Cryptogenic epilepsy: an infectious etiology?

The effect of the HMGB1/RAGE/TLR4/NF-κB signalling pathway in patients with idiopathic epilepsy and its relationship with toxoplasmosis

This study aims to investigate the relationship between toxoplasmosis and this pathway, which may be effective in the formation of epilepsy by acting through the HMGB1/RAGE/TLR4/NF-κB signalling pathway in patients with idiopathic epilepsy. In the study, four different experimental groups were formed by selecting Toxoplasma gondii IgG positive and negative patients with idiopathic epilepsy and healthy controls. Experimental groups were as follows: Group 1: Epilepsy+/Toxo- (E+, T-) (n = 10), Group 2: Epilepsy-/Toxo- (E-, T-) (n = 10), Group 3: Epilepsy-/Toxo+ (E-, T+) (n = 10), Group 4: Epilepsy+/Toxo+ (E+, T+) (n = 10). HMGB1, RAGE, TLR4, TLR1, TLR2, TLR3, IRAK1, IRAK2, IKBKB, IKBKG, BCL3, IL1β, IL10, 1 L8 and TNFα mRNA expression levels in the HMGB/RAGE/TLR4/NF-κB signalling pathway were determined by quantitative simultaneous PCR (qRT-PCR) after collecting blood samples from all patients in the groups. Statistical analysis was performed by one-way ANOVA followed by LSD post-hoc tests, and p < 0.05 was considered to denote statistical significance. The gene expression levels of HMGB1, TLR4, IL10, IL1B, IL8, and TLR2 were significantly higher in the G1 group than in the other groups (p < 0.05). In the G3 group, RAGE and BCL3 gene expression levels were significantly higher than in the other groups (p < 0.05). In the G4 group, however, IRAK2, IKBKB, and IKBKG gene expression levels were significantly higher than in the other groups (p < 0.05). HMGB1, TLR4, IRAK2, IKBKB, IL10, IL1B, IL1B, and IL8 in this signalling pathway are highly expressed in epilepsy patients in G1 and seizures occur with the stimulation of excitatory mechanisms by acting through this pathway. The signalling pathway in epilepsy may be activated by HMGB1, TLR4, and TLR2, which are considered to increase the level of proinflammatory cytokines. In T. gondii, this pathway is activated by RAGE and BCL3.

Seroprevalence and Genetic Characterization of Toxoplasma gondii among Children with Neurodevelopmental Disorders in Egypt

Toxoplasma gondii is a parasite with a special predilection for the central nervous system. Toxoplasmosis's contribution to the triggering of many neurodevelopmental disorders was established. This study aimed to detect the seroprevalence and genotypes of T. gondii strains in children with neurodevelopmental disorders. The study included 180 children with neurodevelopmental disorders and 180 children in the control group. Assessment of seropositivity of Toxoplasma IgM and IgG antibodies in patients and controls was carried out. Genetic characterization of T. gondii was obtained by nested polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) technique targeting dense granule gene (GRA6). Our results showed that the overall seroprevalence of T. gondii antibodies in the patient and controls was 35.6% and 11.7%, respectively. Nested PCR showed positivity in 11.1% of the patient group for T. gondii DNA. T. gondii seropositivity rate was significantly high in patients with hydrocephalus and also in patients with epilepsy. Positive nested PCR was significantly high in children with hydrocephalus only. Genotyping using nested PCR-RFLP showed genotype I (80%) followed by atypical strains (20%) with no association with any specific clinical presentation. In conclusion, among toxoplasmosis-positive children with neurodevelopmental disorders, analysis of T. gondii GRA6 locus revealed the predominance of type I genotype followed by atypical strains.

Modulation of mRNA Expression of Monoacylglycerol Lipase, Diacylglycerol Lipase and Cannabinoid Receptor-1 in Mice Experimentally Infected with T. gondii

Toxoplasma gondii, an obligate intracellular parasite, infects more than 30% of world's population. This parasite is considered to be neurotropic, and has high tropism for the central nervous system, and potentially induces cryptogenic epilepsy by no clear mechanism. The current study aimed to investigate the alteration of the main components of the endocannabinoid signaling systems in T. gondii-infected mice. For this purpose, the levels of mRNA expression of monoacylglycerol lipase (MAGL), diacylglycerol lipase (DAGL) and cannabinoid receptor-1 (CB1), were measured by quantitative real time PCR.The mRNA expression level of MAGL was increased by ~ 8-fold in the brains of the Toxoplasma-infected group in comparison with non-infected mice (P<0.0001). The mRNA expression of CB1 gene in the brain of the infected mice was ~ 2 times higher than that measured in control group (P<0.01). The mRNA expression level of DAGL remained unchanged in the infected mice. Overall a substantial increase in MAGL and CB1 expression without any changes in DAGL, in the brain of infected mice suggests that T. gondii disturbs the endocannabinoid signaling pathways, which are known as neurotransmitter modulators involved in epilepsy.

Comprehensive Overview of Toxoplasma gondii-Induced and Associated Diseases

Toxoplasma gondii (T. gondii) is a prevalent protozoan parasite of medical and veterinary significance. It is the etiologic agent of toxoplasmosis, a neglected disease in which incidence and symptoms differ between patients and regions. In immunocompetent patients, toxoplasmosis manifests as acute and chronic forms. Acute toxoplasmosis presents as mild or asymptomatic disease that evolves, under the host immune response, into a persistent chronic disease in healthy individuals. Chronic toxoplasmosis establishes as latent tissue cysts in the brain and skeletal muscles. In immunocompromised patients, chronic toxoplasmosis may reactivate, leading to a potentially life-threatening condition. Recently, the association between toxoplasmosis and various diseases has been shown. These span primary neuropathies, behavioral and psychiatric disorders, and different types of cancer. Currently, a direct pre-clinical or clinical molecular connotation between toxoplasmosis and most of its associated diseases remains poorly understood. In this review, we provide a comprehensive overview on Toxoplasma-induced and associated diseases with a focus on available knowledge of the molecular players dictating these associations. We will also abridge the existing therapeutic options of toxoplasmosis and highlight the current gaps to explore the implications of toxoplasmosis on its associated diseases to advance treatment modalities.

Neurological and Neurobehavioral Disorders Associated with Toxoplasma gondii Infection in Humans

The intracellular parasite Toxoplasma gondii is estimated to infect up to 30% of the world population, leading to lifelong chronic infection of the brain and muscle tissue. Although most latent T. gondii infections in humans have traditionally been considered asymptomatic, studies in rodents suggest phenotypic neurological changes are possible. Consequently, several studies have examined the link between T. gondii infection and diseases such as schizophrenia, epilepsy, depression, bipolar disorder, dysphoria, Alzheimer's disease, Parkinson's disease, and obsessive-compulsive disorder (OCD). To date, there is varying evidence of the relationship of T. gondii to these human neurological or neurobehavioral disorders. A thorough review of T. gondii literature was conducted to highlight and summarize current findings. We found that schizophrenia was most frequently linked to T. gondii infection, while sleep disruption showed no linkage to T. gondii infection, and other conditions having mixed support for a link to T. gondii. However, infection as a cause of human neurobehavioral disease has yet to be firmly established.

Human toxoplasmosis in Mozambique: gaps in knowledge and research opportunities

Toxoplasmosis is a parasitic zoonotic disease caused by Toxoplasma gondii that afflicts humans worldwide and wild and domestic warm-blooded animals. In immunocompetent individuals, the acute phase of infection presents transient low or mild symptoms that remain unnoticed. In immunocompromised patients, T. gondii is a life-threatening opportunistic infection, which can result from the reactivation of latent infection or primary infection. Moreover, congenital toxoplasmosis, which results from the transplacental passage of tachyzoites into the fetus during a pregnant primary infection, can lead to miscarriage, stillbirth, or ocular and neurologic disease, and neurocognitive deficits in the newborns. Thus, the present review aims to address the current knowledge of T. gondii infection and toxoplasmosis in Africa and especially in Mozambique, stressing the importance of identifying risk factors and promote awareness among the health care providers and population, assessing the gaps in knowledge and define research priorities. In Mozambique, and in general in southern African countries, clinical disease and epidemiological data have not yet been entirely addressed in addition to the implications of T. gondii infection in immunocompetent individuals, in pregnant women, and its relation with neuropsychiatric disorders. The main gaps in knowledge in Mozambique include lack of awareness of the disease, lack of diagnostic methods in health facilities, lack of genetic data, and lack of control strategies.

An updated meta-analysis of the association between Toxoplasma gondii infection and risk of epilepsy

Toxoplasma gondii is a neurotropic pathogen with worldwide distribution. To evaluate the association between Toxoplasma infection and the risk of epilepsy by meta-analysis, observational peer-reviewed studies were retrieved from PubMed, Embase, Web of Science, Scopus and Google Scholar (up to 10 October 2018) and by reference review. Pooled risk estimates were calculated using a random effects model. Heterogeneity was assessed using Cochrane's Q-test and I2. In total, 16 eligible studies involving 19 data sets were included for the final analysis. A total 7897 participants (3771 epileptic patients, 4026 healthy controls) were included. The pooled odds ratio (OR) for Toxoplasma infection was increased to 1.72 (95% confidence interval [CI] 1.37 to 2.16) among patients with epilepsy. There was moderate heterogeneity among the studies (χ2=39.8, I2=62.3%, p=0.001). The ORs from subgroup analyses showed that both cryptogenic epilepsy (OR 2.65 [95% CI 1.91 to 3.68]) and active convulsive epilepsy (OR 1.37 [95% CI 1.09 to 1.72]) were significantly associated with Toxoplasma infection. Another subgroup analyses according to age showed a significant positive association in children (OR 1.33), adults (OR 1.57) and in all ages (OR 1.89). Our findings support the association between Toxoplasma infection and epilepsy. More prospective studies with larger sample sizes and more experimental studies are recommended to elucidate a causative relationship.

Genetic and molecular basis of epilepsy-related cognitive dysfunction

Epilepsy is a common neurological disease characterized by recurrent seizures. About 70 million people were affected by epilepsy or epileptic seizures. Epilepsy is a complicated complex or symptomatic syndromes induced by structural, functional, and genetic causes. Meanwhile, several comorbidities are accompanied by epileptic seizures. Cognitive dysfunction is a long-standing complication associated with epileptic seizures, which severely impairs quality of life. Although the definitive pathogenic mechanisms underlying epilepsy-related cognitive dysfunction remain unclear, accumulating evidence indicates that multiple risk factors are probably involved in the development and progression of cognitive dysfunction in patients with epilepsy. These factors include the underlying etiology, recurrent seizures or status epilepticus, structural damage that induced secondary epilepsy, genetic variants, and molecular alterations. In this review, we summarize several theories that may explain the genetic and molecular basis of epilepsy-related cognitive dysfunction.

An association between latent toxoplasmosis and substance abuse: an Egyptian Center Study

Infection of toxoplasma gondii (TG), an intracellular neurotropic parasitic protozoon, has been associated with various neuropsychiatric disorders. TG is usually diagnosed from serological sample in which a positive test for Anti-TG immunoglobulin G (IgG) indicates TG infection (toxoplasmosis). The research was conducted to test the hypothesis that TG infection may be associated with substance abuse. Anti-TG (IgG) was screened in 444 participants (350 abusers and 94 controls) who attended the Psychiatry Department of Mansoura University Hospitals. All participants were screened for different class of abused substances (tramadol, cannabis, opiates, barbiturates and benzodiazepines) using enzyme multiplied immunoassay technique and positive cases were confirmed using gas chromatography-mass spectroscopy (GC-MS). Substance users were also diagnosed according to DSM IV criteria. GC-MS assays revealed that 116 cases (33.1% of users) had documented use of more than one substance. Tramadol was the most common abused substance [86 cases (24.6%)]. About 56% of the participants were sero-positive for anti-TG IgG. Toxoplasmosis sero-positivity was significantly higher among substance abusers (P < 0.0001) irrespective of the class of substance used. There was a significant relationship between toxoplasma sero-positivity and occurrence of convulsions among tramadol users (P = 0.0007) and those relapsing (P < 0.0001) following short periods of abstinence. The data collected suggest that TG infection is significantly associated with the high incidence of substance use, irrespective of the drug class. These preliminary findings warrant further larger multicenter clinical studies to test the robustness of this association.

The first study on the usefulness of recombinant tetravalent chimeric proteins containing fragments of SAG2, GRA1, ROP1 and AMA1 antigens in the detection of specific anti-Toxoplasma gondii antibodies in mouse and human sera

This study presents an evaluation of four tetravalent recombinant chimeric proteins containing fragments of the Toxoplasma gondii antigens, SAG2, GRA1, ROP1 and AMA1, as potential replacements of a the soluble, whole-cell tachyzoite lysate (TLA) used in serological assays. Recombinant chimeric proteins (SAG2-GRA1-ROP1-AMA1N, AMA1N-SAG2-GRA1-ROP1, AMA1C-SAG2-GRA1-ROP1, and AMA1-SAG2-GRA1-ROP1) obtained by genetic engineering were tested for their reactivity with specific IgM and IgG antibodies from sera of experimentally infected mice and humans with T. gondii infection using an enzyme-linked immunosorbent assay (ELISA). In total 192 serum samples from patients with acquired T. gondii infection and 137 sera from seronegative individuals were examined. The reactivity of chimeric antigens with antibodies generated during T. gondii invasion was measured and compared to the results obtained in assays based on whole-cell Toxoplasma antigen. Chimeric proteins proved effective in differentiation between T. gondii-infected and uninfected individuals (100% sensitivity and specificity in the IgG ELISAs) which shows their potential usefulness as a replacements for TLA in standardized commercial tests for the serodiagnosis of toxoplasmosis. In addition, the chimeric proteins were tested for use in avidity determination. Obtained results were comparable to those of the corresponding commercial assays, suggesting the utility of these proteins for avidity assessment. Furthermore, this study demonstrated that the AMA1-SAG2-GRA1-ROP1 chimeric protein has the potential to distinguish specific antibodies from serum samples of individuals with the early and chronic phase of T. gondii infection.

Seroprevalence of Toxoplasma gondii infection in children with central nervous system disorders in Mansoura, Egypt: a case-control study

Background

Toxoplasma gondii is a global infection with a crucial role in the development of neurological diseases. Data concerning the association between T. gondii and neurological illnesses in Egyptian children is scarce.

Methods

A case-control study was conducted on 60 patients divided into children suffering from central nervous system manifestations without apparent chromosomal anomalies (n=30) and children with Down syndrome (n=30) recruited from Mansoura University Children's Hospital, Mansoura, Egypt. A total of 30 healthy children were included as controls. Demographics and clinical data were collected from all cases and Toxoplasma immunoglobulin (Ig) M and G antibodies were assessed by enzyme-linked immunosorbent assay.

Results

Anti-T. gondii IgG was the most frequent antibody detected and the highest seropositivity rates were ranked for the neurologically disabled non-syndromic children, followed by Down syndrome, compared with controls (p≤0.001). Statistically significant (p=0.05) associations were found between Toxoplasma IgG seropositivity and hydrocephalus and between Toxoplasma IgM and a history of contact with farm animals, soil and cats in children with Down syndrome.

Conclusions

The association between Toxoplasma infection and neurological disorders in children should be kept in mind by paediatricians and assessment of T. gondii antibodies in early childhood is needed for timely management of afflicted patients.

Toxoplasma gondii exposure and epilepsy: A matched case-control study in a public hospital in northern Mexico

Objectives

This study aimed to determine the association between infection with Toxoplasma gondii and epilepsy in patients attended to in a public hospital in the northern Mexican city of Durango.

Methods

We performed an age- and gender-matched case-control study of 99 patients suffering from epilepsy and 99 without epilepsy. Sera of participants were analyzed for anti-T. gondii IgG and IgM antibodies using commercially available enzyme-linked immunoassays. Seropositive samples to T. gondii were further analyzed for detection of T. gondii DNA by polymerase chain reaction.

Results

Anti-T. gondii IgG antibodies were found in 10 (10.1%) of the 99 cases and in 6 (6.1%) of the 99 controls (odds ratio = 1.74; 95% confidence interval: 0.60-4.99; p = 0.43). High (> 150 IU/mL) levels of anti-T. gondii IgG antibodies were found in 6 of the 99 cases and in 4 of the 99 controls (odds ratio = 1.53; 95% confidence interval: 0.41-5.60; p = 0.74). Anti-T. gondii IgM antibodies were found in 2 of the 10 IgG seropositive cases, and in 2 of the 6 IgG seropositive controls (odds ratio = 0.50; 95% confidence interval: 0.05-4.97; p = 0.60). T. gondii DNA was not found in any of the 10 anti-T. gondii IgG positive patients. Bivariate analysis of IgG seropositivity to T. gondii and International Statistical Classification of Diseases and related Health Problems, 10th Edition codes of epilepsy showed an association between seropositivity and G40.1 code (odds ratio = 22.0; 95% confidence interval: 2.59-186.5; p = 0.008). Logistic regression analysis showed an association between T. gondii infection and consumption of goat meat (odds ratio = 6.5; 95% confidence interval: 1.22-34.64; p = 0.02), unwashed raw vegetables (odds ratio = 26.3; 95% confidence interval: 2.61-265.23; p = 0.006), and tobacco use (odds ratio = 6.2; 95% confidence interval: 1.06-36.66; p = 0.04).

Conclusions

Results suggest that T. gondii infection does not increase the risk of epilepsy in our setting; however, infection might be linked to specific types of epilepsy. Factors associated with T. gondii infection found in this study may aid in the design of preventive measures against toxoplasmosis.

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.

Development of Neurological Mouse Model for Toxoplasmosis Using Toxoplasma gondii Isolated from Chicken in Kenya

Animal models for the toxoplasmosis are scarce and have limitations. In this study, a neurological mouse model was developed in BALB/c mice infected intraperitoneally with 15 cysts of a Toxoplasma gondii isolate. The mice were monitored for 42 days and euthanized at different time points. Another group of mice were orally treated with dexamethasone (DXM: 2.66 mg/kg daily, 5.32 mg/kg daily) at 42 days after infection and monitored for a further 42 days. A mortality rate of 15% and 28.6% was observed in mice given 2.66 mg/kg/day and 5.32 mg/kg/day of DXM, respectively. The mean cyst numbers in the brain of DXM treated mice increased up to twofold compared with chronically infected untreated mice. Infections up to 42 days were associated with an increase in both IgM and IgG levels but following dexamethasone treatment, IgM levels declined but IgG levels continued on rising. The brain of toxoplasmosis infected mice showed mononuclear cellular infiltrations, neuronal necrosis, and cuffing. The severity of pathology was higher in mice treated with dexamethasone compared to the positive control groups. The findings of this study demonstrate that DXM-induced reactivation of chronic toxoplasmosis may be a useful development of laboratory animal model in outbred mice used for in vivo studies.

Seroepidemiological study of Toxoplasma gondii infection in a population of Iranian epileptic patients

Epilepsy is one of the most common neurologic disorders. Underlying cause of epilepsy is unknown in 60 % of the patients. Toxoplasma gondii is an intracellular parasite which is capable of forming tissue cysts in brain of chronically infected hosts including humans. Some epidemiological studies suggested an association between toxoplasmosis and acquisition of epilepsy. In this study we determined seroprevalence of latent Toxoplasma infection in a population of Iranian epileptic patients. Participants were classified in three groups as Iranian epileptic patients (IEP, n = 414), non-epileptic patients who had other neurologic disorders (NEP, n = 150), and healthy people without any neurologic disorders (HP, n = 63). The presence of anti-Toxoplasma IgG antibodies and IgG titer in the sera were determined by ELISA method. Anti-T. gondii IgG seroprevalence obtained 35.3 %, 34.7 % and 38.1 % in IEP, NEP and HP, respectively. The seroprevalence rate was not significantly different among the three groups (P = 0.88). Anti-T. gondii IgG titer was 55.7 ± 78, 52.4 ± 74 and 69.7 ± 92 IU/ml in IEP, NEP and HP, respectively. There was not any statistically significant difference in the antibody titer between the study groups (P = 0.32). The rate of T. gondii infection in epileptic patients was not higher than non-epileptic patients and healthy people in the Iranian population.

Contribution of dopamine neurotransmission in proconvulsant effect of Toxoplasma gondii infection in male mice

Epilepsy is one of the most common neurologic disorders worldwide with no distinguishable cause in 60% of patients. One-third of world's population is infected with Toxoplasma gondii (T. gondii). This intracellular parasite has high tendency to excitable cells including neurons. We assessed seizure susceptibility and involvement of dopaminergic system in male mice with acute and chronic T. gondii infection. Mice were infected by intraperitoneal injection of T. gondii cysts. Acute and chronic stages of infection were determined by quantification of SAG1/BAG1 transcripts and level of repetitive REP-529 sequence in the brain of mice by real-time PCR. Threshold of clonic seizures was measured by tail vein infusion of pentylenetetrazole. The infected mice were pretreated with D1 and D2 dopamine receptor antagonists, and seizure threshold was measured. Moreover, seizure threshold was determined after treatment of toxoplasmosis by sulfamethoxazole and trimethoprim. SAG1 level reached the maximum at week 2 after infection and then declined. The maximum level of BAG1 was observed at the week 3 and preserved till the week 8. REP-529 was detected at first week after infection, reached maximum at the week 3 and kept at this level till the eighth week. Threshold of seizures significantly decreased in both acute and chronic phases of infection. D1 and D2 receptors antagonists inhibited proconvulsant effect of toxoplasmosis. Chemotherapy inhibited parasite growth and multiplication, and returned seizure susceptibility to the level of non-infected mice. Dopaminergic neurotransmission participates in proconvulsant effect of T. gondii. The effect of parasite is eliminated by antibiotic therapy. © 2017 Wiley Periodicals, Inc.

A critical assessment of the association between postnatal toxoplasmosis and epilepsy in immune-competent patients

While postnatal toxoplasmosis in immune-competent patients is generally considered a self-limiting and mild illness, it has been associated with a variety of more severe clinical manifestations. The causal relation with some manifestations, e.g. myocarditis, has been microbiologically proven, but this is not unequivocally so for other reported associations, such as with epilepsy. We aimed to systematically assess causality between postnatal toxoplasmosis and epilepsy in immune-competent patients. A literature search was performed. The Bradford Hill criteria for causality were used to score selected articles for each component of causality. Using an arbitrary but defined scoring system, the maximal score was 15 points (13 for case reports). Of 704 articles, five case reports or series and five case–control studies were selected. The strongest evidence for a causal relation was provided by two case reports and one case–control study, with a maximal causality score of, respectively, 9/13, 10/13 and 10/15. The remaining studies had a median causality score of 7 (range 5–9). No selection bias was identified, but 6/10 studies contained potential confounders (it was unsure whether the infection was pre- or postnatal acquired, or immunodeficiency was not specifically excluded). Based on the evaluation of the available literature, although scanty and of limited quality, a causal relationship between postnatal toxoplasmosis and epilepsy seems possible. More definite proof requires further research, e.g. by performing Toxoplasma serology in all de novo epilepsy cases.

Impaired health status and increased incidence of diseases in Toxoplasma-seropositive subjects – an explorative cross-sectional study

The global seroprevalence of latent toxoplasmosis is estimated to be higher than 30%. The presence of slowly dividing parasites in tissue cysts located mainly in immunoprivileged organs was long considered asymptomatic. Recently, many studies have shown that latent Toxoplasma infections could have serious impacts on human health. Here we ran a cross-sectional study in a population of 1486 volunteers. The results showed that 333 infected subjects scored worse than 1153 controls in 28 of 29 health-related variables. Similarly, they reported higher rates of 77 of a list of 134 disorders reported by at least 10 participants of the study. Toxoplasmosis was associated most strongly with musculoskeletal (τ = 0·107, P < 0·0005), followed by neurological (τ = 0·088, P < 0·0005), immune (τ = 0·085, p < 0·0005), metabolic (τ = 0·079, P < 0·0005), respiratory (τ = 0·068, P = 0·0001), allergic (τ = 0·053, P = 0·004), digestive system (τ = 0·052, P = 0·004) and mental health disorders (τ = 0·050, P = 0·008). Results of the present cohort study, along with the previous data from many case-control studies or ecological studies suggest that latent toxoplasmosis represents a large and so far underrated public health problem.

New paradigms for understanding and step changes in treating active and chronic, persistent apicomplexan infections

Toxoplasma gondii, the most common parasitic infection of human brain and eye, persists across lifetimes, can progressively damage sight, and is currently incurable. New, curative medicines are needed urgently. Herein, we develop novel models to facilitate drug development: EGS strain T. gondii forms cysts in vitro that induce oocysts in cats, the gold standard criterion for cysts. These cysts highly express cytochrome b. Using these models, we envisioned, and then created, novel 4-(1H)-quinolone scaffolds that target the cytochrome bc1 complex Qi site, of which, a substituted 5,6,7,8-tetrahydroquinolin-4-one inhibits active infection (IC50, 30 nM) and cysts (IC50, 4 μM) in vitro, and in vivo (25 mg/kg), and drug resistant Plasmodium falciparum (IC50, <30 nM), with clinically relevant synergy. Mutant yeast and co-crystallographic studies demonstrate binding to the bc1 complex Qi site. Our results have direct impact on improving outcomes for those with toxoplasmosis, malaria, and ~2 billion persons chronically infected with encysted bradyzoites.

Seasonality of birth in patients with temporal lobe epilepsy

OBJECTIVES

We investigated the seasonal pattern in births of patients with temporal lobe epilepsy and mesial temporal sclerosis. We hypothesized that the seasonal pattern in births of these patients is different from that in the general population.

MATERIALS AND METHODS

In this retrospective study, all patients who were evaluated for epilepsy surgery at Jefferson Comprehensive Epilepsy Center, Thomas Jefferson, Philadelphia, USA, between 1986 and 2014 and had a diagnosis of mesial temporal sclerosis (made by definite imaging findings of atrophy and/or sclerosis) were included. The seasonality in births of patients was compared with the seasonal pattern in the live births of the general population from Pennsylvania State.

RESULTS

Two hundred and eighty-two patients (146 females and 136 males) were studied. The seasonality pattern in birth of patients was not statistically different from that in the general population.

CONCLUSIONS

The observed contradictory findings among various studies indicate the need for further studies to elucidate whether season of birth brings the possibility of acquiring various epilepsy syndromes in the future. To investigate any possible association between season of birth and epilepsy, we suggest avoid pooling all patients with epilepsy together.

Seropositivity of Toxoplasma gondii and Toxocara spp. in Children with Cryptogenic Epilepsy, Benha, Egypt

The present study aimed to investigate the possible association of Toxoplasma gondii and Toxocara spp. infections with cryptogenic epilepsy in children. The study was carried out between June 2014 and March 2015. Total 90 children (40 with cryptogenic epilepsy, 30 with non-cryptogenic epilepsy, and 20 healthy control children) were evaluated to determine the anti-Toxocara and anti-T. gondii IgG seropositivity using ELISA kits. Epileptic cases were selected from those attending the pediatrics outpatient clinic of Benha University Hospital, Pediatrics Neurology Unit, and from Benha Specialized Hospital of children. The results showed that the level of anti-T. gondii IgG seropositivity was significantly higher among children with cryptogenic epilepsy (20%) than among children with non-cryptogenic children (0%). In healthy controls (10%), there was no association between toxocariasis seropositivity and cryptogenic epilepsy (only 5.7%; 4 out of 70 cases) among cases and 10% (2 out of 20) among controls. Among toxocariasis IgG positive cases, 3 (7.5%) were cryptogenic, and only 1 (3.3%) was non-cryptogenic. These statistically significant results support the association between T. gondii infection and cryptogenic epilepsy while deny this association with toxocariasis.

Phytoecdysteroids as modulators of the Toxoplasma gondii growth rate in human and mouse cells

Background

Searching for new effective drugs against human and animal toxoplasmosis we decided to test the anti-Toxoplasma potential of phytoecdysteroids (α-ecdysone and 20-hydroxyecdysone) characterized by the pleiotropic activity on mammalian organisms including the enhancement of host’s anti-parasitic defence. This objective was accomplished by the in vitro evaluation of T. gondii growth in phytoecdysteroid-treated immunocompetent cells of selected hosts: humans and two strains of inbred mice with genetically determined different susceptibility to toxoplasmosis.

Methods

Peripheral mononuclear blood cells were isolated from Toxoplasma-positive and Toxoplasma-negative women (N = 43) and men (N = 21). Non-infected mice (C57BL/6, N = 10 and BALB/c, N = 14) and mice (BALB/c, N = 10) challenged intraperitoneally with 5 tissue cysts of the T. gondii DX strain were also used in this study as a source of splenocytes. The effects of phytoecdysteroids on the viability of human PBMC and mouse splenocytes were evaluated using the MTT assay. The influence of phytoecdysteroids on PBMCs, splenocytes and T. gondii proliferation was measured using radioactivity tests (the level of 3[H] uracil incorporation by toxoplasms or 3[H] thymidine by PBMCs and splenocytes), which was confirmed by quantitative Real-Time PCR. Statistical analysis was performed using SigmaStat 3.5 (Systat Software GmbH). The best-fit IC50 curves were plotted using GraphPad Prism 6.0 (GraphPad Software, Inc.).

Results

Our results showed that phytoecdysteroids promote the multiplication of Toxoplasma in cultures of human or murine immune cells, in contrast to another apicomplexan parasite, Babesia gibsoni. Additionally, the tested phytoecdysteroids did not stimulate the in vitro secretion of the essential protective cytokines (IFN-γ, IL-2 and IL-10), neither by human nor by murine immune cells involved in an effective intracellular killing of the parasite.

Conclusions

Judging by the effect of phytoecdysteroids on the T. gondii proliferation, demonstrated for the first time in this study, it seems that these compounds should not be taken into consideration as potential medications to treat toxoplasmosis. Phytoecdysteroids included in the food are most likely not harmful for human or animal health but certain nutrients containing ecdysteroids at high concentrations could promote T. gondii proliferation in chronically infected and immunocompromised individuals. In order to assess the real impact of ecdysteroids on the course of natural T. gondii invasion, in vivo research should be undertaken because it cannot be ruled out that the in vivo effect will be different than the in vitro one. However, taking into account the possible stimulating effect of ecdysteroids on some opportunistic parasites (such as Toxoplasma or Strongyloides) further studies are necessary and should focus on the mechanisms of their action, which directly or indirectly enhance the parasite growth. Since ecdysteroids are considered as potential drugs, it is essential to determine their effect on various parasitic pathogens, which may infect the host at the same time, especially in immunocompromised individuals.

Recurrent seizures during acute acquired toxoplasmosis in an immunocompetent traveller returning from Africa

INTRODUCTION

We report an unusual case of acute acquired toxoplasmosis (AAT) presenting as lymphadenopathy and recurrent seizures in an immunocompetent 15-year-old boy.

MATERIALS AND METHODS

The patient reported an 18-day vacation to Africa (Ethiopia), 39 days prior to the first seizure. Electroencephalogram (EEG) showed sporadic single-spike or sharp-wave paroxysms and the magnetic resonance imaging (RMI) of the brain was negative. The serology for T. gondii was compatible with an acute infection defined as positive for both toxoplasma-specific IgG and IgM and a low avidity (6 %), confirmed by a reference laboratory. The patient reported other two episodes of seizures, occurring 7 days apart. He was treated with pyrimethamine plus sulfadiazine and leucovorin for 4 weeks, with an improvement of lymphadenitis and normalization of EEG. After 5 months, new seizures were reported and a diagnosis of epilepsy was done. Toxoplasma polymerase chain reaction (PCR) of cerebrospinal fluid (CSF) and blood were negative. A treatment with valproic acid was started, obtaining control of the neurological disease.

CONCLUSION

Awareness of this neurologic manifestation by clinicians is required, also in immunocompetent patients. The relationship between toxoplasmosis and recurrent seizure needs to be investigated by new studies.

Toxoplasmosis and epilepsy--systematic review and meta analysis

BACKGROUND

Toxoplasmosis is an important, widespread, parasitic infection caused by Toxoplasma gondii. The chronic infection in immunocompetent patients, usually considered as asymptomatic, is now suspected to be a risk factor for various neurological disorders, including epilepsy. We aimed to conduct a systematic review and meta-analysis of the available literature to estimate the risk of epilepsy due to toxoplasmosis.

METHODS

A systematic literature search was conducted of several databases and journals to identify studies published in English or French, without date restriction, which looked at toxoplasmosis (as exposure) and epilepsy (as disease) and met certain other inclusion criteria. The search was based on keywords and suitable combinations in English and French. Fixed and random effects models were used to determine odds ratios, and statistical significance was set at 5.0%.

PRINCIPAL FINDINGS

Six studies were identified, with an estimated total of 2888 subjects, of whom 1280 had epilepsy (477 positive for toxoplasmosis) and 1608 did not (503 positive for toxoplasmosis). The common odds ratio (calculated) by random effects model was 2.25 (95% CI 1.27-3.9), p = 0.005.

CONCLUSIONS

Despite the limited number of studies, and a lack of high-quality data, toxoplasmosis should continue to be regarded as an epilepsy risk factor. More and better studies are needed to determine the real impact of this parasite on the occurrence of epilepsy.

Recurrent headaches may be caused by cerebral toxoplasmosis

AIM

To establish seroprevalence and provide characteristics of Toxoplasma gondii (TG) infection in children with recurrent headaches.

METHODS

The study was performed in 178 children aged 7-17 years admitted consecutively to the Department of Pediatric Neurology from November 2009 to July 2011. The children were surveyed with a questionnaire with the help and assistance of their parents and blood samples taken on admission were studied for the presence of specific anti-TG IgM, IgG antibodies and IgG avidity using enzyme immunoassay Platelia Toxo IgM, IgG.

RESULTS

The study showed that 19 children (8 boys, 11 girls; 8-17 years old, mean age 14.36 years) had high serum anti-TG IgG antibody levels (range: 32.2 > 240 UI/mL, mean 120.18 UI/mL; positive value for IgG was ≥ 9 UI/mL). The avidity index (AI) ranged from 0.202 to 0.925 (scale: ≥ 0.5 high AI). The results for IgM antibodies were all negative and the obtained results ranged from 0.113 to 0.25 U/mL (mean = 0.191 IU/mL) and all values below 0.8 IU/mL were considered negative. The most frequent complaints found in the seropositive patients were headaches that affected the frontal (13 children), occipital (4) and parietal areas (5). Headaches usually had a pulsating (in 7 patients) and squeezing (6) character and rarely were piercing, dull or expanding. Interestingly, 8 children did not feel discomfort during the headaches, probably because they did not have sufficiently increased intracranial pressure yet. The headaches usually appeared 1-2 times/mo, lasted for 2-6 h, and had a mean intensity of 5.5 points in a 10 point subjective scale. The comorbidities included epilepsy (5 patients), various infections in 3 children (chronic eustachitis, chronic rhinitis, chronic purulent tonsillitis, streptococcal pharyngitis, meningitis, allergic diseases), disturbances of behavior, deficits of attention, and ocular and motor concentration disorders in 1 child. The electroencephalographic and neuroimaging studies performed in our patients had a very limited value in establishing cerebral toxoplasmosis.

CONCLUSION

Ten point six seven percent of the studied children had markedly increased serum anti-TG IgG antibodies and high AI indicated chronic infestation. It is suggested that tests for TG infection should be introduced to routine diagnostics in patients with recurrent headaches.

Toxoplasmosis--a global threat. Correlation of latent toxoplasmosis with specific disease burden in a set of 88 countries

BACKGROUND

Toxoplasmosis is becoming a global health hazard as it infects 30-50% of the world human population. Clinically, the life-long presence of the parasite in tissues of a majority of infected individuals is usually considered asymptomatic. However, a number of studies show that this 'asymptomatic infection' may also lead to development of other human pathologies.

AIMS OF THE STUDY

The purpose of the study was to collect available geoepidemiological data on seroprevalence of toxoplasmosis and search for its relationship with mortality and disability rates in different countries.

METHODS AND FINDINGS

Prevalence data published between 1995-2008 for women in child-bearing age were collected for 88 countries (29 European). The association between prevalence of toxoplasmosis and specific disease burden estimated with age-standardized Disability Adjusted Life Year (DALY) or with mortality, was calculated using General Linear Method with Gross Domestic Product per capita (GDP), geolatitude and humidity as covariates, and also using nonparametric partial Kendall correlation test with GDP as a covariate. The prevalence of toxoplasmosis correlated with specific disease burden in particular countries explaining 23% of variability in disease burden in Europe. The analyses revealed that for example, DALY of 23 of 128 analyzed diseases and disease categories on the WHO list showed correlations (18 positive, 5 negative) with prevalence of toxoplasmosis and another 12 diseases showed positive trends (p<0.1). For several obtained significant correlations between the seroprevalence of toxoplasmosis and specific diseases/clinical entities, possible pathophysiological, biochemical and molecular explanations are presented.

CONCLUSIONS

The seroprevalence of toxoplasmosis correlated with various disease burden. Statistical associations does not necessarily mean causality. The precautionary principle suggests however that possible role of toxoplasmosis as a triggering factor responsible for development of several clinical entities deserves much more attention and financial support both in everyday medical practice and future clinical research.

Transcriptome analysis of mouse brain infected with Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular parasite that invades a wide range of vertebrate host cells. Chronic infections with T. gondii become established in the tissues of the central nervous system, where the parasites may directly or indirectly modulate neuronal function. However, the mechanisms underlying parasite-induced neuronal disorder in the brain remain unclear. This study evaluated host gene expression in mouse brain following infection with T. gondii. BALB/c mice were infected with the PLK strain, and after 32 days of infection, histopathological lesions in the frontal lobe were found to be more severe than in other areas of the brain. Total RNA extracted from infected and uninfected mouse brain samples was subjected to transcriptome analysis using RNA sequencing (RNA-seq). In the T. gondii-infected mice, 935 mouse brain genes were upregulated, whereas 12 genes were downregulated. GOstat analysis predicted that the upregulated genes were primarily involved in host immune responses and cell activation. Positive correlations were found between the numbers of parasites in the infected mouse brains and the expression levels of genes involved in host immune responses. In contrast, genes that had a negative correlation with parasite numbers were predicted to be involved in neurological functions, such as small-GTPase-mediated signal transduction and vesicle-mediated transport. Furthermore, differential gene expression was observed between mice exhibiting the clinical signs of toxoplasmosis and those that did not. Our findings may provide insights into the mechanisms underlying neurological changes during T. gondii infection.

Investigation of anti-Toxocara antibodies in epileptic patients and comparison of two methods: ELISA and Western blotting

The relationship between Toxocara infection and epilepsy was previously demonstrated by several case-control studies and case reports. These previous studies were often based on the enzyme-linked immunosorbent assay (ELISA) using Toxocara excretory-secretory antigens, which are not specific due to cross-reactivity with other parasitic infections such as ascariasis, trichuriasis, and anisakiasis. An immunoblot analysis is highly specific and can detect low levels of Toxocara antibodies. Therefore, this assay may be useful in the identification of toxocariasis in epileptic patients. We examined patients who had epilepsy and healthy subjects for seropositivity for Toxocara infection by ELISA and Western blotting. Out of 85 epileptic patients, 10 (11.8%) and 3 (3.5%) persons exhibited Toxocara immunoglobulin G (IgG) antibodies responses by ELISA and by both techniques, respectively. Moreover, in the healthy group (n = 85), 3 (3.5%) persons were positive by ELISA, but none was detected by Western blotting. This study indicates that Toxocara infection is a risk factor for epilepsy in Iran. These findings strongly suggest the need to perform Western blotting immunodiagnosis, as well as the ELISA using Toxocara excretory-secretory antigens, to improve diagnosis of human toxocariasis in patients with epilepsy.

Toxoplasma gondii antigens recognized by IgG antibodies differ between mice with and without active proliferation of tachyzoites in the brain during the chronic stage of infection

We examined whether tachyzoite proliferation in the brains of immunocompetent hosts during the chronic stage of infection with Toxoplasma gondii induces production of IgG antibodies that recognize parasite antigens different from those recognized by the antibodies of infected hosts that do not have tachyzoite growth. For this purpose, two groups of CBA/J mice, which display continuous tachyzoite growth in their brains during the later stage of infection, were infected, and one group received treatment with sulfadiazine to prevent tachyzoite proliferation during the chronic stage of infection. T. gondii antigens recognized by the IgG antibodies from these two groups of mice were compared using immunoblotting following separation of tachyzoite antigens by two-dimensional gel electrophoresis. Several antigens, including the microneme protein MIC2, the cyst matrix protein MAG1, and the dense granule proteins GRA4 and GRA7, were commonly recognized by IgG antibodies from both groups of mice. There were multiple antigens recognized mostly by IgG antibodies of only one group of mice, either with or without cerebral tachyzoite growth. The antigens recognized only by or mostly by the antibodies of mice with cerebral tachyzoite growth include MIC6, the rhoptry protein ROP1, GRA2, one heat shock protein HSP90, one (putative) HSP70, and the myosin heavy chain. These results indicate that levels of IgG antibody to only selected T. gondii antigens increase in association with cerebral tachyzoite proliferation (reactivation of infection) in immunocompetent hosts with chronic infection.

Toxoplasma gondii actively inhibits neuronal function in chronically infected mice

Upon infection with the obligate intracellular parasite Toxoplasma gondii, fast replicating tachyzoites infect a broad spectrum of host cells including neurons. Under the pressure of the immune response, tachyzoites convert into slow-replicating bradyzoites, which persist as cysts in neurons. Currently, it is unclear whether T. gondii alters the functional activity of neurons, which may contribute to altered behaviour of T. gondii-infected mice and men. In the present study we demonstrate that upon oral infection with T. gondii cysts, chronically infected BALB/c mice lost over time their natural fear against cat urine which was paralleled by the persistence of the parasite in brain regions affecting behaviour and odor perception. Detailed immunohistochemistry showed that in infected neurons not only parasitic cysts but also the host cell cytoplasm and some axons stained positive for Toxoplasma antigen suggesting that parasitic proteins might directly interfere with neuronal function. In fact, in vitro live cell calcium (Ca(2+)) imaging studies revealed that tachyzoites actively manipulated Ca(2+) signalling upon glutamate stimulation leading either to hyper- or hypo-responsive neurons. Experiments with the endoplasmatic reticulum Ca(2+) uptake inhibitor thapsigargin indicate that tachyzoites deplete Ca(2+) stores in the endoplasmatic reticulum. Furthermore in vivo studies revealed that the activity-dependent uptake of the potassium analogue thallium was reduced in cyst harbouring neurons indicating their functional impairment. The percentage of non-functional neurons increased over time In conclusion, both bradyzoites and tachyzoites functionally silence infected neurons, which may significantly contribute to the altered behaviour of the host.

Behavioral changes in mice caused by Toxoplasma gondii invasion of brain

Toxoplasma gondii, a protozoan parasite, is capable of infecting a broad range of intermediate warm-blooded hosts including humans. The parasite undergoes sexual reproduction resulting in genetic variability only in the intestine of the definitive host (a member of the cat family). The parasite seems to be capable of altering the natural behavior of the host to favor its transmission in the environment. The aim of this study was to evaluate the number of parasite cysts formed in the hippocampus and amygdala of experimentally infected mice as these regions are involved in defense behaviors control and emotion processing, and to assess the influence of the infection on mice behavior. The obtained results revealed the presence of parasite cysts both in the hippocampus and the amygdala of infected mice; however, no clear region-dependent distribution was observed. Furthermore, infected mice showed significantly diminished exploratory activity described by climbing and rearing, smaller preference for the central, more exposed part of the OF arena and engaged in less grooming behavior compared to uninfected controls.

Interferon-gamma- and perforin-mediated immune responses for resistance against Toxoplasma gondii in the brain

Toxoplasma gondii is an obligate intracellular protozoan parasite that causes various diseases, including lymphadenitis, congenital infection of fetuses and life-threatening toxoplasmic encephalitis in immunocompromised individuals. Interferon-gamma (IFN-γ)-mediated immune responses are essential for controlling tachyzoite proliferation during both acute acquired infection and reactivation of infection in the brain. Both CD4+ and CD8+ T cells produce this cytokine in response to infection, although the latter has more potent protective activity. IFN-γ can activate microglia, astrocytes and macrophages, and these activated cells control the proliferation of tachyzoites using different molecules, depending on cell type and host species. IFN-γ also has a crucial role in the recruitment of T cells into the brain after infection by inducing expression of the adhesion molecule VCAM-1 on cerebrovascular endothelial cells, and chemokines such as CXCL9, CXCL10 and CCL5. A recent study showed that CD8+ T cells are able to remove T. gondii cysts, which represent the stage of the parasite in chronic infection, from the brain through their perforin-mediated activity. Thus, the resistance to cerebral infection with T. gondii requires a coordinated network using both IFN-γ- and perforin-mediated immune responses. Elucidating how these two protective mechanisms function and collaborate in the brain against T. gondii will be crucial in developing a new method to prevent and eradicate this parasitic infection.

Toxoplasma IgG and IgA, but not IgM, antibody titers increase in sera of immunocompetent mice in association with proliferation of tachyzoites in the brain during the chronic stage of infection

Toxoplasma IgG and IgA, but not IgM, antibody titers were significantly higher in immunocompetent mice with cerebral proliferation of tachyzoites during the chronic stage of infection than those treated with sulfadiazine to inhibit the parasite growth. Their IgG and IgA antibody titers correlated significantly with the amounts of tachyzoite-specific SAG1 mRNA in their brains. In contrast, neither IgG, IgA, nor IgM antibody titers increased following two different doses of challenge infection in chronically infected mice. Increased antibody titers in IgG and IgA but not IgM may be a useful indicator suggesting an occurrence of cerebral tachyzoite growth in immunocompetent individuals chronically infected with Toxoplasma gondii.

Removal of Toxoplasma gondii cysts from the brain by perforin-mediated activity of CD8+ T cells

Chronic infection with Toxoplasma gondii is one of the most common parasitic infections in humans. Formation of tissue cysts is the basis of persistence of the parasite in infected hosts, and this cyst stage has generally been regarded as untouchable. Here we provide the first evidence that the immune system can eliminate T. gondii cysts from the brains of infected hosts when immune T cells are transferred into infected immunodeficient animals that have already developed large numbers of cysts. This T cell-mediated immune process was associated with accumulation of microglia and macrophages around tissue cysts. CD8(+) immune T cells possess a potent activity to remove the cysts. The initiation of this process by CD8(+) T cells does not require their production of interferon-gamma, the major mediator to prevent proliferation of tachyzoites during acute infection, but does require perforin. These results suggest that CD8(+) T cells induce elimination of T. gondii cysts through their perforin-mediated cytotoxic activity. Our findings provide a new mechanism of the immune system to fight against chronic infection with T. gondii and suggest a possibility of developing a novel vaccine to eliminate cysts from patients with chronic infection and to prevent the establishment of chronic infection after a newly acquired infection.

Host Cell Preference of Toxoplasma gondii Cysts in Murine Brain: A Confocal Study

Toxoplasma gondii is a protozoan parasite that is widely prevalent in humans and typically results in a chronic infection characterized by cysts located predominantly in the central nervous system. In immunosuppressed hosts, such as patients with HIV infection, the infection can be reactivated from the cysts in the brain resulting in a severe and potentially fatal encephalitis. Studies suggest that the chronic infection may also have neuropathological and behavioral effects in immune competent hosts. An improved understanding of tissue cyst behavior is of importance for understanding both the reactivation as well as the neurophysiological consequences of chronic infection. In vivo studies have identified neurons as host cells for cysts but in vitro studies have found that astrocytes can also foster development of the cysts. In this study we have addressed the question of which neural cell tissue cysts of T. gondii reside during chronic infection using a mouse model. Mice were infected with Me49 Strain T. gondii and the intracellular localization of the cysts analyzed during the development and establishment of a chronic infection at 1, 2, and 6 months post infection. Brains were fixed, cryosectioned, and stained with FITC-Dolichos biflorans to identify the Toxoplasma cysts and they were labeled with cell specific antibodies to neurons or astrocytes and then analyzed using confocal fluorescence microscopy. Cysts were found to occur almost exclusively in neurons throughout chronic infection. No cysts were identified in astrocytes, using the astrocyte marker, GFAP. Astrocyte interactions with neuronal-cysts, however, were frequently observed.

Is Toxoplasma gondii a causal agent in migraine?

BACKGROUND

Many different tissues may be parasitized by Toxoplasma gondii, particularly, lung, heart, lymphoid organs, and the central nervous tissues. Tissue cysts of this parasite in the brain may spontaneously rupture, releasing parasites that cause antibody titers to rise. In immunocompetent subjects with acquired toxoplasmosis, the most frequent symptoms were lymphadenopathy and headache. In the neurogenic inflammation theory of the pathogenesis of migraine, the cause of initial release of ions and inflammatory agents has not been established. In this study, we aimed to investigate if T. gondii infection is a possible cause of neurogenic inflammation of migraines.

METHODS

The anti-T. gondii antibody status of 104 patients with migraine were studied and compared with those of control groups, 50 healthy subjects and 50 subjects with headache due to rhinosinusitis, by using a micro-enzyme-linked immunosorbent assay technique.

RESULTS

Forty-six (44.2%) patients with migraine, 13 (26.0%) healthy control subjects, and 12 (24%) control subjects with rhinosinusitis were positive for anti-T. gondii IgG antibody. The rate of positivity in the migraine patient group was statistically different from those of the control groups (P < 0.05).

CONCLUSIONS

The results show the presence of chronic Toxoplasma infection in patients with migraine. Toxoplasma infection may contribute to neurogenic inflammation as the pathogenesis of migraine, as many studies in the literature have reported that Toxoplasma infection causes biochemical and immunologic changes.

A possible relationship between Toxoplasma gondii and schizophrenia: A seroprevalence study

Objective. Schizophrenia is a pervasive neuropsychiatric disease of uncertain etiology. We aimed to investigate a possible association between Toxoplasma gondii infection and schizophrenia in this study. Method. We selected individuals with schizophrenia (n=88) and tested them with commercially available enzyme-linked immunosorbent assay (ELISA) for anti-Toxoplasma IgG and IgM antibodies and compared these seropositivity rate to those of controls without psychiatric disease (n=88). Results. The rate of IgG antibody in the schizophrenia patients (47.7%) was higher than the control groups (20.4%) (P<0.001). We did not find any anti-Toxoplasma IgM seropositivity in both schizophrenia patients and control group. In schizophrenic patients with and without anti-Toxoplasma IgG groups statistical analysis did not reveal any correlation between demographic variables and Toxoplasma infection. Conclusion. Our findings supported previous studies indicate that T.gondii may play a role in etiopathogenesis in some cases of schizophrenia.

Meta-analysis of three case controlled studies and an ecological study into the link between cryptogenic epilepsy and chronic toxoplasmosis infection

A meta-analysis was performed on three case controlled studies which examined the relationship between latent toxoplasmosis gondii infection in the immunocompetent host and cryptogenic epilepsy. Further comparison was also made by examining the seroprevalence of toxoplasmosis rates for 17 various countries, cities or regions against the prevalence rates for epilepsy in those regions.

RESULTS

The results for the meta-analysis showed a log-odds ratio of 4.8 which approximates to a similar relative risk, (CI 2.6 to 7.8), with CI for all three studies being above 1. Seroprevalence rates for toxoplasmosis and prevalence rates of epilepsy showed a strong association (p<0.001).

DISCUSSION

The prevalence of toxoplasmosis is an important factor in the prevalence of epilepsy with a probable link in the cryptogenic epilepsies. An area with a reduced burden of toxoplasmosis will also have a reduced burden of epilepsy. Neuropathophysiology findings from various studies show a common physical relationship of microglial nodule formation in Toxoplasma gondii infection and epilepsy. This analysis raises the possibility that one of the many causes of epilepsy may be an infectious agent, or that cryptogenic epilepsy may be a consequence of latent toxoplasmosis infection. This raises the possibility that public health measures to reduce toxoplasmosis infection may also result in a reduction in epilepsy.

Characterization of a new gene WX2 in Toxoplasma gondii

Using hybridization techniques, we prepared the monoclonal antibody (Mab) 7C3-C3 against Toxoplasma gondii. The protection tests showed that the protein (Mab7C3-C3) inhibited the invasion and proliferation of T. gondii RH strain in HeLa cells. The passive transfer test indicated that the antibody significantly prolonged the survival time of the challenged mice. It was also shown that the antibody could be used for the detection of the circulating antigen of T. gondii. After immunoscreening the T. gondii tachyzoite cDNA library with Mab7C3-C3, a new gene wx2 of T. gondii was obtained. Immunofluorescence analysis showed that the WX2 protein was located on the membrane of the parasite. Nucleotide sequence comparison showed 28% identity to the calcium channel alpha-1E unit and shared with the surface antigen related sequence in some conservative residues. However, no match was found in protein databases. Therefore, it was an unknown gene in T. gondii encoding a functional protein on the membrane of T. gondii. Because it has been shown to have a partial protective effect against T. gondii infection and is released as a circulating antigen, it could be a candidate molecule for vaccine or a novel target for new drugs.

Anti-Toxoplasma gondii antibodies in patients with schizophrenia--preliminary findings in a Turkish sample

Schizophrenia is a serious neuropsychiatric disease of uncertain etiology. We investigated the seropositivity rate for anti-Toxoplasma IgG and IgM antibodies by enzyme-linked immunosorbent assay (ELISA) in patients with schizophrenia to ascertain a possible relationship between Toxoplasma gondii and schizophrenia. We selected 100 patients with schizophrenia, 50 with depressive disorder, and 50 healthy volunteers to investigate the seropositivity rate of anti-Toxoplasma antibodies by ELISA. The seropositivity rate for anti-Toxoplasma IgG antibodies among schizophrenia patients (66%) was significantly higher than among patients with depressive disorder or healthy volunteers (P < .01). Thus, there might be a causal relationship between toxoplasmosis and the etiology of schizophrenia.

Epilepsy and seropositivity rates of Toxocara canis and Toxoplasma gondii

PURPOSE

Increased seropositivity for Toxoplasma gondii and Toxocara canis have been observed in epileptic patients. Our aim is to determine whether there is any relationship between these agents and epilepsy in our cryptogenic epilepsy group.

MATERIAL AND METHODS

We studied specific IgG antibodies against T. gondii and T. canis in 100 cryptogenic epileptic patients and 50 healthy volunteers that had no history of epilepsy in their first degree relatives. We studied T. gondii and T. canis-specific IgG antibody serum levels and compared the values of these two groups.

RESULT

We found similar T. gondii and T. canis serum IgG antibodies in patients with cryptogenic epilepsy and in the control group, even though the control group included more animal owners.

CONCLUSION

We did not show any relationships between epilepsy and positive T. gondii and T. canis serology in our epileptic patients.

MYST family histone acetyltransferases in the protozoan parasite Toxoplasma gondii

The restructuring of chromatin precedes tightly regulated events such as DNA transcription, replication, and repair. One type of chromatin remodeling involves the covalent modification of nucleosomes by histone acetyltransferase (HAT) complexes. The observation that apicidin exerts antiprotozoal activity by targeting a histone deacetyltransferase has prompted our search for more components of the histone modifying machinery in parasitic protozoa. We have previously identified GNAT family HATs in the opportunistic pathogen Toxoplasma gondii and now describe the first MYST (named for members MOZ, Ybf2/Sas3, Sas2, and Tip60) family HATs in apicomplexa (TgMYST-A and -B). The TgMYST-A genomic locus is singular and generates a approximately 3.5-kb transcript that can encode two proteins of 411 or 471 amino acids. TgMYST-B mRNA is approximately 7.0 kb and encodes a second MYST homologue. In addition to the canonical MYST HAT catalytic domain, both TgMYST-A and -B possess an atypical C2HC zinc finger and a chromodomain. Recombinant TgMYST-A exhibits a predilection to acetylate histone H4 in vitro at lysines 5, 8, 12, and 16. Antibody generated to TgMYST-A reveals that both the long and short (predominant) versions are present in the nucleus and are also plentiful in the cytoplasm. Moreover, both TgMYST-A forms are far more abundant in rapidly replicating parasites (tachyzoites) than encysted parasites (bradyzoites). A bioinformatics survey of the Toxoplasma genome reveals numerous homologues known to operate in native MYST complexes. The characterization of TgMYST HATs represents another important step toward understanding the regulation of gene expression in pathogenic protozoa and provides evolutionary insight into how these processes operate in eukaryotic cells in general.

Outcomes in pediatric epilepsy: seeing through the fog

To identify clinical and predictive features of outcome in cryptogenic epilepsy in pediatric neurology practice, the medical records of all patients with cryptogenic epilepsy (as defined by the International League Against Epilepsy) in a single pediatric neurology practice over a 12-year interval with at least 2 years of follow-up were systematically and retrospectively reviewed. Review revealed 60 children with cryptogenic epilepsy: 32 (53.3%) males, 11 (18.3%) prior febrile seizure, 9 (15.0%) developmental delay at onset, and 38 (63.3%) placement in regular classes. Twenty-two (35.7%) had generalized seizures. Mean follow-up after initiating antiepileptic medication was 53 months (range 24-128 months). Four (6.7%) were intractable; 4 (6.7%) had very poor outcomes; 8 (13.3%) had poor outcomes; 44 (73.3%) were well controlled. Sixteen (26.7%) and 31 (51.7%) had seizure recurrence within the last 12 and 24 months, respectively. Twenty-nine (48.3%) were seizure-free for at least 24 months. Factors associated with a poor outcome include seizure recurrence in the 6- to 12-month interval after therapy initiation (P = 0.006) and developmental delay at onset (P = 0.023). This case series suggests that children with cryptogenic epilepsy tend to have a favorable outcome. Seizure recurrence in the first months after therapy initiation and developmental delay apparent at onset are predictive of poor outcome.

Molecular cloning and characterization of an SRCAP chromatin remodeling homologue in Toxoplasma gondii

We have identified and mapped a gene in Toxoplasma gondii that encodes a homologue of SRCAP (Snf2-related CBP activator protein), a member of the SNF/SWI family of chromatin remodeling factors. The genomic locus (TgSRCAP) is present as a single copy and contains 16 introns. The predicted cDNA contains an open reading frame of 8,775 bp and encodes a protein of 2,924 amino acids. We have identified additional SRCAP-like sequences in Apicomplexa for comparison by screening genomic databases. An analysis of SRCAP homologues between species reveals signature features that may be indicative of SRCAP members. Expression of mRNA encoding TgSRCAP is upregulated when tachyzoite (invasive form) parasites are induced to differentiate into bradyzoites (encysted form) in vitro. Recombinant TgSRCAP protein is functionally equivalent to the human homologue, being capable of increasing transcription mediated by CREB.

Investigation of probable relationship between Toxoplasma gondii and cryptogenic epilepsy

PURPOSE

Cryptogenic epilepsy, defines a group of epilepsy syndromes for which an aetiology is unknown but an underlying brain disease is suspected. We selected patients in this subgroup of epilepsy and investigated the sero-positivity rate for anti-Toxoplasma IgG antibodies by Enzyme Linked Immunosorbent Assay (ELISA). We investigated the probable relationship between Toxoplasma gondii and cryptogenic epilepsy.

METHODS

We selected 50 patients with cryptogenic epilepsy, 50 patients with known cause epilepsy and 50 healthy volunteers and investigated the sero-positivity rate for anti-Toxoplasma IgG antibodies by ELISA.

RESULTS

The sero-positivity rate for anti-Toxoplasma IgG antibodies among cryptogenic epilepsy patients (52%) was found to be higher than healthy volunteers (18%) and known cause epilepsy patients (22%) with statistical significance, (X(2)=18.095, P<0.01).

CONCLUSION

There might be a causal relationship between chronic toxoplasmosis and the aetiology of cryptogenic epilepsy.