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McGrath JJ, Lim CCW, Saha S. Cat Ownership and Schizophrenia-Related Disorders and Psychotic-Like Experiences: A Systematic Review and Meta-Analysis. Schizophr Bull 2024; 50:489-495. [PMID: 38041862 PMCID: PMC11059813 DOI: 10.1093/schbul/sbad168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2023]
Abstract
BACKGROUND It has been proposed that cat ownership may be a risk-modifying factor for schizophrenia-related disorders and psychotic-like experiences (PLE). This study aimed to systematically review and meta-analyze publications that reported the relationship between cat ownership and schizophrenia-related outcomes. METHODOLOGY We searched Medline, Embase, CINAHL, Web of Science, and gray literature for publications between January 1, 1980, and May 30, 2023, regardless of geographical location and language. Backward citation search methods were used to locate additional articles. We included studies that reported original data on cat ownership and schizophrenia-related outcomes. We meta-analyzed estimates based on broad definitions (cat ownership, cat bites, and cat contact) with estimates with or without covariate adjustments. We pooled comparable estimates using random-effects models and assessed the risk of bias, heterogeneity, and study quality. RESULTS We identified 1915 studies, of which 106 were chosen for full-text review, ultimately resulting in the inclusion of 17 studies. We found an association between broadly defined cat ownership and increased odds of developing schizophrenia-related disorders. For the studies reporting unadjusted odds ratios (OR; n = 10), the pooled OR was 2.14 (95% CI: 1.29-3.55). Exclusion of one outlier study resulted in a pooled OR (n = 9) of 1.56 (95% CI: 1.27-1.92). For the studies reporting adjusted estimates (n = 5), the pooled OR was 2.44 (95% CI: 1.59-3.73). After excluding one study with suboptimal exposure/design features, the pooled adjusted OR (n = 4) was 2.40 (95% CI: 1.50-3.86). We were unable to aggregate the estimates for the PLE outcomes because of the broad range of measures. CONCLUSIONS Our findings provide support for the hypothesis that cat exposure is associated with an increased risk of broadly defined schizophrenia-related disorders; however, the findings related to PLE as an outcome are mixed. There is a need for more high-quality studies in this field. PROSPERO REGISTRATION PROSPERO 2023 CRD42023426974. Available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023426974.
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Affiliation(s)
- John J McGrath
- Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia
- Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia
- National Centre for Register-based Research, Aarhus BSS, Aarhus University, Aarhus, Denmark
| | - Carmen C W Lim
- Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia
| | - Sukanta Saha
- Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia
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2
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Sheikhshoaee S, Taheri F, Esmaeilpour K, Firouzeh N, Fard SRN. Aggravation of cognitive impairments in the valproic acid-induced animal model of autism in BALB/c mice infected with Toxoplasma gondii. Int J Dev Neurosci 2024; 84:64-74. [PMID: 37960995 DOI: 10.1002/jdn.10308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/04/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
PURPOSE Toxoplasmosis is a disease caused by infection with a type of coccidial protozoan parasite called Toxoplasma gondii. The relationship between toxoplasmosis and cognitive disorders in neurodegenerative diseases has been proven. There is also evidence that children born to Toxoplasma-infected mothers are more likely to develop autism. METHODS In the present study, Toxoplasma-infected pregnant BALB/c mice were given valproic acid to induce autism in their male offspring, and their social behaviors, learning, and memory were examined. Chronic toxoplasmosis was established in BALB/c mice by intraperitoneal injection of cyst form of T. gondii. To induce autism, 600 mg/kg of valproic acid was injected intraperitoneally into mice on the 12.5th day of pregnancy. The behavioral experiments, such as social interaction, novel object recognition, and passive avoidance tasks, were performed on male offspring at 50 days. RESULTS Toxoplasma and valproic acid during the embryonic period caused social communication deficits and disrupted recognition memory and avoidance memory in offspring. Our findings showed that administering valproic acid to Toxoplasma-infected mothers exacerbates cognitive disorders in their offspring.
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Affiliation(s)
- Saeed Sheikhshoaee
- Department of Pathobiology, School of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Farahnaz Taheri
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Khadijeh Esmaeilpour
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
- Physics and Astronomy department, University of Waterloo, Waterloo, Ontario, Canada
| | - Nima Firouzeh
- Vector-Borne Diseases Research Center, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Saeid Reza Nourollahi Fard
- Department of Pathobiology, School of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
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3
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Flegr J, Ullmann J, Toman J. Parasitic manipulation or side effects? The effects of past Toxoplasma gondii and Borrelia spp. infections on human personality and cognitive performance are not mediated by impaired health. Folia Parasitol (Praha) 2023; 70:2023.020. [PMID: 38084079 DOI: 10.14411/fp.2023.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 10/31/2023] [Indexed: 12/18/2023]
Abstract
Bacteria Borrelia burgdorferi s. l. and even more the protist Toxoplasma gondii Nicolle et Manceaux, 1908, are known to affect the behaviour and mental health of their animal and human hosts. Both pathogens infect a significant fraction of human population, both are neurotropic and survive in the host's body for a long time. While latent infections were thought to be clinically asymptomatic, recent studies suggest otherwise, revealing adverse effects on human health. It was hypothesised that the specific behavioural effects of these pathogens may be side effects of general health impairments in infected individuals. This hypothesis was tested using about one hour-long survey consisting of questionnaires and performance tests on a cohort of 7,762 members of the internet population. Results showed that individuals infected with T. gondii reported worse physical and mental health, and those infected with Borrelia spp. reported worse physical health than uninfected controls. Furthermore, infected and noninfected individuals differed in several personality traits, including conscientiousness, pathogen disgust, injury disgust, Machiavellianism, narcissism, tribalism, anti-authoritarianism, intelligence, reaction time, and precision. While the majority of behavioural effects associated with Borrelia infection were similar to those associated with Toxoplasma infection, some differences were observed, such as performance in the Stroop test. Path analyses and nonparametric partial Kendall correlation tests showed that these effects were not mediated by impaired health in infected individuals, contradicting the side effects hypothesis.
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Weiner A, Turjeman S, Koren O. Gut microbes and host behavior: The forgotten members of the gut-microbiome. Neuropharmacology 2023; 227:109453. [PMID: 36738776 DOI: 10.1016/j.neuropharm.2023.109453] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/15/2023] [Accepted: 01/28/2023] [Indexed: 02/05/2023]
Abstract
The gut microbiota refers to an entire population of microorganisms that colonize the gut. This community includes viruses, prokaryotes (bacteria and archaea), and eukaryotes (fungi and parasites). Multiple studies in the last decades described the significant involvement of gut bacteria in gut-brain axis communication; however, the involvement of other members of the gut microbiota has been neglected. Recent studies found that these 'forgotten' members of the gut microbiota may also have a role in gut-brain communication, although it is still unclear whether they have a direct effect on the brain or if their effects are mediated by gut bacteria. Here, we provide concrete suggestions for future research to tease out mechanisms of the microbiota-gut-brain axis. This article is part of the Special Issue on "Microbiome & the Brain: Mechanisms & Maladies".
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Affiliation(s)
- Ariel Weiner
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Sondra Turjeman
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Omry Koren
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel.
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Flegr J, Flegr P, Příplatová L. The effects of 105 biological, socioeconomic, behavioral, and environmental factors on the risk of SARS-CoV-2 infection and a severe course of COVID-19: a prospective, explorative cohort study. Biol Methods Protoc 2022; 7:bpac030. [PMID: 36530561 PMCID: PMC9750789 DOI: 10.1093/biomethods/bpac030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/23/2022] [Accepted: 10/26/2022] [Indexed: 12/16/2022] Open
Abstract
The confirmed number of SARS-CoV-2 infections up to 18 October 2022 is 626 million worldwide, but information about factors affecting the probability of infection or a severe course of COVID-19 remains insufficient and often speculative. Only a small number of factors have been rigorously examined, mostly by retrospective or cross-sectional studies. We ran a preregistered study on 5164 Internet users who shared information with us about their exposure to 105 risk factors and reported being COVID-19 negative before the beginning of the fourth wave of COVID-19 in the Czech Republic. After the fourth wave, in which 709 (13.7%) of participants were infected, we used a partial Kendall test controlled for sex, age, and urbanization to compare the risk of infection and a severe course of the disease in subjects who initially did and did not report exposure to particular risk factors. After the correction for multiple tests, we identified 13 factors - including male sex, lower age, blood group B, and larger household size - that increased the risk of infection and 16 factors - including mask-wearing, borreliosis in the past, use of vitamin D supplements, or rooibos drinking - that decreased it. We also identified 23 factors that increased the risk of a severe course of COVID-19 and 12 factors that decreased the risk. This preregistered longitudinal study is of explorative nature. Therefore, although the observed effects were strong and remained highly significant even after correction for multiple tests, it will be necessary to confirm their existence in future independent studies.
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Affiliation(s)
- Jaroslav Flegr
- Division of Biology, Faculty of Science, Charles University, Prague 128 00, Czech Republic
| | - Pavel Flegr
- Faculty of Electrical Engineering, Czech Technical University in Prague, Prague 166 27, Czech Republic
| | - Lenka Příplatová
- Division of Biology, Faculty of Science, Charles University, Prague 128 00, Czech Republic
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6
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Correa Leite PE, de Araujo Portes J, Pereira MR, Russo FB, Martins-Duarte ES, Almeida Dos Santos N, Attias M, Barrantes FJ, Baleeiro Beltrão-Braga PC, de Souza W. Morphological and biochemical repercussions of Toxoplasma gondii infection in a 3D human brain neurospheres model. Brain Behav Immun Health 2021; 11:100190. [PMID: 34589727 PMCID: PMC8474451 DOI: 10.1016/j.bbih.2020.100190] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 12/06/2020] [Indexed: 12/19/2022] Open
Abstract
Background Toxoplasmosis is caused by the parasite Toxoplasma gondii that can infect the central nervous system (CNS), promoting neuroinflammation, neuronal loss, neurotransmitter imbalance and behavioral alterations. T. gondii infection is also related to neuropsychiatric disorders such as schizophrenia. The pathogenicity and inflammatory response in rodents are different to the case of humans, compromising the correlation between the behavioral alterations and physiological modifications observed in the disease. In the present work we used BrainSpheres, a 3D CNS model derived from human pluripotent stem cells (iPSC), to investigate the morphological and biochemical repercussions of T. gondii infection in human neural cells. Methods We evaluated T. gondii ME49 strain proliferation and cyst formation in both 2D cultured human neural cells and BrainSpheres. Aspects of cell morphology, ultrastructure, viability, gene expression of neural phenotype markers, as well as secretion of inflammatory mediators were evaluated for 2 and 4 weeks post infection in BrainSpheres. Results T. gondii can infect BrainSpheres, proliferating and inducing cysts formation, neural cell death, alteration in neural gene expression and triggering the release of several inflammatory mediators. Conclusions BrainSpheres reproduce many aspects of T. gondii infection in human CNS, constituting a useful model to study the neurotoxicity and neuroinflammation mediated by the parasite. In addition, these data could be important for future studies aiming at better understanding possible correlations between psychiatric disorders and human CNS infection with T. gondii. T. gondii infects, proliferates and induce cysts formation in neurospheres. T. gondii infection induces neural cell death in neurospheres. T. gondii infection promotes alteration in neural gene expression in neurospheres. T. gondii infection promotes release of inflammatory mediators in neurospheres.
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Affiliation(s)
- Paulo Emilio Correa Leite
- Institute of Biophysics Carlos Chagas Filho and National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, RJ, Brazil.,Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque de Caxias, RJ, Brazil
| | - Juliana de Araujo Portes
- Institute of Biophysics Carlos Chagas Filho and National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, RJ, Brazil
| | | | - Fabiele Baldino Russo
- Laboratory of Disease Modeling, Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, SP, Brazil
| | - Erica S Martins-Duarte
- Institute of Biophysics Carlos Chagas Filho and National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, RJ, Brazil.,Department of Parasitology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Nathalia Almeida Dos Santos
- Laboratory of Disease Modeling, Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, SP, Brazil.,Centre for Stem Cells and Regenerative Medicine, King's College London, Guy's Hospital, London, UK
| | - Marcia Attias
- Institute of Biophysics Carlos Chagas Filho and National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, RJ, Brazil
| | - Francisco J Barrantes
- Laboratory of Molecular Neurobiology, Institute for Biomedical Research (BIOMED), UCA-CONICET, Buenos Aires, Argentina
| | - Patricia Cristina Baleeiro Beltrão-Braga
- Laboratory of Disease Modeling, Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, SP, Brazil.,Scientific Platform Pasteur-USP, São Paulo, SP, Brazil
| | - Wanderley de Souza
- Institute of Biophysics Carlos Chagas Filho and National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, RJ, Brazil
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7
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Flegr J. Toxoplasmosis is a risk factor for acquiring SARS-CoV-2 infection and a severe course of COVID-19 in the Czech and Slovak population: a preregistered exploratory internet cross-sectional study. Parasit Vectors 2021; 14:508. [PMID: 34583758 PMCID: PMC8477627 DOI: 10.1186/s13071-021-05021-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 09/14/2021] [Indexed: 11/25/2022] Open
Abstract
Background Latent toxoplasmosis, i.e. a lifelong infection with the protozoan parasite Toxoplasma gondii, affects about a third of the human population worldwide. In the past 10 years, numerous studies have shown that infected individuals have a significantly higher incidence of mental and physical health problems and are more prone to exhibiting the adverse effects of various diseases. Methods A cross-sectional internet study was performed on a population of 4499 (786 Toxoplasma-infected) participants and looked for factors which positively or negatively affect the risk of SARS-CoV-2 infection and likelihood of a severe course of COVID-19. Results Logistic regression and partial Kendall correlation controlling for sex, age, and size of the place of residence showed that latent toxoplasmosis had the strongest effect on the risk of infection (OR = 1.50) before sport (OR = 1.30) and borreliosis (1.27). It also had the strongest effect on the risk of severe course of infection (Tau = 0.146), before autoimmunity, immunodeficiency, male sex, keeping a cat, being overweight, borreliosis, higher age, or chronic obstructive pulmonary disease. Toxoplasmosis augmented the adverse effects of other risk factors but was not the proximal cause of the effect of cat-keeping on higher likelihood of COVID infection and higher severity of the course of infection because the effect of cat-keeping was also observed (and in particular) in a subset of Toxoplasma-infected respondents (Tau = 0.153). Effects of keeping a cat were detected only in respondents from multi-member families, suggesting that a cat could be a vector for the transmission of SARS-CoV-2 within a family. Conclusions Toxoplasmosis is currently not considered a risk factor for COVID-19, and Toxoplasma-infected individuals are neither informed about their higher risk nor prioritised in vaccination programs. Because toxoplasmosis affects a large segment of the human population, its impact on COVID-19-associated effects on public health could be considerable. Graphical abstract ![]()
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Affiliation(s)
- Jaroslav Flegr
- Laboratory of Evolutionary Biology, Division of Biology, Department of Philosophy and History of Sciences, Faculty of Science, Charles University, Viničná 7, Prague 2, 128 00, Czech Republic. .,National Institute of Mental Health, Klecany, 250 67, Czech Republic.
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8
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Kankova S, Bicikova M, Macova L, Hlavacova J, Sykorova K, Jandova D, Flegr J. Latent toxoplasmosis and vitamin D concentration in humans: three observational studies. Folia Parasitol (Praha) 2021; 68. [PMID: 33762474 DOI: 10.14411/fp.2021.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 11/11/2020] [Indexed: 12/21/2022]
Abstract
Numerous recent studies show that vitamin D deficiency potentiates various chronic physical and psychiatric disorders and diseases. It has been shown that a similar range of disorders is also associated with latent infection with Toxoplasma gondii (Nicolle et Manceaux, 1908). For instance, among cancer, diabetes and schizophrenia patients, we find a higher prevalence of both toxoplasmosis and vitamin D deficiency. Theoretically, therefore, vitamin D deficiency could be the missing link between toxoplasmosis and these disorders. We tested this hypothesis by searching for decreased vitamin D levels in the serum of subjects infected with T. gondii (furthermore called Toxoplasma-infected subjects) in two cross-sectional and one case-control study. Results of the first cross-sectional study (N = 72) suggest that Toxoplasma-infected neurasthenic patients have non-significantly lower levels of calcidiol than Toxoplasma-free patients (study A: P = 0.26 in women, P = 0.68 in men). However, two other studies (study B: N = 400; study C: N = 191) showed a non-significantly higher concentration of vitamin D in Toxoplasma-infected subjects than in Toxoplasma-free subjects both in men (study B: P = 0.70, study C: P = 0.55) and in women (study B: P = 0.64, study C: P = 0.12). Taken together, our preliminary results thus do not support the hypothesis that toxoplasmosis could be associated with vitamin D decrease.
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Affiliation(s)
- Sarka Kankova
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Prague, Czech Republic.,Applied Neurosciences and Brain Imaging, National Institute of Mental Health, Klecany, Czech Republic
| | | | | | - Jana Hlavacova
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Prague, Czech Republic
| | - Katerina Sykorova
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Prague, Czech Republic
| | | | - Jaroslav Flegr
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Prague, Czech Republic.,Applied Neurosciences and Brain Imaging, National Institute of Mental Health, Klecany, Czech Republic
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Flegr J, Toman J, Hůla M, Kaňková Š. The role of balancing selection in maintaining human RhD blood group polymorphism: A preregistered cross-sectional study. J Evol Biol 2020; 34:426-438. [PMID: 33244840 DOI: 10.1111/jeb.13745] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 11/13/2020] [Accepted: 11/18/2020] [Indexed: 01/05/2023]
Abstract
Maintenance of genetic polymorphism remains one of the big questions of evolutionary biology, which for a long time tended to be explained by balancing selection. This explanation was later criticized, but now is again accepted as an important mechanism in evolution. Human blood group systems seem affected by balancing selection especially strongly. In this preregistered study, we focused on stable coexistence of RhD-positive and RhD-negative subjects in a population. This is an evolutionary conundrum, because carriers of the less frequent negative allele suffer from lower fecundity due to haemolytic disease of the newborn affecting RhD-positive infants born to RhD-negative women. One explanation of persisting stability of RhD polymorphism points to heterozygote advantage. Over the past decade, numerous studies demonstrated that RhD-positive subjects score better than RhD-negative homozygotes in psychomotor tests and physical health-related variables. Still, evidence of better health and performance of heterozygotes is scarce and merely indirect. We compared the physical and mental health of 2,539 subjects whose RhD genotype was estimated based on their and their parents' RhD phenotype. We confirmed that RhD-negative homozygotes fare worse in terms of physical and mental health than subjects with RhD-positive phenotype and that RhD-positive heterozygotes enjoy better health than both homozygotes. For the first time, we demonstrated that RhD-positive homozygotes might suffer from worse health than RhD-negative homozygotes. Our results strongly support the hypothesis that RhD polymorphism is maintained by heterozygote advantage and that balancing selection may have played an important role in human evolution in this context and in general.
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Affiliation(s)
- Jaroslav Flegr
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jan Toman
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Prague, Czech Republic
| | - Martin Hůla
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Prague, Czech Republic
| | - Šárka Kaňková
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Prague, Czech Republic.,Department of Applied Neuroscience and Neuroimaging, National Institute of Mental Health, Klecany, Czech Republic
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Carrillo GL, Ballard VA, Glausen T, Boone Z, Teamer J, Hinkson CL, Wohlfert EA, Blader IJ, Fox MA. Toxoplasma infection induces microglia-neuron contact and the loss of perisomatic inhibitory synapses. Glia 2020; 68:1968-1986. [PMID: 32157745 PMCID: PMC7423646 DOI: 10.1002/glia.23816] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/25/2020] [Accepted: 02/26/2020] [Indexed: 12/17/2022]
Abstract
Infection and inflammation within the brain induces changes in neuronal connectivity and function. The intracellular protozoan parasite, Toxoplasma gondii, is one pathogen that infects the brain and can cause encephalitis and seizures. Persistent infection by this parasite is also associated with behavioral alterations and an increased risk for developing psychiatric illness, including schizophrenia. Current evidence from studies in humans and mouse models suggest that both seizures and schizophrenia result from a loss or dysfunction of inhibitory synapses. In line with this, we recently reported that persistent T. gondii infection alters the distribution of glutamic acid decarboxylase 67 (GAD67), an enzyme that catalyzes GABA synthesis in inhibitory synapses. These changes could reflect a redistribution of presynaptic machinery in inhibitory neurons or a loss of inhibitory nerve terminals. To directly assess the latter possibility, we employed serial block face scanning electron microscopy (SBFSEM) and quantified inhibitory perisomatic synapses in neocortex and hippocampus following parasitic infection. Not only did persistent infection lead to a significant loss of perisomatic synapses, it induced the ensheathment of neuronal somata by myeloid-derived cells. Immunohistochemical, genetic, and ultrastructural analyses revealed that these myeloid-derived cells included activated microglia. Finally, ultrastructural analysis identified myeloid-derived cells enveloping perisomatic nerve terminals, suggesting they may actively displace or phagocytose synaptic elements. Thus, these results suggest that activated microglia contribute to perisomatic inhibitory synapse loss following parasitic infection and offer a novel mechanism as to how persistent T. gondii infection may contribute to both seizures and psychiatric illness.
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Affiliation(s)
- Gabriela L. Carrillo
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA 24061
| | - Valerie A. Ballard
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016
- Roanoke Valley Governor’s School, Roanoke VA 24015
| | - Taylor Glausen
- Department of Microbiology and Immunology, University at Buffalo, Buffalo NY 14260
| | - Zack Boone
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061
| | - Joseph Teamer
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016
- FBRI neuroSURF Program, Roanoke, VA 24016
| | - Cyrus L. Hinkson
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016
| | | | - Ira J. Blader
- Department of Microbiology and Immunology, University at Buffalo, Buffalo NY 14260
| | - Michael A. Fox
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061
- Department of Pediatrics, Virginia Tech Carilion School of Medicine, Roanoke, VA 24016
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Benitez ADN, Gomes JF, Dias MUSS, Navarro IT, Mitsuka-Breganó R, Bresciani KDS. Characterization of prenatal healthcare for implementation of congenital toxoplasmosis surveillance program: cross-sectional study. SAO PAULO MED J 2020; 138:368-376. [PMID: 33111919 PMCID: PMC9673859 DOI: 10.1590/1516-3180.2019.0512.r2.10062020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 06/10/2020] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Prenatal toxoplasmosis remains a neglected disease worldwide and few government programs focusing on its prevention are available. Success in these programs has been extensively reported in the literature, yet the strategies used for their implementation, as a model for such actions in different communities, have not been described. OBJECTIVE To describe the aspects of prenatal care strategies in 13 municipalities within the regional healthcare unit of Araçatuba, in the northwestern region of the state of São Paulo in 2017, focusing on congenital toxoplasmosis. DESIGN AND SETTING Descriptive study on prenatal healthcare within the Brazilian National Health System, in 13 participating municipalities. METHODS Data on serological tests, referral clinics, notifications, healthcare strategies, health education and drugs for infected children were requested through a questionnaire that was sent via e-mail to people responsible for healthcare services in these municipalities. RESULTS Major differences relating to diagnoses, reference outpatient clinics, notifications, health education and healthcare and drugs for infected children were reported among the prenatal strategies of these 13 municipal healthcare services. CONCLUSION The lack of standardized prenatal strategy in the study area may compromise the prevention of infection. However, our identification of each aspect of prenatal care corroborates the need to implement a healthcare surveillance program relating to congenital toxoplasmosis.
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Affiliation(s)
- Aline do Nascimento Benitez
- MSc, PhD. Veterinarian, Specialist in Zoonoses and Public Health and Postdoctoral Student, Postgraduate Program on Child and Adolescent Health, School of Medical Sciences, Universidade Estadual de Campinas (UNICAMP), Campinas (SP), Brazil.
| | - Jancarlo Ferreira Gomes
- MSc, PhD. Parasitologist, Specialist in Public Health and Professor, Postgraduate Program on Child and Adolescent Health, School of Medical Sciences, Universidade Estadual de Campinas (UNICAMP), Campinas (SP), Brazil.
| | - Milenne Ura Seixas Santos Dias
- RN. Nurse, Specialist in Occupational Health and Regional Director, Group XI (GVE), “Prof Alexandre Vranjac” Epidemiological Surveillance Center, State Health Department of São Paulo, Araçatuba (SP), Brazil.
| | - Italmar Teodorico Navarro
- MSc, PhD. Parasitologist, Specialist in Zoonoses and Public Health and Professor, Department of Preventive Veterinary Medicine, Universidade Estadual de Londrina (UEL), Londrina (PR), Brazil.
| | - Regina Mitsuka-Breganó
- MSc, PhD. Parasitologist, Specialist in Zoonoses and Public Health and Professor, Department of Preventive Veterinary Medicine, Universidade Estadual de Londrina (UEL), Londrina (PR), Brazil.
| | - Katia Denise Saraiva Bresciani
- MSc, PhD. Parasitologist, Specialist in Zoonoses and Public Health and Professor, Department of Animal Production and Health, School of Veterinary Medicine, Universidade Estadual Paulista (UNESP), Araçatuba (SP), Brazil.
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12
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Nayeri T, Sarvi S, Moosazadeh M, Hosseininejad Z, Sharif M, Amouei A, Daryani A. Relationship between toxoplasmosis and autism: A systematic review and meta-analysis. Microb Pathog 2020; 147:104434. [PMID: 32777351 DOI: 10.1016/j.micpath.2020.104434] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 07/29/2020] [Accepted: 08/02/2020] [Indexed: 12/14/2022]
Abstract
Toxoplasma gondii (T. gondii) is a foodborne parasite that is investigated in many psychiatric diseases, such as autism spectrum disorders (ASD). Therefore, a systematic literature review was conducted searching seven electronic databases on the prevalence of T. gondii antibodies among autism patients. The current study involved sensitivity analysis, meta-regression, subgroup analysis, publication bias test, and quality assessment of studies. On the basis of the findings, the odds ratio (OR) of latent Toxoplasma infection 1.93 (95% confidence intervals (CI): 1.01-3.66) was associated with ASD risk. However, there was no relationship between acute infection and ASD 0.39 (95% CI: 0.18-0.87). The obtained results of Begg's and Egger's tests showed no publication bias (P = 0.851 and P = 0.297, respectively). The sensitivity analysis confirmed robust and stable estimates with a significant level of heterogeneity (I2 = 78.1%, P < 0.000). Of the investigated patients' characteristics, only the gender variable was analyzed, indicating the combined ORs of 2.63 (95% CI: 0.29-23.63) in females and 2.62 (95% CI: 0.94-7.30) in male participants. This study showed that toxoplasmosis plays an important role as a risk factor for autism. However, further prospective investigations are highly recommended to illuminate the developmental pathways to this disorder and provide new strategies for the prevention and treatment of this disease.
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Affiliation(s)
- Tooran Nayeri
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran; Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran.
| | - Shahabeddin Sarvi
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
| | - Mahmood Moosazadeh
- Health Sciences Research Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran.
| | - Zahra Hosseininejad
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran; Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran.
| | - Mehdi Sharif
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
| | - Afsaneh Amouei
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
| | - Ahmad Daryani
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
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Nayeri T, Sarvi S, Moosazadeh M, Hosseininejad Z, Amouei A, Daryani A. Toxoplasma gondii infection and risk of attention-deficit hyperactivity disorder: a systematic review and meta-analysis. Pathog Glob Health 2020; 114:117-126. [PMID: 32186992 DOI: 10.1080/20477724.2020.1738153] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Toxoplasma gondii (T. gondii), as an opportunistic neurotropic parasite of the Apicomplexa family, was firstly described in 1908. As attention-deficit hyperactivity disorder (ADHD) is one of the most common neuropsychiatric disorders in children and adolescents and often persists into adulthood, the purpose of this systematic review and meta-analysis was to investigate the relationship between T. gondii infection and ADHD.The data were systematically collected from seven electronic databases up to May 1st 2019 with no language restriction. This study was registered at the International Prospective Register of Systematic Reviews (PROSPERO; code: CRD42020149353). Odds ratios (ORs) and 95% confidence intervals (CI) were estimated using a random effects model. Seven studies involving five cross-sectional and two case-control studies were included in this meta-analysis.Results indicated that there was a statistically non-significant association between exposure to T. gondii infection and increased risk of ADHD based on the detection of immunoglobulin G (IgG) antibody (2.02 [95% CI: 0.97-4.20]; I2=58.7%). However, obtained results of Egger's tests for anti-T. gondii IgG antibody showed publication bias (P=0.014).Sensitivity analysis revealed stable results for the association between anti-T. gondii IgG antibody with ADHD.Given the small number of studies in this field and the obtained results, it cannot be conclusively stated that T. gondii is a risk factor for ADHD.It is important to have reliable information about the relationship between T. gondii and ADHD around the world; as it may lead to better insight to elucidate the possible association of toxoplasmosis and the pathogenesis of ADHD.
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Affiliation(s)
- Tooran Nayeri
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.,Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Shahabeddin Sarvi
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.,Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mahmood Moosazadeh
- Health Sciences Research Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran
| | - Zahra Hosseininejad
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.,Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Afsaneh Amouei
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.,Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ahmad Daryani
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.,Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran
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14
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Lindgren M, Holm M, Markkula N, Härkänen T, Dickerson F, Yolken RH, Suvisaari J. Exposure to common infections and risk of suicide and self-harm: a longitudinal general population study. Eur Arch Psychiatry Clin Neurosci 2020; 270:829-839. [PMID: 32219505 PMCID: PMC7474710 DOI: 10.1007/s00406-020-01120-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 03/11/2020] [Indexed: 12/15/2022]
Abstract
Common infectious agents, such as Toxoplasma gondii (T. gondii) and several human herpes viruses, have been linked to increased risk of self-harm. The aim of this study was to investigate the associations between self-harm and seropositivity to T. gondii, Epstein-Barr virus (EBV), Herpes Simplex virus Type 1 (HSV-1), and Cytomegalovirus (CMV). IgM and IgG antibodies to these infections were measured in the Health 2000 project nationally representative of the whole Finnish adult population, and 6250 participants, age 30 and over, were followed for 15 years via registers. In addition, lifetime suicidal ideation and suicide attempts based on medical records and interview were assessed within a subsample of 694 participants screened to a substudy for possible psychotic symptoms or as controls. Among the 6250 participants, 14 individuals died of suicide and an additional 4 individuals had a diagnosis of intentional self-harm during follow-up. Serological evidence of lifetime or acute infections was not found to be associated with these suicidal outcomes. However, in the subsample, those seropositive for CMV had fewer suicide attempts compared to those seronegative, adjusting for gender, age, educational level, childhood family size, regional residence, CRP, and screen status (OR for multiple attempts = 0.40, 95% confidence interval 0.20‒0.83, p = 0.014). To conclude, common infections were not associated with risk of death by suicide or with self-harm diagnoses at a 15-year follow-up in the general population sample. Our finding of an increased number of suicide attempts among persons seronegative for CMV calls for further research.
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Affiliation(s)
- Maija Lindgren
- Mental Health Unit, Finnish Institute for Health and Welfare (THL), PO Box 30, 00271, Helsinki, Finland.
| | - Minna Holm
- Mental Health Unit, Finnish Institute for Health and Welfare (THL), PO Box 30, 00271, Helsinki, Finland
| | - Niina Markkula
- Department of Psychiatry, Helsinki University and Helsinki University Hospital, Helsinki, Finland
| | - Tommi Härkänen
- Health Monitoring Unit, Finnish Institute for Health and Welfare (THL), Helsinki, Finland
| | - Faith Dickerson
- Sheppard Pratt Health System, Stanley Research Program, Baltimore, MD, USA
| | - Robert H Yolken
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jaana Suvisaari
- Mental Health Unit, Finnish Institute for Health and Welfare (THL), PO Box 30, 00271, Helsinki, Finland
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15
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Friends with malefit. The effects of keeping dogs and cats, sustaining animal-related injuries and Toxoplasma infection on health and quality of life. PLoS One 2019; 14:e0221988. [PMID: 31756184 PMCID: PMC6874301 DOI: 10.1371/journal.pone.0221988] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/05/2019] [Indexed: 12/13/2022] Open
Abstract
Many studies show that keeping cats and dogs has a positive impact on humans' physical and mental health and quality of life. The existence of this "pet phenomenon" is now widely discussed because other studies performed recently have demonstrated a negative impact of owning pets or no impact at all. The main problem of many studies was the autoselection-participants were informed about the aims of the study during recruitment and later likely described their health and wellbeing according to their personal beliefs and wishes, not according to their real status. To avoid this source of bias, we did not mention pets during participant recruitment and hid the pet-related questions among many hundreds of questions in an 80-minute Internet questionnaire. Results of our explorative study performed on a sample of 10,858 subjects showed that liking dogs has a weak positive association with quality of life. However, keeping pets, especially cats, and even more being injured by pets, were strongly negatively associated with many facets of quality of life. Our data also confirmed that infection by the cat parasite Toxoplasma had a very strong negative effect on quality of life, especially on mental health. However, the infection was not responsible for the observed negative effects of keeping pets, as these effects were much stronger in 1,527 Toxoplasma-free subjects than in the whole population. Any cross-sectional study cannot discriminate between a cause and an effect. However, because of the large and still growing popularity of keeping pets, the existence and nature of the reverse pet phenomenon deserve the outmost attention.
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Theses for a metatheory of personality. PERSONALITY AND INDIVIDUAL DIFFERENCES 2019. [DOI: 10.1016/j.paid.2019.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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17
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Hajek T. Toxoplasmosis, but not borreliosis, is associated with psychiatric disorders and symptoms - false negative findings? Schizophr Res 2019; 210:289-290. [PMID: 30612843 DOI: 10.1016/j.schres.2018.12.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 12/17/2018] [Accepted: 12/19/2018] [Indexed: 10/27/2022]
Affiliation(s)
- Tomas Hajek
- Dalhousie University, Department of Psychiatry, 5909 Veteran's Memorial Lane, Halifax, NS B3H 2E2, Canada; National Institute of Mental Health, Topolová 748, 250 67 Klecany, Czech Republic.
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Reiling SJ, Dixon BR. Toxoplasma gondii: How an Amazonian parasite became an Inuit health issue. CANADA COMMUNICABLE DISEASE REPORT = RELEVE DES MALADIES TRANSMISSIBLES AU CANADA 2019; 45:183-190. [PMID: 31355827 PMCID: PMC6615440 DOI: 10.4745/ccdr.v45i78a03] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/16/2024]
Abstract
Toxoplasma gondii is a protozoan parasite that originated in the Amazon. Felids (mammals in the cat family) are the only definitive hosts. These animals shed large numbers of infectious oocysts into the environment, which can subsequently infect many intermediate hosts, including birds, mammals and, possibly, fish. Human T. gondii seroprevalence is high in some parts of the Canadian Arctic and is associated with adverse health consequences among Inuit population. Since the range of felids does not extend to the Arctic, it is not immediately obvious how this parasite got from the Amazon to the Arctic. The objectives of this overview are to summarize the health impacts of T. gondii infection in Inuit in Canada's North and to consider how this infection could have reached them. This article reviews the prevalence of T. gondii infection in terrestrial and marine animals in the Canadian Arctic and discusses their potential role in the foodborne transmission of this parasite to humans. Two distribution factors seem plausible. First, felids in more southern habitats may release infectious oocysts into waterways. As these oocysts remain viable for months, they can be transported northward via rivers and ocean currents and could infect Arctic fish and eventually the marine mammals that prey on the fish. Second, migratory terrestrial and marine intermediate hosts may be responsible for carrying T. gondii tissue cysts to the Arctic, where they may then pass on the infection to carnivores. The most likely source of T. gondii in Inuit is from consumption of traditionally-prepared country foods including meat and organs from intermediate hosts, which may be consumed raw. With climate change, northward migration of felids may increase the prevalence of T. gondii in Arctic wildlife.
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Affiliation(s)
- SJ Reiling
- Bureau of Microbial Hazards, Food Directorate, Health Canada, Ottawa, ON
| | - BR Dixon
- Bureau of Microbial Hazards, Food Directorate, Health Canada, Ottawa, ON
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19
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Reiling SJ, Dixon BR. Toxoplasma gondii: How an Amazonian parasite became an Inuit health issue. CANADA COMMUNICABLE DISEASE REPORT = RELEVE DES MALADIES TRANSMISSIBLES AU CANADA 2019; 45:183-190. [PMID: 31355827 PMCID: PMC6615440 DOI: 10.14745/ccdr.v45i78a03] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Toxoplasma gondii is a protozoan parasite that originated in the Amazon. Felids (mammals in the cat family) are the only definitive hosts. These animals shed large numbers of infectious oocysts into the environment, which can subsequently infect many intermediate hosts, including birds, mammals and, possibly, fish. Human T. gondii seroprevalence is high in some parts of the Canadian Arctic and is associated with adverse health consequences among Inuit population. Since the range of felids does not extend to the Arctic, it is not immediately obvious how this parasite got from the Amazon to the Arctic. The objectives of this overview are to summarize the health impacts of T. gondii infection in Inuit in Canada's North and to consider how this infection could have reached them. This article reviews the prevalence of T. gondii infection in terrestrial and marine animals in the Canadian Arctic and discusses their potential role in the foodborne transmission of this parasite to humans. Two distribution factors seem plausible. First, felids in more southern habitats may release infectious oocysts into waterways. As these oocysts remain viable for months, they can be transported northward via rivers and ocean currents and could infect Arctic fish and eventually the marine mammals that prey on the fish. Second, migratory terrestrial and marine intermediate hosts may be responsible for carrying T. gondii tissue cysts to the Arctic, where they may then pass on the infection to carnivores. The most likely source of T. gondii in Inuit is from consumption of traditionally-prepared country foods including meat and organs from intermediate hosts, which may be consumed raw. With climate change, northward migration of felids may increase the prevalence of T. gondii in Arctic wildlife.
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Affiliation(s)
- SJ Reiling
- Bureau of Microbial Hazards, Food Directorate, Health Canada, Ottawa, ON
| | - BR Dixon
- Bureau of Microbial Hazards, Food Directorate, Health Canada, Ottawa, ON
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20
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Relationship between toxoplasmosis and obsessive compulsive disorder: A systematic review and meta-analysis. PLoS Negl Trop Dis 2019; 13:e0007306. [PMID: 30969961 PMCID: PMC6457543 DOI: 10.1371/journal.pntd.0007306] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 03/15/2019] [Indexed: 11/19/2022] Open
Abstract
Background A few studies investigated the relationship between toxoplasmosis and mental disorders, such as obsessive compulsive disorder (OCD). However, the specific nature of the association between Toxoplasma gondii (T. gondii) infection and OCD is not yet clear. The aim of this study was to collect information on the relationship between OCD and toxoplasmosis and assess whether patients with toxoplasmosis are prone to OCD. Methods For the purpose of this study, 6 major electronic databases and the Internet search engine Google Scholar were searched for the published articles up to July 30th, 2018 with no restriction of language. The inverse variance method and the random effect model were used to combine the data. The values of odds ratio (OR) were estimated at 95% confidence interval (CI). Results A total of 9 case-control and 3 cross-sectional studies were included in our systematic review. However, 11 of these 12 articles were entered into the meta-analysis containing 9873 participants, out of whom 389 were with OCD (25.96% positive for toxoplasmosis) and 9484 were without OCD (17.12% positive for toxoplasmosis). The estimation of the random effect model indicated a significant common OR of 1.96 [95% CI: 1.32–2.90]. Conclusion This systematic review and meta-analysis revealed that toxoplasmosis could be as an associated factor for OCD (OR = 1.96). However, further prospective investigations are highly recommended to illuminate the underlying pathophysiological mechanisms of T. gondii infection in OCD and to better investigate the relationship between OCD and T. gondii infection. Toxoplasma gondii (T. gondii) is an obligate neurotropic parasite that infected about 25–30% of the total human population in the developed and developing countries. The obsessive compulsive disorder (OCD) is a psychiatric disease that affects the income and quality of life. Some studies confirmed an association between infectious agents as the associated or protective factors specifying the development of psychiatry diseases. Among various pathogens associated with psychological disorders, most of the attention is on T. gondii, which has a life-long asymptomatic latent phase after a short acute stage in healthy individuals. The detrimental effect of T. gondii on immunocompromised people and pregnant women is an important concern for public health. The correlation between toxoplasmosis and OCD is still relatively understudied with a paucity of documented findings. The previous meta-analysis reviewed only two studies and reported a 3.4-fold greater chance of OCD. The results of our study presented stronger evidence of a positive relationship between toxoplasmosis and OCD. Eventually, our research team hopes to present an overview of what is known and encourage more intensive research to determine the real impact of this parasite on the occurrence of OCD that may contribute to the prevention of OCD worldwide.
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Bay-Richter C, Buttenschøn HN, Mors O, Eskelund A, Budac D, Kærlev L, Wegener G. Latent toxoplasmosis and psychiatric symptoms - A role of tryptophan metabolism? J Psychiatr Res 2019; 110:45-50. [PMID: 30583085 DOI: 10.1016/j.jpsychires.2018.12.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 12/12/2018] [Accepted: 12/12/2018] [Indexed: 02/02/2023]
Abstract
Toxoplasma gondii (TOX) is a common parasite which infects approximately one third of the human population. In recent years, it has been suggested that latent toxoplasmosis may be a risk factor for the development of mental disorders, particularly schizophrenia and anxiety. With regards to depression the results have been varied. The main objective of this study was to examine subpopulations from the Danish PRISME and GENDEP populations for TOX IgG antibodies. These consisted of: a group with symptoms of anxiety, a group suffering from burnout syndrome, as well as two different subpopulations with depression of differing severity. The secondary objective of this study was to examine whether tryptophan metabolism was altered in TOX-positive subjects within each subpopulation. Our results show that the anxiety and burnout populations were more likely to be TOX IgG seropositive. Furthermore, we find that the moderate-severe but not mild-moderate depressive subpopulation were associated with TOX seropositivety, suggesting a possible role of symptom severity. Additionally, we found that TOX positive subjects in the anxiety and burnout subpopulations had altered tryptophan metabolism. This relationship did not exist in the mild-moderate depressive subpopulation. These results suggest that TOX seropositivity may be related to anxiety, burnout and potentially to severity of depression. We furthermore show that the psychiatric symptoms could be associated with an altered tryptophan metabolism.
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Affiliation(s)
- Cecilie Bay-Richter
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Risskov, Denmark.
| | | | - Ole Mors
- Psychosis Research Unit, Aarhus University Hospital, Risskov, Denmark; The Lundbeck Foundation Initiative for Integrative Psychiatric Research (iPSYCH), Aarhus University, Aarhus, Denmark
| | - Amanda Eskelund
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | | | - Linda Kærlev
- Research Unit of Clinical Epidemiology, Institute of Clinical Research, University of Southern Denmark, Odense, Denmark; Center for Clinical Epidemiology, Odense University Hospital, Odense, Denmark
| | - Gregers Wegener
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Risskov, Denmark
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Flegr J, Horáček J. Negative Effects of Latent Toxoplasmosis on Mental Health. Front Psychiatry 2019; 10:1012. [PMID: 32132937 PMCID: PMC7040223 DOI: 10.3389/fpsyt.2019.01012] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 12/20/2019] [Indexed: 12/31/2022] Open
Abstract
Infection by the parasite Toxoplasma, which affects about 33% of world population, is associated with an increased risk of several mental health disorders, the most strongly with schizophrenia. It is unknown whether schizophrenia is associated with this infection the most strongly, or whether this association has just been the most intensively studied for historical reasons. We used the data from 6,367 subjects tested for toxoplasmosis who took part in an internet survey to search for associations of these infections with 24 mental health disorders and evidence of otherwise impaired mental health. The typical symptom associated with toxoplasmosis was anxiety, and the typical toxoplasmosis-associated disorders were autism (OR = 4.78), schizophrenia (OR = 3.33), attention deficit hyperactivity disorder (OR = 2.50), obsessive compulsive disorder (OR = 1.86), antisocial personality disorder (OR = 1.63), learning disabilities (OR = 1.59), and anxiety disorder (OR = 1.48). Toxoplasmosis could play a substantial role in the etiopathogenesis of mental health disorders and its association with schizophrenia is the second strongest association, after autism.
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Affiliation(s)
- Jaroslav Flegr
- Division of Biology, Faculty of Science, Charles University in Prague, Prague, Czechia.,Applied Neurosciences and Brain Imagination, National Institute of Mental Health, Klecany, Czechia
| | - Jiří Horáček
- Applied Neurosciences and Brain Imagination, National Institute of Mental Health, Klecany, Czechia
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Xiao J, Prandovszky E, Kannan G, Pletnikov MV, Dickerson F, Severance EG, Yolken RH. Toxoplasma gondii: Biological Parameters of the Connection to Schizophrenia. Schizophr Bull 2018; 44:983-992. [PMID: 29889280 PMCID: PMC6101499 DOI: 10.1093/schbul/sby082] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
It is increasingly evident that the brain is not truly an immune privileged site and that cells of the central nervous system are sensitive to the inflammation generated when the brain is fighting off infection. Among the many microorganisms that have access to the brain, the apicomplexan protozoan Toxoplasma gondii has been one of the most studied. This parasite has been associated with many neuropsychiatric disorders including schizophrenia. This article provides a comprehensive review of the status of Toxoplasma research in schizophrenia. Areas of interest include (1) the limitations and improvements of immune-based assays to detect these infections in humans, (2) recent discoveries concerning the schizophrenia-Toxoplasma association, (3) findings of Toxoplasma neuropathology in animal models related to schizophrenia pathogenesis, (4) interactions of Toxoplasma with the host genome, (5) gastrointestinal effects of Toxoplasma infections, and (6) therapeutic intervention of Toxoplasma infections.
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Affiliation(s)
- Jianchun Xiao
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD
| | - Emese Prandovszky
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD
| | - Geetha Kannan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI
| | - Mikhail V Pletnikov
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Faith Dickerson
- Stanley Research Program, Sheppard Pratt Health System, Baltimore, MD
| | - Emily G Severance
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD
| | - Robert H Yolken
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD,To whom correspondence should be addressed; Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD 21287 USA; tel: +1-410-614-0004, fax: +1-410-955-3723, e-mail:
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