Determination of parasitic burden in the brain tissue of infected mice in acute toxoplasmosis after treatment by fluconazole combined with sulfadiazine and pyrimethamine

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.

Effect of the mitochondrial uncoupling agent BAM15 against the Toxoplasma gondii RH strain and Prugniaud strain

BACKGROUND

Toxoplasmosis is a zoonotic disease caused by the infection of the protozoa Toxoplasma gondii (T. gondii), and safe and effective therapeutic drugs are lacking. Mitochondria, is an important organelle that maintains T. gondii survival, however, drugs targeting mitochondria are lacking.

METHODS

The cytotoxicity of BAM15 was detected by CCK-8 and the in vitro effects of BAM15 was detected by qPCR, plaque assay and flow cytometry. Furthermore, the ultrastructural changes of T. gondii after BAM15 treatment were observed by transmission electron microscopy, and further the mitochondrial membrane potential (ΔΨm), ATP level and reactive oxygen species (ROS) of T. gondii after BAM15 treatment were detected. The pharmacokinetic experiments and in vivo infection assays were performed in mice to determine the in vivo effect of BAM15.

RESULTS

BAM15 had excellent anti-T. gondii activity in vitro and in vivo with an EC50 value of 1.25 μM, while the IC50 of BAM15 in Vero cells was 27.07 μM. Notably, BAM15 significantly inhibited proliferation activity of T. gondii RH strain and Prugniaud strain (PRU), caused T. gondii death. Furthermore, BAM15 treatment induced T. gondii mitochondrial vacuolation and autolysis by TEM. Moreover, the decrease in ΔΨm and ATP level, as well as the increase in ROS production further confirmed the changes CONCLUSIONS: Our study identifies a useful T. gondii mitochondrial inhibitor, which may also serve as a leading molecule to develop therapeutic mitochondrial inhibitors in toxoplasmosis.'

Parasitological, Molecular, and Histopathological Investigation of the Potential Activity of Propolis and Wheat Germ Oil against Acute Toxoplasmosis in Mice

Toxoplasmosis is one of the most common parasitic zoonoses that affects all vertebrates. The drugs most commonly used against toxoplasmosis have many side effects, making the development of new antiparasitic drugs a big challenge. The present study evaluated the therapeutic effectiveness of novel herbal treatments, including propolis and wheat germ oil (WGO), against acute toxoplasmosis. A total of 50 albino mice were divided into five groups: group 1 (G1) (non-infected and non-treated); group 2 (G2) (infected without treatment); group 3 (G3) (treated with propolis); group 4 (G4) (treated with WGO); group 5 (G5) (treated with a combination of propolis and WGO). The effects of the herbal substances on different organs, mainly liver, spleen, and lungs, were investigated using parasitological, molecular, and histopathological examinations. The results of parasitological examination demonstrated statistically significant (p < 0.05) differences in the parasitic load between treated groups (G3, G4, and G5) compared to the control positive group (G2). These differences were represented by a significant reduction in the parasite load in stained tissue smears from the liver obtained from the animals treated with propolis (G3) compared to the parasite load in the positive control group. Similarly, animals (G4) treated with WGO exhibited a significant reduction in the parasite load versus the positive control group, while the lowest parasite load was found in G5, treated with propolis and WGO. Quantification of the parasite burden through molecular methods (PCR) revealed similar findings represented by reduction in the parasite burden in all treated groups with WGO and propolis as compared to the control group. Importantly, these previous parasitological and molecular findings were accompanied by a marked improvement in the histopathological picture of the liver, spleen, and lungs. In conclusion, propolis and WGO showed a good combination of therapeutic efficacy against acute toxoplasmosis.

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

Toxoplasmosis has been categorized as one of the long-lasting protozoan parasitic infections. It affects almost one-third of the world's population. In recent years, several documented studies have elucidated that infected individuals have a remarkably higher incidence of distinct health problems and show various adverse effects. In the PCR-positive COVID-19 patients in Gonbad-e-Kavus, Kalaleh, and Minoodasht counties in the northern part of Iran from June 2021 to December 2021, we sought to investigate any potential relationships between the severity of COVID-19 symptoms and acute and latent toxoplasmosis caused by Toxoplasma gondii (T. gondii). Whole blood samples of 161 COVID-19 patients with positive PCR. The samples were centrifuged to separate serum and screened for two important antibodies against T. gondii (IgM and IgG) by using ELISA kits for human anti-T. gondii IgM and IgG. Anti-T. gondii IgM and IgG antibodies were detected in 8/161 (5.0%) and 42/161 (26.1%) COVID-19 patients, respectively. No significant relationships were found between Toxoplasma IgM and IgG results with clinical signs, age, sex, contact with animals, comorbidities, and also the mortality rate of people with COVID-19. These findings showed that acute and latent toxoplasmosis infections are common among patients with COVID-19; however, no significant associations were found between toxoplasma infections and the symptoms of COVID-19. Therefore, toxoplasmosis is not considered a risk factor for COVID-19.

Sulfadiazine Plus Pyrimethamine Therapy Reversed Multiple Behavioral and Neurocognitive Changes in Long-Term Chronic Toxoplasmosis by Reducing Brain Cyst Load and Inflammation-Related Alterations

Toxoplasma gondii infects one-third of the world population. For decades, it has been considered a silent lifelong infection. However, chronically T. gondii-infected persons may present psychiatric and neurocognitive changes as anxiety, depression, and memory loss. In a model of long-term chronic infection, behavioral alterations parallel neuroinflammation and systemic high cytokine levels, and may reflect brain cyst load. Recent findings support that in chronic infection an active parasite-host interplay involves an immune-mediated control of tissue cysts. Here, we tested the idea that etiological treatment in chronic phase may add advantage to intrinsic immune-mediated cyst control and impact behavioral changes. Thus, we combined sulfadiazine-plus-pyrimethamine (S+P), the first-choice therapy for toxoplasmosis, to study the association of brain cyst load and biological processes related to the immune response (neuroinflammation, blood-brain barrier -BBB- disruption and serum cytokine levels), with behavioral and neurocognitive changes of long-term chronic infection. Female C57BL/6 mice (H-2^b) were infected (5 cysts, ME-49 strain) and treated with S+P from 30 to 60 days postinfection (dpi), compared with vehicle (Veh)-treated and noninfected controls. At endpoints (pre-therapy, 30 dpi; S+P therapy, 60 dpi; after ceased therapy, 90 dpi), independent groups were subjected to behavioral tests, and brain tissues and sera were collected. Multiple behavioral and neurocognitive changes were detected in the early (30 dpi) and long-term (60 and 90 dpi) chronic infection. S+P therapy resolved locomotor alterations, anxiety, and depressive-like behavior, partially or transiently ameliorated hyperactivity and habituation memory loss. Analysis after therapy cessation showed that S+P therapy reduced the number of stimuli required for aversive memory consolidation. S+P therapy resulted in reduced brain cyst load, neuroinflammation and BBB disruption, and lowered systemic Th1-cytokine levels. Correlation analysis revealed association between IFNγ, TNF and MCP-1/CCL2 serum levels, brain cyst load and behavioral and neurocognitive alterations. Moreover, principal-component analysis (PCA-2D and 3D projections) highlighted distinction between clusters (noninfected; Veh-treated and S+P-treated infected). Thus, our data suggest that S+P therapy added gain to intrinsic brain cyst control and, direct or indirectly, ameliorated inflammation-related alterations, traits associated with behavioral and neurocognitive alterations.