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The potential risk of toxoplasmosis for traffic accidents: A systematic review and meta-analysis
... Despite the lack of symptoms in those with good health, T. gondii is a significant threat to AIDS patients and otherwise immunosuppressed patients, as well as pregnant women [3]. Recently, T. gondii has attracted public attention due to numerous publications linking toxoplasmosis to mental disorders [4][5][6][7] and problematic behaviors (e.g., increased likelihood of risky road behaviors that have been associated with traffic accidents and 'risk taking' related to business decisions) [8,9]. decisions) [8,9]. ...
... Recently, T. gondii has attracted public attention due to numerous publications linking toxoplasmosis to mental disorders [4][5][6][7] and problematic behaviors (e.g., increased likelihood of risky road behaviors that have been associated with traffic accidents and 'risk taking' related to business decisions) [8,9]. decisions) [8,9]. Reports exist of T. gondii in marine mammals including sea otters (Enhydra lutris) [10], beluga whales (Delphinapterus leucas) [11]. ...
Shellfish are known as a potential source of Toxoplasma gondii (responsible for toxoplasmosis), and Cryptosporidium parvum, which is one of the major causes of gastroenteritis in the world. Here we performed a comprehensive qPCR-based monthly survey for T. gondii and C. parvum during 2016 and 2017 in oysters (Crassostrea virginica) (n = 1440) from all six sites along the coast of Maine (USA). Pooled samples (mantle, gills, and rectum) from individual oysters were used for DNA extraction and qPCR. Our study resulted in detections of qPCR positives oysters for T. gondii and C. parvum at each of the six sites sampled (in 31% and 10% of total oysters, respectively). The prevalence of T. gondii was low in 2016, and in September 2017 several sites peaked in prevalence with 100% of the samples testing positive. The prevalence of C. parvum was very low except in one estuarine location (Jack's Point) in June 2016 (58%), and in October of 2016, when both prevalence and density of C. parvum at most of the sampling sites were among the highest values detected. Statistical analysis of environmental data did not identify clear drivers of retention, but there were some notable statistically significant patterns including current direction and nitrate along with the T. gondii prevalence. The major C. parvum retention event (in October 2016) corresponded with the month of highest dissolved oxygen measurements as well as a shift in the current direction revealed by nearby instrumentation. This study may guide future research to locate any contributing parasite reservoirs and evaluate the potential risk to human consumption.
... Toxoplasmosis-related motor function de cits and behavioral alterations may contribute to an increase in tra c accidents among infected individuals (13,14). ...
Background: Toxoplasmosis appears to be not only an infectious disease with observable symptoms but also one that can affect the social and behavioral aspects of both animals and humans. These social issues, particularly memory dysfunction, may result in dangerous occurrences such as traffic accidents. The purpose of this study was to investigate and compare the rate of traffic accidents among individuals with positive and negative Toxoplasma gondii (T. gondii) serology.
Materials and Methods: This was a retrospective cohort study conducted in the province of Yazd, central Iran, from 2018 to 2021 based on the statistics available in the province’s laboratories. We analyzed the results of the IgG test against Toxoplasma gondii collected in the laboratories of Yazd, Iran, from a total of 360 individuals with valid driver’s licenses who were divided into two groups. One group was Toxoplasma gondii-seropositive, while the other was negative. The traffic police system recorded the statistical analysis of traffic accidents from 2018 to 2021.
Results: The age of the toxoplasmosis group was slightly greater than that of the control group (36.2 and 34.08, respectively; p-value = 0.03). There was no significant difference between the toxoplasmosis group and the control group regarding driving time (p-value = 0.06). The incidence of accidents was greater in the toxoplasmosis group (36.7% vs. 20.6%; p < 0.001). This rate was significantly higher in people aged 35-69 than younger people (40% vs. 32.9%, respectively; p-value = 0.01).
Conclusion: Individuals with latent toxoplasmosis had a significantly higher risk of car accidents than those with negative serology, with the risk increasing with age. Due to contradictory findings regarding the effect of toxoplasmosis on traffic accidents and the higher incidence of toxoplasmosis in Persian cats, these findings should be considered when developing public health strategies.
... The studies on humans and mice showed that in latent stage of toxoplasmosis, the parasite affected the nervous and muscoskeletal system and induced prolonged time of reaction, impaired motor function, and changes in personality pro les. Impaired motor function and changes in behavior caused by toxoplasmosis may lead to higher amount of tra c accidents in infected people (13,14). ...
Background
Toxoplasmosis seems to be not only an infectious disease with known signs and symptoms, but it can also disturb the social behavioral aspects of animals and human. These social problems, especially memory disfunction, may lead to dangerous events like traffic accidents. The purpose of the study is to investigate and compare the rate of traffic accidents in people with positive serology for Toxoplasma gondiiand people with negative serology.
Materials and Methods
This is a retrospective cohort study conducted according to the statistics available in the laboratories of Yazd province, in the center of Iran, from 2018 to 2021.
We used information of 360 people with driving licenses divided into two groups related to the data of the results of IgG test against Toxoplasma gondii, collected in the laboratories of Yazd, Iran. One group was seropositive and the other one was seronegative for Toxoplasma gondii. The statistical analysis of the traffic accidents during 2018-2021 were recorded by the traffic police system.
Results
The age of toxoplasmosis group was slightly more than control group. (36.2 and 34.08, respectively; p-value= 0.03). There was no significant difference between time of driving in toxoplasmosis and control group. (P-value= 0.06). The rate of accidents was higher in toxoplasmosis group. (36.7% and 20.6%; p-value<0.001). This rate was significantly higher in people of 35-69 years old compared with younger ones. (40% and 32.9% respectively; p-value=0.01)
Conclusion
People with latent toxoplasmosis had a significantly higher risk of car accidents than seronegative ones and this risk was higher in older people. Due to contradictory results about the effect of toxoplasmosis on traffic accidents and higher rate of toxoplasmosis in Persian cats, these findings should be taken into consideration in designing strategies for public health.
... This is thought to be an evolutionary mechanism of transmission to feline definitive hosts by increasing the likelihood of predation of the intermediate host (Havlícek et al., 2001). In humans, there is evidence to suggest that infection with T. gondii leads to slower reaction times (Havlícek et al., 2001) and, as a result, can increase the risk of the host being involved in road traffic collisions (Flegr et al., 2002;Galván-Ramírez et al., 2013;Gohardehi et al., 2018;Kocazeybek et al., 2009;Stepanova et al., 2017;Yereli et al., 2006). ...
... Besides, a personality investigation of 230 women with acute Toxoplasma infection by Flegr et al. (2000) showed that latent toxoplasmosis may led to personality changes in the subjects, and the degree of change tended to be obvious with the extension of infection time. Two meta-analysis reports in this community showed that T. gondii infection increased the risk of traffic accidents, which might be related to "road rage" triggered by emotional irritation (Gohardehi et al., 2018;Sutterland et al., 2019). In addition, numerous studies demonstrated T. gondii as a replicated risk factor in human psychiatric disorders such as unknown temporal lobe epileptic seizure (Ngoungou et al., 2015;Uzorka and Arend, 2017;Sadeghi et al., 2019), Alzheimer's disease (Bayani et al., 2019), cognitive impairment in several cognitive domains including short-term verbal memory and processing speed (Gale et al., 2015;de Haan et al., 2021), depression (Kamal et al., 2020), autism (Flegr and Horacek, 2019;Nayeri et al., 2020;Al et al., 2021), suicide and suicidal behavior (Kamal et al., 2020;Soleymani et al., 2020;Postolache et al., 2021), and other neurological disorders (Desmettre, 2020;Nayeri et al., 2021). ...
Toxoplasma gondii is known to have a complex life cycle and infect almost all kinds of warm-blooded animals around the world. The brain of the host could be persistently infected by cerebral cysts, and a variety of psychiatric disorders such as schizophrenia and suicide have been reported to be related with latent toxoplasmosis. The infected animals showed fear reduction and a tendency to be preyed upon. However, the mechanism of this “parasites manipulation” effects have not been elucidated. Here, we reviewed the recent infection prevalence of toxoplasmosis and the evidence of mental and behavioral disorders induced by T. gondii and discussed the related physiological basis including dopamine dysregulation and gamma-aminobutyric acid (GABA) pathway and the controversial opinion of the necessity for cerebral cysts existence. Based on the recent advances, we speculated that the neuroendocrine programs and neurotransmitter imbalance may play a key role in this process. Simultaneously, studies in the evaluation of the expression pattern of related genes, long noncoding RNAs (lncRNAs), and mRNAs of the host provides a new point for understanding the mechanism of neurotransmitter dysfunction induced by parasite manipulation. Therefore, we summarized the animal models, T. gondii strains, and behavioral tests used in the related epigenetic studies and the responsible epigenetic processes; pinpointed opportunities and challenges in future research including the causality evidence of human psychiatric disorders, the statistical analysis for rodent-infected host to be more vulnerable preyed upon; and identified responsible genes and drug targets through epigenetics.
... A relatively high number of papers relate traffic accident risk not to driving patterns but to the driver's specific health conditions, which may influence driving style and driving issues. Gohardehi et al. (2018) reviewed papers that studied toxoplasmosis as a potential influence on the risk of having a traffic accident. In a meta-analysis, they use conclusions from studies carried out in different countries to evaluate whether this disease could be a significant risk factor. ...
Quantile regression provides a way to estimate a driver’s risk of a traffic accident by means of predicting the percentile of observed distance driven above the legal speed limits over a one year time interval, conditional on some given characteristics such as total distance driven, age, gender, percent of urban zone driving and night time driving. This study proposes an approximation of quantile regression coefficients by interpolating only a few quantile levels, which can be chosen carefully from the unconditional empirical distribution function of the response. Choosing the levels before interpolation improves accuracy. This approximation method is convenient for real-time implementation of risky driving identification and provides a fast approximate calculation of a risk score. We illustrate our results with data on 9614 drivers observed over one year.
... Moreover, numerous studies have suggested that this protozoan plays a potential role in increasing the incidence of psychiatric diseases (e.g. schizophrenia, autism, and major depression), suicide, traffic accidents, and addiction [15][16][17][18][19]. ...
Background: Up to now, epidemiological studies on the prevalence of Toxoplasma gondii infection among drug
addicted individuals have been rarely performed. By designing an age and sex matched case–control study, we
sought to determine the prevalence and associated factors with T. gondii infection in these population using serologi-
cal and molecular techniques.
Methods: One hundred and thirty-seven drug addicted individuals and 141 healthy subjects were enrolled in this
study. Informed consent as well as a standard questionnaire were obtained from all subjects participating. Blood sam-
ples were collected from each participant and the serum was screened for anti-Toxoplasma antibodies (IgG and IgM).
PCR assay was performed using the primer pair targeting the RE and GRA6 genes of T. gondii. Then, PCR products
were sequenced to determine genotype.
Results: The seroprevalence of T. gondii infection based on IgG titer was 34.3% in case and 9.9% in the control
groups, revealing a statistically signifcant diference (OR=4.37; 95% CI=2.46–9.12; P=0.001). After analyzing the
variables studied through the questionnaire, age was the only signifcantly factor associated with the anti-T. gondii IgG
antibody in case group. Considering PCR assays with RE genomic target, the prevalence of T. gondii infection was 5.1%
in the case and 3.5% in control groups which the diference was no statistically signifcant (OR=1.46; 95% CI=0.45–
4.73; P=0.521). Subsequently, all sequenced samples were genotype #1 using the GRA6 genomic target.
Conclusions: T. gondii exposure is relatively high among drug addicted individuals in Iran, and there is a need for
health policymakers and researchers to establish enlightenment and prevention programs for these population at risk
of infection.
... The most common of these disorders are major depression disorder (MDD) (Nayeri Chegeni, et al. 2019a;Sutterland et al. 2015), schizophrenia (SZ) (Sutterland et al. 2015;E. F. Torrey et al. 2007), bipolar disorder (BD) (de Barros et al. 2017;Sutterland et al. 2015), addiction (Sutterland et al. 2015), obsessive-compulsive disorder (OCD) (Nayeri Chegeni et al. 2019b), Alzheimer's disease (AD) (Bayani et al. 2019;Nayeri Chegeni, et al. 2019c), Parkinson's disease (PD) (Bayani et al. 2019), attention-deficit hyperactivity disorder (ADHD) (Nayeri et al. 2020a), epilepsy (Ngoungou et al. 2015;Sadeghi et al. 2019), suicide attempts (Sutterland et al. 2019;Amouei et al. 2020), traffic accidents (Gohardehi et al. 2018;Sutterland et al. 2019), autism (Nayeri et al. 2020b), and headache (Nayeri et al. 2020c). The results of these studies showed that chronic T. gondii infection is a factor associated with SZ, BD, OCD, AD, addiction, epilepsy, suicide attempts, autism, headache and traffic accidents but not with MDD, ADHD, and PD. ...
The most common form of the disease caused by Toxoplasma gondii (T. gondii) is latent toxoplasmosis due to the formation of tissue cysts in various organs, such as the brain. Latent toxoplasmosis is probably a risk factor in the development of some neuropsychiatric disorders. Behavioral changes after infection are caused by the host immune response, manipulation by the parasite, central nervous system (CNS) inflammation, as well as changes in hormonal and neuromodulator relationships. The present review focused on the exact mechanisms of T. gondii effect on the alteration of behavior and neurotransmitter levels, their catabolites and metabolites, as well as the interaction between immune responses and this parasite in the etiopathogenesis of psychiatric disorders. The dysfunction of neurotransmitters in the neural transmission is associated with several neuropsychiatric disorders. However, further intensive studies are required to determine the effect of this parasite on altering the level of neurotransmitters and the role of neurotransmitters in the etiology of host behavioral changes.
... This is thought to be an evolutionary mechanism of transmission to feline definitive hosts by increasing the likelihood of predation of the intermediate host (Havlícek et al., 2001). In humans, there is evidence to suggest that infection with T. gondii leads to slower reaction times (Havlícek et al., 2001) and, as a result, can increase the risk of the host being involved in road traffic collisions (Flegr et al., 2002;Galván-Ramírez et al., 2013;Gohardehi et al., 2018;Kocazeybek et al., 2009;Stepanova et al., 2017;Yereli et al., 2006). ...
This report was commissioned to inform Natural England’s advice to government on the reintroduction of beavers in England.
Beaver reintroduction is a topic of increasing interest in England. Although species reintroductions are a key conservation tool used to help restore species populations and/or ecosystem function, species translocations can facilitate the movement of parasites and risk animals encountering parasites that they normally would not be exposed to. Risks from disease associated with wildlife translocations arise because individual translocated specimens are a ‘biological package’, consisting of the host and all the associated viruses, bacteria, fungi and other parasites that the animal or plant may naturally harbour. Reintroduced beavers may, therefore, act as a mechanism for the introduction of new or previously eradicated parasites or may establish new transmission routes for the infection of humans, domesticated livestock and existing wildlife.
Disease risk analysis is a qualitative risk assessment method undertaken in the planning stage of a conservation intervention such as a reintroduction. During a disease risk analysis, the risk that infectious and non-infectious hazards will precipitate during or following an intervention is analysed in the absence of mitigating measures. Subsequent mitigating measures are proposed to reduce this risk. Preventing the introduction of alien parasites to native populations is crucial because parasite invasions have the potential to cause catastrophic mortality outbreaks in potentially immunologically naïve populations.
Disease risk analysis and the evaluation of mitigation measures is, therefore, a key step in understanding and controlling any disease risks for humans, livestock and wildlife that may arise from a reintroduction or translocation of wildlife.
This report provides an update to existing disease risk analyses for beavers in Britain and investigates the translocation pathways specifically relevant to reintroductions in England.
... While seropositivity for T. gondii indicates past infection or exposure, it does not confirm acute infection and therefore makes the causal relationship between acute infection and postinfectious sequelae harder to discern. Other analyses have reviewed development of diabetes (Majidiani et al., 2016), vision disorders (Barisani-Asenbauer et al., 2012), hearing loss (Brown et al., 2009), Parkinson's (Bayani et al., 2019;Zhou et al., 2019), multiple sclerosis (Saberi et al., 2018), and involvement in traffic accidents (Gohardehi et al., 2018). Similar limitations are present in these studies, with many noting heterogeneous results, limited data, and absence of association between Toxoplasma exposure and development of these conditions. ...
Previous economic estimates of infection with Toxoplasma gondii and chronic sequelae following infection lack sufficient data to establish the true burden of disease and its chronic sequelae. This scoping review aims to fill this gap by updating existing literature regarding the development of postinfectious sequelae following T. gondii infection. Literature published between January 1, 2000, and November 6, 2018, in PubMed, EMBASE, and Scopus was searched for a wide range of postinfectious sequelae and economic estimate terms. This scoping review includes summaries from the 108 articles covering 5 main groupings of outcomes (categories are not exclusive) including vision disorders (n = 58), psychological and mental health disorders (n = 27), neurological disorders (n = 17), fetal death and infection (n = 15), and hearing loss (n = 6), as well as a description of other outcomes reported. While the majority of the included studies assessed the incidence of these outcomes postinfection, very few followed participants long-term. These prospective studies are needed to understand the true burden of postinfectious sequelae over the life course, particularly because congenital infection with Toxoplasma can lead to severe outcomes for newborns. This scoping review can be used as an important resource for other researchers wishing to conduct future systematic reviews and meta-analyses, as well as for policy makers interested in developing guidance for public and health care partners.
... T. gondii infection has also been associated with relevant biological processes, including increased dopamine production (Prandovszky et al., 2011), and pro-inflammatory factors related to mania and neuropathologic disorders (Hamdani et al., 2015). Behavioral alterations such as increased aggression and impulsivity (Cook et al., 2015) and increased risk of road traffic accidents (Gohardehi et al., 2018) have also been documented. ...
Schizophrenia (SZ) and bipolar disorder (BD) are severe psychiatric disorders which result from complex interplay between genetic and environmental factors. It is well-established that they are highly heritable disorders, and considerable progress has been made identifying their shared and distinct genetic risk factors. However, the 15–40% of risk that is derived from environmental sources is less definitively known. Environmental factors that have been repeatedly investigated and often associated with SZ include: obstetric complications, infections, winter or spring birth, migration, urban living, childhood adversity, and cannabis use. There is evidence that childhood adversity and some types of infections are also associated with BD. Evidence for other risk factors in BD is weaker due to fewer studies and often smaller sample sizes. Relatively few environmental exposures have ever been examined for SZ or BD, and additional ones likely remain to be discovered. A complete picture of how genetic and environmental risk factors confer risk for these disorders requires an understanding of how they interact. Early gene-by-environment interaction studies for both SZ and BD often involved candidate genes and were underpowered. Larger samples with genome-wide data and polygenic risk scores now offer enhanced prospects to reveal genetic interactions with environmental exposures that contribute to risk for these disorders. Overall, although some environmental risk factors have been identified for SZ, few have been for BD, and the extent to which these account for the total risk from environmental sources remains unknown. For both disorders, interactions between genetic and environmental risk factors are also not well understood and merit further investigation. Questions remain regarding the mechanisms by which risk factors exert their effects, and the ways in which environmental factors differ by sex. Concurrent investigations of environmental and genetic risk factors in SZ and BD are needed as we work toward a more comprehensive understanding of the ways in which these disorders arise.
... Most of the primary infections are usually benign in the immunocompetent hosts. Although different systematic review and meta-analysis studies suggested that T. gondii infection could be associated with psychiatric and neurological disorders [28,29], the results revealed that the seroprevalence rates of toxoplasmosis were higher in various mental disorders, including schizophrenia [30], obsessive-compulsive disorder [31], bipolar disorder [32], addiction [30], epilepsy [33,34], suicide attempts [35,36], traffic accidents [35,37], and headache [38]. Neurological disorders caused by T. gondii may be the result of the persistence of parasitic cysts in the CNS, host immune response to the parasite, and damage caused by the primary infection [39]. ...
Toxoplasma gondii (T. gondii) is one of the most pervasive neurotropic pathogens causing different lesions in a wide variety of mammals as intermediate hosts, including humans. It is estimated that one-third of the world population is infected with T. gondii; however, for a long time, there has been much interest in the examination of the possible role of this parasite in the development of mental disorders, such as Alzheimer's disease (AD). T. gondii may play a role in the progression of AD using mechanisms, such as the induction of the host's immune responses, inflammation of the central nervous system (CNS), alteration in the levels of neurotransmitters, and activation of indoleamine-2,3-dyoxigenase. This paper presents an appraisal of the literature, reports, and studies that seek to the possible role of T. gondii in the development of AD. For achieving the purpose of the current study, a search of six English databases (PubMed, ScienceDirect, Web of Science, Scopus, ProQuest, and Google Scholar) was performed. The results support the involvement of T. gondii in the induction and development of AD. Indeed, T. gondii can be considered a risk factor for the development of AD and requires the special attention of specialists and patients. Furthermore, the results of this study may contribute to prevent or delay the progress of AD worldwide. Therefore, it is required to carry out further studies in order to better perceive the parasitic mechanisms in the progression of AD.
... However, raptors with subclinical disease due to T. gondii might be predisposed to trauma, the reason some of the sampled birds were admitted to a rehabilitation clinic. Toxoplasmosis has been related to increased risk of having a car crash and changes in personality profiles in humans (Gohardehi et al., 2018;Kocazeybek et al., 2009). Further research is needed to determine possible correlations between T. gondii subclinical disease and trauma in raptors. ...
Toxoplasma gondii is an important zoonotic protozoan parasite that can infect all warm-blooded animals including mammals and birds. Raptors can be intermediate hosts for T. gondii and the infection may be dependent on their feeding habits. In this study, we investigated the seroprevalence of T. gondii in ten raptor species from Florida, Pennsylvania, and Tennessee followed by a parasite bioassay on select seropositive samples. From a total of 155 raptors, we detected T. gondii antibodies using a modified agglutination test (cutoff 1:25) in 32 (20.6%) birds. The T. gondii seroprevalence was 44.8% in Falconiformes (13/29), 75% in Strigiformes (15/20), and 3.8% in Ciconiiformes (4/106). All Ciconiiformes samples (hearts and sera) were collected from Pennsylvania during nuisance wildlife removal projects and all birds were apparently healthy. Falconiform and Strigiform samples were collected from an exotics clinic in Tennessee and a rehabilitation center in Florida. All sampled birds were dead or euthanatized due to failure of rehabilitation or treatment. There was no statistically significant difference in T. gondii seroprevalence between Tennessee and Florida in the tested raptors. There was also no statistically significant difference in T. gondii exposure between males and females or adults and subadults. Mice bioassay attempts using fresh brain and/or heart tissue were performed on four seropositive birds. We isolated viable T. gondii tachyzoites from one red-shouldered hawk (Buteo lineatus) and genotyped the isolate using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of ten genetic markers. The isolated strain was designated as TgHawkFL1, which is ToxoDB PCR-RFLP genotype #28. Further research is needed to investigate the prevalence of T. gondii in raptors in the United States to obtain a better understanding of the life cycle, wildlife population impacts, and transmission dynamics of the parasite.
... Suicide attempters have shown a higher seroprevalence of T. gondii infection than healthy controls [10]. In addition, infections with T. gondii have been linked to traffic [11,12] and work accidents [13]. ...
The seroepidemiology of infection with Toxoplasma gondii (T. gondii) in alcohol consumers is largely undeveloped. In light of this, we sought to determine the seroprevalence of T. gondii infection in alcohol consumers in Durango, Mexico, and the association of T. gondii seroprevalence with characteristics of the population studied. Anti-T. gondii IgG and IgM antibodies were searched in sera of participants using commercially available enzyme immunoassays. Bivariate and logistic regression analyses were then used to determine the association between T. gondii infection and the characteristics of the population studied. Of the 1544 people studied (mean age: 39.4±14.0 years), 173 (11.2%) tested positive for anti-T. gondii IgG antibodies. We were able to test 167 of the 173 anti-T. gondii IgG positive sera for anti-T. gondii IgM antibodies. Fifty-five (32.9%) of these 167 serum samples were positive for anti-T. gondii IgM antibodies. Bivariate analysis showed that visual impairment, history of surgery, and hepatitis were negatively associated with T. gondii IgG seropositivity (P
... Latent T. gondii infections in humans are associated with behavioural shifts, including decreased conscientiousness, extrovert and entrepreneurial behaviour, and slower reaction times (Flegr et al. 2013;Johnson et al. 2018). The latter might explain the greater representation of people seropositive to T. gondii in accidents, including car accidents (Flegr et al. 2002;Gohardehi et al. 2018;Sutterland et al. 2019). There is increasing evidence of links between latent T. gondii infection and psychiatric diseases including depression, bipolar disorder, schizophrenia, behavioural disorders and poor cognitive function (Henriquez et al. 2009;Torrey et al. 2012;Pearce et al. 2014;Fuglewicz et al. 2017;Houdek 2017;Akaltun et al. 2019). ...
Context. Cats are the definitive or primary host for pathogens that cause diseases in people and livestock. These cat-dependent diseases would not occur in Australia if cats had not been introduced, and their ongoing persistence depends on contacts with cats. Toxoplasma gondii is a protozoan parasite that cycles between cats and any other warm-blooded animals. People infected by T. gondii may appear asymptomatic, or have a mild illness, or experience severe, potentially lethal symptoms; the parasite may also affect behaviour and mental health. T. gondii is also a major contributor to spontaneous abortion in sheep and goats. Two species of Sarcocystis, another genus of protozoan parasite, cycle through cats and sheep, causing macroscopic cysts to form in sheep tissues that reduce meat saleability. Toxocara cati, the cat roundworm, causes minor illnesses in humans and livestock, and the bacterium Bartonella henselae causes cat scratch disease, an infection that can be contracted by people when scratched or bitten by cats carrying the pathogen.
Aims. We estimated the economic costs of cat-dependent pathogens in Australia.
Methods. We collated national and global data on infection rates, health and production consequences.
Key results. We estimated the costs of two cat-dependent diseases (toxoplasmosis, cat scratch disease) in people at AU $6.06 billion (plausible range AU$2.11–10.7 billion) annually, and the costs to livestock production from toxoplasmosis and sarcocystosis at AU$11.7 million (plausible range AU$7.67–18.3 million). Most of the human health costs are due to the associations between T. gondii and higher rates of traffic accidents and mental illness in people. The causality behind these associations remains uncertain, so those costs may be overestimated. Conversely, our estimates are incomplete, infections and illness are under-reported or misdiagnosed, and our understanding of disease outcomes is still imperfect, all of which make our costs underestimated.
Conclusions. Our analysis suggests that substantial benefits to public health and livestock production could be realised by reducing exposure to cats and breaking parasite transmission cycles.
Implications. Reducing feral cat populations in farming and urban areas, reducing the pet cat population and increasing rates of pet cat containment could help reduce the burden of cat-dependent diseases to people and livestock.
... With growing evidence that T. gondii infection in and of itself may result in subtle behavioral abnormalities, it could be the case that these behaviors result in either increased or decreased risk of sustaining a future TBI. For example, T. gondii infection has been demonstrated to increase the risk of having a traffic accident [268]. As motor accidents are a common cause of TBI, these adults may consequently be at a higher risk of sustaining a TBI [18]. ...
Abstract Traumatic brain injury (TBI) is one of the leading causes of morbidity and mortality worldwide; however, treatment development is hindered by the heterogenous nature of TBI presentation and pathophysiology. In particular, the degree of neuroinflammation after TBI varies between individuals and may be modified by other factors such as infection. Toxoplasma gondii, a parasite that infects approximately one-third of the world’s population, has a tropism for brain tissue and can persist as a life-long infection. Importantly, there is notable overlap in the pathophysiology between TBI and T. gondii infection, including neuroinflammation. This paper will review current understandings of the clinical problems, pathophysiological mechanisms, and functional outcomes of TBI and T. gondii, before considering the potential synergy between the two conditions. In particular, the discussion will focus on neuroinflammatory processes such as microglial activation, inflammatory cytokines, and peripheral immune cell recruitment that occur during T. gondii infection and after TBI. We will present the notion that these overlapping pathologies in TBI individuals with a chronic T. gondii infection have the strong potential to exacerbate neuroinflammation and related brain damage, leading to amplified functional deficits. The impact of chronic T. gondii infection on TBI should therefore be investigated in both preclinical and clinical studies as the possible interplay could influence treatment strategies.
... For example, Samojłowicz and colleagues (2017) found a significant positive relationship between file.v12.2 8 infection and risky behaviors such as with not wearing a helmet during certain activities or with swimming while intoxicated. Infection has also been linked to car accidents in both men and women (Gohardehi et al., 2018). On the other hand, a study on a small sample of exclusively women did not find an effect of TG on financial risk-taking (Lanchava et al., 2015). ...
There is growing evidence that human biology and behavior are influenced by infectious microorganisms. One such microorganism is the protozoan Toxoplasma gondii ( TG). Using longitudinal data covering the female population of Denmark, we extend research on the relationship between TG infection and entrepreneurial activity and outcomes. Results indicate that TG infection is associated with a subsequent increase in the probability of becoming an entrepreneur, and is linked to other outcomes including venture performance. With parasite behavioral manipulation antithetical to rational judgment, we join a growing conversation on biology and alternative drivers of business venturing.
... For example, Samojłowicz and colleagues (2017) found a significant positive relationship between infection and risky behaviors such as with not wearing a helmet during certain activities or with swimming while intoxicated. Infection has also been linked to car accidents in both men and women (Gohardehi et al., 2018). On the other hand, a study on a small sample of exclusively women did not find an effect of TG on financial risk-taking (Lanchava et al., 2015). ...
There is growing evidence that human biology and behavior is influenced by infectious microorganisms. One such microorganism is the protozoan Toxoplasma gondii (TG). Using longitudinal data covering the female population of Denmark, we extend research on the relationship between TG infection and entrepreneurial activity and outcomes. Results indicate that TG infection is associated with a subsequent increase in the probability of becoming an entrepreneur, and is linked to other outcomes including venture performance. With parasite behavioral manipulation antithetical to rational judgement, we join a growing conversation on biology and alternative drivers of business venturing.
[ Note: the Article can be found at
https://www.researchgate.net/publication/338857788_Nothing_Ventured_Nothing_Gained_Parasite_Infection_is_Associated_with_Entrepreneurial_Initiation_Engagement_and_Performance ]
... T. gondii can infect humans orally or via blood transfusion through infected donors, organ transplantation, and congenital transmission from a mother to her fetus [5]. The factors affecting the incidence of toxoplasmosis are geographic location, lifestyle, cultural traditions, and personal health habits. ...
Toxoplasmosis is a major public health concern due to neurotropic nature and role in the development of mental and behavioral disorders. Alzheimer's disease (AD) is an important nervous disease that results in the reduction of the amount of beta-amyloid plaque deposition and irreversible loss of neurons in the brain. Although a few studies evaluated the association between AD and toxoplasmosis, the present study as a systematic review and meta-analysis of published studies investigated the possible association between Toxoplasma gondii (T. gondii) and AD. A systematic literature search was conducted using seven electronic databases from the inception to 25th of November 2018 with no restriction of language that looked at toxoplasmosis (as an exposure) and AD (as a disease). The random effect model was used to determine the total odds ratio (OR) and total p-value. Generally, eight studies containing 3239 subjects (360 patients and 2879 controls) met the eligibility criteria. Then, eight articles were used for meta-analysis with respect to inclusion and exclusion criteria. The results of the meta-analysis (random effect model) showed a common OR of 1.53 (95% CI: 1.07-2.18). Despite the fact that there was no evidence of publication bias (P = 0.079) using formal statistical test, the visual inspection of the funnel graph suggested that the observed effect was fueled mainly by three studies with large effects (and large standard errors). Moreover, the file-drawer effect (i.e. publishing mainly studies with positive results) might play a role in the phenomenon. Results of this meta-analytic study suggested that T. gondii can be considered a risk factor for the development of AD and exacerbation of its symptoms. However, the number of published relevant studies is still relatively low, and the risk of the presence of publication bias is relatively high. Therefore, the investigation of the clinically important question of the possible association between toxoplasmosis and AD definitively deserves further attention.
... Tel: +98-35-31492256 cientists have recently revealed that there might be a relationship between driving accident's problems, especially in the elder people with one of the important food-borne diseases named toxoplasmosis which is caused by Toxoplasma gondii (1,2). ...
... The difference in RhD status could also apply to our study and may explain why we only found a very weak association between toxoplasmosis and traffic accidents. A recent systematic review and metaanalysis concluded that exposure to T. gondii significantly increases the risk of having traffic accidents (Gohardehi et al., 2018) which our results also supports. In addition, T. gondii infected individuals have been found also to have an increased risk of workplace accidents (perhaps due to decreased concentration and prolonged reaction times) (Alvarado-Esquivel et al., 2012) and of starting their own business (Johnson et al., 2018), but not of increased financial risk-taking (Lanchava et al., 2015). ...
Background:
Common infectious pathogens have been associated with psychiatric disorders, self-violence and risk-taking behavior.
Methods:
This case-control study reviews register data on 81,912 individuals from the Danish Blood Donor Study to identify individuals who have a psychiatric diagnosis (N = 2591), have attempted or committed suicide (N = 655), or have had traffic accidents (N = 2724). For all cases, controls were frequency matched by age and sex, resulting in 11,546 participants. Plasma samples were analyzed for immunoglobulin G (IgG) antibodies against Toxoplasma gondii and cytomegalovirus (CMV).
Results:
T. gondii was detected in 25·9% of the population and was associated with schizophrenia (odds ratio [OR], 1·47; 95% confidence interval [CI], 1·03-2·09). Accounting for temporality, with pathogen exposure preceding outcome, the association was even stronger (IRR, 2·78; 95% CI, 1·27-6·09). A very weak association between traffic accident and toxoplasmosis (OR, 1·11; 95% CI, 1·00-1·23, p = 0.054) was found. CMV was detected in 60·8% of the studied population and was associated with any psychiatric disorder (OR, 1·17; 95% CI, 1·06-1·29), but also with a smaller group of neurotic, stress-related, and somatoform disorders (OR, 1·27; 95% CI, 1·12-1·44), and with attempting or committing suicide (OR, 1·31; 95% CI, 1·10-1·56). Accounting for temporality, any psychiatric disorder (IRR, 1·37; 95% CI, 1·08-1·74) and mood disorders (IRR, 1·43; 95% CI, 1·01-2·04) were associated with exposure to CMV. No association between traffic accident and CMV (OR, 1·06; 95% CI, 0·97-1·17) was found.
Conclusions:
This large-scale serological study is the first study to examine temporality of pathogen exposure and to provide evidence of a causal relationship between T. gondii and schizophrenia, and between CMV and any psychiatric disorder.
... Die gängige Meinung, eine abgelaufene Infektion beim Menschen, die bekanntermaßen Zysten im Gehirn des Betroffenen hinterlässt, habe keine oder vernachlässigbar kleine Auswirkungen auf das Erleben und Verhalten einer Person, muss daher überdacht werden.Man könnte nun meinen, dass diese Erkenntnisse unter den heutigen Lebensbedingungen irrelevant seien. Bei weltweit mehr als zwei Milliarden infizierten Menschen und einer hohen Variabilität der Infektionsraten (von 8,6% in Norwegen bis 60,4% in Brasilien; ▶Tab. 1) können jedoch auch kleine Effekte eine große Wirkung haben: Eine Häufung von Verkehrsunfällen(13,30) und Suizidversuchen sowie Suiziden (2, 6) nach abgelaufener Toxoplasmose-Infektion ist tatsächlich zu verzeichnen und lässt auf vermehrte Aggressivität, Impulsivität und risikoreicheres Verhalten schließen. Da die Durchseuchung der Bevölkerung in Deutschland etwa 50% beträgt, geht das uns alle durchaus an: Eine abgelaufene Infektion mit Toxoplasma gondii ist nicht völlig ohne Folgen.Ein internationales Wissenschaftlerteam aus Großbritannien, den USA, Deutschland, Norwegen, Spanien und Hongkong hat eine Arbeit mit drei Studien zu den Auswirkungen einer abgelaufenen Toxoplasmose-Infektion auf Risikoverhalten (englisch: "risk-taking") publiziert, die es wert sind, einer breiteren Öffentlichkeit vorgestellt zu werden. ...
Toxoplasma gondii est un parasite intra-cellulaire infectant près d’un tiers de la population mondiale. Généralement asymptomatique, la toxoplasmose est associée à une symptomatologie grave chez les patients immunodéprimés et dans le cas d’infection congénitale. Négligée par les pouvoirs publics, la phase chronique de l’infection a longtemps été sous-estimée. Cette méconnaissance entraîne donc des questions telles que quel est le meilleur protocole thérapeutique ? quelle est la meilleure stratégie diagnostique ? Récemment une stratégie de dissémination très avancée a été suspectée, sur la base de la théorie de la manipulation comportementale de l’hôte. Chez l’Homme, une telle manipulation peut avoir des effets majeurs cérébraux, neurologiques ou psychologiques. Quoi qu’il en soit, son impact sur le sommeil, qui constitue un index particulièrement sensible des fonctions cérébrales, est pour le moment inconnu. C’est pourquoi nous avons établi un modèle murin expérimental afin d’étudier les effets de Toxoplasma gondii sur le cycle éveil-sommeil. Nous avons montré que l’infection chronique par T. gondii était associée de manière persistante avec une augmentation de l’éveil et une diminution du sommeil, ce qui cadre avec la stratégie du parasite pour faciliter sa dissémination grâce à la prédation de son hôte. Nos résultats montrent pour la première fois les conséquences directes de l’infection toxoplasmique sur le comportement, pouvant avoir un impact majeur sur l’apparition de pathologies neuropsychiatriques et neurodégénératives.
Schizophrenia is a serious mental disorder characterized by chronic relapsing episodes of psychosis. The disease is multifactorial, where infections, genetic vulnerability and environmental factors are involved in the development of the illness. Toxoplasma gondii is one of the parasites that has long been known associated with schizophrenia in many studies. To date, there is growing evidence of association between T. gondii infections and schizophrenia. Herein we report a rare case of reactivated toxoplasmosis in a schizophrenia individual. This patient was incidentally diagnosed with reactivated T. gondii infection. He denied any symptoms of toxoplasmosis but experienced a mild psychiatric auditory hallucination. Serology test for T. gondii immunoglobulin antibodies measured a high positive IgG titer (135.9 IU/ml) and negative for IgM. Interestingly, nested PCR exhibited a positive result for the type I strain of T. gondii dense granular (GRA) 7 gene (GRA7). This case highlights the detection of probable reactivation of toxoplasmosis in an immunocompetent schizophrenic patient without psychiatric treatment-resistant and remains asymptomatic for toxoplasmosis. Both serology and molecular tools have been a helpful aid in establishing the diagnosis. Nonetheless, early detection as in this case may aid the patient management in the future.
Humans, wildlife, and domestic animals are intimately linked through shared infections. Many parasites and pathogens use multiple host species, either opportunistically or sequentially, such that managing disease risk frequently requires a broader understanding of the ecological community. The coccidian protozoan Toxoplasma gondii infects more than one hundred species of vertebrates, ranging from bats to beluga whales. In humans, acute toxoplasmosis can have serious health consequences for immunocompromised individuals. Even amongst asymptomatic patients, however, toxoplasmosis has been linked to a range of behavioral alterations and conditions, such as changes in risk tolerance, neuroticism, mental illness, suicide, and accident proneness. Whether such links are causal or simply correlational has been the subject of intense study and debate; from an evolutionary standpoint, selection may favor parasite-induced alterations in host behavior that increase the likelihood a host is consumed by the definitive host—in this case a domestic or wild felid. Here, we examine current evidence for parasite-induced manipulations of host behavior, in both humans and other animals. We critically evaluate proposed mechanisms through which infection might influence host behavior, which range from inflammation in the brain to changes in hormones or neurotransmitters. Considering estimates that T. gondii may infect up to one-third of the global human population, we conclude by examining the implications of these changes for human behavior, individual fitness, and emergent cultural properties.
Expected final online publication date for the Annual Review of Animal Biosciences, Volume 9 is February 16, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Traditionally, the protozoan parasite Toxoplasma gondii has been thought of as relevant to public health primarily within the context of congenital toxoplasmosis or postnatally acquired disease in immunocompromised patients. However, latent T. gondii infection has been increasingly associated with a wide variety of neuropsychiatric disorders and, more recently, causal frameworks for these epidemiological associations have been proposed. We present assimilated evidence on the associations between T. gondii and various human neuropsychiatric disorders and outline how these may be explained within a unifying causal framework. We argue that the occult effects of latent T. gondii infection likely outweigh the recognised overt morbidity caused by toxoplasmosis, substantially raising the public health importance of this parasite.
The National Health and Nutrition Examination Survey (NHANES) evaluates the epidemiology in the U.S. population of certain infectious diseases, including Toxoplasma gondii (T. gondii), a protozoan parasite. This study aims to evaluate the seroprevalence of T. gondii -IgG antibodies using NHANES data to identify risk factors related to T. gondii. Using NHANES 2009–10, 2011–12, and 2013–14 cycles, univariate analyses and logistic regression models were conducted to determine the relationship between T. gondii seropositivity and various risk factors. Across the three cycles, 13.3% of participants tested positive for T. gondii-IgG seroprevalence, with a significant decrease in seroprevalence from the earlier to later cycles. 53.4% of individuals with positive serology were male. The probability of testing positive for T. gondii -IgG significantly increases between four and five times from the 18–29 age group to 70–79 age group. Seroprevalence also differed by ethnicity, with Latinos of any race having two times higher odds of testing positive for T. gondii compared to other ethnicities. Other sociodemographic factors were associated with lower odds of T. gondii seropositivity, including college education, higher household income, and health insurance. Most clinical conditions were not significantly associated with T. gondii, excluding depression, which was observed in 25% of patients positive for T. gondii-IgG. Further research on the influence of this parasite on infected individuals, including predispositions for risk-taking, is needed to better understand the relationship between Toxoplasma gondii, depression, and other mental illnesses.
Cytomegalovirus (CMV) is the herpetic virus, which infects 45–100% people worldwide. Many reports suggest that CMV could impair cognitive functions of infected subjects. Here we searched for indices of effects of CMV on infected subjects’ intelligence and knowledge. The Intelligence Structure Test I-S-T 2000 R was used to compare IQ of 148 CMV-infected and 135 CMV-free university students. Infected students expressed higher intelligence. Paradoxically, their IQ decreased with decreasing concentration of anti-CMV antibodies, which can be used, statistically, as a proxy of the time passed from the moment of infection in young subjects when the age of subjects is statistically controlled. The paradox of seemingly higher intelligence of CMV infected subjects could be explained by the presence of the subpopulation of about 5–10% CMV-positive individuals in the population of “CMV-negative students”. These false negative subjects had probably not only the oldest infections and therefore the lowest concentration of anamnestic antibodies, but also the lowest intelligence among the infected students. Prevalence of CMV infection in all countries is very high, approaching sometimes 90%. Therefore, the total impact of CMV on human intelligence may be large.
Studies carried out in Moscow residents have revealed that the prevalence of chronic toxoplasmosis is very close to those in countries of Eastern and Central Europe. Our findings also demonstrated a statistically significant relationship between the rate of traffic accidents and the seroprevalence of chronic toxoplasmosis in drivers who were held responsible for accidents. The latter was 2.37 times higher in drivers who were involved in road accidents compared with control groups. These results suggest that the consequences of chronic toxoplasmosis (particularly a slower reaction time and decreased concentration) might contribute to the peculiarities of the epidemiology of road traffic accidents in the Russian Federation and might interfere with the successful implementation of the Federal Programme named “Increase road traffic safety”. Suggestions for how to address overcome this problem are discussed in this paper.
Latent toxoplasmosis is probably the most common protistan parasitic disease with many indirect negative impacts on human health. One of the important impacts is impaired psychomotor function leading to reduced driving efficiency in Toxoplasma-seropositive subjects. Numerous case-control studies have established a positive relation between the seroprevalence of Toxoplasma gondii (Nicolle et Manceaux, 1908) and probability of traffic accidents in study populations. The prevalence of toxoplasmosis varies between populations according to local geographical conditions, hygienic practices and kitchen habits. Similarly, we see a striking variation in the incidence of traffic accidents across countries. Hence, we compiled the largest ever data set on the seroprevalence of toxoplasmosis and tried to understand its role in traffic accident-related deaths and disabilities across 87 countries. Simple non-parametric analysis showed a positive and strong relation of T. gondii seroprevalence and traffic accident related disabilities. Further, we conducted multivariate analysis to control for confounding factors. After controlling for wealth, geographical latitude, health of population, length of roads and number of vehicles, the correlation disappeared. When the frequency of RhD negativity and its interaction with toxoplasmosis were included into the model, the effects of toxoplasmosis seemingly returned. However, the analysed data suffered from the problem of multicollinearity. When a proper method of analysis, ridge regression, was applied, the effects of toxoplasmosis prevalence and RhD negativity frequency disappeared again. The existence of a strong correlation between the prevalence of toxoplasmosis and health of population in particular countries, which was the probable cause of multicollinearity and possible reason for the negative result of the present study, suggests that 'asymptomatic' latent toxoplasmosis could have a large impact on public health.
Although toxoplasmosis in immunocompetent individuals is generally asymptomatic, in immunocompromised patients (HIV/AIDS, cancer, and transplant patients), it can lead to serious pathological effects. This study included a systematic review and meta-analysis to comprehensively assess the seroprevalence rate of Toxoplasma infection in immunocompromised patients in Iran. Electronic English and Persian databases (PubMed, Google Scholar, ScienceDirect, Scopus, Magiran, Scientific Information Database [SID], IranMedex, and IranDoc), parasitology congresses, and projects and theses of Iranian medical universities, were systematically searched from 1997 to 2013 (published or unpublished data). In this paper, several studies that used serological methods for diagnosis of toxoplasmosis were selected. Analysis of seroprevalence estimates was pooled using a random-effects meta-analysis. Twenty-two studies, comprising 2,805 individuals, were included in the meta-analysis. Overall seroprevalence rate of Toxoplasma infection in Iranian immunocompromised patients was 50.01% (95% confidence interval, 43.85 to 56.17); however, there was significant heterogeneity among study groups. The results showed that seroprevalence rate of toxoplasmosis among transplant recipients, HIV/AIDS, and cancer patients in Iran was 55.1%, 50.05%, and 45.06%, respectively. In addition, IgM seroprevalence rate was estimated to be 4.85% (95% confidence interval, 2.22 to 8.41). This systematic review and meta-analysis identified a high seroprevalence rate of Toxoplasma infection among immunocompromised patients (50%).Consideration of management , design and provision of appropriate control measures of toxoplasmosis is highly recommended.
Background
The prevalence of toxoplasmosis in the general population of Guadalajara, Mexico, is around 32%. Toxoplasmosis can cause ocular lesions and slowing of reaction reflexes. Latent toxoplasmosis has been related with traffic accidents. We aimed to assess the prevalence of anti-Toxoplasma gondii antibodies and visual impairments related with traffic accidents in drivers from the metropolitan Guadalajara.
Methods
We prospectively evaluated the prevalence of IgG and IgM anti-T. gondii antibodies in 159 individuals involved in traffic accidents, and in 164 control drivers never involved in accidents. Cases of toxoplasmosis reactivation or acute infection were detected by PCR in a subset of 71 drivers studied for the presence of T. gondii DNA in blood samples. Ophthalmologic examinations were performed in drivers with IgG anti-T. gondii antibodies in search of ocular toxoplasmosis.
Results
Fifty-four (34%) traffic accident drivers and 59 (36%) controls were positive to IgG anti-T. gondii antibodies (p = 0.70). Among the 113 seropositive participants, mean anti-T. gondii IgG antibodies titers were higher in traffic accident drivers than in controls (237.9 ± 308.5 IU/ml vs. 122.9 ± 112.7 IU/ml, respectively; p = 0.01 by Student’s t test, p = 0.037 by Mann–Whitney U test). In multivariate analyses, anti-T. gondii IgG antibody titers were consistently associated with an increased risk of traffic accidents, whereas age showed an inverse association. The presence of IgM-anti-T. gondii antibodies was found in three (1.9%) subjects among traffic accident drives, and in two (1.2%) controls. Three (4.2%) samples were positive for the presence of T. gondii DNA, all among seropositive individuals. No signs of ocular toxoplasmosis were found in the entire cohort. Moreover, no other ocular conditions were found to be associated with the risk of traffic accidents in a multivariate analysis.
Conclusions
Anti-T. gondii antibody titers are associated with the risk of traffic accidents. We could not determine any association of ocular toxoplasmosis with traffic accidents. Our results warrant further analyses in order to clarify the link between toxoplasmosis and traffic accidents.
BACGROUND: It has recently been shown that the behavioural effects resulting from latent T. gondii infection in immunocompetent people could pose as a threat to their welfare. AIM. The aim of the study was to evaluate the prevalence of T. gondii infection in a group of people who died suddenly in Warsaw and its vicinity.
The studied group (n = 169 people) included 42 road traffic accident victims who were driving a vehicle (bicycle (n = 6), a motorbike (n = 3), a motorcycle (n = 13), a car (n = 20)) prior to sudden death and 41 people whose death resulted from suicide. Blood samples were collected post-mortem and examined for the presence of T. gondii, IgG antibodies and ethyl alcohol.
Of the 169 people tested, T. gondii IgG antibodies were found in the serum of 93 (55%) of which 25 (59.5%) were drivers and 26 (63.4%) people who died as a result of suicide. With respect to the prevalence of T. gondii infection no statistically significant differences were found between the study (61.4%) and control group (49.4%); (p = 0.09). A statistically significant result was recorded in the 38-58 age group between suicide and control groups (71.4% vs. 44.4%; p < 0.05). Positive test results for the presence of ethyl alcohol in the blood were reported among 49.7% of the studied population: 25.7% among drivers, 67.6% among suicides and 51.8% in the control group. To a statisctically siginificant degree, IgG T. gondii antibodies were found to occur more frequently in people with positive blood alcohol test results among suicides (72% vs. 50%; p < 0.05) and among the control group (60% vs. 40%; p < 0.05) than in their equivalents with negative test results.
Our work confirmed the usefulness of serologically testing samples collected post-mortem for epidemiological purposes. The small size of the study group made it impossible to evaluate the potential associations between exposure to T. gondii infection and the probability of sudden death. The significance of Toxoplasma gondii infection as a risk factor for self-destructive behaviour merits further study.
Toxoplasma gondii is known to induce specific behavioural changes in its intermediate hosts. This is usually considered to be an evolutionary adaptation aimed to increase the probability of transmission of the parasite into its definitive host, the cat, by predation. In rodents an increase of reaction time as well as many other specific behavioural patterns have been observed. Here we report the results of our double blind study showing the significantly longer reaction times of 60 subjects with latent toxoplasmosis in comparison with those of 56 controls. Moreover, the existence of a positive correlation between length of infection and mean reaction time suggested that slow and cumulative effects of latent toxoplasmosis rather than a one-step (and possibly transient) effect of acute toxoplasmosis disease are responsible for the decrease of psychomotor performance of infected subjects. To our knowledge, this is the first study confirming the existence of such parasite-induced changes in human behaviour that could be considered in evolutionary history of the human species as adaptive from the point of view of parasite transmission.
The apicomplexan parasite Toxoplasma gondii was discovered a little over 100 years ago, but knowledge of its biological life cycle and its medical importance has grown in the last 40 years. This obligate intracellular parasite was identified early as a pathogen responsible for congenital infection, but its clinical expression and the importance of reactivations of infections in immunocompromised patients were recognized later, in the era of organ transplantation and HIV infection. Recent knowledge of host cell-parasite interactions and of parasite virulence has brought new insights into the comprehension of the pathophysiology of infection. In this review, we focus on epidemiological and diagnostic aspects, putting them in perspective with current knowledge of parasite genotypes. In particular, we provide critical information on diagnostic methods according to the patient's background and discuss the implementation of screening tools for congenital toxoplasmosis according to health policies.
Latent toxoplasmosis, protozoan parasitosis with prevalence rates from 20 to 60% in most populations, is known to impair reaction times in infected subjects, which results, for example, in a higher risk of traffic accidents in subjects with this life-long infection. Two recent studies have reported that RhD-positive subjects, especially RhD heterozygotes, are protected against latent toxoplasmosis-induced impairment of reaction times. In the present study we searched for increased incidence of traffic accidents and for protective effect of RhD positivity in 3890 military drivers.
Male draftees who attended the Central Military Hospital in Prague for regular entrance psychological examinations between 2000 and 2003 were tested for Toxoplasma infection and RhD phenotype at the beginning of their 1 to 1.5-year compulsory military service. Subsequently, the data on Toxoplasma infection and RhD phenotype were matched with those on traffic accidents from military police records and the effects of RhD phenotype and Toxoplasma infection on probability of traffic accident was estimated with logistic regression.
We confirmed, using for the first time a prospective cohort study design, increased risk of traffic accidents in Toxoplasma-infected subjects and demonstrated a strong protective effect of RhD positivity against the risk of traffic accidents posed by latent toxoplasmosis. Our results show that RhD-negative subjects with high titers of anti-Toxoplasma antibodies had a probability of a traffic accident of about 16.7%, i.e. a more than six times higher rate than Toxoplasma-free or RhD-positive subjects.
Our results showed that a common infection by Toxoplasma gondii could have strong impact on the probability of traffic accident in RhD negative subjects. The observed effects could provide not only a clue to the long-standing evolutionary enigma of the origin of RhD polymorphism in humans (the effect of balancing selection), but might also be the missing piece in the puzzle of the physiological function of the RhD molecule.
Toxoplasma gondii, the coccidian parasite, is known to induce changes in the behaviour of its intermediate hosts. The high prevalence of this parasite in the human population (20-80%) offers the opportunity of studying the influence of the parasite on human behaviour by screening of a normal population. A total of 224 men and 170 women were tested for toxoplasmosis and their personality profiles were measured by Cattell's questionnaire. Highly significant differences between Toxoplasma-infected and uninfected subjects were observed (P < 0.01). For men the factors G (low superego strength), L (protension), O (guilt proneness), and Q2 (group dependency) were positively influenced in infected subjects. For women the prevailing factors were A (affectothymia, P < 0.01), L (alaxia), O (untroubled adequacy) and Q2 (self-sufficiency). To reveal whether toxoplasmosis induces personality factor-shifts or whether certain combinations of personality factors influence the probability of acquiring Toxoplasma infection, we examined the personality profiles of 164 male patients diagnosed with acute toxoplasmosis during the past 13 years. The existence of a positive correlation between the duration of latent toxoplasmosis and the intensity of superego strength decrease (P < 0.02) suggested that the decrease of superego strength (the willingness to accept group moral standards) was induced by T. gondii infection.
Latent toxoplasmosis is the most widespread parasite infection in developed and developing countries. The prevalence of Toxoplasma gondii infection varies mostly between 20 to 80% in different territories. This form of toxoplasmosis is generally considered to be asymptomatic. Recently published results, however, suggest that the personality profiles of infected subjects differ from those of uninfected controls. These results, however, were obtained on non-standard populations (biologists or former acute toxoplasmosis patients). Here we studied the personality profiles of 191 young women tested for anti-Toxoplasma immunity during gravidity. The results showed that the differences between Toxoplasma-negative and Toxoplasma-positive subjects exits also in this sample of healthy women. The subjects with latent toxoplasmosis had higher intelligence, lower guilt proneness, and possibly also higher ergic tension. The difference in several other factors (desurgency/surgency, alaxia/protension, naiveté/shrewdness, and self-sentiment integration) concerned changes in the variances, rather than the mean values of the factors.
The parasite Toxoplasma gondii infects 30-60% of humans worldwide. Latent toxoplasmosis, i.e., the life-long presence of Toxoplasma cysts in neural and muscular tissues, leads to prolongation of reaction times in infected subjects. It is not know, however, whether the changes observed in laboratory influence the performance of subjects in real-life situations.
The seroprevalence of latent toxoplasmosis in subjects involved in traffic accidents (N=146) and in the general population living in the same area (N=446) was compared by a Mantel-Haenszel test for age-stratified data. Correlation between relative risk of traffic accident and a level of anti-Toxoplasma antibody titre was evaluated with the Cochran-Armitage test for trend.
A higher seroprevalence was found in the traffic accident set than in the general population (Chi2MH=21.45, p<0.0001). The value of the odds ratio (OR) suggests that subjects with latent toxoplasmosis had a 2.65 (C.I.95= 1.764.01) times higher risk of an accident than the toxoplasmosis-negative subjects. The OR significantly increased with level of anti-Toxoplasma antibody titre (p<0.0001), being low (OR=1.86, C.I.95=1.14-3.03) for the 99 subjects with low antibody titres (8 and 16), higher (OR=4.78, C.I.95=2.39-9.59) for the 37 subjects with moderate titres (32 and 64), and very high (OR=16.03, C.I.95=1.89-135.66) for the 6 subjects with titres higher than 64.
The subjects with latent toxoplasmosis have significantly increased risk of traffic accidents than the noninfected subjects. Relative risk of traffic accidents decreases with the duration of infection. These results suggest that 'asymptomatic' acquired toxoplasmosis might in fact represent a serious and highly underestimated public health as well as economic problem.
Recent epidemiologic studies indicate that infectious agents may contribute to some cases of schizophrenia. In animals, infections with Toxoplasma gondii can alter behavior and neurotransmitter function. In humans, acute infection with T. gondii can produce psychotic symptoms similar to those displayed by persons with schizophrenia. Since 1953, a total of 19 studies of T. gondii antibodies in persons with schizophrenia and other severe psychiatric disorders and in controls have been reported; 18 reported a higher percentage of antibodies in the affected persons; in 11 studies the difference was statistically significant. Two other studies found that exposure to cats in childhood was a risk factor for the development of schizophrenia. Some medications used to treat schizophrenia inhibit the replication of T. gondii in cell culture. Establishing the role of T. gondii in the etiopathogenesis of schizophrenia might lead to new medications for its prevention and treatment.
The latent toxoplasmosis is usually considered to be asymptomatic, however, this paradigm has never been rigorously tested. Here we searched for symptoms of deterioration of physical health (decrease of weight) in infected people by analysis of clinical records of 758 women tested for toxoplasmosis in the 16th week of gravidity. Toxoplasma-positive women have a lower body weight in the 16th week of gravidity (p = 0.02) than Toxoplasma-negative women. Moreover, a negative correlation between weight and the duration of toxoplasmosis was found in a subset of 174 Toxoplasma-positive women (p = 0.04), suggesting that slow and cumulative effects of latent toxoplasmosis, rather than a transient effect of acute toxoplasmosis, are responsible for the decreased weight of infected subjects. Longer duration of gravidity estimated from the date of last menstruation in the set of Toxoplasma-positive women in the 16th week of gravidity estimated with ultrasonography (p = 0.04) suggests a possibility of retarded foetal growth in Toxoplasma-positive women. The prevalence of latent toxoplasmosis is extremely high. Therefore, even its mild symptoms such as the decreased body weight in Toxoplasma-positive pregnant women might in fact indicate an unrecognized serious public health problem.
In Turkey, traffic accidents are the major causes of mortality and morbidity. According to the statistics made by Turkish Security Headquarters in the year 2000, 7500 people are killed in the traffic accidents every year. Drivers are mostly blamed for the traffic accidents. Tired, weary, sleepy and absentminded driving are common reasons for traffic accidents due to many reasons. Among these reasons mental and reflex conditions of drivers are significant. Toxoplasmosis is one of the most common zoonoses throughout the world. In immunocomponent adults, toxoplasmosis has no clinical signs or symptoms and infection in such people can only be detected by serological examinations. This kind of latent or dormant toxoplasmosis can be located in neural or muscular tissues and cause prolonged reaction times of the muscles. Extended reaction times also lead to deceleration of the reflexes which could be a major cause of the traffic accidents. By the light of this situation, the incidence of Toxoplasma gondii is investigated among the population who were involved in a traffic accident while driving. A total of 185 people (100 men and 85 women), aged between 21 and 40 years, living in Izmir and Manisa cities, were enrolled in the study group (SG) during a period of 6 months time. Their informed consents were taken initially and the laboratory tests of all these individuals related to blood alcohol levels after the accidents were found negative. The control group (CG) were also consisted 185 people (95 men and 90 women), residents of the same region, in same age group. The people in CG had no clinical signs or symptoms concerning toxoplasmosis. All collected sera were examined using a commercial IgG and IgM ELISA kit. According to the results of serological tests of the SG, 45 (24.32%) sera were IgG positive, six (3.24%) were IgM positive and 10 (5.40%) were both IgG and IgM positive. On the other hand in CG, 12 (6.48%) people found IgG positive, one (0.54%) found IgM positive and three (1.62%) found both IgG and IgM positive. This data was considered as statistically significant by Yates corrected chi2-test. (p < 0.05). In conclusion, there is an increased risk for traffic accidents for drivers owing to these high seroprevalence of latent toxoplasmosis. Prospective studies are still necessary on this subject but latent toxoplasmosis of drivers should be taken into account while developing strategies to prevent traffic accidents in Turkey.
Road traffic accidents are considered significant problems on global level and associated with economic and social impacts. The relationship between latent toxoplasmosis and the involvement of road traffic accidents has received much attention by researchers and scientists all over the world. The objectives of the present study were to assess the prevalence of T. gondii IgG among the drivers involved in road traffic accidents and to examine the possible association between latent toxoplasmosis and the involvement of road traffic accidents. The study participants involved 13 persons who were arrested for being involved in road traffic accidents. A cross-sectional design was employed. A total of 200 participants from normal population were involved as a control group to compare T. gondii IgG of drivers. A questionnaire was constructed to collect data from all participants. A blood sample was withdrawn from each participant to assay T. gondii IgG and IgM. Study findings showed that prevalence of T. gondii IgG was 15.4% in study group and 12% in control group. The association of seroprevalance of T. gondii IgG between study and control groups was lacked (p = 0.828). On the other hand, there was a significant association between level of 0 IgG in both study and control groups (p = 0.009). All participants in study group were negative for T. gondii IgG. As a conclusion, The results of this study did not show a significant relationship between the seroprevalence of T. gondii IgG and the involvement of road traffic accidents whereas the level of T. gondii IgG was varied significantly between study and control group (p = 0.009). The researchers recommend to conduct more studies regarding latent toxoplasmosis with larger size and to involve both groups of drivers and victims. We also recommend to monitor all involved persons for positivity of RhD.
Toxoplasmosis is a widespread parasitic disease caused by the intracellular parasite Toxoplasma gondii with a wide spectrum of clinical outcomes. The biological diagnosis of toxoplasmosis is often difficult and of paramount importance because clinical features are not sufficient to discriminate between toxoplasmosis and other illnesses. Serological tests are the most widely used biological tools for the diagnosis of toxoplasmosis worldwide. This review focuses on the crucial role of serology in providing answers to the most important questions related to the epidemiology and diagnosis of toxoplasmosis in human pathology. Notwithstanding their undeniable importance, serological tools need to be continuously improved and the interpretation of the ensuing results remains complex in many circumstances.
Background: This study investigated the possible role of toxoplasmosis in increasing the risk
of traffic accidents.
Materials and Methods:This unmatched casecontrol study was done on a total of 103 people
(102 men and one woman) involved in a traffic accident as drivers for a time period of one year during 2011–2012.The controls were consisted of 200
people (88 men and 112 women), residents of the
same region and in same age group. Blood samples
were driven and all serum samples were separated
and stored at -20 ºC until the testing. All collected
sera were examined using ELISA technique.
Results:For IgG seropositivity, a 2.02-fold increase (χ
2
= 7.84, P = 0.004, 95%CI: 1.23 – 3.33)
in risk for traffic accident was estimated. Furthermore, IgM seropositivity could not significantly
increase the risk of traffic accident, with an OR of
0.73 (χ
2
= 0.209, P = 0.461, 95%CI: 0.19 – 2.81).
However, stratification analysis showed that only
the individuals with age range ≤ 30-year were significantly more common in traffic accident than in
controls (OR: 2.15, χ
2
= 6.91, P = 0.007, 95%CI:
1.20 – 3.85). There was no statistically significant
difference between the IgM and IgG seropositivity in case and control groups (X
2
= 3.65, P = 0.09,
95%CI: 0.99 – 2.67).
Conclusion: There is an increased risk for traffic accidents for drivers owing to these high seroprevalence of latent toxoplasmosis. Latent toxoplasmosis in drivers should be taken into account
while developing preventive strategies for traffic
accidents in Iran
Toxoplasma gondii, an Apicomplexan, is a pathogic protozoan that can infect the central nervous system. Infection during pregnancy can result in a congenial infection with severe neurological sequelae. In immunocompromisedindividuals reactivation of latent neurological foci can result in encephalitis. Immunocompetent individuals infected with T. gondii are typically asymptomatic and maintain this infection for life. However, recent studies suggest that these asymptomatic infections may have effects on behavior and other physiological processes. Toxoplasma gondii infects approximately one-third of the world population, making it one of the most successful parasitic organisms. Cats and other felidae serve as the definite host producing oocysts, an environmentally resistant life cycle stage found in cat feces, which can transmit the infection when ingested orally. A wide variety of warm-blooded animals, including humans, can serve as the intermediate host in which tissue cysts (containing bradyzoites) develop. Transmission also occurs due to ingestion of the tissue cysts. There are three predominant clonal lineages, termed Types I, II and III, and an association with higher pathogenicity with the Type I strains in humans has emerged. This chapter presents a review of the biology of this infection including the life cycle, transmission, epidemiology, parasite strains, and the host immune response. The major clinical outcomes of congenital infection, chorioretinitis and encephalitis, and the possible association of infection of toxoplasmosis with neuropsychiatric disorders such as schizophrenia, are reviewed.
Studies of neurotransmitter metabolites in cerebrospinal fluid (CSF) were initially focused on depressive illness. Although several studies have demonstrated low concentrations of the serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA), and the dopamine metabolite, homovanillic acid (HVA), in depressed patients, these early studies may have been biased by concomitant administration of antidepressant drugs (which tend to lower CSF 5-HIAA), amount of CSF drawn (there is a concentration gradient for both metabolites), and selection of control subjects. Once these methodological details are controlled for, the differences between depressed patients and controls are unimpressive.However, there is a remarkably consistent association between low concentrations of CSF 5-HIAA and suicidal behavior, as evidenced by over 20 studies. The association is not confined to depressive illness but has also been found in schizophrenia, personality disorder, and certain impulse control disorders (but, interstingly, not in bipolar disorder). A low concentration of CSF 5-HIAA in a suicide attempter is associated with a substantial increase in short-term suicide risk. CSF studies in violent criminals, and in nonhuman primates, suggest that aggression dyscontrol may partly explain the association between suicide and serotonin, which is of considerable theoretical interest. CSF 5-HIAA determinations may also be helpful in the clinical assessment of suicide risk.
Reflexes of drivers who have toxoplasmosis have been shown to deteriorate from the actions of the parasitic cysts. The cysts can change the level of the neurotransmitters such as dopamine in the brain and by doing so extend the muscle response time and change personality profiles. In this study, we aimed to determine the frequency of the latent toxoplasmosis (LT) in the driver population who were either injured or died in traffic accidents reported in Istanbul and its suburbs. We compared the results with a control group and discussed the relationship between the LT and the traffic accidents. We included 218 (89.7%) non-fatal, 25 (10.3%) fatal cases in our study as study groups. A total 243 subjects, 234 (96%) male, 9 (4%) female (who were alcohol negative) compared with 191 (95.5%) male and 9 (4.5%) female subjects (control group) who had a traffic accident before but no history of toxoplasmosis were studied. Serologic tests, enzyme immunoassay (EIA) for IgG and IgM, and microimmunoflorescence (MIF) for IgG were used as the reference test, the Sabin-Feldman Dye test (SFDT) was used. According to serologic test results, LT seroprevalence in the study groups was 130 (53.5%) and in the control group 56 (28%) (p<0.0001). A LT was present in 126 out of 234 (53.8%) males in the study groups, and 54 out of 191 (28.3%) males in the control group (p<0.0001). In the 31-44 year age group, there was a significant difference with regard to toxoplasmosis between the study subjects and control groups (p<0.0001). This difference was statistically very significant in (recent and former) cases with middle-aged men (31-44 years old). The results of this retrospective study suggest that LT in drivers, especially those who are between 31 and 44 years might increase the risk for getting involved in a car accident. In a prospective study, Toxoplasma positive and negative subjects can be monitored before they are involved in a traffic accident to clarify the cause and result relationship.
Motor performance in Toxoplasma-infected mice and uninfected controls was assessed by placing them, individually, on a rotating cylinder. The infected mice fell significantly more often than the controls. The difference was independent of differences in fearfulness (as measured by defaecation counts) and general bodily health (as measured by body weight). Although Toxoplasmatissue cysts were present in the brains of all of the infected animals, there was no significant correlation between cyst counts (either in the cerebellum or brain minus cerebellum) and number of falls within the infected group. It is suggested that the absence of significant correlations may have been due to the restricted range and variability in tissue cyst counts.
Many parasites induce characteristic changes in behavior of their hosts. In humans latent toxoplasmosis is associated with changes in personality profiles. It has been already shown that a decrease in superego strength is correlated with duration of toxoplasmosis in men. Here we studied changes in personality profiles with Cattell's 16 PF questionnaire in Toxoplasma-infected women. The changes were measured as differences in personality factors between Toxoplasma-infected subjects and uninfected controls of the same age. The low-rate changes were studied in 230 women diagnosed with acute toxoplasmosis during past 14 years. The results showed the correlation between duration of toxoplasmosis and level of factors G (high superego strength) and Q3 (high strength of self sentiment). The high-rate changes were estimated by measuring the correlation between level of Toxoplasma-antibody titers (which rapidly decline after the end of acute phase of toxoplasmosis) and personality factors in an experimental set of 55 young mothers with latent toxoplasmosis. Again, certain factors, namely A (affectothymia), F (surgence), G (high superego strength), H (parmia), and L (protension), correlated with the length of the infection. We suggest that the parasite induced the changes in the personality profiles of the women because of our observation of an increasingly different personality profile over time between women with latent infection and controls. The same evidence questions the view that women with a particular personality profile are more prone to acquisition of T. gondii infection.