trxs). Results of IFA showed that both CTrp26 and CTrx1 were located in the cytoplasm of T. gondii. Functional characterizations of CTrp26 and CTrx1-deficient parasites were performed by plaque assay, intracellular replication, egress, H₂O₂ resistance, detection of reactive oxygen species (ROS) level and total antioxidant capacity (T-AOC) assays in vitro, as well as mouse infection in vivo. Our results showed that deletion of CTrp26 or CTrx1 did not influence the ability of T. gondii RH strain to replicate, egress, form plaque, resist H₂O₂ exposure, maintain the ROS level, and T-AOC, and also did not serve as virulence factors in Kunming mice. Taken together, these results provide new properties of the two Trxs. Although they are not essential for RH strain, they may have roles in other strains of this parasite due to their different expression patterns, which warrants future research.

Serosurvey of Anti-Toxoplasma gondii Antibodies in Homeless Persons of São Paulo City, Southeastern Brazil

Seroprevalence of Toxoplasma gondii has been extensively studied in a variety of different human populations. However, no study has focused on homeless populations. Accordingly, the present study aimed to assess the seroprevalence of anti-T. gondii antibodies and the risk factors associated in homeless persons from homeless shelter of São Paulo city, southeastern Brazil. In addition, anti-HIV antibodies and associated risk of T. gondii and HIV coinfection have been evaluated. Anti-T. gondii antibodies were detected by indirect fluorescent antibody test. In addition, anti-HIV levels were tested by chemiluminescence enzyme immunoassay, with positive samples confirmed by rapid immunoblot assay. Overall, IgG anti-T. gondii seropositivity was found in 43/120 (35.8%) homeless persons, with endpoint titers varying from 16 to 1,024. The only two pregnant women tested were negative for IgM by chemiluminescence enzyme immunoassay, with normal parturition and clinically healthy newborns in both cases. There were no statistical differences in the risk factors for anti-T. gondii serology (p > 0.05). Anti-HIV seropositivity was found in 2/120 (1.7%) homeless persons, confirmed as HIV-1. One HIV seropositive individual was also sero-reactive to IgG anti-T. gondii, and both were negative to IgM anti-T. gondii. This is the first study that reports the serosurvey of T. gondii in homeless persons worldwide. Despite the limited sample size available in the present study, our findings have shown that the prevalence of anti-T. gondii antibodies in homeless persons herein was lower than the general population, probably due to homeless diet habit of eating mainly processed food intake. No statistical differences were found regarding risk factors for anti-T. gondii exposure in homeless persons. Future studies should be conducted to fully establish risk factors for anti-T. gondii exposure in homeless persons.

Toxoplasma gondii infection as a potential risk for chronic liver diseases: A systematic review and meta-analysis

Toxoplasma gondii, the etiological agent of toxoplasmosis, can cause serious public health problems. Although Toxoplasma gondii tends more to neurotropic and ocular organs, some existing evidence suggest that this disease might induce serious pathological effects on liver. Hence, this study aimed to evaluate the relationship between chronic liver diseases and toxoplasmosis. Meanwhile, it attempted to assess whether patients with toxoplasmosis are susceptible to chronic liver diseases. To achieve this aim, the published studies related to the subject were systematically searched in five major electronic databases between the January 1, 1950 and October 1, 2019. The meta-analysis was carried out using the StatsDirect statistical software and a p-value less than 0.05 was considered significant for any test. Out of 691 identified studies, 10 studies met our inclusion criteria and entered this systematic review. The pooled prevalence rates of Toxoplasma gondii in patients with liver diseases (35.97%; 95% CI: 28.38-43.93) were higher than those in the control group (18.24%; 95% CI: 13.85-23.09). The meta-analysis indicated that the common Odd Ratio by a random effect model was 2.7 (95% CI: 2.30-3.24), revealing a significant association between chronic liver diseases and anti-Toxoplasma IgG antibody. The results of this systematic review confirmed the positive connection between toxoplasmosis and chronic liver diseases. Nonetheless, more studies are needed to clarify the detailed association between these diseases.