Toxoplasmosis and symptoms severity in patients with COVID-19 in referral centers in Northern Iran

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.

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).

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

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

Sero-prevalence of Toxoplasma gondii before and during the COVID-19 pandemic in Northwestern Iran

BACKGROUND

Toxoplasma gondii (T. gondii) is a ubiquitous protozoan parasite on our planet that causes toxoplasmosis. This study evaluated the seroprevalence and related risk factors for T. gondii infection in a population referred to healthcare centers in Meshkin-Shahr, Northwest Iran.

METHODS

A total of 400 blood samples were randomly collected from the general population and assessed using the anti-Toxoplasma antibodies, Immunoglobulin G and M (IgG and IgM) Enzyme-linked immunosorbent assay (ELISA) Kits in two steps before and during the coronavirus disease 2019 (COVID-19) pandemic, 2019-2020. The results were analyzed through logistic regression via SPSS 26 software.

RESULTS

Before the COVID-19 pandemic, anti-toxoplasma antibodies were detected in 39% of individuals (IgG: 38%, IgM: 0.5%, and IgG-IgM: 0.5%). Among the eleven risk factors evaluated, contact with soil and people awareness were significantly associated with T. gondii infection (p < 0.05). However, factors such as females, 20-39 age groups, junior high schools, housewives, rural areas, raw meat or vegetable consumption, vegetable or fruits washed by water, not detergent, and cat owners did not show a significant relationship with seropositivity (p > 0.05). After the outbreak of the COVID-19 pandemic, the overall seroprevalence for anti-T. gondii antibody increased to 49.7% (IgG: 47.7%, IgM: 0.5%, and IgG and IgM: 1.5%). Among these patients, 26% were positive for COVID-19. Additionally, before the COVID-19 pandemic, 40 samples were negative for anti-T. gondii antibodies but later became positive. The crude and adjusted models suggested that toxoplasmosis may be a possible risk factor for increased susceptibility to COVID-19, with an odds ratio (OR) of 1.28 (95% confidence interval (CI), 0.82-1.99; P < 0.05). Conversely, a non-significant protective effect against latent toxoplasmosis was observed in COVID-19-positive individuals (OR = 0.99; 95% CI, 0.51-1.92; P > 0.05), and COVID-19 positivity did not increase the levels of anti-T. gondii IgG antibodies.

CONCLUSIONS

The general population in this region had a moderate seroprevalence of T. gondii. The increased number of COVID-19-positive patients with latent toxoplasmosis highlights the need to pay attention to the early diagnosis and proper treatment of toxoplasmosis in these patients and implement preventive programs in these areas for future possible viral infections.

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.

Insights into parasites and COVID-19 co-infections in Iran: a systematic review

BACKGROUND

It is well-documented that using immunosuppressive drugs such as corticosteroids or cytokine blockers in treating coronavirus disease 2019 (COVID-19) increases the risk of co-infections. Here we systematically summarized the cases of COVID-19-associated parasitic infections (CAPIs) in Iran.

METHODS

From 19 February 2020 to 10 May 2023, all studies on Iranian patients suffering from CAPIs were collected from several databases using a systematic search strategy.

RESULTS

Of 540 records, 11 studies remained for data extraction. In this research, most of the studies were related to Lophomonas and Toxoplasma. Of 411 cases of CAPIs, toxoplasmosis (385 [93.7%]) had the highest rate of infection among Iranian patients, followed by blastocystosis (15 [3.6%]), fascioliasis (4 [0.97%]), leishmaniasis (3 [0.7%]), lophomoniasis (3 [0.7%]) and strongyloidiasis (1 [0.2%]). In general, Blastocystis enhanced diarrhoea in patients with COVID-19. Lophomonas, Toxoplasma and Strongyloides increased the severity of COVID-19, but Fasciola decreased its intensity. Patients with a history of cutaneous leishmaniasis showed mild symptoms of COVID-19. Also, patients with a prior history of hydatid cysts were not affected by COVID-19.

CONCLUSIONS

Due to the similar symptoms of some parasitic diseases and COVID-19 and immunosuppressive treatment regimens in these patients that may cause the reactivation or recurrence of parasitic infections, early diagnosis and treatment are required.

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.

Clinical and Immunological Impacts of Latent Toxoplasmosis on COVID-19 Patients

Background Parasites are well-known immune-modulators. They inhibit some aspects of the immune system to ensure persistence inside the host for a long time; meanwhile, they stimulate other immune aspects to assure the survival of the host. Wide variations in the severity of coronavirus disease 2019 (COVID-19) among developed and developing countries were reported during the COVID-19 pandemic. Parasitic infections, including Toxoplasma gondii (T. gondii), were claimed to contribute to such variations. Methods To explore a possible relationship between latent toxoplasmosis and COVID-19 severity, our study included 44 blood samples from moderate/severe COVID-19 patients, who were admitted to Mansoura University Hospitals, Egypt, during the pandemic. Patients' sera were screened for Toxoplasma IgG antibodies using ELISA (Roche Diagnostics, Indianapolis, USA), and the gene expression of important immune markers (iNOS, arginase-1, IFN-γ, TNF-α, IL-6, IL-10, and TGF-β) was checked using real-time quantitative PCR. Clinical and laboratory data were obtained from the patients' medical records. Results Toxoplasma IgG antibodies were detected in 33 (75%) of patients. None of the studied clinical or laboratory parameters showed any significant changes in relation to toxoplasmosis seroprevalence. Further classification of the patients according to COVID-19 severity and Toxoplasma seroprevalence did not reveal any changes related to toxoplasmosis as well. Conclusion Our study indicates that latent toxoplasmosis has no effect on the severity of COVID-19.

Co-infection of COVID-19 and parasitic diseases: A systematic review

Co-infection of COVID-19 with other diseases increases the challenges related to its treatment management. COVID-19 co-infection with parasites is studied with low frequency. Here, we systematically reviewed the cases of parasitic disease co-infection with COVID-19. All articles on COVID-19 co-infected with parasites (protozoa, helminths, and ectoparasites), were screened through defined inclusion/exclusion criteria.

Of 2190 records, 35 studies remained for data extraction. The majority of studies were about COVID-19 co-infected with malaria, followed by strongyloidiasis, amoebiasis, chagas, filariasis, giardiasis, leishmaniasis, lophomoniasis, myiasis, and toxoplasmosis. No or low manifestation differences were reported between the co-infected cases and naïve COVID-19 or naïve parasitic disease.

Although there was a relatively low number of reports on parasitic diseases-COVID-19 co-infection, COVID-19 and some parasitic diseases have overlapping symptoms and also COVID-19 conditions and treatment regimens may cause some parasites re-emergence, relapse, or re-activation. Therefore, more attention should be paid to the on-time diagnosis of COVID-19 and the co-infected parasites.