Toxoplasmosis as a cause for behaviour disorders--overview of evidence and mechanisms

Toxoplasma gondii, suicidal behaviour and suicide risk factors in US Veterans enrolled in mental health treatment

Markers of chronic infection Toxoplasma gondii (Nicolle et Manceaux, 1908) have been associated with suicidal self-directed violence (SSDV). We present the results of the first study relating T. gondii IgG serology with suicide attempts and suicidal ideation in United States Veterans, known to have higher suicide rates than members of the general population. We also related T. gondii serology to SSDV risk factors, including valid and reliable measures of trait impulsivity, aggression, self-reported depression, and sleep disturbance. We recruited 407 Veterans enrolled at three Veterans Affairs Medical Centers with mean (S.D.) age = 45.6 (11.6) years; 304 men (74.7%); 203 with a history of SSDV and 204 with no history of any self-directed violence (SDV). Seropositivity and serointensity, categorised as high (top quartile) or low (lower three quartiles), were analysed in relationship to SSDV, suicidal ideation and clinical risk factors using age and gender-adjusted linear and logistic methods, after transformations and nonparametric tests when appropriate. Associations between seropositivity and SSDV and its risk factors were not significant in all groups. High serointensity, while not associated with SSDV or repeat suicide attempts, was positively associated with suicidal ideation, depression, impulsivity, and daytime dysfunction due to sleepiness (p < 0.05), but only in Veterans with a history of SSDV. In Veterans without a history of SDV, no associations were significant. These associations remained significant after adjustment for certain socioeconomic factors (i.e., income, homelessness, military rank). Including education in the model downgraded the statistical significance of suicidal ideation and depression to statistical trends, but the significance of associations with impulsivity and daytime dysfunction due to sleepiness remained. Major limitations include the cross-sectional design, overall low seropositivity within the sample, and potentially spurious results due to multiple comparisons. Thus, the results of this report need to be replicated in larger samples, ideally longitudinally.

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.

Synthesis and In vitro evaluation of bichalcones as novel anti-toxoplasma agents

Toxoplasmosis is a zoonotic disease caused by Toxoplasma gondii, an apicomplexan parasite that infects approximately a third of the world's human population. This disease can cause serious complications during pregnancy and can be fatal in immunocompromised hosts. The current treatment options for toxoplasmosis face several limitations. Thus, to address the urgent medical need for the discovery of novel anti-toxoplasma potential drug candidates, our research focused on exploring a series of monomeric and dimeric chalcones, polyphenolic molecules belonging to the class of flavonoids. Chalcones 1aa-1bg and axially chiral A-A'-connected bichalcones 2aa-2bg were evaluated in vitro against the proliferation of the parasite in a cell-based assay. A comparison of the efficacy demonstrated that, in several cases, bichalcones exhibited increased bioactivity compared to their corresponding monomeric counterparts. Among these compounds, a bichalcone with a phenyl substituent and a methyl moiety 2ab showed the most potent and selective inhibitory activity in the nanomolar range. Both enantiomers of this bichalcone were synthesized using an axially chiral biphenol building block. The biaryl bond was forged using Suzuki cross-coupling in water under micellar catalysis conditions. Separation of the atropisomers of this biphenol building block was conducted by chiral HPLC on a preparative scale. The biological evaluation of the enantiomers revealed that the (R a)-enantiomer (R a)-2ab is the eutomer. These studies suggest that bichalcones may be important drug candidates for further in vivo evaluations for the discovery of anti-toxoplasma drugs.

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.

Prevalence of Toxoplasma gondii IgG Antibodies and Associated Risk Factors in Psychiatric Patients from Western Romania: A Cross-Sectional Study

Infection with the coccidian parasite Toxoplasma gondii was associated with an increased risk of several mental disorders. We conducted a case-control study of 464 consecutive psychiatric patients and assessed the prevalence of IgG antibodies against T. gondii and the potential risk factors associated with infection. T. gondii-specific antibodies were determined using a chemiluminescence assay. A questionnaire was utilized to assess the potential correlation between risk factors and Toxoplasma gondii seropositivity. IgG antibodies were found in 325 (70.04%) of the patients. We observed a higher likelihood of positive IgG antibodies against Toxoplasma gondii in older individuals, patients residing in rural areas, and females. We also noted associations between Toxoplasma gondii infection and certain risk factors, like activities that involve contact with soil, low-income levels, and limited educational attainment. Our findings indicate a high prevalence of T. gondii infection among psychiatric patients from Western Romania and provide new information regarding the potential risk factors associated with T. gondii in this population group. This study may serve as a foundation for future research and the development of preventive strategies.

Toxoplasma infection and Rhesus blood group system: A systematic review and meta-analysis

BACKGROUND

Toxoplasmosis is one of the most common infections in humans and animals, which is caused by an obligate intracellular opportunistic parasite known as Toxoplasma gondii (T. gondii). Some data have shown that both Rhesus (Rh)-positive and Rh-negative individuals differ in response to biological factors, including Toxoplasma infection. Therefore, this systematic review and meta-analysis was conducted to investigate the scientific evidence regarding the possible association between the Rh blood group and Toxoplasma infection and to determine the seroprevalence of T. gondii in the Rh blood group system.

METHODS

The research was conducted on PubMed, ScienceDirect, ProQuest, and Google Scholar databases until January 2023. Twenty-one cross-sectional studies were included with a total of 10910 people. The data were synthesized using a random effect model with 95% confidence intervals (CIs).

RESULTS

The overall prevalence of T. gondii was calculated at 32.34% (CI 95%: 28.23-36.45%) and 33.35% (CI 95%: 19.73-46.96%) in Rh-positive and Rh-negative blood groups. In addition, the pooled OR for the relationship between the Rh blood group and the seroprevalence of T. gondii was 0.96 (95% CI: 0.72-1.28).

CONCLUSIONS

This meta-analysis showed a high prevalence of Toxoplasma infection in both Rh-negative and positive blood groups. This systematic review and meta-analysis revealed that no significant association was found between toxoplasmosis and Rh factor. Because of the limited number of studies in this field, more research is recommended to determine the exact relationship between toxoplasmosis and the Rh factor.

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.

Intestinal infectious diseases increase the risk of psychiatric disorders: A nationwide population-based cohort study

Intestinal infectious diseases (IIDs) are among the most common diseases and are prevalent worldwide. IIDs are also one of the major disease groups with the highest incidence worldwide, especially among children and older adults. We observed a higher probability of IIDs in patients from the psychiatric department of Tri-Service General Hospital. Therefore, our objective was to investigate if there is an association between IIDs and the risk of developing psychiatric disorders. This nationwide population-based study used the database of the National Health Insurance (NHI) program in Taiwan. The study included 150,995 patients from 2000 to 2015, comprising 30,199 patients with IIDs as the study group and 120,796 patients without IIDs as the control group. Cox proportional hazards regression analysis was performed to calculate the hazard ratio of psychiatric disorders during the 16-year follow-up. Of the patients with IIDs, 4022 (13.32%) developed psychiatric disorders compared to 8119 (6.72%) who did not (P < .001). The adjusted hazard ratio (aHR) for overall psychiatric disorders in the study group was 2.724 (95% confidence interval [CI]: 2.482-2.976; P < .001). More specifically, the study group had a higher risk of developing a psychiatric disorder, including sleep disorders, depression, anxiety, bipolar disorder, post-traumatic stress disorder (PTSD)/acute stress disorder (ASD), schizophrenia, mental retardation (MR), substance abuse, and other psychiatric disorders. Furthermore, refractory IIDs (seeking medical attention for IIDs 3 or more times) increased the risk (aHR: 3.918; 95% CI: 3.569-4.280; P < .001) of developing psychiatric disorders. There was an association between IIDs and the increased risk of developing psychiatric disorders. The novel role of etiological factors in the development of psychiatric disorders deserves more attention, and the control of pathogens that cause IIDs is of urgent public health importance.

Association between Toxoplasma gondii infection and psychiatric disorders: a cross-sectional study in China

Psychiatric patients have become the focus of public attention, and current research suggests a possible link between Toxoplasma gondii (T. gondii) infection and mental illness. To understand the current situation of T. gondii infection in psychiatric patients in the study area, the relationship between T. gondii infection and mental diseases, and the influence of T. gondii infection on psychiatric patients, this study examined 3101 psychiatric inpatients from 2015 to 2020. All people included in the study were tested for anti-Toxoplasma IgM antibody and anti-Toxoplasma IgG antibody. Additionally, 4040 individuals from the general population were included as controls. The chi-square test and logistic regression analysis were carried out to determine the association between psychiatric disorders and T. gondii infection. The seroprevalence of anti-Toxoplasma IgM antibody was 0.23% (7/3101) in psychiatric inpatients and 0.11% (2/1846) in the general population, and there was no significant difference (p > 0.05). The seroprevalence rate of anti-Toxoplasma IgG antibodies was 3.03% (94/3101) in psychiatric inpatients and 1.05% (23/2194) in the general population, and there was a significant difference (p < 0.01). The seroprevalence of anti-Toxoplasma IgG antibody in psychiatric inpatients was significantly different between different age groups (p < 0.01). The positivity rate of anti-Toxoplasma IgG antibodies was 5.17% (3/58) in patients with mania, 3.24% (8/247) in patients with recurrent depressive disorder, 3.54% (13/367) in patients with depression, 3.22% (39/1213) in patients with schizophrenia, 2.41% (18/748) in patients with bipolar disorder and 2.25% (2/89) in patients with dissociative disorder. Compared to the general population, patients with mania (OR = 5.149 95% CI 1.501–17.659 p = 0.009), schizophrenia (OR = 3.136 95% CI 1.864–5.275 p = 0.000), depression (OR = 3.466 95% CI 1.740–6.906 p = 0.000), recurrent depressive disorder (OR = 3.160 95% CI 1.398–7.142 p = 0.006) and bipolar disorder (OR = 2.327 95% CI 1.249–4.337 p = 0.008) were found to be significantly associated with the seroprevalence of anti-Toxoplasma IgG antibody. This study suggests that the seroprevalence of T. gondii infection in psychiatric patients was higher and that age was an influencing factor of T. gondii infection in psychiatric patients. T. gondii infection was associated with mania, schizophrenia, depression, recurrent depressive disorder and bipolar disorder.

Seroprevalence and Risk Factors for Toxoplasma gondii and Neospora caninum in Cattle in Portugal

Simple Summary

Neospora caninum and Toxoplasma gondii are apicomplexan parasites with a worldwide distribution and both infect cattle. While the importance of N. caninum is mainly linked to reproductive losses, concern has been raised about the role of beef as a source of food-borne toxoplasmosis in humans. Little is known about the prevalence of these parasites in cattle in Portugal. This study aimed to evaluate the seroprevalence and risk factors for N. caninum and T. gondii in naturally exposed cattle from different geographical areas in the country. Results point to a low but widespread seroprevalence of T. gondii, while that of N. caninum was found to be in the same range as reported in other Mediterranean countries. Distribution of both parasites may be explained by common climate factors and management practices identified as significant predictors of infection in the study.

Abstract

Neospora caninum has a worldwide economic impact as an important cause of abortion in cattle, while Toxoplasma gondii, another abortifacient pathogen, is globally a major foodborne zoonotic threat. The study aimed to evaluate the seroprevalence and risk factors for the two parasites in cattle in Portugal. A total of 612 sera from 35 farms were tested by an in-house p30 ELISA for T. gondii and p38 ELISA for N. caninum. T. gondii positive and suspicious sera were confirmed by p30 Western blot or IFAT. T. gondii and N. caninum animal seroprevalence was 9.2% (95%CI 7.1–11.7) and 17.2% (95% CI 14.4–20.4) and herd seroprevalence was 51.4% (95% CI 35.6–67.0) and 68.6% (95% CI 52.0–81.5), respectively. At the univariable level, climate area and precipitation of wettest month, driest month, driest quarter, and warmest quarter were significant predictors of seropositivity for both. N. caninum seropositivity was more likely in the region Norte, densely populated areas, and intensive production, and the probability of T. gondii seropositivity decreased with herd size. Results confirm the need to consider neosporosis in the differential diagnosis of cattle reproductive disorders in Portugal and may be valuable to inform source attribution models for human toxoplasmosis.

Le Petit Machiavellian Prince: Effects of Latent Toxoplasmosis on Political Beliefs and Values

Humans infected by Toxoplasma gondii express no specific symptoms but manifest higher incidence of many diseases, disorders and differences in personality and behavior. The aim of this study was to compare the political beliefs and values of Toxoplasma-infected and Toxoplasma-free participants. We measured beliefs and values of 2315 responders via an online survey (477 Toxoplasma-infected) using the Political Beliefs and Values Inventory (PI34). This study showed Toxoplasma-infected and Toxoplasma-free participants of our cross-sectional study differed in three of four factors of PI34, scoring higher in Tribalism and lower in Cultural liberalism and Anti-Authoritarianism. We found sex differences in political beliefs associated with Toxoplasma infection. Infected women scored higher in tribalism and lower in cultural liberalism, compared with the Toxoplasma-free control group, while infected men scored higher in economic equity. These results fit with sexual differences in behavior and attitude observed after toxoplasmosis infection. Controlling for the effect of worse physical health and mental health had little impact, suggesting that impaired health did not cause these changes. Rather than adaptation to prevalence of parasites, as suggested by parasite-stress theory, the differences might be side-effects of long-term mild inflammatory reaction. However, to get clear picture of the mild inflammation effects, more research focused on different infectious diseases is needed.

Is latent Toxoplasma gondii infection associated with the occurrence of schizophrenia? A case-control study

Introduction

Neurotropic pathogens such as Toxoplasma gondii (T. gondii) which result in chronic infections in the brain are associated with mental illnesses. In view of this, a growing body of literature has revealed the possible interaction of schizophrenia and T. gondii infection.

Method

A case-control study was conducted from February 2018 to January 2019 among 47 Schizophrenia patients and 47 age and sex-matched controls. Data was collected using a structured questionnaire. Serum was used for serological analysis of anti-T. gondii IgG and IgM antibodies through chemiluminescent immunoassay. Proportions and mean with standard deviations (SD) were used as descriptive measures and variables with p-values <0.05 were considered as statistically significant and independently associated with schizophrenia.

Result

The mean ages of schizophrenia patients and controls were 29.64 ± 5.8 yrs and 30.98 ± 7.3 yrs, respectively. We found that 81.9% (77/94) of the study subjects had a positive anti-T. gondii IgG antibody. While the difference is statistically insignificant, schizophrenic patients have a marginally higher seroprevalence of toxoplasmosis than controls (87.2% vs 80.9%; p = 0.398). Schizophrenia cases who live in homes with soil floors have a significantly higher T. gondii infection as compared to those who live in homes with cement/ceramic floors (90.9% vs 33.3%; p = 0.004). Furthermore, there was a significantly lower T. gondii infection among schizophrenic cases who were taking antipsychotic medication for more than three yrs (79.3% vs 100.0%, p = 0.039). On the other hand, among all study subjects who have T. gondii infection, subjects who are addicted to khat and alcohol were about seven times more likely to develop schizophrenia (71.4% vs 47.7%, OR = 7.13, p = 0.024).

Conclusion

Our data is not sufficient to show a significant positive correlation between T. gondii infection and schizophrenia. For study subjects with T. gondii infection, addiction to khat and alcohol is one of the risk factors for schizophrenia.

Misdiagnosis of HIV With Toxoplasmosis Encephalopathy With Progressive Memory Loss as the Initial Symptom: A Case Report

Toxoplasmosis encephalopathy (TE) is a kind of encephalopathy parasitic disease caused by Toxoplasma gondii. It is the most common opportunistic for central system infection in patients with acquired immunodeficiency syndrome (AIDS) or human immunodeficiency virus. Without early diagnosis and proper treatment, this opportunistic infection can be life-threatening. The common clinical manifestations of the disease include altered mental state, epilepsy, cranial nerve damage, paresthesia, cerebellar signs, meningitis, motor disorders, and neuropsychiatry. The most common presentation in about 75% of cases is a subacute episode of focal neurological abnormalities such as hemiplegia, personality changes, or aphasia. Imaging needs to be differentiated from multiple sclerosis, lymphoma, and metastases. We report a case of acquired immune deficiency syndrome complicated with toxoplasma encephalopathy with rapid progressive memory loss as the initial symptom and misdiagnosed as multiple sclerosis. Through the comprehensive analysis of the clinical symptoms and imaging examination of this disease, we hope to enhance the confidence of clinicians in the diagnosis of this disease.

Immunohistochemical detection and pathology of toxoplasmosis in Nigerian wild rats

Toxoplasmosis is a zoonotic disease of economic importance found worldwide, and it is caused by Toxoplasma gondii, which affects a wide range of hosts. High prevalence of toxoplasmosis has been reported in rodents, and they are considered very important in the circulation and maintenance of the disease. However, epidemiologic studies of the disease in rodents are generally scarce in the Tropics. This study utilized the immunohistochemical (IHC) technique to detect Toxoplasma gondii in wild rats sampled from across the North Central Nigeria. The brain, intestine, diaphragm, lungs and kidney tissue samples from 227 wild rats (Zyzomys pedunculatus) were routinely processed for histopathology, out of which 86 were further selected for IHC detection of T. gondii antigens using the streptavidin-peroxidase method. The histologic lesions observed were mild to moderate in severity, including meningitis, focal gliosis, neuronal degeneration and necrosis, villous atrophy and denudation, enteritis, diaphragmatic myositis, broncho-interstitial pneumonia and interstitial nephritis. Toxoplasma gondii was detected in 82.6% of the selected samples showing various degrees of immunoreaction intensity. We conclude that IHC is a useful tool in the detection of T. gondii in wild rats, and lungs and kidney may be the organ of choice for the detection of T. gondii.

Toxoplasmosis: Targeting neurotransmitter systems in psychiatric disorders

The most common form of the disease caused by Toxoplasma gondii (T. gondii) is latent toxoplasmosis due to the formation of tissue cysts in various organs, such as the brain. Latent toxoplasmosis is probably a risk factor in the development of some neuropsychiatric disorders. Behavioral changes after infection are caused by the host immune response, manipulation by the parasite, central nervous system (CNS) inflammation, as well as changes in hormonal and neuromodulator relationships. The present review focused on the exact mechanisms of T. gondii effect on the alteration of behavior and neurotransmitter levels, their catabolites and metabolites, as well as the interaction between immune responses and this parasite in the etiopathogenesis of psychiatric disorders. The dysfunction of neurotransmitters in the neural transmission is associated with several neuropsychiatric disorders. However, further intensive studies are required to determine the effect of this parasite on altering the level of neurotransmitters and the role of neurotransmitters in the etiology of host behavioral changes.

Research on demographic, clinical and paraclinical aspects in pregnant women infected with Toxoplasma gondii

Toxoplasmosis is a zoonotic disease caused by the Toxoplasma gondii protozoan parasite. The aim of this study was to determine the frequency of acute toxoplasmosis or its presence in the medical history of 240 pregnant women, depending on age and geographical background. The second purpose was to analyze several medical aspects (clinical and paraclinical) in pregnant women with acute toxoplasmosis. The study identified several serological changes including positive toxoplasma IgM, IgG, and IgA antibodies. The chemiluminescence immunoassay (CLIA) method was used to detect T. gondii-specific IgM and IgG antibodies and the enzyme immunoassay (EIA) method to detect T. gondii-specific IgA antibodies. Of the 96 pregnant women (40%) infected with T. gondii, approximately 1/3 had acquired acute infection and 2/3 had a history of prior acute infection (P<0.0001). No statistically significant differences according to age groups (P=0.9384) were found in terms of serological profile. The number of patients with negative serology was significantly higher in urban areas than in rural areas (P<0.0001). The highest incidence among the pregnant women with acute toxoplasmosis with a single chain of ganglia affected was represented by those with the involvement of cervical lymph nodes (75%), the difference compared to the involvement of other chains of ganglia being statistically significant (P=0.0087). All 35 pregnant women with acute toxoplasmosis tested positive for T. gondii-specific IgM antibodies. Most pregnant women with acute T. gondii infection (57.1%) tested negative for T. gondii-specific IgM antibody serum titres within 3-6 months of presentation. The difference compared to other intervals from the moment pregnant women sought care was statistically significant (P=00002). Only 80% of all pregnant women with acute toxoplasmosis tested positive for T. gondii-specific IgA antibodies. Pregnant women with acute toxoplasmosis have a 3.3 times higher risk of pregnancy loss.

The emerging paradigm of calcium homeostasis as a new therapeutic target for protozoan parasites

Calcium channels (CCs), a group of ubiquitously expressed membrane proteins, are involved in many pathophysiological processes of protozoan parasites. Our understanding of CCs in cell signaling, organelle function, cellular homeostasis, and cell cycle control has led to improved insights into their structure and functions. In this article, we discuss CCs characteristics of five major protozoan parasites Plasmodium, Leishmania, Toxoplasma, Trypanosoma, and Cryptosporidium. We provide a comprehensive review of current antiparasitic drugs and the potential of using CCs as new therapeutic targets. Interestingly, previous studies have demonstrated that human CC modulators can kill or sensitize parasites to antiparasitic drugs. Still, none of the parasite CCs, pumps, or transporters has been validated as drug targets. Information for this review draws from extensive data mining of genome sequences, chemical library screenings, and drug design studies. Parasitic resistance to currently approved therapeutics is a serious and emerging threat to both disease control and management efforts. In this article, we suggest that the disruption of calcium homeostasis may be an effective approach to develop new anti-parasite drug candidates and reduce parasite resistance.

Toxoplasma gondii, Herpesviridae and long-term risk of transition to first-episode psychosis in an ultra high-risk sample

BACKGROUND

Ultra high-risk (UHR) criteria were introduced to identify people at imminent risk of developing psychosis. To improve prognostic accuracy, additional clinical and biological risk factors have been researched. Associations between psychotic disorders and infections with Toxoplasma gondii and Herpesviridae have been found. It is unknown if exposure to those pathogens increases the risk of transition to psychosis in UHR cohorts.

METHODS

We conducted a long-term follow-up of 96 people meeting UHR criteria, previously seen at the Personal Assessment and Crisis Evaluation (PACE) clinic, a specialized service in Melbourne, Australia. Transition to psychosis was assessed using the Comprehensive Assessment of the At-Risk Mental State (CAARMS) and state public mental health records. The relationship between IgG antibodies to Herpesviridae (HSV-1, HSV-2, CMV, EBV, VZV) and Toxoplasma gondii and risk for transition was examined with Cox regression models.

RESULTS

Mean follow-up duration was 6.46 (±3.65) years. Participants who transitioned to psychosis (n = 14) had significantly higher antibody titers for Toxoplasma gondii compared to those who did not develop psychosis (p = 0.03). After adjusting for age, gender and year of baseline assessment, seropositivity for Toxoplasma gondii was associated with a 3.6-fold increase in transition hazard in multivariate Cox regression models (HR = 3.6; p = 0.036). No significant association was found between serostatus for Herpesviridae and risk of transition.

CONCLUSIONS

Exposure to Toxoplasma gondii may contribute to the manifestation of positive psychotic symptoms and increase the risk of transitioning to psychosis in UHR individuals.

Serum Tyrosine Level in Acute Murine Toxoplasmosis

Background

Toxoplasmosis is a zoonotic disease caused by the obligate intracellular parasite, Toxoplasma gondii. This global infectious disease has been associated with behavioral changes in rodents and can result in humans' neuropsychiatric symptoms. Since the neurotransmitters alteration can cause a behavioral change, in this study, tyrosine level, as a precursor of dopamine, was evaluated in acute murine toxoplasmosis during 2015 and 2016 in Shiraz, Iran.

Methods

At the first, 10⁵ tachyzoites of T. gondii were subcutaneously inoculated to 50 BALB/c mice as experimental groups and 10 mice inoculated by PBS considered as the control group. After that, daily, one group of mice was bled, and sera were collected. Then, their serum tyrosine level was evaluated by HPLC method.

Results

After data analysis, the maximum mean serum tyrosine level was seen at 2^th day of post parasite inoculation (0.0194 mg/ ml), with a significant difference compared to the control group (0.0117 mg/ ml, P=0.025). Moreover, the least quantity of serum tyrosine (0.076 mg/ml) was seen on the 5^th day, after parasite inoculation, however, no significant difference was seen.

Conclusion

Serum tyrosine level increased in 2 d after inoculation of Toxoplasma, but the level regularly decreased in successive days. Tyrosine level increased by phenylalanine hydroxylase 2 days after inoculation, then tyrosine decreased by tyrosine hydroxylase in the next days. Toxoplasma tyrosine hydroxylase enzymes, at primary days of toxoplasmosis, effect on tyrosine production, and after that, the most effect on tyrosine consumption.

Imiquimod Targets Toxoplasmosis Through Modulating Host Toll-Like Receptor-MyD88 Signaling

Toxoplasma gondii is a prevalent parasite of medical and veterinary importance. Tachyzoïtes and bradyzoïtes are responsible for acute and chronic toxoplasmosis (AT and CT), respectively. In immunocompetent hosts, AT evolves into a persistent CT, which can reactivate in immunocompromised patients with dire consequences. Imiquimod is an efficient immunomodulatory drug against certain viral and parasitic infections. In vivo, treatment with Imiquimod, throughout AT, reduces the number of brain cysts while rendering the remaining cysts un-infectious. Post-establishment of CT, Imiquimod significantly reduces the number of brain cysts, leading to a delay or abortion of reactivation. At the molecular level, Imiquimod upregulates the expression of Toll-like receptors 7, 11, and 12, following interconversion from bradyzoïtes to tachyzoïtes. Consequently, MyD88 pathway is activated, resulting in the induction of the immune response to control reactivated Toxoplasma foci. This study positions Imiquimod as a potent drug against toxoplasmosis and elucidates its mechanism of action particularly against chronic toxoplasmosis, which is the most prevalent form of the disease.

Latent Toxoplasma gondii infections are associated with elevated biomarkers of inflammation and vascular injury

BACKGROUND

Toxoplasma gondii is a protozoan parasite that infects cats as definitive hosts and other warm-blooded animals including humans as intermediate hosts. It forms infectious cysts in the brain, muscle and other tissues establishing life-long latent infection. Approximately 10% of the US population is infected. While latent infections are largely asymptomatic, they are associated with neurological deficits and elevated risks of neuropsychiatric diseases.

METHODS

This cross-sectional epidemiological study investigated associations of T. gondii infections with biomarkers of inflammation and vascular injury: soluble intercellular adhesion molecule 1 (ICAM-1), soluble vascular cell adhesion molecule 1 (VCAM-1), C-reactive protein (CRP), and serum amyloid A (SAA). Serum samples from 694 adults in the Raleigh-Durham-Chapel Hill, North Carolina metropolitan area were tested for IgG antibody response to T. gondii, and for the above biomarkers using commercially available assays.

RESULTS

T. gondii seroprevalence rate in this sample was 9.7%. Seropositivity was significantly associated with 11% (95% confidence limits 4, 20%) greater median levels of VCAM-1 (p = 0.003), and marginally significantly with 9% (1, 17%), and 36% (1, 83%) greater median levels of ICAM-1, and CRP, respectively (p = 0.04 for each) after adjusting for sociodemographic and behavioral covariates, while the 23% (- 7, 64%) adjusted effect on SAA was not statistically significant (p = 0.15).

CONCLUSIONS

Latent infections with T. gondii are associated with elevated biomarkers of chronic inflammation and vascular injury that are also known to be affected by ambient air pollution.

Memory impairment in chronic experimental Chagas disease: Benznidazole therapy reversed cognitive deficit in association with reduction of parasite load and oxidative stress in the nervous tissue

Memory impairment has been associated with chronic Chagas disease (CD), a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. In degenerative diseases, memory loss has been associated with increased oxidative stress, revealed as enhanced lipid peroxidation, in the cerebral cortex. Benznidazole (Bz), a trypanocidal drug efficient to reduce blood parasite load in the acute and chronic phases of infection, showed controversial effects on heart disease progression, the main clinical manifestation of CD. Here, we evaluated whether C57BL/6 mice infected with the Colombian type I T. cruzi strain present memory deficit assessed by (i) the novel object recognition task, (ii) the open field test and (iii) the aversive shock evoked test, at 120 days post infection (dpi). Next, we tested the effects of Bz therapy (25mg/Kg/day, for 30 consecutive days) on memory evocation, and tried to establish a relation between memory loss, parasite load and oxidative stress in the central nervous system (CNS). At 120 dpi, T. cruzi-infected mice showed memory impairment, compared with age-matched non-infected controls. Bz therapy (from 120 to 150 dpi) hampered the progression of habituation and aversive memory loss and, moreover, reversed memory impairment in object recognition. In vehicle-administered infected mice, neuroinflammation was absent albeit rare perivascular mononuclear cells were found in meninges and choroid plexus. Bz therapy abrogated the infiltration of the CNS by inflammatory cells, and reduced parasite load in hippocampus and cerebral cortex. At 120 and 150 dpi, lipid peroxidation was increased in the hippocampus and cortex tissue extracts. Notably, Bz therapy reduced levels of lipid peroxidation in the cerebral cortex. Therefore, in experimental chronic T. cruzi infection Bz therapy improved memory loss, in association with reduction of parasite load and oxidative stress in the CNS, providing a new perspective to improve the quality of life of Chagas disease patients.

Toxoplasma gondii, Suicidal Behavior, and Intermediate Phenotypes for Suicidal Behavior

Within the general literature on infections and suicidal behavior, studies on Toxoplasma gondii (T. gondii) occupy a central position. This is related to the parasite's neurotropism, high prevalence of chronic infection, as well as specific and non-specific behavioral alterations in rodents that lead to increased risk taking, which are recapitulated in humans by T. gondii's associations with suicidal behavior, as well as trait impulsivity and aggression, mental illness and traffic accidents. This paper is a detailed review of the associations between T. gondii serology and suicidal behavior, a field of study that started 15 years ago with our publication of associations between T. gondii IgG serology and suicidal behavior in persons with mood disorders. This "legacy" article presents, chronologically, our primary studies in individuals with mood disorders and schizophrenia in Germany, recent attempters in Sweden, and in a large cohort of mothers in Denmark. Then, it reviews findings from all three meta-analyses published to date, confirming our reported associations and overall consistent in effect size [ranging between 39 and 57% elevation of odds of suicide attempt in T. gondii immunoglobulin (IgG) positives]. Finally, the article introduces certain links between T. gondii and biomarkers previously associated with suicidal behavior (kynurenines, phenylalanine/tyrosine), intermediate phenotypes of suicidal behavior (impulsivity, aggression) and state-dependent suicide risk factors (hopelessness/dysphoria, sleep impairment). In sum, an abundance of evidence supports a positive link between suicide attempts (but not suicidal ideation) and T. gondii IgG (but not IgM) seropositivity and serointensity. Trait impulsivity and aggression, endophenotypes of suicidal behavior have also been positively associated with T. gondii seropositivity in both the psychiatrically healthy as well as in patients with Intermittent Explosive Disorder. Yet, causality has not been demonstrated. Thus, randomized interventional studies are necessary to advance causal inferences and, if causality is confirmed, to provide hope that an etiological treatment for a distinct subgroup of individuals at an increased risk for suicide could emerge.

Higher Extraversion and Lower Conscientiousness in Humans Infected with Toxoplasma

Toxoplasmosis is associated with specific differences in the personality of infected subjects relative to non–infected subjects. These differences are usually considered to be a side effect of the manipulative activity of the parasite aimed to increase the probability of its transmission from the intermediate host to the definitive host by predation. The personality of infected subjects was studied mostly using the Cattell's questionnaire. However, this questionnaire is now considered outdated and has been mostly substituted with the Neuroticism–Extraversion–Openness Personality Inventory—Revised (NEO–PI–R) questionnaire in clinical practice. Here, we searched for the association between toxoplasmosis and the personality by screening a population of students with the NEO–PI–R questionnaire. We found that Toxoplasma–infected male and female students had significantly higher extraversion and lower conscientiousness. The conscientiousness negatively correlated with the length of infection in men, which suggested that the toxoplasmosis associated differences were more probably the result of slow cumulative changes induced by latent toxoplasmosis, rather than transient side effect of acute Toxoplasma infection. The existence of this correlation also supported (but of course not proved) the hypothesis that Toxoplasma infection influenced the personality, rather than the hypothesis that the personality influenced the probability of the infection. Copyright © 2011 John Wiley & Sons, Ltd.

A negative covariation between toxoplasmosis and CoVID-19 with alternative interpretations

Coronaviruses may exert severely negative effects on the mortality and morbidity of birds and mammals including humans and domestic animals. Most recently CoVID-19 has killed about half million people (27th of June, 2020). Susceptibility to this disease appears to differ markedly across different societies but the factors underlying this variability are not known. Given that prevalence of toxoplasmosis in human societies may serve as a proxy for hygiene, and it also exerts both direct and immune-mediated antiviral effects, we hypothesize a negative covariation between toxoplasmosis and measures of the CoVID-19 pandemic across countries. We obtained aged-adjusted toxoplasmosis prevalence of pregnant women from the literature. Since the differences in the CoVID-19 morbidity and mortality may depend on the different timing of the epidemics in each country, we applied the date of first documented CoVID-19 in each country as a proxy of susceptibility, with a statistical control for population size effects. Using these two indices, we show a highly significant negative co-variation between the two pandemics across 86 countries. Then, considering that the wealth of nations often co-varies with the prevalence of diseases, we introduced GDP per capita into our model. The prevalence of toxoplasmosis co-varies negatively, while the date of first CoVID-19 co-varies positively with GDP per capita across countries. Further, to control for the strong spatial autocorrelation among countries, we carried out a Spatial Structure Analyses of the relationships between the date of first CoVID-19, prevalence of toxoplasmosis, and GDP per capita. Results of this analysis did not confirm a direct causal relationship between toxoplasmosis and susceptibility to the CoVID-19 pandemics. As far as an analysis of observational data let us to suggest, it appears that the interaction between CoVID-19 and toxoplasmosis is mediated by GDP per capita and spatial effects. This prompts the question whether the formerly known covariations of CoVID-19 and BCG vaccination or air pollution might have also emerged as spurious indirect effects.

Expression of serotonin 2A, 2C, 6 and 7 receptor and IL-6 mRNA in experimental toxoplasmic encephalitis in mice

The neurotropic pathogen Toxoplasma gondii infects about one-third of the human population. Both acute and chronic (latent or life-long) forms of toxoplasmosis are associated with specific neurologic and neuropsychiatric symptoms. In the present study, swiss albino mice were inoculated intraperitoneally with 15–20 tissue cysts of the ME-49 strain of Toxoplasma gondii. The brain samples were collected on the days 10, 20, and 30 for determining the histopathological scores and the number of cysts. Furthermore, a real-time quantitative polymerase chain reaction (RT-PCR) was conducted to find out the gene expression levels of the serotonin 2A receptor (5-HTR2A), serotonin 2C receptor (5-HTR2C), serotonin 6 receptor (5-HTR6), serotonin 7 receptor (5-HTR7), and interleukin-6. The results were compared to the histopathological findings of encephalitic toxoplasmosis. The expression levels were observed to increase for all receptors; however at different time points of infection. This experimental model demonstrates that the expression of serotonin receptors was induced in Toxoplasma gondii infections, displaying unique findings for each of the individual receptors.

Microglia in neuropathology caused by protozoan parasites

Involvement of the central nervous system (CNS) is the most severe consequence of some parasitic infections. Protozoal infections comprise a group of diseases that together affect billions of people worldwide and, according to the World Health Organization, are responsible for more than 500000 deaths annually. They include African and American trypanosomiasis, leishmaniasis, malaria, toxoplasmosis, and amoebiasis. Mechanisms underlying invasion of the brain parenchyma by protozoa are not well understood and may depend on parasite nature: a vascular invasion route is most common. Immunosuppression favors parasite invasion into the CNS and therefore the host immune response plays a pivotal role in the development of a neuropathology in these infectious diseases. In the brain, microglia are the resident immune cells active in defense against pathogens that target the CNS. Beside their direct role in innate immunity, they also play a principal role in coordinating the trafficking and recruitment of other immune cells from the periphery to the CNS. Despite their evident involvement in the neuropathology of protozoan infections, little attention has given to microglia-parasite interactions. This review describes the most prominent features of microglial cells and protozoan parasites and summarizes the most recent information regarding the reaction of microglial cells to parasitic infections. We highlight the involvement of the periphery-brain axis and emphasize possible scenarios for microglia-parasite interactions.

Acute Complications and Sequelae from Foodborne Infections: Informing Priorities for Cost of Foodborne Illness Estimates

Cost of foodborne illness (CoFI) estimates provide estimates of the overall impact of foodborne illnesses, including hospitalizations, long-term complications, and deaths. CoFI estimates are needed in countries that require cost-benefit analysis as part of the process of adopting new regulations, as is the case in the United States. Monetary estimates of the impact of disease also provide a meaningful way of communicating with the public about the impact of foodborne disease. In 2014, researchers at the U.S. Department of Agriculture, Economic Research Service (ERS), published CoFI estimates for 15 pathogens that account for roughly 95% of illnesses and deaths from the 31 major foodborne pathogens included in the Centers for Disease Control and Prevention (CDC) foodborne disease incidence estimates. ERS is currently updating their estimates to include all 31 known pathogens and unspecific agents included in CDC incidence estimates. CoFI estimates are based on quantitative models of the health outcomes people experience as a result of these illnesses and an assessment of the costs associated with these health outcomes. Research on the incidence of foodborne disease provides a starting point for this disease modeling, but it usually must be supplemented by other additional synthesis of research on acute complications and long-term health outcomes of different foodborne diseases. As part of its current work revising CoFI estimates, ERS convened a workshop attended by leading foodborne disease public health scientists to discuss how changes in scientific research on the incidence and outcomes of foodborne illnesses should inform the next revision of ERS's CoFI estimates. This article presents a summary, based on discussion at this workshop, of the state of scientific research available to inform updated economic modeling of the CoFI in the United States.

Relationship between Toxoplasma gondii seropositivity and depression in children and adolescents

Identification of the structural causes of depression is important for the treatment process, and toxoplasmosis may be related to psychiatric disorders. The aim of this study was to evaluate the relationship between Toxoplasma gondii (T. gondii) seropositivity and depression in children and adolescents. This case-control study included 37 children and adolescents aged 11-18 years diagnosed with depression who were followed by the Manisa Celal Bayar University Child and Adolescent Mental Health Service and 36 children and adolescents aged 11-18 years with no history of depressive episodes or psychiatric disorder treated by the Pediatric Outpatient Department. The T. gondii serology of these two groups was evaluated and compared. There were no statistically significant age or sex differences between the 37 participants with depression and the 36 healthy controls. Eight patients and two controls were seropositive for T. gondii, a statistically significant difference (p = 0.046). Seropositivity was significantly higher in patients with suicidal ideation (p = 0.005) than in those without suicidal ideation. The seropositivity of seven of the nine participants who attempted suicide was significantly higher (p < 0.001) than that of participants who did not. Thus, T. gondii infection may affect the predisposition for and severity of depression.

Sero-prevalence of Toxoplasma gondii and associated risk factors among psychiatric outpatients attending University of Gondar Hospital, Northwest Ethiopia

Background

Toxoplasmosis is caused by an obligatory intracellular coccidian protozoan organism, Toxoplasma gondii. It has a worldwide distribution, affecting one-third of the world population. Psychiatric patients have a higher risk of exposure to Toxoplasma gondii infection due to lack of good personal hygiene. The burden of toxoplasmosis among psychiatric patients in Ethiopia has not been studied extensively. Thus, the study aimed to determine the seroprevalence of Toxoplasma gondii and associated risk factors among psychiatric outpatients at the University of Gondar Comprehensive and Specialized Hospital Psychiatric clinic.

Methods

A cross-sectional study was conducted at the University of Gondar Comprehensive and Specialized Hospital from February to May 2018. Venous blood was collected from 304 study participants (152 psychiatric outpatients and 152 control groups). Anti-toxoplasma antibodies were determined using Onsite Toxo immunoglobulin G (IgG) and immunoglobulin M (IgM) Rapid Test. A Chi-square test was carried out to compare the two groups and a logistic regression analysis was conducted to check the association between variables. P-value less than 0.05 was taken as statistically significant.

Results

The seroprevalence rate of anti-Toxoplasma gondii IgG antibodies was 33.6, and 16.4% in the psychiatric outpatients and the control samples, respectively. Anti-Toxoplasma gondii IgM sero-prevalence was 1.3% in the former patients and 3.9% in the latter group. Owing cat (AOR = 2.862 95% CI = 1.445–5.666 P = 0.003), cleaning cat excreta (AOR = 2.966 95% CI = 1.317–2.652 P = 0.007), and farming (AOR = 2.058 95% CI = 1.018–4.163 P = 0.045) were found to be significantly associated with the sero-prevalence of anti-Toxoplasma gondii IgG antibody.

Conclusions

This study highlighted that, the prevalence of anti-Toxoplasma gondii IgG antibodies was significantly higher in psychiatric outpatients than the control group (p = 0.001). Cat ownership, cleaning of cat excreta, and farming were found to be statistically significantly associated with the seroprevalence of anti-Toxoplasma gondii IgG antibody.

Guanabenz Reverses a Key Behavioral Change Caused by Latent Toxoplasmosis in Mice by Reducing Neuroinflammation

Toxoplasma gondii is an intracellular parasite that has infected one-third of humans. The infection is permanent because the replicative form (tachyzoite) converts into a latent tissue cyst form (bradyzoite) that evades host immunity and is impervious to current drugs. The continued presence of these parasitic cysts hinders treatment and leads to chronic infection that has been linked to behavioral changes in rodents and neurological disease in humans. How these behavioral changes occur, and whether they are due to parasite manipulation or the host response to infection, remains an outstanding question. We previously showed that guanabenz possesses antiparasitic activity; here, we show that guanabenz reproducibly lowers brain cyst burden up to 80% in chronically infected male and female BALB/cJ mice when given intraperitoneally but not when administered by gavage or in food. Regardless of the administration route, guanabenz reverses Toxoplasma-induced hyperactivity in latently infected mice. In contrast, guanabenz increases cyst burden when given to chronically infected C57BL/6J mice yet still reverses Toxoplasma-induced hyperactivity. Examination of the brains from chronically infected BALB/cJ and C57BL/6J mice shows that guanabenz decreases inflammation and perivascular cuffing in each strain. Our study establishes a robust model for cyst reduction in BALB/cJ mice and shows for the first time that it is possible to reverse a key behavioral change associated with latent toxoplasmosis. The rescue from parasite-induced hyperactivity correlates with a decrease in neuroinflammation rather than reduced cyst counts, suggesting that some behavioral changes arise from host responses to infection.IMPORTANCE Toxoplasma gondii is a common parasite of animals, including up to one-third of humans. The single-celled parasite persists within hosts for the duration of their life as tissue cysts, giving rise to chronic infection. Latent toxoplasmosis is correlated with neurological dysfunction in humans and results in dramatic behavioral changes in rodents. When infected, mice and rats adapt behaviors that make them more likely to be devoured by cats, the only host that supports the sexual stage of the parasite. In this study, we establish a new mouse model of tissue cyst depletion using a drug called guanabenz and show that it is possible to reverse a key behavior change back to normal in infected animals. We also show that the mechanism appears to have nothing to do with parasite cyst burden but rather the degree of neuroinflammation produced by chronic infection.

Efficient genome engineering of Toxoplasma gondii using the TALEN technique

Background

Aromatic amino acid hydroxylase 2 (AAH2) is a bradyzoite-specific upregulated protein that may alter host behaviour by altering the host dopaminergic pathway. To better understand the role of the parasite’s AAH2 in host-parasite interactions, we generated an AAH2 fluorescent marker strain of T. gondii using the TALEN technique.

Methods

We generated an AAH2 fluorescent marker strain of T. gondii, which was designated PRU/AAH2-eGFP, using the TALEN technique. This strain stably expressed pyrimethamine resistance for screening and expressed enhanced green fluorescent protein (eGFP)-tagged AAH2 in the bradyzoite stage. The bradyzoite conversion of PRU/AAH2-eGFP was observed both in vitro and in vivo. The fluorescence localization of AAH2 in mouse models of chronic infection was observed by a Bruker in vivo imaging system.

Results

Transgenic T. gondii was successfully generated by the TALEN system. The eGFP-tagged AAH2 could be detected by in vivo imaging.

Conclusions

This study verified the feasibility of using TALEN technology for T. gondii research and provided an in vivo imaging method for in vivo research of bradyzoite-stage proteins.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3378-y) contains supplementary material, which is available to authorized users.

Infection with Trichomonas vaginalis increases the risk of psychiatric disorders in women: a nationwide population-based cohort study

Background

Trichomonas vaginalis is a protozoan parasite that causes trichomoniasis and annually infects approximately 276 million people worldwide. We observed an ambiguously higher probability of trichomoniasis in patients from the psychiatric department of Tri-Service General Hospital. Herein, we aimed to investigate the association between trichomoniasis and the risk of developing psychiatric disorders.

Methods

The nationwide population-based study utilized the database of the National Health Insurance (NHI) programme in Taiwan. A total of 46,865 subjects were enrolled in this study from 2000–2013, comprising 9373 study subjects with trichomoniasis and 37,492 subjects without trichomoniasis as the control group. Cox proportional hazards regression analysis was performed to calculate the hazard ratio (HR) of psychiatric disorders during the 14 years of follow-up.

Results

Of the study subjects with trichomoniasis, 875 (9.34%) developed psychiatric disorders compared with 1988 (5.30%) in the control group (P < 0.001). The adjusted hazard ratio (aHR) of overall psychiatric disorders in the study subjects was 1.644 (95% confidence interval, CI: 1.514–1.766; P < 0.001). More specifically, the study subjects had a higher risk for developing an individual psychiatric disorder, including depression, anxiety, bipolar disorder, schizophrenia and substance abuse. Although metronidazole treatment reduced the risk for developing several subgroups of psychiatric disorders, significant reduction was detected for depression only. Furthermore, refractory trichomoniasis (trichomoniasis visits ≥ 2) enhanced the risk of psychiatric disorders.

Conclusions

We show herein that T. vaginalis infection increases the overall risk for psychiatric disorders. The novel role of T. vaginalis in developing psychiatric disorders deserves more attention, and the control of such a neglected pathogen is of urgent public health importance.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3350-x) contains supplementary material, which is available to authorized users.

Behavioral evaluation of BALB/c (Mus musculus) mice infected with genetically distinct strains of Toxoplasma gondii

In relation to behavioral changes in rodents infected with Toxoplasma gondii (T. gondii), it is believed that the genotype of the infecting strain can have some influence. In this sense, the present work has sought to evaluate the effect of chronic infection by genetically distinct cystogenic strains of T. gondii on the behavior of mice. For this, experimental models of infection with ME-49 (type II) and VEG (type III) strains were developed in isogenic BALB/c mice. ELISA test was performed to evaluate the humoral immune response and real-time PCR test to quantify parasites in the CNS. Behavioral tests such as passive avoidance, open-field and Y-maze tests were also used for, respectively, evaluation of learning and memory, locomotor activity and aversion to feline odor. The results showed that mice infected with VEG strain had higher total IgG level of anti-toxoplasma, higher tissue burden of T. gondii in the CNS, reduction in the long-term memory, lower activity (mobility) and lower aversion to cat urine and l-felinine than mice infected with ME-49 strain. The results suggest that different T. gondii genotypes have a differential impact on behavioral changes in infected mice.

Animal hoarding: The challenge for mental health, law enforcement, and animal welfare professionals

Animal hoarding has been considered a significant problem by animal welfare and law enforcement professionals for over a century. However, it has only been recognized as an indication of a mental disorder in the last decade. I review the different forms that animal hoarding can take and the current understanding of the prevalence, demographics and possible etiology of this disorder. Conventional animal cruelty laws have often been inadequate to respond to animal hoarding cases until they reach levels that may involve serious harm to animals and people. I document how prosecution of such cases can be difficult and often does not adequately consider the mental health issues underlying the problem or the high likelihood of recidivism. Attempts to solve these problems by enacting new laws specifically addressing animal hoarding have been controversial and ineffective. I explore new approaches that coordinate a variety of community resources in response to hoarding cases that offer the best opportunity to respond to both the human and animal problems associated with animal hoarding.

Toxoplasma gondii infection and behavioral outcomes in humans: a systematic review

Studies suggest that the protozoan Toxoplasma gondii can disturb human behavior. This study aimed to systematically review the scientific literature on the possible associations between Toxoplasma gondii infection and neurobehavioral abnormalities in humans. We reviewed and summarized the studies published since 1990. The descriptors used were related to T. gondii infection and behavioral outcomes in humans; the main databases of the medical literature were accessed. The results of eight original articles published between 1994 and 2016 were evaluated and described. The most common serological method was the enzyme immunoassay. Most of the researchers used validated instruments for behavioral evaluation. Seven studies reported some association between the prevalence of anti-T. gondii antibodies and some altered behavioral aspects in adult humans; these studies focused on adult population in Europe and the USA. The most reported behavioral deviations are related to greater impulsivity and aggressiveness. There are very few studies on this subject, which present some limitations for inference and conclusions: most were cross-sectional studies, with a small sample size and in similar populations. Investigations with a larger sample size of different population groups should be performed to evaluate multiple factors.

Toxoplasma gondii - obsessive -compulsive disorder relationship: is it different in children?

BACKGROUND AND AIM

Obsessive-compulsive disorder (OCD) is a common neuropsychiatric illness. Although the etiology of OCD is still unknown, recent investigations have associated development of OCD with infectious illness. Toxoplasma gondii (T. gondii) is a neurotropic protozoan parasite that causes infection of the central nervous system. In the last decade, a lot of researches have focused on the possible relationship between exposure to T. gondii and neuropsychiatric disorders such as schizophrenia. Therefore, in this study, it was aimed to investigate a possible association between Toxoplasma infection and OCD in children and adolescents.

METHODS

We selected 55 patients with OCD (aged between 7 and 16 years) and 59 healthy children and adolescents (aged between 7 and 16 years), and investigated the seropositivity rate for anti-Toxoplasma IgG antibodies by enzyme-linked immunosorbent assay.

RESULTS

The seropositivity rate for anti-T. gondii IgG antibodies among OCD patients (21.82%) was found to be higher than the rate in control group (15.25%). However, the difference between the OCD group and the control group was not statistically significant (p > .05).

CONCLUSION

In contrast to studies in adult patients, the results of this study do not support the relationship between T. gondii and OCD children and adolescents.

Environmental risk factors for Toxoplasma gondii infections and the impact of latent infections on allostatic load in residents of Central North Carolina

BACKGROUND

Toxoplasma gondii infection can be acquired through ingestion of infectious tissue cysts in undercooked meat or environmental oocysts excreted by cats. This cross-sectional study assessed environmental risk factors for T. gondii infections and an association between latent infections and a measure of physiologic dysregulation known as allostatic load.

METHODS

Serum samples from 206 adults in the Durham-Chapel Hill, North Carolina area were tested for immunoglobulin (IgG) responses to T. gondii using commercial ELISA kits. Allostatic load was estimated as a sum of 15 serum biomarkers of metabolic, neuroendocrine and immune functions dichotomized at distribution-based cutoffs. Vegetated land cover within 500 m of residences was estimated using 1 m resolution data from US EPA's EnviroAtlas.

RESULTS

Handling soil with bare hands at least weekly and currently owning a cat were associated with 5.3 (95% confidence limits 1.4; 20.7) and 10.0 (2.0; 50.6) adjusted odds ratios (aOR) of T. gondii seropositivity, respectively. There was also a significant positive interaction effect of handling soil and owning cats on seropositivity. An interquartile range increase in weighted mean vegetated land cover within 500 m of residence was associated with 3.7 (1.5; 9.1) aOR of T. gondii seropositivity. Greater age and consumption of undercooked pork were other significant predictors of seropositivity. In turn, T. gondii seropositivity was associated with 61% (13%; 130%) greater adjusted mean allostatic load compared to seronegative individuals. In contrast, greater vegetated land cover around residence was associated with significantly reduced allostatic load in both seronegative (p < 0.0001) and seropositive (p = 0.004) individuals.

CONCLUSIONS

Residents of greener areas may be at a higher risk of acquiring T. gondii infections through inadvertent ingestion of soil contaminated with cat feces. T. gondii infections may partially offset health benefits of exposure to the natural living environment.

Seroprevalance Anti-Toxoplasma gondii antibodies in children and adolescents with tourette syndrome/chronic motor or vocal tic disorder: A case-control study

Toxoplasma gondii infection may be associated with psychiatric disorders due to its neurological effects. The purpose of this study was to investigate the relation between tic disorders in children and adolescents and Anti-Toxoplasma IgG. 43 children diagnosed with Tourette's syndrome(TS) and 87 with chronic motor or vocal tic disorder(CMVTD), and 130 healthy volunteers, all aged 7-18, were enrolled. Anti-Toxoplasma IgG antibody levels obtained from blood specimens were investigated. Toxoplasma IgG positivity was determined in 16(37.2%) of the patients with TS, in 27(31%) of those with CMVTD and in 12(9.2%) members of the control group. Anti-Toxoplasma gondii antibody positivity was 5.827-fold higher in subjects with TS and 4.425-fold higher in subjects with CMVTD compared to the control group. Correlation was determined between a diagnosis of TS or CMVTD and Anti-Toxoplasma gondii antibodies. We think that it will be useful for the neuropsychiatric process associated with Anti-Toxoplasma gondii antibodies to be clarified.

The Association between Suicide Attempts and Toxoplasma gondii Infection

Objective

Chronic ‘latent’ infection by Toxoplasma gondii is common and most of the hosts have minimal symptoms or they are even asymptomatic. However, there are possible mechanisms by which T. gondii may affect human behavior and it may also cause humans to attempt suicide. This article aimed to investigate the potential pathophysiological relationship between suicide attempts and T. gondii infection in Korea.

Methods

One hundred fifty-five psychiatric patients with a history of suicide attempt and 135 healthy control individuals were examined with enzyme-linked immunoassays and fluorescent antibody technique for T. gondii seropositivity and antibody titers. The group of suicide attempters was interviewed regarding the history of suicide attempt during lifetime and evaluated using 17-item Korean version of Hamilton Depression Scale (HAMD), Columbia Suicide Severity Rating Scale (C-SSRS), State-Trait Anxiety Inventory (STAI) and Korean-Barratt Impulsiveness Scale (BIS).

Results

Immunoglobulin G antibodies were found in 21 of the 155 suicide attempters and in 8 of the 135 controls (p=0.011). The Toxoplasma-seropositive suicide attempters had a higher HAMD score on the depressed mood and feeling of guilt subscales and a higher total score than the seronegative suicide attempters. T. gondii seropositive status was associated with higher C-SSRS in the severity and lethality subscales. T. gondii IgG seropositivity was significantly associated with higher STAI-X1 scores in the suicide attempters group.

Conclusion

Suicide attempters showed higher seroprevalence of T. gondii than healthy controls. Among the suicide attempters, the T. gondii seropositive and seronegative groups showed several differences in the aspects of suicide. These results suggested a significant association between T. gondii infection and psychiatric problems in suicidality.

Human Immunodeficiency Virus in the Brain-Culprit or Facilitator?

Introduction:

Human immunodeficiency virus (HIV) enters the brain early, where it can persist, evolve, and become compartmentalized. Central nervous system (CNS) disease can be attributed to HIV alone or to the complex interplay between the virus and other neurotropic pathogens.

Aim:

The current review aims to describe the direct impact of HIV on the brain as well as its relationship with other pathogens from a practitioner’s perspective, to provide a general clinical overview, brief workup, and, whenever possible, treatment guidance.

Methods:

A review of PubMed was conducted to identify studies on neuropathogenesis of HIV in relation to host responses. Furthermore, the interaction between the CNS pathogens and the host damage responses were revised in the setting of advanced and also well-controlled HIV infection.

Results:

Similar to other pathogens, HIV leads to CNS immune activation, inflammation, and viral persistence. Therefore, almost half of the infected individuals present with neurocognitive disorders, albeit mild. Compartmentalized HIV in the CNS can be responsible in a minority of cases for the dramatic presentation of symptomatic HIV escape. Disruption of the immune system secondary to HIV may reactivate latent infections or allow new pathogens to enter the CNS. Opportunistic infections with an inflammatory component are associated with elevated HIV loads in the cerebrospinal fluid and also with greater cognitive impairment. The inflammatory immune reconstitution syndrome associated with CNS opportunistic infections can be a life-threatening condition, which needs to be recognized and managed by efficiently controlling the pathogen burden and timely balanced combination antiretroviral therapy. Latent neurotropic pathogens can reactivate in the brain and mimic HIV-associated severe neurological diseases or contribute to neurocognitive impairment in the setting of stable HIV infection.

Conclusions:

As HIV can be responsible for considerable brain damage directly or by facilitating other pathogens, more effort is needed to recognize and manage HIV-associated CNS disorders and to eventually target HIV eradication from the brain.

The relationship between Toxoplasma gondii IgG antibodies and generalized anxiety disorder and obsessive-compulsive disorder in children and adolescents: a new approach

AIM

Toxoplasma gondii may play a role in the development of psychiatric diseases by affecting the brain. The purpose of this study was to examine the relation between serum toxoplasma IgG positivity and obsessive-compulsive disorder (OCD) and generalized anxiety disorder (GAD) in children and adolescents.

METHOD

Sixty patients diagnosed with OCD and 60 patients with GAD presenting to the pediatric psychiatry clinic, together with 60 control group subjects with no psychiatric diagnosis, were included in the study. The patients were administered the State-Trait Anxiety Inventory for Children and the Children's Yale-Brown Obsessive Compulsive Scale. Serum toxoplasma IgG levels were determined from blood specimens collected from the study and control groups. The results were then compared using statistical methods.

RESULTS

State and trait anxiety levels were significantly higher in the OCD and GAD patients than in the control group (p = .0001/.0001). Serum toxoplasma IgG levels were positive in 21 (35%) of the OCD patients, 19 (31.7%) of the GAD patients and 6 (10%) of the control group. A significant relation was determined between IgG positivity and GAD (p = .003). IgG-positive individuals were determined to have a 4.171-fold greater risk of GAD compared to those without positivity (4.171[1.529-11.378]) (p = .005). A significant relation was also determined between IgG positivity and OCD (p = .001). IgG-positive individuals were determined to have a 4.846-fold greater risk of OCD compared to those without positivity (4.846[1.789-13.126]) (p = .002).

CONCLUSION

This study shows that serum toxoplasma IgG positivity indicating previous toxoplasma infection increased the risk of GAD 4.171-fold and the risk of OCD 4.846-fold in children and adolescents. Further studies are now needed to investigate the relation between T. gondii infection and GAD/OCD and to determine the pathophysiology involved.

More Than an Association: Latent Toxoplasmosis Might Provoke a Local Oxidative Stress That Triggers the Development of Bipolar Disorder

Introduction:

Toxoplasma gondii, a common parasitic infection, has a special affinity to the brain. It has a lifelong existence without an apparent clinical disease. While the etiology of bipolar disorder (BD) remains unclear, epidemiological studies suggest a role for infections. Central nervous system is particularly susceptible to oxidative stress (OS) because of its high metabolic rate and its low levels of antioxidant defenses. OS is a contributor to the initiation and progression of many neurological illnesses. OS injury is a constantly and compelling finding associated with BD and toxoplasmosis.

Aim:

This cross-sectional study has investigated a possible role of toxoplasma-induced OS in the development of BD.

Methods:

Healthy controls and BD patients were examined for anti-Toxoplasma immunoglobulin-G (IgG) and two protein (3-nitrotyrosine) and DNA (8-hydroxy-2’ deoxyguanosine [8-OHdG]) OS markers.

Results:

Toxoplasma positivity was higher (40%) among BD patients compared to controls (12%). Significantly higher levels of anti-Toxoplasma IgG were detected in BD patients compared to controls. Nitrotyrosine (796.7 ± 106.28) and especially 8-OHdG (20.31 ± 8.38) were significantly higher among toxo-positive BD compared to toxo-negative BD (675.97 ± 144.19 and 7.44 ± 2.86) and healthy controls (464.02 ± 134.6 and 4.17 ± 1.43).

Conclusion:

These findings might indicate a role for Toxoplasma infection in the development of BD, possibly through creating a highly oxidative brain environment.

Fetomaternal and Pediatric Toxoplasmosis

Toxoplasmosis is one of the most important causes of foodborne illnesses and inflammatory complications, as well as congenital disorders. Promiscuous Toxoplasma is transmitted by contaminated food and animal produce, water, vegetations, fruits and sexually through semen. Toxoplasma infects nucleated cells with a unique tropism for muscles and central nervous system and a mind bugging malicious effect. Pregnant women with acute or reactivated toxoplasmosis can transmit Toxoplasma via transplacental to the fetus. The severity of congenital toxoplasmosis depends on the gestation period, as infection in early pregnancy causes more severe consequences. Congenital toxoplasmosis complications include miscarriage, encephalitis, neurological retardation, mental illnesses, auditory and visual inflammatory disorders, cardiovascular abnormalities, and pains. Current therapies are inefficient for congenital and chronic toxoplasmosis or have severe side effects with life threatening complications. There is an urgent need for effective and safe therapeutic modalities to treat complications of toxoplasmosis and effective vaccines to eliminate the infectious agent. This investigation will discuss pathogenesis of feto-maternal, congenital and pediatric toxoplasmosis, the current available therapies in practice, and explore those therapeutic modalities in experimental stages for promising future trials.

Toxoplasmosis accelerates acquisition of epilepsy in rats undergoing chemical kindling

Epilepsy is one of the most common neurologic disorders worldwide with no distinguishable cause in 60% of patients. One-third of the world population has been infected with Toxoplasma gondii. This intracellular parasite has high tropism for excitable cells including neurons. We assessed impact of acute and chronic T. gondii infection on epileptogenesis in pentylenetetrazole (PTZ) kindling model in male rats. T. gondii cysts were administered to rats by intraperitoneal (i.p.) injection. The presence of T. gondii cysts in the brain of rats was verified by hematoxylin-eosin staining. One and eight weeks after cysts injection, as acute and chronic phases of infection, PTZ (30mg/kg, i.p.) was injected to the rats every other day until manifestation of generalized seizures. Histologic findings confirmed cerebral toxoplasmosis in rats. The rats with acute or chronic Toxoplasma infection became kindled by lower number of PTZ injections (14.8±1 and 13.6±1 injections, respectively) compared to corresponding uninfected rats (18.7±1 and 16.9±1 injections, p<0.05). Toxoplasma infection increased the rate of kindling in rats. The chronically-infected rats achieved focal and also generalized seizures earlier than the rats with acute infection. Toxoplasmosis might be considered as a risk factor for acquisition of epilepsy.