Association of Toxoplasmosis and COVID-19 in a MexicanPopulation

Prevalence of Toxoplasma gondii infection in COVID-19 patients: A systematic review and meta-analysis

Toxoplasma gondii is a parasite that affects over one billion people worldwide. COVID-19, caused by the SARS-CoV-2 virus, has resulted in over 4.8 million deaths worldwide. Both diseases activate the innate immune response via the same pathway. Studies have suggested that toxoplasmosis may either protect against or worsen the severity of COVID-19. This meta-analysis investigated the relationship between toxoplasmosis prevalence and COVID-19. The selection of studies was based on a systematic search using specific keywords in Scopus, Web of Science, PubMed, and Google Scholar databases between 2019 and 2023. The study findings were analyzed using STATA software version 17.0, and the prevalence of toxoplasmosis in people with COVID-19 and its confidence interval were extracted from the selected studies. The study's heterogeneity was assessed using the I2 test, and publication bias was evaluated using a funnel plot and Egger's test. A p value of 0.05 was considered significant. The meta-analysis included nine studies with a total of 1745 COVID-19-positive individuals, and the results showed a significant association between toxoplasmosis and COVID-19 severity. The I2 statistic was almost 99 %, indicating large heterogeneity among the studies. The Egger's test showed no publication bias. The pooled prevalence of toxoplasmosis in COVID-19-positive individuals was 0.48 (95 % CI: 0.30-0.66), which was significantly different from that of 0 % (P < 0.001). The meta-analysis found that the prevalence oftoxoplasmosis was significantly higher in individuals with COVID-19 than in the general population, indicating a possible association between the two infections. However, the significant heterogeneity among the studies underscores the need for further research to understand the underlying mechanisms and clinical implications of this association.

Coinfection of Toxoplasma gondii and Other Microorganisms: A Systematic Review and Meta-Analysis

Toxoplasmosis is a disease caused by the intracellular protozoan Toxoplasma gondii, which has infected a third of the global population. Immunocompromised individuals and children with congenital disorders are most likely to be impacted by toxoplasmosis, and accurate diagnosis is essential. Toxoplasmosis is associated with HIV, schizophrenia, and diabetes. However, few studies have analyzed the association with other microorganisms. The purpose of this study was to determine the prevalence of coinfection of Toxoplasma gondii with other pathogens. From November 1997 to June 2024, PubMed, Science Direct, LAT index, Web of Science, Google Scholar, and Research Gate were searched. The keywords used were "Toxoplasma and microorganism coinfection", "Toxoplasma coinfection and parasites", "Toxoplasma coinfection and Protozoans or Bacteria or Helminths or Nematodes or Trematodes or Mycobacterium", "Toxoplasma gondii in coinfection with virus", and "Human Toxoplasmosis and coinfection". Next, OpenMeta Analyst Software version 12.11 was used for meta-analysis, creating forest plots, and determining heterogeneity I2. A total of 17,535 patients in 48 articles, of whom 5848 were seropositive to T. gondii, were included in this review. Population studies showed that the prevalence of virus infection was most frequent (32%), followed by parasites (18.4%), bacteria (29.7%), and fungi (5.8%). The pooled prevalence of coinfection was found to be 29.1%, with a lower bound of 0.232, an upper bound of 0.350, a standard error of 0.030, and p < 0.001. Heterogeneity (I2) was 99.12%, p < 0.001, with a global variance tau2 = 0.042. Toxoplasma gondii is an opportunist that mainly affects immunocompromised populations. The main coinfections were found to be viral infections, with HIV ranking first, followed by cytomegalovirus, hepatitis B and C, rubella, herpes simplex 1 and 2, SARS-CoV-2, and coxsackie virus.

Frequency of exposure to Toxoplasma gondii in COVID-19 patients: a systematic review and meta-analysis

BACKGROUND

Toxoplasmosis is a chronic protozoan parasitic infection that affects nearly one-third of the global population. During the COVID-19 pandemic, cases were observed in patients with COVID-19 and toxoplasmosis. Therefore, this systematic review and meta-analysis aimed to determine the frequency of Toxoplasma gondii exposure in patients with COVID-19.

METHODS

A literature search was conducted in six databases or search tools (PubMed, Scopus, Embase, Web of Science, ScienceDirect, and Google Scholar) until March 3, 2024. Study selection, quality assessment, and data extraction were performed independently by three investigators. Statistical analysis was performed using R version 4.3, applying a random-effects model. The quality of the included observational studies was assessed using the "JBI-MAStARI".

RESULTS

A total of 5,936 studies were retrieved, 13 of which were included in the final meta-analysis. The sample included a total of 2,947 patients with COVID-19 from four countries, of whom approximately 43.3% were men and 49.4% were women. Among the patients, 1,323 showed evidence of exposure to T. gondii through IgG detection, while 1,302 COVID-19 patients were explicitly examined for T. gondii by IgM detection, and 36 positive cases were identified. The frequency of exposure to T. gondii, determined by the presence of IgG in patients with COVID-19, reached 49% (95% CI: 34-63%; 2,947 participants; 13 studies; I2 = 98%, p < 0.01). In addition, the frequency of exposure to T. gondii, evaluated by IgM presence in patients with COVID-19, was 2% (95% CI: 0-6%; 1,302 participants; 6 studies; I2 = 94%, p < 0.01).

CONCLUSION

It was shown that almost half of COVID-19 patients had previous exposure to T. gondii through the presence of IgG, and a small percentage, 2%, showed active infection through IgM detection. Although the results indicate a possible correlation between exposure to T. gondii and the presence of COVID-19, it is essential to note that this study is based on observational research, which precludes establishing a causal relationship. Consequently, further research is required to deepen understanding of the interaction between the two conditions.

TERMS USED

The Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI), Prospective International Registry of Systematic Reviews (PROSPERO), and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

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

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

Impact of latent toxoplasmosis on pneumonic and non-pneumonic COVID-19 patients with estimation of relevant oxidative stress biomarkers

Susceptibility to COVID-19, the most devastating global pandemic, appears to vary widely across different population groups. Exposure to toxoplasmosis has been proposed as a theory to explain the diversity of these populations. The aim of the present study was to investigate the possible association between latent toxoplasmosis and COVID-19 and its probable correlation with markers of oxidative stress, C-reactive protein (CRP) and ferritin. In a case-control study, blood samples were collected from 91 confirmed (48 non-pneumonic; NP, and 43 pneumonic; P) COVID-19 patients and 45 healthy controls. All participants were tested for IgG anti-Toxoplasma gondii antibodies and oxidative stress markers (nitric oxide [NO], superoxide dismutase [SOD] and reduced glutathione [GSH]), and CRP and serum ferritin levels were determined. In COVID-19 patients, IgG anti-T. gondii antibodies were found in 54% compared to 7% in the control group, with the difference being statistically significant (P ˂ 0.001). However, no significant correlation was found between the severity of COVID-19 and latent T. gondii infection. Latent toxoplasmosis had a strong influence on the risk of COVID-19. NO and SOD levels were significantly increased in COVID-19 patients, while GSH levels decreased significantly in them compared to control subjects (P ˂ 0.001 for both values). CRP and ferritin levels were also significantly elevated in P COVID-19 patients infected with toxoplasmosis. This is the first study to look at the importance of oxidative stress indicators in co-infection between COVID-19 and T. gondii. The high prevalence of latent toxoplasmosis in COVID-19 suggests that T. gondii infection can be considered a strong indicator of the high risk of COVID-19.

Genetic diversity and seroprevalence of Toxoplasma gondii in COVID‑19 patients; a first case-control study in Iran

BACKGROUND

Toxoplasmosis is a serious or life-threatening disease in immunosuppressed patients and pregnant women. This study examined the likely association between Toxoplasma gondii infection and COVID-19 patients with moderate illness.

METHODS

Seventy blood samples were collected from patients at the Health Reference Laboratory of Tabriz, Northwest Iran from April 2021 to September 2021. In addition, 70 healthy subjects of the same age (37 ± 15 years) and sex distribution were ethnically matched. Sera samples were examined for the detection of anti-Toxoplasma antibodies using ELISA. Nested-PCR targets were amplified based on the B1 and GRA6 genes. GRA6 amplicons were subjected to sequencing and phylogenetic analysis.

RESULTS

The seroprevalence of toxoplasmosis based on IgG titer was 35.7% in the COVID‑19 patients and 27.1% in the control group, representing not to be associated with the Toxoplasma seropositivity in COVID‑19 patients (P = 0.18) compared to healthy subjects. Anti-T. gondii IgM was not found in any of the patients and healthy individuals. According to PCR amplification of the B1 and GRA6 genes, the frequency of T. gondii in COVID-19 patients was 14.2% (10/70). However, no T. gondii infection was detected in the healthy group. The CD4+T cell count was relatively lower in toxoplasmosis-infected patients (430-450 cells/mm3) than in control group (500-1500 cells/mm3). High genetic diversity (Hd: 0.710) of the type I strain of T. gondii was characterized in the patients. Present results showed that consumption of raw vegetables and close contact with stray cats can increase the transmission of T. gondii to COVID-19 patients (P < 0.01).

CONCLUSIONS

The current study revealed that T. gondii type I infection is unequivocally circulating among the COVID-19 patients in Tabriz; However, no significant association was observed between the occurrence of Toxoplasma and the severity of COVID-19. To make more accurate health decisions, multicenter investigations with a larger sample size of different ethnic groups of the Iranian population are needed.

Association between breakthrough infection with COVID-19 and Toxoplasma gondii: a cross-sectional study

The breakthrough infection following COVID-19 vaccination has been a subject of concern recently. Evidence suggests that COVID-19 vaccine efficacy diminishes over time due to multiple factors related to the host, and vaccine. Coinfection with other pathogens was claimed earlier as a contributing cause for this phenomenon. Hence, we aimed to stratify the association of post-COVID-19 vaccination breakthrough coinfection with Toxoplasma gondii (T. gondii) and its impact on disease severity. This cross-sectional study included 330 COVID-19-vaccinated patients confirmed by RT-PCR. They were also screened for anti- T. gondii antibodies using ELISA. Toxoplasma seropositive cases' whole blood was screened for DNA using PCR to correlate results with COVID-19 severity. Out of 330 COVID-19 vaccinated patients with breakthrough infection, 34.5% (114 patients) showed positivity for Toxoplasma IgG by ELISA, and none of the cases was IgM positive. Eleven patients (9.6%) of the IgG-positive cases were positive by PCR. Positive PCR cases correlated positively with the Toxoplasma IgG titer (P < 0.001), and the Cutoff point was 191.5. Molecular analysis of Toxoplasma and COVID-19 severity showed that 8 (72.7%), 1 (9.1%), and 2 cases (18.2%) had mild, moderate, and severe courses of the disease, respectively, with no significant correlation. Our study reported a heightened prevalence of latent toxoplasmosis among mild cases of COVID-19 breakthrough infection. Nevertheless, a discernible correlation between latent toxoplasmosis and COVID-19 severity is lacking. Hence, implementing studies on a larger scale could provide a more comprehensive comprehension of this association.