Investigation of anti-Toxocara and anti-toxoplasma antibodies in patients with schizophrenia disorder

Association between Toxocara Spp. Exposure and Schizophrenia: A Case-Control Study

Background

Toxocariasis is a zoonotic disease caused by the larvae of Toxocara canis or Toxocara cati. Patients with schizophrenia may be at higher risk of infection, possibly due to their cognitive and personal self-care impairments. We aimed to assess the association between Toxocara spp. exposure and schizophrenia.

Methods

This case-control study was conducted on 109 patients with schizophrenia admitted to Ibn Sina Hospital, Shiraz, Iran, and 104 age- and gender-matched healthy controls from May to September 2021. A questionnaire was obtained and serum samples were tested for IgG antibodies to Toxocara excretory/secretory (TES) antigens using an enzyme-linked immunosorbent assay (ELISA).

Results

Anti-Toxocara IgG was detected in 12 schizophrenic patients and 10 control subjects, giving respective seroprevalences of 11.0% (95% confidence interval [95% CI]=5.8-18.4%) and 9.6% (95% CI=4.7-17.0%). Univariate logistic analyses estimated an odds ratio (OR) of 1.16 (95% CI=0.44-3.16); however, it was not statistically significant (P=0.915). Individuals with a history of eating unwashed vegetables or fruits (23.1%, 95% CI=9.0-43.6, crude odds ratio [COR]=3.21, 95% CI=1.13-9.13) and rural residency (19.5%, 95% CI=8.8-34.9, COR=2.74, 95% CI=1.06-7.05) had significantly higher rates of seropositivity using the univariate logistic analyses. After multivariate logistic analyses, the differences were not statistically significant.

Conclusion

The toxocariasis seroprevalence among schizophrenic and healthy participants was not significantly different (11% vs. 9.6%). Since the disease severity, onset, and cognitive sequelae are not the same among schizophrenic patients, clinically matched studies with larger samples are required to address the current inconsistency between the studies.

Berberine improves inhibitory avoidance memory impairment of Toxoplasma gondii-infected rat model of ketamine-induced schizophrenia

BACKGROUND

Memory impairment caused by Toxoplasma gondii infection has been documented. Berberine (BRB) is well known for its enhancing effects on memory and has shown promising results. However, the impact of BRB on T. gondii infection and schizophrenia-induced consolidation and reconsolidation memory impairment is still unclear. Here; we examined the effect of BRB on the inhibitory avoidance (IA) memory consolidation and reconsolidation impairment induced by T. gondii infection, and ketamine (Ket) as a pharmacological model of schizophrenia. Also; the brain-derived neurotrophic factor (BDNF) levels in the medial prefrontal cortex (mPFC) and hippocampus were analyzed.

METHODS

Rats were infected with T. gondii RH strain or received Ket (30 mg/kg/day) intraperitoneally (i.p) for at least five consecutive days (as the model of schizophrenia). Then followed by oral administration with BRB (25 mg/kg/day) for five days. Finally, the IA memory retention test was examined 48 post-conditioning, and BDNF was measured.

RESULTS

Results indicated IA memory impairment in T. gondii-infected animals since lower step-through latency (STL) was observed than in control animals. We found significant (P = 0.01, P = 0.001) elevations in STL and a significant decrease (P = 0.001) in total time spent in the dark area following BRB administration in infected and Ket-treated rats, indicating improvement (increased STL) in consolidation and reconsolidation memory. Moreover, BDNF levels were reduced (P = 0.01) in the hippocampus and mPFC regions of both T. gondii- infected and Ket-induced groups, which remarkably enhanced after BRB treatment. Furthermore; we found that BRB administration notably increased the mPFC BDNF levels in mPFC (P < 0.01) and hippocampus (P = 0.001) in the Ket-treated and rats infected with T. gondii.

CONCLUSION

Taken together; BRB may be a valuable preclinical treatment for improving memory impairment through BDNF expression in PFC and hippocampus, therefore; BRB is suggested for memory disturbances induced by T. gondii infection.

Relationship between Toxoplasma gondii infection and psychiatric disorders in Iran: A systematic review with meta-analysis

BACKGROUND

Toxoplasma gondii, a ubiquitous parasitic protozoan, may be an important cause of neurological and psychiatric diseases. The present systematic review and meta-analysis, therefore, was conducted to investigate the scientific evidence regarding the potential association between T. gondii infection and psychiatric disorders in Iran.

METHODS

We systematically reviewed articles from world-wide databases, including PubMed, Scopus, Science Direct, Web of Science, Google Scholar, and Iranian national databases up to July 30th, 2021. The Newcastle Ottawa Scale (NOS) was used to assess the quality of included studies. The common odds ratio (OR) was estimated using inverse variance and a random-effects model. Heterogeneity was assessed using the χ2-based Cochrane test (Q) and the I2 index. Also, sensitivity analyses and publication bias were calculated. Moreover, subgroup analysis was performed based on the type of disorder and quality score of different eligible studies.

RESULTS

16 studies were included in this meta-analysis. Our meta-analyses found that the OR of the risk of anti- T. gondii IgG and IgM in psychiatric patients compared to the control group was 1.56 (95% CI; 1.23-1.99) and 1.76 (95% CI: 1.19-2.61), respectively. Subgroup analysis based on the type of disorder showed that the OR of the risk of anti- T. gondii IgG in Iranian schizophrenia patients and other psychiatric disorders compared to the control group were 1.50 (95% CI; 1.09-2.07) and 2.03 (95% CI: 1.14-3.60), respectively, which are statistically significant. Also, the OR of the risk of anti- T. gondii IgM in Iranian schizophrenia and depression patients compared to the control group was 1.54 (95% CI; 0.9-2.64) and 1.03 (95% CI: 0.2-5.24), respectively, which are not statistically significant. Additionally, subgroup analysis based on quality scores showed no significant influence on the results according to the moderate quality studies. However, this association was significant according to the high quality studies. The obtained results of Egger's test were 1.5 (95% CI; -0.62-3.73, P = 0.15) and 0.47 (95% CI; -0.82-1.76, P = 0.45), respectively, indicating publication bias. The significant results of the heterogeneity analysis confirmed a high level of heterogeneity in the IgG test (P = 0.000, I2 = 66.6%). However, no significant results from the test of heterogeneity were detected in the IgM test (P = 0.15, I2 = 27.5%). The results of the sensitivity analysis showed that the impact of each study on the meta-analysis was not significant on overall estimates.

CONCLUSIONS

Despite the limited number of studies, these outcomes supported a possible link between T. gondii infection and psychiatric disorders in Iran. However, more high-quality investigations are needed in the future.

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.

The role of helminths in the development of non-communicable diseases

Non-communicable diseases (NCDs) like cardiovascular disease, chronic respiratory diseases, cancers, diabetes, and neuropsychiatric diseases cause significant global morbidity and mortality which disproportionately affect those living in low resource regions including low- and middle-income countries (LMICs). In order to reduce NCD morbidity and mortality in LMIC it is imperative to understand risk factors associated with the development of NCDs. Certain infections are known risk factors for many NCDs. Several parasitic helminth infections, which occur most commonly in LMICs, have been identified as potential drivers of NCDs in parasite-endemic regions. Though understudied, the impact of helminth infections on the development of NCDs is likely related to helminth-specific factors, including species, developmental stage and disease burden. Mechanical and chemical damage induced by the helminth in combination with pathologic host immune responses contribute to the long-term inflammation that increases risk for NCD development. Robust studies from animal models and human clinical trials are needed to understand the immunologic mechanisms of helminth-induced NCDs. Understanding the complex connection between helminths and NCDs will aid in targeted public health programs to reduce helminth-induced NCDs and reduce the high rates of morbidity that affects millions of people living in parasite-endemic, LMICs globally.

Toxocara infection/exposure and the risk of schizophrenia: a systematic review and meta-analysis

Toxocariasis is an important neglected disease that could have a role in the development of some neurological disorders, such as schizophrenia (SCZ). We performed the first systematic review and meta-analysis on observational studies to evaluate the possible association between Toxocara infection/exposure and SCZ. Systematic searching (PubMed, Scopus, Web of Science and Google Scholar) was performed, up to 15 August 2020, to identify the relevant studies. We used a random effects meta-analysis model to generate the pooled OR and 95% CIs. The research process resulted in the identification of six studies related to the subject of interest entailing 411 SCZ patients and 2047 controls. Our results demonstrated that the SCZ patients (15%; 95% CI 6.8 to 29.9%) had higher pooled seroprevalence of Toxocara infection/exposure than the control group (3.3%; 95% CI 1.1 to 9.4%), showing a significant association (pooled OR, 4.06; 95% CI 1.14 to 14.43). Our findings suggested that Toxocara infection/exposure might have an important but neglected contribution to SCZ development. However, further well-designed and large-scale observational studies are needed to illuminate this association. Because many other environmental and genetic factors may be strong confounders, more mechanistic/experimental studies in animal models are also necessary to further define the mechanism of this association.

Seroprevalence, risk factors, and clinical symptoms of Toxocara spp. infection among children 3-15 years old in northern Iran

The World Health Organization has categorized toxocarosis as a neglected tropical disease despite its significant impact on high-risk groups such as children. This study aimed to investigate the seroprevalence, risk factors, and clinical symptoms of Toxocara spp. infection among children 3-15 years old in northern Iran. A total of 386 children were enrolled in the study. All serum samples were tested for the presence of IgG antibodies against Toxocara spp. infection using an enzyme-linked immunosorbent assay. Moreover, relevant risk factors and clinical symptom data were obtained using questionnaires. Data analysis was performed using the SPSS software version 24. The overall seroprevalence of Toxocara spp. infection was found 2.85 % (11/386). However, Toxocara spp. infection was high for some risk factors, including eating soil (14.3 %), contacting cats (6.7 %), and consuming raw vegetables (3.7 %). However, there were no statistically significant differences regarding the risk factors and socio-demographic characteristics. Considering the clinical symptoms, Toxocara spp. infection was different in children with eosinophilia (20 %), ocular disorders (8.3 %), skin disorders (7.7 %), liver disorders (4.5 %), and stomach ache (4.2 %), although not statistically significant. The results revealed that the seroprevalence of Toxocara spp. infection was relatively low in children in northern Iran. It is suggested to conduct more studies in different parts of Iran to gain a deeper understanding of the toxocarosis seroprevalence and its status in high-risk groups such as children with asthma, hypereosinophilic syndrome, allergic skin disorders, and epilepsy.

Toxocara Awareness Among Medical Practitioners in Saudi Arabia

Human toxocariasis is a zoonotic infection with global and regional impacts. Worldwide it is underestimated and clinically overlooked. Medical practitioners are generally unaware of the extent of the resulting disease spectrum. The objective of the study was to assess knowledge and disease awareness among medical practitioners in Aseer, south-western Saudi Arabia. A questionnaire addressing knowledge about the parasite, its visceral larva migrans and the disease spectrum generated was used to interview participants. The study included 285 participants. In answer to the question what is toxocara, only 27%, answered correctly that it is a nematode, paediatricians being the majority. With regard to years of experience among participants, 56.8% of those who answered correctly had less than 5-year experience, as opposed to 35.4% for those with more than 10-year experience. The cumulative awareness about the disease manifestations and spectrum, i.e. those who knew, was less than 30% across specialties and years of experiences. Lack of awareness regarding Toxocara infection and the disease spectrum it can generate is evident. The consequence for such lack of knowledge within our practising medical community is simply unacceptable as it might translate into misdiagnosis and consequently misguided treatment.

Association between exposure to toxoplasmosis and major psychiatric disorders: a systematic review

Objective:

To assess the association between exposure to toxoplasmosis and major psychiatric disorders through a systematic review of the literature.

Methods:

The literature review was performed in the MEDLINE, SciELO, and PsycINFO databases. To evaluate the quality of the studies included in the review, the Newcastle-Ottawa Scale was used.

Results:

Thirty-one studies were included, and the majority found an association between exposure to toxoplasmosis and schizophrenia or bipolar disorder (58.3 and 54.5% of the included papers, respectively), but not major depressive disorder. We found no significant difference in mean quality scores between studies that corroborated and contradicted the association hypothesis for either schizophrenia or bipolar disorder. All included papers were considered at least satisfactory according to the Newcastle-Ottawa Scale (total scores ≥ 6 out of 9).

Conclusion:

Although there was no association between exposure to toxoplasmosis and major depressive disorder, the results indicate an association with both bipolar disorder and schizophrenia, despite their heterogeneity. Further studies should be performed with more specific variables so that the nature of these relationships can be elucidated.

Loop-Mediated Isothermal Amplification (LAMP) Assay to Detect Toxoplasmosis in Schizophrenia Patients

Background

Toxoplasma gondii (T. gondii) causes an important parasitic infection known as toxoplasmosis, which is a globally distributed important zoonosis. One of the major serious characteristics of T. gondii is its ability to manipulate the behavior of intermediate hosts. We performed a cross-sectional study to determine toxoplasmosis in schizophrenic patients, as one of the major neuropsychiatric disorders, using loop-mediated isothermal amplification (LAMP) technic by targeting parasite B1 gene.

Methods

Blood samples were taken from 118 schizophrenic patients hospitalized in tow hospitals including Baharan, Clinic of Psychiatric Ali-ibn-Abi-Talib Hospital (in Zahedan City), and Amir-al Momenin Psychiatric Hospital (in Zabol City), Sistan and Baluchestan Province, southeast Iran in 2016. They were analyzed using LAMP, and compared with the previous data of nested-PCR and serology.

Results

Out of the 118 schizophrenic individuals, 56 patients (47.4%) were found to be infected with T. gondii. The diagnosis of toxoplasmosis was confirmed in 41 patients (34.7%) via the nested-PCR. The seroprevalence of toxoplasmosis in schizophrenic patients was 55.9% (66/118).

Conclusion

We found a high efficiency of LAMP method in identifying toxoplasmosis and its high prevalence among schizophrenic patients. Our findings could provide viable offer implications for the prevention of schizophrenia.

Study of toxoplasmosis and toxocariasis in patients suffering from ophthalmic disorders using serological and molecular methods

Introduction

Toxoplasma gondii is an intracellular protozoan parasite that can cause ocular toxoplasmosis with most complications such as retinal detachment. Toxocara parasite, round worm, found in dogs and cats appears as larva migrans in humans can cause serious ocular complications such as debilitating vision loss.In Khuzestan province, southwest of Iran, T. gondii infection has been reported to be significant but toxocariasis was rare. However, the frequency of ocular toxoplasmosis and toxocariasis has not been studied in this area. The aim of this study was to evaluate the ocular toxoplasmosis and ocular toxocariasis using serological and molecular methods.

Method

In this case control study, 310 patients were identified by ophthalmologist as ocular toxoplasmosis and then 5 cc of venous blood samples were taken from each of them. Serum samples and buffy coat were prepared and ELISA was used to detect IgG and IgM anti-Toxoplasma antibodies and the molecular PCR was used to detect Toxoplasma DNA parasite in buffy coats. ELISA test was used to detect of IgG anti-Toxocara antibodies.

Results

Totally, for ocular toxoplasmosis, 130 (41.93%) of 310 patients were positive by ELISA, of them 121 (39%) IgG positive and nine (2.9%) IgM positive were diagnosed. Of 121 cases with IgG⁺, 119 (98.35%) were diagnosed with high IgG avidity indicating chronic phase of the infection. For ocular toxocariasis evaluation, antibodies against Toxocara were not detected in any of the samples. By PCR molecular method, 11 out of 310 patients (3.54%) had T. gondii DNA in the blood. In control, in total, 21 cases were detected positive by serology method, which showed a significant difference with the results of the case group(P < 0.05).By PCR method, only three cases showed positive which also indicated significant difference with result of case group (3 vs 9) (P < 0.05). In the control group, also no anti-toxocara antibodies were found.

Conclusion

It can be concluded that T. gondii in Khuzestan province as the etiologic agent of ocular toxoplasmosis and physicians should consider diagnostic methods for identifying the infection when they visit the patients.

Neurocognitive and neuropsychiatric effects of toxocariasis

Caused by the neuroinvasive nematodes Toxocara canis and Toxocara cati, human toxocariasis has a worldwide distribution with seroprevalence in humans associated with low socioeconomic status and low educational attainment. Third-stage Toxocara larvae can invade human tissues, including the brain and spine, where they can result in encephalitis, meningitis, and inflammation. Toxocara infection in animal models has been associated with cognitive and behavioural changes. In humans, preliminary cross-sectional research suggests that Toxocara seropositivity is associated with worse cognitive function in children and adults. Additional preliminary cross-sectional findings suggest associations between Toxocara seropositivity and neuropsychiatric function, including schizophrenia and neurologic conditions such as epilepsy. Given the widespread distribution of human toxocariasis and early evidence suggesting that it can be associated with cognitive and neuropsychiatric function in humans, additional research regarding the effects of toxocariasis on the human brain is required.

Toxoplasma gondii Exposure and the Risk of Attention Deficit Hyperactivity Disorder in Children and Adolescents

BACKGROUND

Evidence suggests that Toxoplasma gondii, which causes toxoplasmosis, changes the metabolism of neurotransmitters, especially dopamine, resulting in both neurologic and psychiatric disorders. On the other hand, the dysregulation of catecholamines, especially of both norepinephrine and dopamine, has been proposed in the pathophysiology of attention deficit hyperactivity disorder (ADHD). The aim of the present study was to investigate anti-toxoplasma antibodies in children and adolescents with ADHD and compare it with a control group, to determine whether toxoplasmosis is a risk factor for ADHD.

METHODS

A total of 200 children and adolescents (117 patients with ADHD and 83 individuals without ADHD) participated in the study. Participants were tested for the presence of anti-T. gondii antibodies by enzyme-linked immunosorbent assay. A Parent ADHD Rating Scale and Clinical Global Impression-severity Scale were also completed. Data were analyzed using a χ test and Fisher exact test.

RESULTS

Anti-toxoplasma antibodies were detected in 18.1% of patients with ADHD disorder and 24% of individuals without ADHD. There was no significant difference in seropositivity between the 2 groups (P > 0.05). The number of patients with T. gondii infection in the 3 subgroups was 0, 9 and 12, respectively. The differences in infection rate among subgroups were not statistically significant (P > 0.05).

CONCLUSION

Although not conclusive, the present study does not support the theory that T. gondii is a risk factor for ADHD.

A systematic review and meta-analysis of the prevalence of toxoplasmosis in hemodialysis patients in Iran

OBJECTIVES

Toxoplasmosis is a parasitic disease that occurs worldwide, with a wide range of complications in immunocompromised patients. This systematic review and meta-analysis was performed to evaluate the seroprevalence of Toxoplasma gondii among patients undergoing hemodialysis in Iran.

METHODS

We searched English and Persian databases for studies reporting T. gondii seroprevalence in Iranian hemodialysis patients through December 31, 2017. Inclusion and exclusion criteria were applied.

RESULTS

A total of 10 studies containing 1,865 participants (1,048 patients and 817 controls) met the eligibility criteria. Immunoglobulin G (IgG) antibodies against T. gondii were found in 58% (95% confidence interval [CI], 46 to 70) of hemodialysis patients and 40% (95% CI, 31 to 50) of healthy controls, while immunoglobulin M (IgM) antibodies were found in 2% (95% CI, 0 to 6) of hemodialysis patients and 0% (95% CI, 0 to 1) of healthy controls. The meta-analysis showed that hemodialysis patients were significantly more likely to be seropositive for IgG (odds ratio [OR], 2.04; 95% CI, 1.54 to 2.70; p<0.001) and IgM (OR, 2.53; 95% CI, 1.23 to 5.22; p<0.001) antibodies against T. gondii infection than healthy individuals.

CONCLUSIONS

The current study revealed a high prevalence of T. gondii infection in hemodialysis patients. Since hemodialysis patients are immunocompromised and T. gondii can cause serious clinical complications, we recommend that periodic screenings for T. gondii infection should be incorporated into the routine clinical care of these patients.

Seroepidemiological Study of Toxoplasma gondii Infection among Psychiatric Patients in Mashhad, Northeast of Iran

BACKGROUND

Psychiatric patients have an increased risk of some infections like toxoplasmosis. Investigations on Toxoplasma gondii infection among psychiatric patients have been limited in Mashhad, Northeast of Iran. In this case-control study, prevalence of T. gondii was investigated by serological method.

METHODS

This case-control study was performed among psychiatric patients admitted to Avicenna Hospital in Mashhad, Northeast of Iran. Three hundred and fifty inpatients and 350 controls were examined in 2012-2013 for detection of IgG and IgM antibodies against T. gondii in their blood sera by ELISA. Socio-demographic and clinical manifestations of the patients were obtained.

RESULTS

Anti-T. gondii IgG antibodies was found in 164 (46.85%) of 350 psychiatric inpatients and 120 (34.28%) of 350 controls. Seventeen (4.85%) of psychiatric individuals and 3 (0.85%) of control group were IgM+/IgG- indicating acute form of toxoplasmosis. There were no statistically significant differences between the case and control groups. In patient group, schizophrenic patients had the highest positive rate (46.28%) and bipolar mood disorder had the second most prevalent rate (20%). Of 162 schizophrenia patients, 65 (40.1%) had latent infection which was higher than that observed in controls.

CONCLUSION

The prevalence of T. gondii infection among psychiatric patients suffering from schizophrenia was more in Mashhad, compared with control group.

Risk and other factors associated with toxoplasmosis and toxocariasis in pregnant women from southern Brazil

Toxoplasmosis causes complications during pregnancy that have serious effects on fetal development. Thus far, toxocariasis has been reported to spread only via vertical transmission. Nonetheless, the population of pregnant women is also exposed to this infection. Co-infection with both Toxoplasma gondii and Toxocara spp. has been reported in children, but there are no reports of co-infection in the population of pregnant women. The aim of this study was to determine the prevalence of co-infection with T. gondii and Toxocara spp. in pregnant women at a university hospital in southern Brazil, and to identify the risk factors associated with infection by both parasites. Two hundred pregnant women were tested for the presence of anti-T. gondii and anti-Toxocara spp. antibodies and were asked to complete an epidemiological questionnaire. In this study, the co-infection rate observed in the total population of pregnant women was 8%. In addition, women with a positive result for a serology test for Toxocara spp. were at increased risk of infection by T. gondii (P = 0.019). Co-infection with both parasites in pregnant women was associated with low birth weights in neonates. The similar modes of transmission of both parasites could explain the co-infection. Only a few previous studies have investigated this phenomenon. The findings of the present study emphasize the importance of serological diagnosis during prenatal care and further research in this area to identify risk factors associated with this co-infection, and the possible implications of this co-infection during pregnancy and on the health of newborns.

Comparison of Plasma Neurosteroid and Prolactin Levels in Patients with Schizophrenia and Healthy Individuals

Background. The present study aimed to compare plasma levels of cortisol, testosterone, dehydroepiandrosterone (DHEA), and prolactin in patients with schizophrenia and healthy individuals. Method. A total of 100 patients with schizophrenia disorder (69 men and 31 women) and 190 healthy individuals (94 men and 96 women) participated in this cross-sectional study. They were tested for hormone levels and completed demographic questionnaires. Data were analyzed using multivariate analysis of variance (MANOVA) and one-way analysis of variance. Results. Serum testosterone level was significantly higher in men with schizophrenia than in healthy men. Women with schizophrenia had a significantly higher level of testosterone and lower level of prolactin compared to healthy women. There were no significant differences in hormone levels across various subtypes of schizophrenia. No significant differences also were observed in hormones levels in patients with first-episode schizophrenia disorder compared to those in patients with recurrent episodes. Conclusion. This study indicated that abnormal testosterone and prolactin levels might be associated with pathophysiology of schizophrenia disorder.

Cerebral Toxocariasis: Silent Progression to Neurodegenerative Disorders?

Toxocara canis and T. cati are highly prevalent nematode infections of the intestines of dogs and cats. In paratenic hosts, larvae do not mature in the intestine but instead migrate through the somatic tissues and organs of the body. The presence of these migrating larvae can contribute to pathology. Toxocara larvae can invade the brains of humans, and while case descriptions of cerebral toxocariasis are historically rare, improved diagnosis and greater awareness have contributed to increased detection. Despite this, cerebral or neurological toxocariasis (NT) remains a poorly understood phenomenon. Furthermore, our understanding of cognitive deficits due to toxocariasis in human populations remains particularly deficient. Recent data describe an enhanced expression of biomarkers associated with brain injury, such as GFAP, AβPP, transforming growth factor β1 (TGF-β1), NF-L, S100B, tTG, and p-tau, in mice receiving even low doses of Toxocara ova. Finally, this review outlines a hypothesis to explore the relationship between the presence of T. canis larvae in the brain and the progression of Alzheimer's disease (AD) due to enhanced AD-associated neurodegenerative biomarker expression.

The association between antibodies to neurotropic pathogens and schizophrenia: a case-control study

Background:

Exposure to neurotropic pathogens has been proposed as an environmental risk factor for schizophrenia and can be evaluated by measuring pathogen-specific immunoglobulin G (IgG). Seroprevalence of pathogen-specific IgG reflects prior exposure, whereas IgG levels are associated with reactivity or reinfection. Several studies have examined these parameters in schizophrenia. However, results still remain inconclusive, as several previous studies did not correct for important confounding factors.

Aims:

To investigate whether schizophrenia is associated with prior exposure to neurotropic pathogens, or with their reactivation.

Methods:

We examined the seroprevalence and titer of IgG antibodies against herpes simplex virus-1 and -2 (HSV-1/HSV-2), varicella zoster virus (VZV), Epstein–Barr virus (EBV), cytomegalovirus (CMV), and Toxoplasma gondii (TG) in plasma of 368 adult patients with a schizophrenia spectrum disorder and 282 controls using ELISA.

Results:

We did not find evidence for an increased exposure to HSV-1, HSV-2, EBV, and TG in patients. There was a significantly higher seroprevalence of VZV (98.9% vs. 95.6%, P<0.05) and CMV (40.4% vs. 27.7%, P<0.001) in controls as compared with patients, which did not remain statistically significant after adjustment for various potential confounders. We did not find significant differences in antibody titers of seropositive patients and controls for any of the six pathogens.

Conclusions:

Our results do not support the hypothesis that increased exposure to neurotropic pathogens after birth is associated with schizophrenia.

Beyond the association. Toxoplasma gondii in schizophrenia, bipolar disorder, and addiction: systematic review and meta-analysis

OBJECTIVE

To perform a meta-analysis on studies reporting prevalence of Toxoplasma gondii (T. gondii) infection in any psychiatric disorder compared with healthy controls. Our secondary objective was to analyze factors possibly moderating heterogeneity.

METHOD

A systematic search was performed to identify studies into T. gondii infection for all major psychiatric disorders versus healthy controls. Methodological quality, publication bias, and possible moderators were assessed.

RESULTS

A total of 2866 citations were retrieved and 50 studies finally included. Significant odds ratios (ORs) with IgG antibodies were found in schizophrenia (OR 1.81, P < 0.00001), bipolar disorder (OR 1.52, P = 0.02), obsessive-compulsive disorder (OR 3.4, P < 0.001), and addiction (OR 1.91, P < 0.00001), but not for major depression (OR 1.21, P = 0.28). Exploration of the association between T. gondii and schizophrenia yielded a significant effect of seropositivity before onset and serointensity, but not IgM antibodies or gender. The amplitude of the OR was influenced by region and general seroprevalence. Moderators together accounted for 56% of the observed variance in study effects. After controlling for publication bias, the adjusted OR (1.43) in schizophrenia remained significant.

CONCLUSION

These findings suggest that T. gondii infection is associated with several psychiatric disorders and that in schizophrenia reactivation of latent T. gondii infection may occur.

Frequency of Toxoplasma and Toxocara Sp. Antibodies in Epileptic Patients, in South Western Iran

OBJECTIVE

Epilepsy is a disorder of the brain characterized by an enduring predisposition to generate seizures. Infectious agents are mentioned in its etiology. With identifying and appropriate treatment of these infectious agents, preventing their secondary outcomes, including seizure is possible. This study was conducted to determine frequency of anti-Toxoplasma antibodies (IgG, IgM) and anti-Toxocara antibody (IgG) in epileptic patients.

MATERIALS & METHODS

Study sample consisted of 141 epileptic patients and 144 healthy people. After obtaining informed consents and completing demographic questionnaire, serum samples were taken from participants. The diagnostic test of Toxoplasma IgG & IgM and Toxocara antibodies was performed under the same conditions using ELISA method in a qualified private laboratory. Samples from patients and control groups with positive ELISA test in terms of anti-Toxocara antibody were also used for confirmatory Western blot test.

RESULT

According to ELISA results, 28 (19.85%) epileptic patients and 2(1.38%) of healthy people had anti-Toxocara antibodies (P<001), while 39 (30.46%) of the control group people and 14.18% of patients had anti-Toxoplsma antibodies (P=0.001).

CONCLUSION

Frequency of anti-Toxoplasma gondii is lower in epileptic than healthy individuals and this result is contrary to investigations that have reported higher levels of this antibody in such patient groups. ELISA results for Toxocara showed that the frequency of anti-Toxocara antibody in epileptic patients might empower the probability that this parasite may cause central nervous system damage. Western blotting has high specificity and is a proper confirmative method for diagnosis of toxocariasis.

Prevalence of toxoplasmosis and related risk factors among humans referred to main laboratories of Urmia city, North West of Iran, 2013

Toxoplasmosis is mostly asymptomatic infection in immunocompetent individuals while it can cause a severe infection in human fetus during pregnancy and immunocompromised patients. This study aimed to determine the prevalence of anti-Toxoplasma IgM and IgG seropositivity and potential risk factors of the infection in humans referred to Urmia City main diagnostic laboratories, Urmia, Iran. Totally 195 blood samples were collected from the individuals referred to main diagnostic laboratories of Urmia City, 2013. Serum concentration of anti-Toxoplasma IgG and IgM were determined using ELISA method. Demographic variables of the participants were collected by interviewing, which are including sex, age, occupation, educational and residential status, eating undercooked meat, consumption of raw vegetable and the method of washing raw vegetables. None of all 200 serum sample were anti-Toxoplasma IgM positive, but different concentrations of anti-Toxoplasma IgG were observed in 88 (45.12 %) of samples. The significant higher rate of anti-Toxoplasma IgG seropositivity were observed in people with soil related jobs (P = 0.005, OR = 2.266; 95 % CI 1.260, 4.078) and history of eating raw vegetables at restaurant (P = 0.036, OR = 1.985; 95 % CI 0.991, 3.978). Also anti-Toxoplasma IgG concentration mean was significantly higher in people who were commonly eaten raw vegetable at restaurants (P < 0.001, t = 7.918). The prevalence of chronic toxoplasmosis is considerably high while the acute infection is very low in the studied area. Having soil related jobs and eating raw vegetables at restaurants increases the risk of acquiring the infection.