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Bathini P, Brai E, Balin BJ, Bimler L, Corry DB, Devanand DP, Doty RL, Ehrlich GD, Eimer WA, Fulop T, Hahn DL, Hammond CJ, Infanti J, Itzhaki R, Lathe R, Little CS, McLeod R, Moein ST, Nelson AR, Perry G, Shemesh OA, Tanzi RE, Webley WC, Schultek NM, Alberi Auber L. Sensory Dysfunction, Microbial Infections, and Host Responses in Alzheimer's Disease. J Infect Dis 2024; 230:S150-S164. [PMID: 39255393 DOI: 10.1093/infdis/jiae328] [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] [Indexed: 09/12/2024] Open
Abstract
Sensory functions of organs of the head and neck allow humans to interact with the environment and establish social bonds. With aging, smell, taste, vision, and hearing decline. Evidence suggests that accelerated impairment in sensory abilities can reflect a shift from healthy to pathological aging, including the development of Alzheimer's disease (AD) and other neurological disorders. While the drivers of early sensory alteration in AD are not elucidated, insults such as trauma and infections can affect sensory function. Herein, we review the involvement of the major head and neck sensory systems in AD, with emphasis on microbes exploiting sensory pathways to enter the brain (the "gateway" hypothesis) and the potential feedback loop by which sensory function may be impacted by central nervous system infection. We emphasize detection of sensory changes as first-line surveillance in senior adults to identify and remove potential insults, like microbial infections, that could precipitate brain pathology.
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Affiliation(s)
- Praveen Bathini
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
| | | | - Brian J Balin
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Center for Chronic Disorders of Aging, Philadelphia College of Osteopathic Medicine, Philadelphia, Pennsylvania, USA
- Intracell Research Group, LLC, Wake Forest, North Carolina, USA
| | - Lynn Bimler
- Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - David B Corry
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
- Department of Medicine, Dan L. Duncan Comprehensive Cancer Center, Biology of Inflammation Center, and the Michael E. DeBakey VA Center for Translational Research in Inflammatory Diseases, Baylor College of Medicine, Houston, Texas, USA
- Department of Pathology and Immunology, Dan L. Duncan Comprehensive Cancer Center, Biology of Inflammation Center, and the Michael E. DeBakey VA Center for Translational Research in Inflammatory Diseases, Baylor College of Medicine, Houston, Texas, USA
| | - Davangere P Devanand
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Department of Psychiatry and Neurology, Irving Medical Center, Columbia University, New York, USA
| | - Richard L Doty
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Smell and Taste Center, Department of Otorhinolaryngology-Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Garth D Ehrlich
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Center for Genomic Sciences, Institute for Molecular Medicine and Infectious Disease, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - William A Eimer
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Genetics and Aging Research Unit, Mass General Institute for Neurodegenerative Disease, Charlestown, Massachusetts, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
- Harvard Medical School, Harvard University, Cambridge, Massachusetts, USA
| | - Tamas Fulop
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Department of Medicine, Division of Geriatrics, Faculty of Medicine and Health Sciences, Research Center on Aging, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - David L Hahn
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Intracell Research Group, LLC, Wake Forest, North Carolina, USA
| | - Christine J Hammond
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Division of Research, Philadelphia College of Osteopathic Medicine, Philadelphia, Pennsylvania, USA
| | - Joseph Infanti
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Division of Research, Philadelphia College of Osteopathic Medicine, Philadelphia, Pennsylvania, USA
| | - Ruth Itzhaki
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Institute of Population Ageing, University of Oxford, Oxford, United Kingdom
| | - Richard Lathe
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Division of Infection Medicine, University of Edinburgh Medical School, Edinburgh, United Kingdom
| | - Christopher Scott Little
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Center for Chronic Disorders of Aging, Philadelphia College of Osteopathic Medicine, Philadelphia, Pennsylvania, USA
| | - Rima McLeod
- Departments of Ophthalmology and Visual Sciences, University of Chicago, Chicago, Illinois, USA
- Department of Pediatrics Infectious Diseases, University of Chicago, Chicago, Illinois, USA
| | - Shima T Moein
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Smell and Taste Center, Department of Otorhinolaryngology-Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Amy R Nelson
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, USA
| | - George Perry
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Intracell Research Group, LLC, Wake Forest, North Carolina, USA
- Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, USA
| | - Or A Shemesh
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Intracell Research Group, LLC, Wake Forest, North Carolina, USA
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Department of Bioengineering, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Rudolph E Tanzi
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Genetics and Aging Research Unit, Mass General Institute for Neurodegenerative Disease, Charlestown, Massachusetts, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
- Harvard Medical School, Harvard University, Cambridge, Massachusetts, USA
| | - Wilmore C Webley
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Intracell Research Group, LLC, Wake Forest, North Carolina, USA
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
| | - Nikki M Schultek
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- Intracell Research Group, LLC, Wake Forest, North Carolina, USA
| | - Lavinia Alberi Auber
- The Alzheimer's Pathobiome Initiative (AlzPI), Wake Forest, North Carolina, USA
- BrainFit4Life, Fribourg, Switzerland
- Intracell Research Group, LLC, Wake Forest, North Carolina, USA
- Department of Medicine, University of Fribourg, Fribourg, Switzerland
- VitalizeDx, Epalinges, Switzerland
- VitalizeDx Eu, Trieste, Italy
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Beaumont E, Brodeur J, Thomas F, Dujon AM, Lupien SJ. Toxoplasma gondii infection in people with schizophrenia is related to higher hair glucocorticoid levels. Front Psychiatry 2024; 15:1286135. [PMID: 38435971 PMCID: PMC10904596 DOI: 10.3389/fpsyt.2024.1286135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 01/26/2024] [Indexed: 03/05/2024] Open
Abstract
Introduction Toxoplasma gondii (TG) is a common protozoan parasite infecting approximately one third of the human population. Animal studies have shown that this parasite can manipulate its host behavior. Based on this, human studies have assessed if TG can be involved in mental health disorders associated with important behavioral modifications such as schizophrenia. However, results have been discrepant. Given that TG has a strong impact on fear and risk-taking processes in animal studies and that fear and risk-taking behaviors are associated with the human stress response, we tested whether glucocorticoid biomarkers (salivary and hair) differ in people with schizophrenia and controls as a function of TG status. Methods We measured TG antibodies in blood samples, as well as salivary and hair glucocorticoid levels in 226 people with schizophrenia (19.9% women, mean age = 39 years old) and 129 healthy individuals (controls) (45.7% women, mean age = 41 years old). Results The results showed that people with schizophrenia infected with TG presented significantly higher hair glucocorticoid concentrations than non-infected people with schizophrenia. This effect was not found in control participants. No effect was observed for salivary glucocorticoid levels. Additionally, there were no associations between TG infection and positive psychotic symptoms nor impulsivity. Discussion These results show that people with schizophrenia present high levels of hair glucocorticoid levels only when they are infected with TG. Further studies performed in populations suffering from other mental health disorders are needed to determine if this effect is specific to schizophrenia, or whether it is generalized across mental health disorders.
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Affiliation(s)
- Emy Beaumont
- Institut Universitaire en Santé Mentale de Montréal, Center for Studies on Human Stress, Montréal, QC, Canada
- Research Center, Institut Universitaire en Santé Mentale de Montréal, Montréal, QC, Canada
- Department of Psychology, Université de Montréal, Montréal, QC, Canada
| | - Jacques Brodeur
- Department of Biological Sciences, Université de Montréal, Montréal, QC, Canada
| | - Frédéric Thomas
- Center for Ecological and Evolutionary Research on Cancer (CREEC), Université de Montpellier, Montpellier, France
| | - Antoine M. Dujon
- Center for Ecological and Evolutionary Research on Cancer (CREEC), Université de Montpellier, Montpellier, France
- Center for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, VIC, Australia
| | | | - Sonia J. Lupien
- Institut Universitaire en Santé Mentale de Montréal, Center for Studies on Human Stress, Montréal, QC, Canada
- Research Center, Institut Universitaire en Santé Mentale de Montréal, Montréal, QC, Canada
- Depatment of Psychiatry and Addiction, Université de Montréal, Montréal, QC, Canada
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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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Nayeri T, Moosazadeh M, Asl AD, Ghaffarifar F, Sarvi S, Daryani A. Toxoplasma infection and Rhesus blood group system: A systematic review and meta-analysis. PLoS One 2023; 18:e0287992. [PMID: 37406027 DOI: 10.1371/journal.pone.0287992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 06/17/2023] [Indexed: 07/07/2023] Open
Abstract
BACKGROUND Toxoplasmosis is one of the most common infections in humans and animals, which is caused by an obligate intracellular opportunistic parasite known as Toxoplasma gondii (T. gondii). Some data have shown that both Rhesus (Rh)-positive and Rh-negative individuals differ in response to biological factors, including Toxoplasma infection. Therefore, this systematic review and meta-analysis was conducted to investigate the scientific evidence regarding the possible association between the Rh blood group and Toxoplasma infection and to determine the seroprevalence of T. gondii in the Rh blood group system. METHODS The research was conducted on PubMed, ScienceDirect, ProQuest, and Google Scholar databases until January 2023. Twenty-one cross-sectional studies were included with a total of 10910 people. The data were synthesized using a random effect model with 95% confidence intervals (CIs). RESULTS The overall prevalence of T. gondii was calculated at 32.34% (CI 95%: 28.23-36.45%) and 33.35% (CI 95%: 19.73-46.96%) in Rh-positive and Rh-negative blood groups. In addition, the pooled OR for the relationship between the Rh blood group and the seroprevalence of T. gondii was 0.96 (95% CI: 0.72-1.28). CONCLUSIONS This meta-analysis showed a high prevalence of Toxoplasma infection in both Rh-negative and positive blood groups. This systematic review and meta-analysis revealed that no significant association was found between toxoplasmosis and Rh factor. Because of the limited number of studies in this field, more research is recommended to determine the exact relationship between toxoplasmosis and the Rh factor.
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Affiliation(s)
- Tooran Nayeri
- Toxoplasmosis Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mahmood Moosazadeh
- Gastrointestitional Cancer Research Center, Non-communicable Disease Institute, Mazandaran University of Medical Sciences, Sari, Iran
| | - Abdolhossein Dalimi Asl
- Department of Parasitology and Entomology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Fatemeh Ghaffarifar
- Department of Parasitology and Entomology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Shahabeddin Sarvi
- Toxoplasmosis Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ahmad Daryani
- Toxoplasmosis Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
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Cromar GL, Epp JR, Popovic A, Gu Y, Ha V, Walters BJ, St. Pierre J, Xiong X, Howland JG, Josselyn SA, Frankland PW, Parkinson J. Toxoplasma infection in male mice alters dopamine-sensitive behaviors and host gene expression patterns associated with neuropsychiatric disease. PLoS Negl Trop Dis 2022; 16:e0010600. [PMID: 35857765 PMCID: PMC9342775 DOI: 10.1371/journal.pntd.0010600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 08/01/2022] [Accepted: 06/21/2022] [Indexed: 11/18/2022] Open
Abstract
During chronic infection, the single celled parasite, Toxoplasma gondii, can migrate to the brain where it has been associated with altered dopamine function and the capacity to modulate host behavior, increasing risk of neurocognitive disorders. Here we explore alterations in dopamine-related behavior in a new mouse model based on stimulant (cocaine)-induced hyperactivity. In combination with cocaine, infection resulted in heightened sensorimotor deficits and impairment in prepulse inhibition response, which are commonly disrupted in neuropsychiatric conditions. To identify molecular pathways in the brain affected by chronic T. gondii infection, we investigated patterns of gene expression. As expected, infection was associated with an enrichment of genes associated with general immune response pathways, that otherwise limits statistical power to identify more informative pathways. To overcome this limitation and focus on pathways of neurological relevance, we developed a novel context enrichment approach that relies on a customized ontology. Applying this approach, we identified genes that exhibited unexpected patterns of expression arising from the combination of cocaine exposure and infection. These include sets of genes which exhibited dampened response to cocaine in infected mice, suggesting a possible mechanism for some observed behaviors and a neuroprotective effect that may be advantageous to parasite persistence. This model offers a powerful new approach to dissect the molecular pathways by which T. gondii infection contributes to neurocognitive disorders.
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Affiliation(s)
- Graham L. Cromar
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Canada
| | - Jonathan R. Epp
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Canada
| | - Ana Popovic
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Canada
- Dept. of Biochemistry, University of Toronto, Toronto, Canada
| | - Yusing Gu
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Canada
| | - Violet Ha
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Canada
| | - Brandon J. Walters
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Canada
| | - James St. Pierre
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Canada
| | - Xuejian Xiong
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Canada
| | - John G. Howland
- Dept. of Anatomy, Physiology and Pharmacology, University of Saskatchewan, Saskatoon, Canada
| | - Sheena A. Josselyn
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Canada
- Dept. of Physiology, University of Toronto, Toronto, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Canada
- Dept. of Psychology, University of Toronto, Toronto, Canada
| | - Paul W. Frankland
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Canada
- Dept. of Physiology, University of Toronto, Toronto, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Canada
- Dept. of Psychology, University of Toronto, Toronto, Canada
- * E-mail: (PF); (JP)
| | - John Parkinson
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Canada
- Dept. of Biochemistry, University of Toronto, Toronto, Canada
- Dept. of Molecular Genetics, University of Toronto, Toronto, Canada
- * E-mail: (PF); (JP)
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Ademe M, Kebede T, Teferra S, Alemayehu M, Girma F, Abebe T. Is latent Toxoplasma gondii infection associated with the occurrence of schizophrenia? A case-control study. PLoS One 2022; 17:e0270377. [PMID: 35737701 PMCID: PMC9223392 DOI: 10.1371/journal.pone.0270377] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 06/08/2022] [Indexed: 11/18/2022] Open
Abstract
Introduction
Neurotropic pathogens such as Toxoplasma gondii (T. gondii) which result in chronic infections in the brain are associated with mental illnesses. In view of this, a growing body of literature has revealed the possible interaction of schizophrenia and T. gondii infection.
Method
A case-control study was conducted from February 2018 to January 2019 among 47 Schizophrenia patients and 47 age and sex-matched controls. Data was collected using a structured questionnaire. Serum was used for serological analysis of anti-T. gondii IgG and IgM antibodies through chemiluminescent immunoassay. Proportions and mean with standard deviations (SD) were used as descriptive measures and variables with p-values <0.05 were considered as statistically significant and independently associated with schizophrenia.
Result
The mean ages of schizophrenia patients and controls were 29.64 ± 5.8 yrs and 30.98 ± 7.3 yrs, respectively. We found that 81.9% (77/94) of the study subjects had a positive anti-T. gondii IgG antibody. While the difference is statistically insignificant, schizophrenic patients have a marginally higher seroprevalence of toxoplasmosis than controls (87.2% vs 80.9%; p = 0.398). Schizophrenia cases who live in homes with soil floors have a significantly higher T. gondii infection as compared to those who live in homes with cement/ceramic floors (90.9% vs 33.3%; p = 0.004). Furthermore, there was a significantly lower T. gondii infection among schizophrenic cases who were taking antipsychotic medication for more than three yrs (79.3% vs 100.0%, p = 0.039). On the other hand, among all study subjects who have T. gondii infection, subjects who are addicted to khat and alcohol were about seven times more likely to develop schizophrenia (71.4% vs 47.7%, OR = 7.13, p = 0.024).
Conclusion
Our data is not sufficient to show a significant positive correlation between T. gondii infection and schizophrenia. For study subjects with T. gondii infection, addiction to khat and alcohol is one of the risk factors for schizophrenia.
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Affiliation(s)
- Muluneh Ademe
- Department of Microbiology, Immunology and Parasitology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
- * E-mail:
| | - Tadesse Kebede
- Department of Microbiology, Immunology and Parasitology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Solomon Teferra
- Department of Psychiatry, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Melkam Alemayehu
- Department of Psychiatry, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Friehiwot Girma
- Department of Pediatrics and Child Health Nursing, School of Health Sciences, College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Tamrat Abebe
- Department of Microbiology, Immunology and Parasitology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
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Conditional associations between childhood cat ownership and psychotic experiences in adulthood: A retrospective study. J Psychiatr Res 2022; 148:197-203. [PMID: 35131588 DOI: 10.1016/j.jpsychires.2022.01.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 11/16/2021] [Accepted: 01/26/2022] [Indexed: 11/23/2022]
Abstract
Ownership of cats in childhood has been inconsistently associated with psychosis in adulthood. Parasitic exposure, the putative mechanism of this association, may be more common with rodent-hunting cats, and its association with psychosis may depend on other environmental exposures. We examined the conditional associations between childhood cat ownership and the frequency of psychotic experiences in adulthood. Adults (n = 2206) were recruited in downtown Montreal to complete a survey about childhood cat ownership (non-hunting or rodent-hunting), winter birth, residential moves in childhood, head trauma history, and tobacco smoking. The frequency of psychotic experiences (PE) was measured with the 15-item positive subscale of the Community Assessment of Psychic Experiences. Associations between exposures and PE were examined in linear regressions adjusted for age and sex. Interactions among variables were explored using a conditional inference tree. Rodent-hunting cat ownership was associated with higher PE scores in male participants (vs. non-hunting or no cat ownership: SMD = 0.57; 95% CI: 0.27, 0.86), but not in female participants (SMD = 0.10; 95% CI: -0.18, 0.38). In the conditional inference tree, the highest mean PE score was in the class comprised of non-smokers with >1 residential move, head trauma history, and rodent-hunting cat ownership (n = 22; mean standard score = 0.96). The interaction between rodent-hunting cat ownership and head trauma history was supported by a post-hoc linear regression model. Our findings suggest childhood cat ownership has conditional associations with psychotic experiences in adulthood.
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Kamal AM, Kamal AM, Abd El-Fatah AS, Rizk MM, Hassan EE. Latent Toxoplasmosis is Associated with Depression and Suicidal Behavior. Arch Suicide Res 2022; 26:819-830. [PMID: 33166476 DOI: 10.1080/13811118.2020.1838368] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Neuroinflammation is implicated in the pathophysiology of depression. Toxoplasma gondii (T. gondii) causes chronic brain inflammatory process and may thus contribute to both depression and its most serious complication, suicidal behavior. In this study, we hypothesized that latent toxoplasmosis may underlie current depression and/or suicidal behavior. METHOD Currently depressed individuals (N = 384) and age, sex, and residence-matched healthy controls (HC) (N = 400) were tested for latent toxoplasmosis (i.e., positive serum T. gondii IgG antibodies). Exclusions included positive IgM and negative IgG antibodies indicating acute T. gondii infection and history of cognitive problems. Depression severity and history of lifetime suicide attempts were assessed using Beck Depression Inventory (BDI) and Columbia Suicide Severity Rating Scale, respectively. RESULTS Participants with seropositive anti-T. gondii IgG antibody had a significantly higher odds of being depressed compared with seronegative participants (OR = 2.9, 95% CI: 1.9-4.3; p < 0.001). BDI score was significantly different between depressed seropositive and depressed seronegative individuals (IgG+: mean (SD)= 39.65 (11.83) vs. IgG-: mean (SD)= 33.44(9.80); t = 5.03, p < 0.001). Further, seropositive depressed participants were more likely to have prior history of actual suicide attempts compared with seronegative participants (OR= 6.2, 95% CI: 3.4-11.2, p < 0.001). CONCLUSIONS Latent toxoplasmosis may represent be a risk factor for depression and suicidal behavior. Screening for, and treatment of, underlying T. gondii infection may help improve depression and curb the increasing suicide rates. Future studies should prospectively test these hypotheses to be adequately implemented.HIGHLIGHTSLatent toxoplasmosis has been linked to history of psychiatric disorders.Depressed individuals have higher positivity rate of T. gondii IgG antibody than healthy controls.Depressed T. gondii seropositive individuals have increased likelihood to have history of suicidal behavior.
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Borráz-León JI, Rantala MJ, Krams IA, Cerda-Molina AL, Contreras-Garduño J. Are Toxoplasma-infected subjects more attractive, symmetrical, or healthier than non-infected ones? Evidence from subjective and objective measurements. PeerJ 2022; 10:e13122. [PMID: 35356475 PMCID: PMC8958965 DOI: 10.7717/peerj.13122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/24/2022] [Indexed: 01/12/2023] Open
Abstract
Background Parasites are among the main factors that negatively impact the health and reproductive success of organisms. However, if parasites diminish a host's health and attractiveness to such an extent that finding a mate becomes almost impossible, the parasite would decrease its odds of reproducing and passing to the next generation. There is evidence that Toxoplasma gondii (T. gondii) manipulates phenotypic characteristics of its intermediate hosts to increase its spread. However, whether T. gondii manipulates phenotypic characteristics in humans remains poorly studied. Therefore, the present research had two main aims: (1) To compare traits associated with health and parasite resistance in Toxoplasma-infected and non-infected subjects. (2) To investigate whether other people perceive differences in attractiveness and health between Toxoplasma-infected and non-infected subjects of both sexes. Methods For the first aim, Toxoplasma-infected (n = 35) and non-infected subjects (n = 178) were compared for self-perceived attractiveness, number of sexual partners, number of minor ailments, body mass index, mate value, handgrip strength, facial fluctuating asymmetry, and facial width-to-height ratio. For the second aim, an independent group of 205 raters (59 men and 146 women) evaluated the attractiveness and perceived health of facial pictures of Toxoplasma-infected and non-infected subjects. Results First, we found that infected men had lower facial fluctuating asymmetry whereas infected women had lower body mass, lower body mass index, a tendency for lower facial fluctuating asymmetry, higher self-perceived attractiveness, and a higher number of sexual partners than non-infected ones. Then, we found that infected men and women were rated as more attractive and healthier than non-infected ones. Conclusions Our results suggest that some sexually transmitted parasites, such as T. gondii, may produce changes in the appearance and behavior of the human host, either as a by-product of the infection or as the result of the manipulation of the parasite to increase its spread to new hosts. Taken together, these results lay the foundation for future research on the manipulation of the human host by sexually transmitted pathogens and parasites.
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Affiliation(s)
| | | | - Indrikis A. Krams
- Department of Biotechnology, Daugavpils University, Daugavpils, Latvia
- Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia
- Department of Zoology and Animal Ecology, University of Latvia, Riga, Latvia
| | - Ana Lilia Cerda-Molina
- Department of Ethology, National Institute of Psychiatry “Ramón de la Fuente Muñiz”, Mexico City, Mexico
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Soares GLDS, Leão ERLPD, Freitas SF, Alves RMC, Tavares NDP, Costa MVN, Menezes GCD, Oliveira JHPD, Guerreiro LCF, Assis ACLD, Araújo SC, Franco FTDC, Anaissi AKM, Carmo ELD, Morais RDAPB, Demachki S, Diniz JAP, Nunes HM, Anthony DC, Diniz DG, Diniz CWP. Behavioral and Neuropathological Changes After Toxoplasma gondii Ocular Conjunctival Infection in BALB/c Mice. Front Cell Infect Microbiol 2022; 12:812152. [PMID: 35372100 PMCID: PMC8965508 DOI: 10.3389/fcimb.2022.812152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 02/07/2022] [Indexed: 11/15/2022] Open
Abstract
Ocular infection with Toxoplasma gondii causes toxoplasmosis in mice. However, following ocular infection with tachyzoites, the cause of the accompanying progressive changes in hippocampal-dependent tasks, and their relationship with the morphology and number of microglia, is less well understood. Here, in 6-month-old, female BALB/c mice, 5 μl of a suspension containing 48.5 × 106 tachyzoites/ml was introduced into the conjunctival sac; control received an equal volume of saline. Before and after instillation, all mice were subject to an olfactory discrimination (OD) test, using predator (cat) feces, and to an open-field (OF) task. After the behavioral tests, the animals were culled at either 22 or 44 days post-instillation (dpi), and the brains and retinas were dissected and processed for immunohistochemistry. The total number of Iba-1-immunolabeled microglia in the molecular layer of the dentate gyrus was estimated, and three-dimensional reconstructions of the cells were evaluated. Immobility was increased in the infected group at 12, 22, and 43 dpi, but the greatest immobility was observed at 22 dpi and was associated with reduced line crossing in the OF and distance traveled. In the OD test, infected animals spent more time in the compartment with feline fecal material at 14 and at 43 dpi. No OD changes were observed in the control group. The number of microglia was increased at 22 dpi but returned to control levels by 44 dpi. These changes were associated with the differentiation of T. gondii tachyzoites into bradyzoite-enclosed cysts within the brain and retina. Thus, infection of mice with T. gondii alters exploratory behavior, gives rise to a loss in predator’s odor avoidance from 2 weeks after infection, increased microglia number, and altered their morphology in the molecular layer of the dentate gyrus.
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11
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Neupane SP. Psychoneuroimmunology: The new frontier in suicide research. Brain Behav Immun Health 2021; 17:100344. [PMID: 34589823 PMCID: PMC8474243 DOI: 10.1016/j.bbih.2021.100344] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 09/03/2021] [Accepted: 09/06/2021] [Indexed: 12/14/2022] Open
Abstract
Elucidating complex, multifactorial phenomena like suicide and suicidal behaviors (SSB) require multidisciplinary fields such as Psychoneuroimmunology (PNI). Indeed, our appreciation of the bidirectional communication channels between the brain and the rest of the body with its immune arsenal as the key player has positioned PNI as a promising field of research. We now know that major psychiatric, behavioral, and somatic disorders related to SSB accompany neuroimmune dysregulation. These disorders range from depression, emotional dysregulation, atopy, and epilepsy to certain viral and parasitic infections. By utilizing epidemiological, genetic, microbial, and molecular approaches, the PNI research community has excogitated novel biomarker candidates and pathways in support of SSB risk stratification at individual level. This remarkable progress in just two previous decades shall, if successful, help implement personalized prevention and treatment strategies, using PNI-assisted tools. The aims of this narrative review and opinion piece are to summarize important discoveries concerning the role of neuroimmune activation in SSB and to highlight important future directions for the field. Major caveats of the findings concerning methodological approaches, clinical reality of frequent comorbid psychopathology, and novel molecular targets are presented. Finally, this review calls on the PNI research community for increased attention towards factors that promote resilience to suicide, while accepting "consciousness" under its wing. Thus, PNI represents the new frontier in suicide research. Future breakthroughs in this discipline shall bring us closer to understanding the biological substrates of qualia i.e., subjective, and experiential meanings of life and death.
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Affiliation(s)
- Sudan Prasad Neupane
- National Centre for Suicide Research and Prevention, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Oral Health Center of Expertise in Rogaland, Stavanger, Norway
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12
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Virus MA, Ehrhorn EG, Lui LM, Davis PH. Neurological and Neurobehavioral Disorders Associated with Toxoplasma gondii Infection in Humans. J Parasitol Res 2021; 2021:6634807. [PMID: 34712493 PMCID: PMC8548174 DOI: 10.1155/2021/6634807] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 09/15/2021] [Indexed: 01/17/2023] Open
Abstract
The intracellular parasite Toxoplasma gondii is estimated to infect up to 30% of the world population, leading to lifelong chronic infection of the brain and muscle tissue. Although most latent T. gondii infections in humans have traditionally been considered asymptomatic, studies in rodents suggest phenotypic neurological changes are possible. Consequently, several studies have examined the link between T. gondii infection and diseases such as schizophrenia, epilepsy, depression, bipolar disorder, dysphoria, Alzheimer's disease, Parkinson's disease, and obsessive-compulsive disorder (OCD). To date, there is varying evidence of the relationship of T. gondii to these human neurological or neurobehavioral disorders. A thorough review of T. gondii literature was conducted to highlight and summarize current findings. We found that schizophrenia was most frequently linked to T. gondii infection, while sleep disruption showed no linkage to T. gondii infection, and other conditions having mixed support for a link to T. gondii. However, infection as a cause of human neurobehavioral disease has yet to be firmly established.
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Affiliation(s)
- Maxwell A. Virus
- Department of Biology, University of Nebraska at Omaha, Omaha, Nebraska, USA
| | - Evie G. Ehrhorn
- Department of Biology, University of Nebraska at Omaha, Omaha, Nebraska, USA
| | - LeeAnna M. Lui
- Department of Biology, University of Nebraska at Omaha, Omaha, Nebraska, USA
| | - Paul H. Davis
- Department of Biology, University of Nebraska at Omaha, Omaha, Nebraska, USA
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13
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Turner DC. Unanswered Questions and Hypotheses about Domestic Cat Behavior, Ecology, and the Cat-Human Relationship. Animals (Basel) 2021; 11:ani11102823. [PMID: 34679844 PMCID: PMC8532687 DOI: 10.3390/ani11102823] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/22/2021] [Accepted: 09/25/2021] [Indexed: 02/02/2023] Open
Abstract
Simple Summary Over the last three and a half decades, many studies have been published about cat behavior and cat–human interactions (many by the author and his former team of assistants and university students); these have been summarized in recent review articles. Although we have learned much about domestic cats and their relationships with people, there are still many unanswered questions of interest to scientists and the lay public. The author has briefly referred to the past results and formulated the unanswered questions (some as hypotheses), even suggesting possible ways to answer or test them. Although the author is now retired, his intent is to encourage young researchers beginning their academic careers to take up the torch and work on this fascinating companion animal species. Abstract After recent publication of several reviews covering research results from the last 35 years of domestic cat studies, a number of important unanswered questions and hypotheses have arisen that could interest active researchers, especially those beginning their academic careers. Some sections of this paper concern methodologies that have yielded new insights and could provide more in the future; other sections concern findings and interpretations of those that need further testing. First, hypotheses arise from combining subjective (or psychological) assessments of cat and human personality traits and observational (ethological) studies of cat–human interactions: e.g., do owners with high attachment to their cats interact differently with them than owners with low attachment levels? New analytical methods of dyadic interaction observations open the door for testing further hypotheses. In particular, the Theme® (Noldus bv, NL) program could be used to determine if there are differences between cat breeds in interaction patterns with people, which is not only of interest to owners but also therapists employing cats in their practices. Cat breed differences have been found using subjective ratings, but these need to be corroborated by direct observational data from the home setting and/or non-invasive colony observations, since ratings based on anthropomorphic projections might not be reliable. This should be done before searching for the genetic basis of such differences. Reliable information on breed differences is also needed before prescribing certain breeds for animal-assisted interventions. A model has predicted that the degree of socialization as a kitten affects cats’ responses to positive and negative experiences with unfamiliar humans and their formation of feline–human relationships later on. This needs to be tested in an ethically approved manner on cats of known socialization status and has enormous consequences for cat adoptions from animal shelters. Observations of human–cat interactions have yielded many correlations, which can be tested by non-invasive manipulations of human behavior in the home setting. Examples of these will be given and are of general interest to the cat-owning public. A review of first findings on social cognition in cats has resulted in further unanswered questions and hypotheses. Finally, two aspects of domestic cat ecology will be considered (effects on wildlife and space utilization), which are of great interest to the public and conservationists alike.
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Affiliation(s)
- Dennis C Turner
- Institute for Applied Ethology and Animal Psychology, I.E.A.P./I.E.T., 8810 Horgen, ZH, Switzerland
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14
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Gering E, Laubach ZM, Weber PSD, Soboll Hussey G, Lehmann KDS, Montgomery TM, Turner JW, Perng W, Pioon MO, Holekamp KE, Getty T. Toxoplasma gondii infections are associated with costly boldness toward felids in a wild host. Nat Commun 2021; 12:3842. [PMID: 34158487 PMCID: PMC8219747 DOI: 10.1038/s41467-021-24092-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 05/18/2021] [Indexed: 01/17/2023] Open
Abstract
Toxoplasma gondii is hypothesized to manipulate the behavior of warm-blooded hosts to promote trophic transmission into the parasite's definitive feline hosts. A key prediction of this hypothesis is that T. gondii infections of non-feline hosts are associated with costly behavior toward T. gondii's definitive hosts; however, this effect has not been documented in any of the parasite's diverse wild hosts during naturally occurring interactions with felines. Here, three decades of field observations reveal that T. gondii-infected hyena cubs approach lions more closely than uninfected peers and have higher rates of lion mortality. We discuss these results in light of 1) the possibility that hyena boldness represents an extended phenotype of the parasite, and 2) alternative scenarios in which T. gondii has not undergone selection to manipulate behavior in host hyenas. Both cases remain plausible and have important ramifications for T. gondii's impacts on host behavior and fitness in the wild.
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Affiliation(s)
- Eben Gering
- Michigan State University, Department of Integrative Biology and Program in Ecology, Evolution and Behavior, East Lansing, MI, USA
- Nova Southeastern University, Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Fort Lauderdale, FL, USA
| | - Zachary M Laubach
- Michigan State University, Department of Integrative Biology and Program in Ecology, Evolution and Behavior, East Lansing, MI, USA.
- University of Colorado Boulder, Department of Ecology and Evolutionary Biology, Boulder, CO, USA.
- Mara Hyena Project, Narok County, Kenya.
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, USA.
| | - Patty Sue D Weber
- Michigan State University, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, East Lansing, MI, USA
| | - Gisela Soboll Hussey
- Michigan State University, Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, East Lansing, MI, USA
| | - Kenna D S Lehmann
- Michigan State University, Department of Integrative Biology and Program in Ecology, Evolution and Behavior, East Lansing, MI, USA
- Mara Hyena Project, Narok County, Kenya
| | - Tracy M Montgomery
- Michigan State University, Department of Integrative Biology and Program in Ecology, Evolution and Behavior, East Lansing, MI, USA
- Mara Hyena Project, Narok County, Kenya
- Max Planck Institute of Animal Behavior, Department for the Ecology of Animal Societies, Konstanz, Germany
| | - Julie W Turner
- Michigan State University, Department of Integrative Biology and Program in Ecology, Evolution and Behavior, East Lansing, MI, USA
- Mara Hyena Project, Narok County, Kenya
- Memorial University of Newfoundland, Department of Biology, St. John's, NL, Canada
| | - Wei Perng
- LEAD Center & University of Colorado, School of Public Health, Aurora, CO, United States
| | | | - Kay E Holekamp
- Michigan State University, Department of Integrative Biology and Program in Ecology, Evolution and Behavior, East Lansing, MI, USA
- Mara Hyena Project, Narok County, Kenya
| | - Thomas Getty
- Michigan State University, Department of Integrative Biology and Program in Ecology, Evolution and Behavior, East Lansing, MI, USA
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15
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Behavioral Manipulation by Toxoplasma gondii: Does Brain Residence Matter? Trends Parasitol 2021; 37:381-390. [PMID: 33461902 DOI: 10.1016/j.pt.2020.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 12/04/2020] [Accepted: 12/27/2020] [Indexed: 11/22/2022]
Abstract
The protozoan parasite Toxoplasma gondii infects a wide range of intermediate hosts. The parasite produces brain cysts during the latent phase of its infection, in parallel to causing a loss of innate aversion in the rat host towards cat odors. Host behavioral change presumably reflects a parasitic manipulation to increase predation by definitive felid hosts, although evidence for increased predation is not yet available. In this opinion piece, we propose a neuroendocrine loop to explain the role of gonadal steroids in the parasitized hosts in mediating the behavioral manipulation. We argue that the presence of tissue cysts within the host brain is merely incidental to the behavioral change, without a necessary or sufficient role.
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16
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Borráz-León JI, Rantala MJ, Luoto S, Krams I, Contreras-Garduño J, Cerda-Molina AL, Krama T. Toxoplasma gondii and Psychopathology: Latent Infection Is Associated with Interpersonal Sensitivity, Psychoticism, and Higher Testosterone Levels in Men, but Not in Women. ADAPTIVE HUMAN BEHAVIOR AND PHYSIOLOGY 2021. [DOI: 10.1007/s40750-020-00160-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Abstract
Objective
The ability of parasites to hijack the nervous system, manipulating the host’s physiology and behavior in ways that enhance the parasite’s fitness while damaging host fitness, is a topic of ongoing research interest in evolutionary biology, but is largely overlooked in mental health research. Nevertheless, recent evidence has shown that Toxoplasma gondii infection can change host testosterone levels and influence the development of some psychiatric disorders. Here, we tested this hypothesis in a mixed sample of 213 non-clinical subjects.
Methods
Participants (nmales = 108, nfemales = 105) provided 5 ml of blood to quantify testosterone levels and Toxoplasma gondii antibodies. The Symptom Checklist-90-Revised was used to assess psychopathological symptoms.
Results
The results showed that Toxoplasma-infected men had higher testosterone levels and scored higher in Interpersonal Sensitivity and Psychoticism symptoms than non-infected men. Toxoplasma-infected women did not differ from control women.
Conclusions
Framed in an evolutionary framework, the findings suggest that the elevated testosterone levels and the expression of psychopathological symptoms can be seen as the result of the manipulation exerted by Toxoplasma gondii either to reach its definitive host or to increase its spread. Future research can benefit from integrating insights from evolutionary biology and parasite-host interactions with physiology, immunology, and mental health to develop a better understanding of mental health etiology.
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17
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Steffen HM. Wie beeinflussen Parasiten das Verhalten ihres Wirts? Die parasitäre Manipulationshypothese. Dtsch Med Wochenschr 2020; 145:1848-1854. [DOI: 10.1055/a-1220-8737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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18
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Johnson SK, Johnson PTJ. Toxoplasmosis: Recent Advances in Understanding the Link Between Infection and Host Behavior. Annu Rev Anim Biosci 2020; 9:249-264. [PMID: 33138620 DOI: 10.1146/annurev-animal-081720-111125] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
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.
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Affiliation(s)
- Stefanie K Johnson
- Leeds School of Business, University of Colorado Boulder, Boulder, Colorado 80309, USA;
| | - Pieter T J Johnson
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado 80309, USA
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19
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Crippen M. Enactive Pragmatism and Ecological Psychology. Front Psychol 2020; 11:538644. [PMID: 33192781 PMCID: PMC7606921 DOI: 10.3389/fpsyg.2020.538644] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 09/07/2020] [Indexed: 12/26/2022] Open
Abstract
A widely cited roadblock to bridging ecological psychology and enactivism is that the former identifies with realism and the latter identifies with constructivism, which critics charge is subjectivist. A pragmatic reading, however, suggests non-mental forms of constructivism that simultaneously fit core tenets of enactivism and ecological realism. After advancing a pragmatic version of enactive constructivism that does not obviate realism, I reinforce the position with an empirical illustration: Physarum polycephalum, a communal unicellular organism that leaves slime trails that form chemical barriers that it avoids in foraging explorations. Here, environmental building and sensorimotor engagement are part of the same process with P. polycephalum coordinating around self-created, affordance-bearing geographies, which nonetheless exist independently in ways described by ecological realists. For ecological psychologists, affordances are values, meaning values are external to the perceiver. I argue that agent-enacted values have the same status and thus do not obviate ecological realism or generate subjectivism. The constructivist-realist debate organizes around the emphasis that enactivists and ecological theorists respectively place on the inner constitution of organisms vs. the structure of environments. Building on alimentary themes introduced in the P. polycephalum example and also in Gibson’s work, I go on to consider how environment, brain, visceral systems, and even bacteria within them enter perceptual loops. This highlights almost unfathomable degrees of mutually modulating internal and external synchronization. It also shows instances in which internal conditions alter worldly configurations and invert values, in Gibson’s sense of the term, albeit without implying subjectivism. My aim is to cut across the somatic focus of enactive constructivism and the external environment-oriented emphasis of ecological realism and show that enactivism can enrich ecological accounts of value.
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Affiliation(s)
- Matthew Crippen
- Department of Philosophy, Grand Valley State University, Allendale Charter Township, MI, United States.,Berlin School of Mind and Brain, Humboldt University of Berlin, Berlin, Germany
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20
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Toxoplasma gondii: AnUnderestimated Threat? Trends Parasitol 2020; 36:959-969. [PMID: 33012669 DOI: 10.1016/j.pt.2020.08.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/17/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023]
Abstract
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.
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21
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Lathe R, St Clair D. From conifers to cognition: Microbes, brain and behavior. GENES BRAIN AND BEHAVIOR 2020; 19:e12680. [PMID: 32515128 DOI: 10.1111/gbb.12680] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 05/12/2020] [Accepted: 05/29/2020] [Indexed: 12/25/2022]
Abstract
A diversity of bacteria, protozoans and viruses ("endozoites") were recently uncovered within healthy tissues including the human brain. By contrast, it was already recognized a century ago that healthy plants tissues contain abundant endogenous microbes ("endophytes"). Taking endophytes as an informative precedent, we overview the nature, prevalence, and role of endozoites in mammalian tissues, centrally focusing on the brain, concluding that endozoites are ubiquitous in diverse tissues. These passengers often remain subclinical, but they are not silent. We address their routes of entry, mechanisms of persistence, tissue specificity, and potential to cause long-term behavioral changes and/or immunosuppression in mammals, where rabies virus is the exemplar. We extend the discussion to Herpesviridae, Coronaviridae, and Toxoplasma, as well as to diverse bacteria and yeasts, and debate the advantages and disadvantages that endozoite infection might afford to the host and to the ecosystem. We provide a clinical perspective in which endozoites are implicated in neurodegenerative disease, anxiety/depression, and schizophrenia. We conclude that endozoites are instrumental in the delicate balance between health and disease, including age-related brain disease, and that endozoites have played an important role in the evolution of brain function and human behavior.
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Affiliation(s)
- Richard Lathe
- Division of Infection Medicine, University of Edinburgh Medical School, Edinburgh, UK
| | - David St Clair
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK
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22
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Mathuru AS, Libersat F, Vyas A, Teseo S. Why behavioral neuroscience still needs diversity?: A curious case of a persistent need. Neurosci Biobehav Rev 2020; 116:130-141. [PMID: 32565172 DOI: 10.1016/j.neubiorev.2020.06.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/29/2020] [Accepted: 06/16/2020] [Indexed: 12/26/2022]
Abstract
In the past few decades, a substantial portion of neuroscience research has moved from studies conducted across a spectrum of animals to reliance on a few species. While this undoubtedly promotes consistency, in-depth analysis, and a better claim to unraveling molecular mechanisms, investing heavily in a subset of species also restricts the type of questions that can be asked, and impacts the generalizability of findings. A conspicuous body of literature has long advocated the need to expand the diversity of animal systems used in neuroscience research. Part of this need is utilitarian with respect to translation, but the remaining is the knowledge that historically, a diverse set of species were instrumental in obtaining transformative understanding. We argue that diversifying matters also because the current approach limits the scope of what can be discovered. Technological advancements are already bridging several practical gaps separating these two worlds. What remains is a wholehearted embrace by the community that has benefitted from past history. We suggest the time for it is now.
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Affiliation(s)
- Ajay S Mathuru
- Yale-NUS College, 12 College Avenue West, Singapore; Institute of Molecular and Cell Biology, A⁎STAR, 61 Biopolis Drive, Singapore; Dept. of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
| | - Frédéric Libersat
- Dept. of Life Sciences and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Ben Gurion University, Beer Sheva 8410501 Israel
| | - Ajai Vyas
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Serafino Teseo
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
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23
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Milne G, Fujimoto C, Bean T, Peters HJ, Hemmington M, Taylor C, Fowkes RC, Martineau HM, Hamilton CM, Walker M, Mitchell JA, Léger E, Priestnall SL, Webster JP. Infectious Causation of Abnormal Host Behavior: Toxoplasma gondii and Its Potential Association With Dopey Fox Syndrome. Front Psychiatry 2020; 11:513536. [PMID: 33192643 PMCID: PMC7525129 DOI: 10.3389/fpsyt.2020.513536] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 09/02/2020] [Indexed: 11/13/2022] Open
Abstract
The apicomplexan parasite Toxoplasma gondii, the causative agent of toxoplasmosis, can infect all warm-blooded animals. T. gondii can subtly alter host behaviors-either through manipulation to enhance transmission to the feline definitive host or as a side-effect, or "constraint," of infection. In humans, T. gondii infection, either alone or in association with other co-infecting neurotropic agents, has been reliably associated with both subtle behavioral changes and, in some cases, severe neuropsychiatric disorders, including schizophrenia. Research on the potential impact of T. gondii on the behavior of other long-lived naturally infected hosts is lacking. Recent studies reported a large number of wild red foxes exhibiting a range of aberrant behavioral traits, subsequently classified as Dopey Fox Syndrome (DFS). Here we assessed the potential association between T. gondii and/or other neurotropic agents with DFS. Live, captive foxes within welfare centers were serologically tested for T. gondii and, if they died naturally, PCR-tested for vulpine circovirus (FoxCV). Post-mortem pseudo-control wild foxes, obtained from pest management companies, were PCR-tested for T. gondii, FoxCV, canine distemper virus (CDV), canine adenovirus type (CAV)-1 and CAV-2. We also assessed, using non-invasive assays, whether T. gondii-infected foxes showed subtle behavioral alterations as observed among infected rodent (and other) hosts, including altered activity, risk, and stress levels. All foxes tested negative for CAV, CDV, CHV, and DogCV. DFS was found to be associated with singular T. gondii infection (captives vs. pseudo-controls, 33.3% (3/9) vs. 6.8% (5/74)) and singular FoxCV infection (66.7% (6/9) vs. 11.1% (1/9)) and with T. gondii/FoxCV co-infection (33.3% (3/9) vs. 11.1% (1/9)). Overall, a higher proportion of captive foxes had signs of neuroinflammation compared to pseudo-controls (66.7% (4/6) vs. 11.1% (1/9)). Consistent with behavioral changes seen in infected rodents, T. gondii-infected foxes displayed increased attraction toward feline odor (n=6 foxes). These preliminary results suggest that wild foxes with DFS are infected with T. gondii and likely co-infected with FoxCV and/or another co-infecting neurotropic agent. Our findings using this novel system have important implications for our understanding of both the impact of parasites on mammalian host behavior in general and, potentially, of the infectious causation of certain neuropsychiatric disorders.
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Affiliation(s)
- Gregory Milne
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom.,London Centre for Neglected Tropical Disease Research, Imperial College London Faculty of Medicine, London, United Kingdom
| | - Chelsea Fujimoto
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom
| | - Theodor Bean
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom
| | - Harry J Peters
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom
| | | | - Charly Taylor
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom
| | - Robert C Fowkes
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom
| | - Henny M Martineau
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom
| | - Clare M Hamilton
- Parasitology Division, Moredun Research Institute, Edinburgh, United Kingdom
| | - Martin Walker
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom.,London Centre for Neglected Tropical Disease Research, Imperial College London Faculty of Medicine, London, United Kingdom
| | - Judy A Mitchell
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom
| | - Elsa Léger
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom.,London Centre for Neglected Tropical Disease Research, Imperial College London Faculty of Medicine, London, United Kingdom
| | - Simon L Priestnall
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom
| | - Joanne P Webster
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom.,London Centre for Neglected Tropical Disease Research, Imperial College London Faculty of Medicine, London, United Kingdom
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24
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Burgdorf KS, Trabjerg BB, Pedersen MG, Nissen J, Banasik K, Pedersen OB, Sørensen E, Nielsen KR, Larsen MH, Erikstrup C, Bruun-Rasmussen P, Westergaard D, Thørner LW, Hjalgrim H, Paarup HM, Brunak S, Pedersen CB, Torrey EF, Werge T, Mortensen PB, Yolken RH, Ullum H. Large-scale study of Toxoplasma and Cytomegalovirus shows an association between infection and serious psychiatric disorders. Brain Behav Immun 2019; 79:152-158. [PMID: 30685531 DOI: 10.1016/j.bbi.2019.01.026] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/11/2019] [Accepted: 01/23/2019] [Indexed: 10/27/2022] Open
Abstract
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.
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Affiliation(s)
| | - Betina B Trabjerg
- National Centre for Register-Based Research, Aarhus University, Aarhus, Denmark; The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark
| | - Marianne Giørtz Pedersen
- National Centre for Register-Based Research, Aarhus University, Aarhus, Denmark; The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark; Centre for Integrated Register-based Research, CIRRAU, Aarhus University, Aarhus, Denmark
| | - Janna Nissen
- Department of Clinical Immunology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Karina Banasik
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | | | - Erik Sørensen
- Department of Clinical Immunology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Kaspar René Nielsen
- Department of Clinical Immunology, Aalborg University Hospital, Aalborg, Denmark
| | - Margit Hørup Larsen
- Department of Clinical Immunology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Christian Erikstrup
- Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark
| | - Peter Bruun-Rasmussen
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - David Westergaard
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Lise Wegner Thørner
- Department of Clinical Immunology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Henrik Hjalgrim
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark,; Department of Hematology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | | | - Søren Brunak
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Carsten B Pedersen
- National Centre for Register-Based Research, Aarhus University, Aarhus, Denmark; The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark; Centre for Integrated Register-based Research, CIRRAU, Aarhus University, Aarhus, Denmark
| | | | - Thomas Werge
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark; Institute of Biological Psychiatry, Mental Health Centre Sct. Hans, Copenhagen University Hospital, Roskilde, Denmark
| | - Preben Bo Mortensen
- National Centre for Register-Based Research, Aarhus University, Aarhus, Denmark; The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Denmark; Centre for Integrated Register-based Research, CIRRAU, Aarhus University, Aarhus, Denmark
| | - Robert H Yolken
- Stanley Division of Developmental Neurovirology, Stanley Neurovirology Laboratory, Johns Hopkins University, USA
| | - Henrik Ullum
- Department of Clinical Immunology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
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25
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Chen X, Chen B, Hou X, Zheng C, Yang X, Ke J, Hu X, Tan F. Association between Toxoplasma gondii infection and psychiatric disorders in Zhejiang, Southeastern China. Acta Trop 2019; 192:82-86. [PMID: 30731066 DOI: 10.1016/j.actatropica.2019.02.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 02/02/2019] [Accepted: 02/02/2019] [Indexed: 12/13/2022]
Abstract
Increased rates of exposure to Toxoplasma gondii have been found in patients with psychiatric disorders globally, but there is scarce information about the epidemiology of T. gondii infection in psychiatric patients in Zhejiang Province, Southeastern China. In a case-control survey, we measured IgG and IgM class antibodies against T. gondii in 798 patients from a public psychiatric hospital in the city of Wenzhou, Zhejiang Province, and in 681 non-psychiatric controls from the general population in the same region. Subjects in each group were matched by sex and age with an enzyme-linked immunoassay. Seroprevalence of anti-Toxoplasma IgG antibodies in psychiatric patients (13.3%, 106/798) was significantly higher than in the control population (9.4%, 64/681) (P = 0.022). Anti-Toxoplasma IgM antibodies were also significantly higher in the psychiatric patients (4.1%, 33/798) than in the control group (1.9%, 13/681) (P = 0.016). Additionally, we found significantly elevated seropositive rates of anti-Toxoplasma IgG and IgM in patients with schizophrenia, as well as those with bipolar disorder. The identification of specific anti-Toxoplasma antibodies in psychiatric patients may be useful for assessing infection and timely initiation of treatment.
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Affiliation(s)
- Xiaojian Chen
- Department of Clinical laboratory, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Bi Chen
- Department of Clinical laboratory, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiangqing Hou
- Department of Preventive Medicine, School of Public Health, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Cunqing Zheng
- Department of Clinical laboratory, Wenzhou Seventh People's Hospital, Wenzhou, Zhejiang, China
| | - Xunjun Yang
- Department of Clinical laboratory, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jiangqiong Ke
- Department of Neurology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xin Hu
- School of Medical laboratory science and school of life science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Feng Tan
- Department of Parasitology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China.
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Latent toxoplasmosis and olfactory functions of Rh positive and Rh negative subjects. PLoS One 2018; 13:e0209773. [PMID: 30589911 PMCID: PMC6307871 DOI: 10.1371/journal.pone.0209773] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 12/11/2018] [Indexed: 12/11/2022] Open
Abstract
Backgrounds The prevalence of toxoplasmosis is higher in schizophrenics than in the general population. It has been suggested that certain symptoms of schizophrenia, including changes in olfactory functions, are in fact symptoms of toxoplasmosis that can be easily detected in schizophrenics only due to the increased prevalence of toxoplasmosis in this population. Schizophrenics have impaired identification of odors and lower sensitivity of odor detection, however, no information about these parameters of non-schizophrenic Toxoplasma-infected subjects is available. Methods Here we searched for differences in olfactory functions between 62 infected and 61 noninfected non-schizophrenic subjects using the case-controls experimental design. Results The infected men scored better than the non-infected controls in the standard odor-identification test. The infected women rated all smells as more intensive while the infected men rated nearly all smells as less intensive. Infected women rated the pleasantness of the smell of the cat urine as higher than the non-infected women and the opposite was true for the men–in contrast, higher pleasantness of odor in infected men and lower in infected women were observed and described in the 2011 study. Toxoplasmosis, Rh, and toxoplasmosis-Rh interaction were not associated with the rated pleasantness of the smell of other stimuli. However, our sample contained only 17 Rh negative men and 30 Rh negative women. Therefore, all results concerning the main effects of Rh factor and the interaction with Rh factor must be considered only preliminary. Conclusions Our results suggest that latent toxoplasmosis is associated with changes in the olfactory functions in humans; however, the observed changes differ from those observed in schizophrenics.
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27
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Behavioral evaluation of BALB/c (Mus musculus) mice infected with genetically distinct strains of Toxoplasma gondii. Microb Pathog 2018; 126:279-286. [PMID: 30447421 DOI: 10.1016/j.micpath.2018.11.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 11/09/2018] [Accepted: 11/13/2018] [Indexed: 02/07/2023]
Abstract
In relation to behavioral changes in rodents infected with Toxoplasma gondii (T. gondii), it is believed that the genotype of the infecting strain can have some influence. In this sense, the present work has sought to evaluate the effect of chronic infection by genetically distinct cystogenic strains of T. gondii on the behavior of mice. For this, experimental models of infection with ME-49 (type II) and VEG (type III) strains were developed in isogenic BALB/c mice. ELISA test was performed to evaluate the humoral immune response and real-time PCR test to quantify parasites in the CNS. Behavioral tests such as passive avoidance, open-field and Y-maze tests were also used for, respectively, evaluation of learning and memory, locomotor activity and aversion to feline odor. The results showed that mice infected with VEG strain had higher total IgG level of anti-toxoplasma, higher tissue burden of T. gondii in the CNS, reduction in the long-term memory, lower activity (mobility) and lower aversion to cat urine and l-felinine than mice infected with ME-49 strain. The results suggest that different T. gondii genotypes have a differential impact on behavioral changes in infected mice.
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28
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Houdek P. Economic Holobiont: Influence of Parasites, Microbiota and Chemosignals on Economic Behavior. Front Behav Neurosci 2018; 12:77. [PMID: 29765310 PMCID: PMC5938411 DOI: 10.3389/fnbeh.2018.00077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 04/09/2018] [Indexed: 11/29/2022] Open
Abstract
The article is a perspective on utilization of microorganisms and chemosignals in studying human economic behavior. Research in biological roots of economic development has already confirmed that parasitic pressure influenced the creation and development of cultural norms and institutions. However, other effects of microorganisms on human groups and individual decision-making and behavior are heavily understudied. The perspective discusses how parasitic infections, sexually transmitted organisms and microbiota (i.e., “human holobiont”) could causally influence risk-seeking behavior, impulsivity, social dominance, empathy, political views and gender differences. As a case study, the parasite Toxoplasma gondii and its influence on economic preferences, personal characteristics and human appearance are examined. I also briefly review how chemosignals influence decision-making, particularly in the social preferences domain. I mention some predictions that arise from the paradigm of economic holobiont for the economic science. The conclusion summarizes limitations of the discussed findings and the stated speculations.
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Affiliation(s)
- Petr Houdek
- Faculty of Social and Economic Studies, Jan Evangelista Purkyně University in Ústí nad Labem, Ústí nad Labem, Czechia
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29
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Gatkowska J, Wieczorek M, Dziadek B, Dzitko K, Dziadek J, Długońska H. Assessment of the antigenic and neuroprotective activity of the subunit anti-Toxoplasma vaccine in T. gondii experimentally infected mice. Vet Parasitol 2018; 254:82-94. [PMID: 29657017 DOI: 10.1016/j.vetpar.2018.02.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 02/22/2018] [Accepted: 02/28/2018] [Indexed: 11/30/2022]
Abstract
The aim of this study was to evaluate the immunogenic and immunoprotective activities and to determine the neuroprotective capacity of the tetravalent vaccine containing selected recombinant T. gondii antigens (ROP2 + ROP4 + SAG1 + MAG1) administered with safe adjuvants (MPL and alum) using male and female inbred mice. The tested antigenic combination provided partial protection against brain cyst formation, especially in males (reduction in cyst burden by 72%). The decrease in cyst burden was observed for the whole brain as well as for specified brain regions associated with natural defensive behaviors, emotion processing and integration of motor and sensory stimuli. The vaccine triggered a strong, specific immune response, regardless of sex, which was characterized by the antigen-specific in vitro synthesis of cytokines (IL-2, IFN-γ and IL-10) and in vivo production of systemic IgG1 and IgG2a immunoglobulins. Immunization prior to the parasite challenge seemed to influence T. gondii - associated behavioral and neurochemical changes, although the impact of vaccination strongly depended on sex and time post-infection. Interestingly, in the vaccinated and T. gondii infected mice there was a significant delay in the parasite-induced loss of aversion toward cat smell (cats are the definitive hosts of the parasite). The regained attraction toward feline scent in vaccinated males, observed during chronic parasite invasion, correlated with the increase in the dopamine metabolism.
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Affiliation(s)
- Justyna Gatkowska
- Department of Immunoparasitology, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Łódź, Banacha 12/16, Poland.
| | - Marek Wieczorek
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Łódź, Pomorska 141/143, Poland.
| | - Bożena Dziadek
- Department of Immunoparasitology, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Łódź, Banacha 12/16, Poland.
| | - Katarzyna Dzitko
- Department of Immunoparasitology, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Łódź, Banacha 12/16, Poland.
| | - Jarosław Dziadek
- Institute of Medical Biology, Polish Academy of Sciences, 93-232 Łódź, Lodowa 106, Poland.
| | - Henryka Długońska
- Department of Immunoparasitology, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Łódź, Banacha 12/16, Poland.
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30
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Is there a relation between the manipulative activity of Toxoplasma and personalized medicine? Expert Rev Anti Infect Ther 2017; 16:1-3. [DOI: 10.1080/14787210.2018.1417838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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31
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Abdulai-Saiku S, Hegde A, Vyas A, Mitra R. Effects of stress or infection on rat behavior show robust reversals due to environmental disturbance. F1000Res 2017; 6:2097. [PMID: 29416851 PMCID: PMC5782406 DOI: 10.12688/f1000research.13171.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/28/2017] [Indexed: 12/16/2022] Open
Abstract
Background: The behavior of animals is intricately linked to the environment; a relationship that is often studied in laboratory conditions by using environmental perturbations to study biological mechanisms underlying the behavioral change. Methods: This study pertains to two such well-studied and well-replicated perturbations, i.e., stress-induced anxiogenesis and Toxoplasmagondii -induced loss of innate fear. Here, we demonstrate that behavioral outcomes of these experimental manipulations are contingent upon the ambient quality of the wider environment where animal facilities are situated. Results: During late 2014 and early 2015, a building construction project started adjacent to our animal facility. During this phase, we observed that maternal separation stress caused anxiolysis, rather than historically observed anxiogenesis, in laboratory rats. We also found that Toxoplasma gondii infection caused an increase, rather than historically observed decrease, in innate aversion to predator odors in rats. Conclusion: These observations suggest that effects of stress and Toxoplasma gondii are dependent on variables in the environment that often go unreported in the published literature.
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Affiliation(s)
- Samira Abdulai-Saiku
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Akshaya Hegde
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Ajai Vyas
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Rupshi Mitra
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
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32
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Abdulai-Saiku S, Hegde A, Vyas A, Mitra R. Effects of stress or infection on rat behavior show robust reversals due to environmental disturbance. F1000Res 2017; 6:2097. [PMID: 29416851 PMCID: PMC5782406 DOI: 10.12688/f1000research.13171.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/30/2017] [Indexed: 12/13/2022] Open
Abstract
Background: The behavior of animals is intricately linked to the environment; a relationship that is often studied in laboratory conditions by using environmental perturbations to study biological mechanisms underlying the behavioral change. Methods: This study pertains to two such well-studied and well-replicated perturbations, i.e., stress-induced anxiogenesis and Toxoplasma-induced loss of innate fear. Here, we demonstrate that behavioral outcomes of these experimental manipulations are contingent upon the ambient quality of the wider environment where animal facilities are situated. Results: During late 2014 and early 2015, a building construction project started adjacent to our animal facility. During this phase, we observed that maternal separation stress caused anxiolysis, rather than historically observed anxiogenesis, in laboratory rats. We also found that Toxoplasma infection caused an increase, rather than historically observed decrease, in innate aversion to predator odors in rats. Conclusion: These observations suggest that effects of stress and Toxoplasma are dependent on variables in the environment that often go unreported in the published literature.
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Affiliation(s)
- Samira Abdulai-Saiku
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Akshaya Hegde
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Ajai Vyas
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Rupshi Mitra
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
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33
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Flegr J. Does Toxoplasma infection increase sexual masochism and submissiveness? Yes and no. Commun Integr Biol 2017; 10:e1303590. [PMID: 29259726 PMCID: PMC5731508 DOI: 10.1080/19420889.2017.1303590] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 03/02/2017] [Accepted: 03/02/2017] [Indexed: 12/19/2022] Open
Abstract
The parasite Toxoplasma needs to get from its intermediate hosts, e.g. rodents, to its definitive hosts, cats, by predation. To increase the probability of this occurrence, Toxoplasma manipulates the behavior of its hosts, for example, by the demethylation of promoters of certain genes in the host's amygdala. After this modification, the stimuli that normally activate fear-related circuits, e.g., the smell of a cat in mice, or smell of leopards in chimpanzees, start to additionally co-activate sexual arousal-related circuits in the infected animals. In humans, the increased attraction to masochistic sexual practices was recently observed in a study performed on 36,564 subjects. Here I show that lower rather than higher attraction to sexual masochism and submissiveness among infected subjects is detected if simple univariate tests instead of multivariate tests are applied to the same data. I show and discuss that when analyzing multiple effects of complex stimuli on complex biological systems we need to use multivariate techniques and very large data sets. We must also accept the fact that any single factor usually explains only a small fraction of variability in the focal variable.
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Affiliation(s)
- Jaroslav Flegr
- Division of Biology, Faculty of Science, Charles University, Prague, Czech Republic.,National Institute of Mental Health, Klecany, Czechia
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Ahmad Z, Moustafa YW, Stiller JW, Pavlovich MA, Raheja UK, Gragnoli C, Snitker S, Nazem S, Dagdag A, Fang B, Fuchs D, Lowry CA, Postolache TT. Sleep onset insomnia, daytime sleepiness and sleep duration in relationship to Toxoplasma gondii IgG seropositivity and serointensity. Pteridines 2017; 28:195-204. [PMID: 29657364 PMCID: PMC5894504 DOI: 10.1515/pterid-2017-0010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Toxoplasma gondii (T. gondii) infects central nervous tissue and is kept in relative dormancy by a healthy immune system. Sleep disturbances have been found to precipitate mental illness, suicidal behavior and car accidents, which have been previously linked to T. gondii as well. We speculated that if sleep disruption, particularly insomnia, would mediate, at least partly, the link between T. gondii infection and related behavioral dysregulation, then we would be able to identify significant associations between sleep disruption and T. gondii. The mechanisms for such an association may involve dopamine (DA) production by T. gondii, or collateral effects of immune activation necessary to keep T. gondii in check. Sleep questionnaires from 2031 Old Order Amish were analyzed in relationship to T. gondii-IgG antibodies measured by enzyme-linked immunosorbent assay (ELISA). Toxoplasma gondii seropositivity and serointensity were not associated with any of the sleep latency variables or Epworth Sleepiness Scale (ESS). A secondary analysis identified, after adjustment for age group, a statistical trend toward shorter sleep duration in seropositive men (p = 0.07). In conclusion, it is unlikely that sleep disruption mediates links between T. gondii and mental illness or behavioral dysregulation. Trending gender differences in associations between T. gondii and shorter sleep need further investigation.
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Affiliation(s)
- Zaki Ahmad
- Mood and Anxiety Program, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Yara W. Moustafa
- Mood and Anxiety Program, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA; and Saint Elizabeths’ Hospital, Psychiatry Residency Training Program, Washington, DC, USA
| | - John W. Stiller
- Mood and Anxiety Program, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA; Saint Elizabeths’ Hospital, Department of Neurology, Washington, DC, USA; and Maryland State Athletic Commission, Baltimore, MD, USA
| | - Mary A. Pavlovich
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA; and Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Uttam K. Raheja
- Mood and Anxiety Program, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA; and Child and Adolescent Psychiatry Residency Program, Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA
| | - Claudia Gragnoli
- Division of Endocrinology, Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA; Department of Public Health Sciences, Penn State College of Medicine, Hershey, PA, USA; and Molecular Biology Laboratory, Bios Biotech Multi Diagnostic Health Center, Rome, Italy
| | - Soren Snitker
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Sarra Nazem
- Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Denver, CO, USA; Department of Psychiatry, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA; and Department of Physical Medicine and Rehabilitation, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - Aline Dagdag
- Mood and Anxiety Program, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Beverly Fang
- Mood and Anxiety Program, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Dietmar Fuchs
- Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Christopher A. Lowry
- Department of Integrative Physiology and Center for Neuroscience, University of Colorado Boulder, Boulder, CO, USA; Department of Physical Medicine and Rehabilitation and Center for Neuroscience, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA; and Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Veterans Integrated Service Network (VISN) 19, Military and Veteran Microbiome: Consortium for Research and Education (MVM-CoRE), Denver, CO, USA
| | - Teodor T. Postolache
- Mood and Anxiety Program, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA; Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Veterans Integrated Service Network (VISN) 19, Military and Veteran Microbiome: Consortium for Research and Education (MVM-CoRE), Denver, CO, USA; and Mental Illness Research, Education and Clinical Center (MIRECC), Veterans Integrated Service Network (VISN) 5, VA Capitol Health Care Network, Baltimore, MD, USA
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35
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Šebánková B, Flegr J. Physical and Mental Health Status in Toxoplasma-Infected Women before and 3 Years after They Learn about Their Infection: Manipulation or Side-Effects of Impaired Health? Front Ecol Evol 2017. [DOI: 10.3389/fevo.2017.00144] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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36
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Abdulai-Saiku S, Vyas A. Loss of predator aversion in female rats after Toxoplasma gondii infection is not dependent on ovarian steroids. Brain Behav Immun 2017; 65:95-98. [PMID: 28400143 DOI: 10.1016/j.bbi.2017.04.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 04/07/2017] [Accepted: 04/07/2017] [Indexed: 01/07/2023] Open
Abstract
Toxoplasma gondii infection reduces aversion to cat odors in male rats. Relevant proximate mechanisms include interaction of gonadal testosterone and brain nonapeptide arginine-vasopressin. Both of these substrates are sexually dimorphic with preferential expression in males; suggesting either absence of behavioral change in females or mediation by analogous neuroendocrine substrates. Here we demonstrate that Toxoplasma gondii infection reduces aversion to cat odor in female rats. This change is not accompanied by altered steroid hormones; cannot be rescued by gonadal removal; and, does not depend on arginine-vasopressin. Thus behavioral change in males and female occur through non-analogous mechanisms that remain hitherto unknown.
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Affiliation(s)
- Samira Abdulai-Saiku
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Ajai Vyas
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
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37
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Ngô HM, Zhou Y, Lorenzi H, Wang K, Kim TK, Zhou Y, El Bissati K, Mui E, Fraczek L, Rajagopala SV, Roberts CW, Henriquez FL, Montpetit A, Blackwell JM, Jamieson SE, Wheeler K, Begeman IJ, Naranjo-Galvis C, Alliey-Rodriguez N, Davis RG, Soroceanu L, Cobbs C, Steindler DA, Boyer K, Noble AG, Swisher CN, Heydemann PT, Rabiah P, Withers S, Soteropoulos P, Hood L, McLeod R. Toxoplasma Modulates Signature Pathways of Human Epilepsy, Neurodegeneration & Cancer. Sci Rep 2017; 7:11496. [PMID: 28904337 PMCID: PMC5597608 DOI: 10.1038/s41598-017-10675-6] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 08/14/2017] [Indexed: 12/27/2022] Open
Abstract
One third of humans are infected lifelong with the brain-dwelling, protozoan parasite, Toxoplasma gondii. Approximately fifteen million of these have congenital toxoplasmosis. Although neurobehavioral disease is associated with seropositivity, causality is unproven. To better understand what this parasite does to human brains, we performed a comprehensive systems analysis of the infected brain: We identified susceptibility genes for congenital toxoplasmosis in our cohort of infected humans and found these genes are expressed in human brain. Transcriptomic and quantitative proteomic analyses of infected human, primary, neuronal stem and monocytic cells revealed effects on neurodevelopment and plasticity in neural, immune, and endocrine networks. These findings were supported by identification of protein and miRNA biomarkers in sera of ill children reflecting brain damage and T. gondii infection. These data were deconvoluted using three systems biology approaches: "Orbital-deconvolution" elucidated upstream, regulatory pathways interconnecting human susceptibility genes, biomarkers, proteomes, and transcriptomes. "Cluster-deconvolution" revealed visual protein-protein interaction clusters involved in processes affecting brain functions and circuitry, including lipid metabolism, leukocyte migration and olfaction. Finally, "disease-deconvolution" identified associations between the parasite-brain interactions and epilepsy, movement disorders, Alzheimer's disease, and cancer. This "reconstruction-deconvolution" logic provides templates of progenitor cells' potentiating effects, and components affecting human brain parasitism and diseases.
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Affiliation(s)
- Huân M Ngô
- The University of Chicago, Chicago, IL, 60637, USA.,Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA.,BrainMicro LLC, New Haven, CT, 06511, USA
| | - Ying Zhou
- The University of Chicago, Chicago, IL, 60637, USA
| | | | - Kai Wang
- Institute for Systems Biology, Seattle, WA, 98109, USA
| | - Taek-Kyun Kim
- Institute for Systems Biology, Seattle, WA, 98109, USA
| | - Yong Zhou
- Institute for Systems Biology, Seattle, WA, 98109, USA
| | | | - Ernest Mui
- The University of Chicago, Chicago, IL, 60637, USA
| | | | | | | | - Fiona L Henriquez
- The University of Chicago, Chicago, IL, 60637, USA.,FLH, IBEHR School of Science and Sport, University of the West of Scotland, Paisley, PA1 2BE, UK
| | - Alexandre Montpetit
- Genome Quebec, Montréal, QC H3B 1S6, Canada; McGill University, Montréal, QC H3A 0G4, Canada
| | - Jenefer M Blackwell
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, United Kingdom.,Telethon Kids Institute, The University of Western Australia, Perth, Australia
| | - Sarra E Jamieson
- Telethon Kids Institute, The University of Western Australia, Perth, Australia
| | | | | | | | | | | | | | - Charles Cobbs
- California Pacific Medical Center, San Francisco, CA, 94114, USA
| | - Dennis A Steindler
- JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, 02111, USA
| | - Kenneth Boyer
- Rush University Medical Center, Chicago, IL, 60612, USA
| | - A Gwendolyn Noble
- Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Charles N Swisher
- Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | | | - Peter Rabiah
- Northshore University Health System, Evanston, IL, 60201, USA
| | | | | | - Leroy Hood
- Institute for Systems Biology, Seattle, WA, 98109, USA
| | - Rima McLeod
- The University of Chicago, Chicago, IL, 60637, USA.
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38
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Predictors of Toxoplasma gondii infection in Czech and Slovak populations: the possible role of cat-related injuries and risky sexual behavior in the parasite transmission. Epidemiol Infect 2017; 145:1351-1362. [PMID: 28183362 DOI: 10.1017/s095026881700019x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The protozoan Toxoplasma gondii infects about one-third of the world's population. The consumption of raw meat, contact with cats, contact with soil, and ingestion of food or water contaminated with soil are considered to be the most important sources of infection. Still in most women who were infected during pregnancy, no definitive source of infection is found. In 2014-2016, independent sources of T. gondii infection were searched for by gathering epidemiological data from 1865 (519 infected) responders. Touching garden soil (odds ratio (OR) 3·14, 95% confidence interval (CI) 1·3-6·35), sustaining cat-related injuries (OR 2·16, 95% CI 1·25-3·74), and eating improperly washed root vegetables (OR 1·71, 95% CI 1·02-2·87), but not risky sexual behavior (OR 1·22, 95% CI 0·79-1·90), were the predictors of infection. The seroprevalence of T. gondii infection had been increasing up to ages 35-50 in men and ages 50-54 in women. Past those ages, seroprevalence of toxoplasmosis has been decreasing. This suggests that the natural decrease of anamnestic antibodies concentrations over time leads to positivity-to-negativity seroconversion in many subjects. If this is true, then the prevalence of T. gondii infection in a general population and its potential impacts on public health could be much larger than generally believed.
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Klein RS, Garber C, Howard N. Infectious immunity in the central nervous system and brain function. Nat Immunol 2017; 18:132-141. [PMID: 28092376 DOI: 10.1038/ni.3656] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 12/02/2016] [Indexed: 11/09/2022]
Abstract
Inflammation is emerging as a critical mechanism underlying neurological disorders of various etiologies, yet its role in altering brain function as a consequence of neuroinfectious disease remains unclear. Although acute alterations in mental status due to inflammation are a hallmark of central nervous system (CNS) infections with neurotropic pathogens, post-infectious neurologic dysfunction has traditionally been attributed to irreversible damage caused by the pathogens themselves. More recently, studies indicate that pathogen eradication within the CNS may require immune responses that interfere with neural cell function and communication without affecting their survival. In this Review we explore inflammatory processes underlying neurological impairments caused by CNS infection and discuss their potential links to established mechanisms of psychiatric and neurodegenerative diseases.
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Affiliation(s)
- Robyn S Klein
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Charise Garber
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nicole Howard
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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40
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Poirotte C, Kappeler PM, Ngoubangoye B, Bourgeois S, Moussodji M, Charpentier MJE. Morbid attraction to leopard urine in Toxoplasma-infected chimpanzees. Curr Biol 2016; 26:R98-9. [PMID: 26859275 DOI: 10.1016/j.cub.2015.12.020] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Parasites are sometimes capable of inducing phenotypic changes in their hosts to improve transmission [1]. Toxoplasma gondii, a protozoan that infects a broad range of warm-blooded species, is one example that supports the so-called 'parasite manipulation hypothesis': it induces modifications in rodents' olfactory preferences, converting an innate aversion for cat odor into attraction and probably favoring trophic transmission to feline species, its only definitive hosts [2]. In humans, T. gondii induces behavioral modifications such as personality changes, prolonged reaction times and decreased long-term concentration [3]. However, modern humans are not suitable intermediate hosts because they are no longer preyed upon by felines. Consequently, behavioral modifications in infected people are generally assumed to be side effects of toxoplasmosis or residual manipulation traits that evolved in appropriate intermediate hosts. An alternative hypothesis, however, states that these changes result from parasite manipulative abilities that evolved when human ancestors were still under significant feline predation [3,4]. As such, T. gondii also alters olfactory preferences in humans; infected men rate cat urine, but not tiger urine, as pleasant while non-infected men do not [5]. To unravel the origin of Toxoplasma-induced modifications in humans, we performed olfactory tests on a living primate still predated by a feline species. We found in our closest relative, the chimpanzee (Pan troglodytes troglodytes), that Toxoplasma-infected (TI) animals lost their innate aversion towards the urine of leopards (Panthera pardus), their only natural predator. By contrast, we observed no clear difference in the response of TI and Toxoplasma-non-infected (TN) animals towards urine collected from other definitive feline hosts that chimpanzees do not encounter in nature. Although the adaptive value of parasitically induced behavior should be assessed carefully, we suggest that the behavioral modification we report could increase the probability of chimpanzee predation by leopards for the parasite's own benefit. This possible parasite adaptation would hence suggest that Toxoplasma-induced modifications in modern humans are an ancestral legacy of our evolutionary past.
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Affiliation(s)
- Clémence Poirotte
- CEFE-CNRS UMR 5175, 1919 Route de Mende, 34293 Montpellier Cedex 5, France.
| | - Peter M Kappeler
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
| | - Barthelemy Ngoubangoye
- Centre de Primatologie, Centre International de Recherche Médicale de Franceville (CIRMF), BP 769, Franceville, Gabon
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41
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Flegr J, Kuba R. The Relation of Toxoplasma Infection and Sexual Attraction to Fear, Danger, Pain, and Submissiveness. EVOLUTIONARY PSYCHOLOGY 2016. [DOI: 10.1177/1474704916659746] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Behavioral patterns, including sexual behavioral patterns, are usually understood as biological adaptations increasing the fitness of their carriers. Many parasites, so-called manipulators, are known to induce changes in the behavior of their hosts to increase their own fitness. Such changes are also induced by a parasite of cats, Toxoplasma gondii. The most remarkable change is the fatal attraction phenomenon, the switch of infected mice’s and rat’s native fear of the smell of cats toward an attraction to this smell. The stimuli that activate fear-related circuits in healthy rodents start to also activate sex-related circuits in the infected animals. An analogy of the fatal attraction phenomenon has also been observed in infected humans. Therefore, we tried to test a hypothesis that sexual arousal by fear-, violence-, and danger-related stimuli occurs more frequently in Toxoplasma-infected subjects. A cross-sectional cohort study performed on 36,564 subjects (5,087 Toxoplasma free and 741 Toxoplasma infected) showed that infected and noninfected subjects differ in their sexual behavior, fantasies, and preferences when age, health, and the size of the place where they spent childhood were controlled ( F(24, 3719) = 2.800, p < .0001). In agreement with our a priori hypothesis, infected subjects are more often aroused by their own fear, danger, and sexual submission although they practice more conventional sexual activities than Toxoplasma-free subjects. We suggest that the later changes can be related to a decrease in the personality trait of novelty seeking in infected subjects, which is potentially a side effect of increased concentration of dopamine in their brain.
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Affiliation(s)
- Jaroslav Flegr
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Prague, Czech Republic
| | - Radim Kuba
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Prague, Czech Republic
- National Institute of Mental Health, Klecany, Czech Republic
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42
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Elsheikha HM, Büsselberg D, Zhu XQ. The known and missing links between Toxoplasma gondii and schizophrenia. Metab Brain Dis 2016; 31:749-59. [PMID: 27041387 DOI: 10.1007/s11011-016-9822-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/20/2016] [Indexed: 12/14/2022]
Abstract
Toxoplasma gondii, an intracellular protozoan parasite, has a striking predilection for infecting the Central Nervous System and has been linked to an increased incidence of a number of psychiatric diseases. Several in vitro and in vivo studies have shown that T. gondii infection can affect the structure, bioenergetics and function of brain cells, and alters several host cell processes, including dopaminergic, tryptophan-kynurenine, GABAergic, AKT1, Jak/STAT, and vasopressinergic pathways. These mechanisms underlying the neuropathology of latent toxoplasmosis seem to operate also in schizophrenia, supporting the link between the two disorders. Better understanding of the intricate parasite-neuroglial communications holds the key to unlocking the mystery of T. gondii-mediated schizophrenia and offers substantial prospects for the development of disease-modifying therapies.
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Affiliation(s)
- Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, Leicestershire, LE12 5RD, UK.
| | - Dietrich Büsselberg
- Weill Cornell Medical College in Qatar, Qatar Foundation - Education City, P.O. Box: 24144, Doha, Qatar
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, People's Republic of China
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43
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44
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Tan D, Vyas A. Toxoplasma gondii infection and testosterone congruently increase tolerance of male rats for risk of reward forfeiture. Horm Behav 2016; 79:37-44. [PMID: 26774464 DOI: 10.1016/j.yhbeh.2016.01.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 01/01/2016] [Accepted: 01/11/2016] [Indexed: 12/26/2022]
Abstract
Decision making under risk involves balancing the potential of gaining rewards with the possibility of loss and/or punishment. Tolerance to risk varies between individuals. Understanding the biological basis of risk tolerance is pertinent because excessive tolerance contributes to adverse health and safety outcomes. Yet, not much is known about biological factors mediating inter-individual variability in this regard. We investigate if latent Toxoplasma gondii infection can cause risk tolerance. Using a rodent model of the balloon analogous risk task, we show that latent T. gondii infection leads to a greater tolerance of reward forfeiture. Furthermore, effects of the infection on risk can be recapitulated with testosterone supplementation alone, demonstrating that greater testosterone synthesis by the host post-infection is sufficient to change risk tolerance. T. gondii is a frequent parasite of humans and animals. Thus, the infection status can potentially explain some of the inter-individual variability in the risky decision making.
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Affiliation(s)
- Donna Tan
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Ajai Vyas
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
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45
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Flegr J, Hodný Z. Cat scratches, not bites, are associated with unipolar depression--cross-sectional study. Parasit Vectors 2016; 9:8. [PMID: 26728406 PMCID: PMC4700762 DOI: 10.1186/s13071-015-1290-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 12/28/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A recent study performed on 1.3 million patients showed a strong association between being bitten by a cat and probability of being diagnosed with depression. Authors suggested that infection with cat parasite Toxoplasma could be the reason for this association. METHOD A cross sectional internet study on a non-clinical population of 5,535 subjects was undertaken. RESULTS The subjects that reported having been bitten by a dog and a cat or scratched by a cat have higher Beck depression score. They were more likely to have visited psychiatrists, psychotherapists and neurologists in past two years, to have been previously diagnosed with depression (but not with bipolar disorder). Multivariate analysis of models with cat biting, cat scratching, toxoplasmosis, the number of cats at home, and the age of subjects as independent variables showed that only cat scratching had positive effect on depression (p = 0.004). Cat biting and toxoplasmosis had no effect on the depression, and the number of cats at home had a negative effect on depression (p = 0.021). CONCLUSIONS Absence of association between toxoplasmosis and depression and five times stronger association of depression with cat scratching than with cat biting suggests that the pathogen responsible for mood disorders in animals-injured subjects is probably not the protozoon Toxoplasma gondii but another organism; possibly the agent of cat-scratched disease - the bacteria Bartonella henselae.
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Affiliation(s)
- Jaroslav Flegr
- Department of Biology, Faculty of Science, Charles University in Prague, Viničná 7, 128 44, Prague, Czech Republic.
| | - Zdeněk Hodný
- Department of Genome Integrity, Institute of Molecular Genetics ASCR, v.v.i, Prague, Czech Republic.
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46
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Diamond DM, Zoladz PR. Dysfunctional or hyperfunctional? The amygdala in posttraumatic stress disorder is the bull in the evolutionary China shop. J Neurosci Res 2015; 94:437-44. [PMID: 26511328 DOI: 10.1002/jnr.23684] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 09/26/2015] [Accepted: 10/11/2015] [Indexed: 12/30/2022]
Abstract
Our motivation in writing this Review arose not only from the great value in contributing to this special issue of the Journal of Neuroscience Research but also from the desire to express our opinion that the description of the amygdala as "dysfunctional" in posttraumatic stress disorder (PTSD) might not be appropriate. We acknowledge that excessive activation of the amygdala contributes to the cluster of PTSD symptoms, including hypervigilance, intrusive memories, and impaired sleep, that underlies the devastating mental and physical outcomes in trauma victims. The issue that we address is whether the symptoms of PTSD represent an impaired (dysfunctional) or sensitized (hyperfunctional) amygdala status. We propose that the amygdala in PTSD is hyperfunctional rather than dysfunctional in recognition of the fact that the individual has already survived one life-threatening attack and that another may be forthcoming. We therefore consider PTSD to be a state in which the amygdala is functioning optimally if the goal is to ensure a person's survival. The misery caused by a hyperfunctional amygdala in PTSD is the cost of inheriting an evolutionarily primitive mechanism that considers survival more important than the quality of one's life.
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Affiliation(s)
- David M Diamond
- Medical Research Service, Veterans Administration Hospital, Tampa, Florida.,Department of Psychology, University of South Florida, Tampa, Florida.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida.,Center for Preclinical and Clinical Research on PTSD, University of South Florida, Tampa, Florida
| | - Phillip R Zoladz
- Department of Psychology, Sociology, and Criminal Justice, Ohio Northern University, Ada, Ohio
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47
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Abstract
UNLABELLED During infections with the protozoan parasite Toxoplasma gondii, gamma-aminobutyric acid (GABA) is utilized as a carbon source for parasite metabolism and also to facilitate parasite dissemination by stimulating dendritic-cell motility. The best-recognized function for GABA, however, is its role in the nervous system as an inhibitory neurotransmitter that regulates the flow and timing of excitatory neurotransmission. When this pathway is altered, seizures develop. Human toxoplasmosis patients suffer from seizures, suggesting that Toxoplasma interferes with GABA signaling in the brain. Here, we show that while excitatory glutamatergic presynaptic proteins appeared normal, infection with type II ME49 Toxoplasma tissue cysts led to global changes in the distribution of glutamic acid decarboxylase 67 (GAD67), a key enzyme that catalyzes GABA synthesis in the brain. Alterations in GAD67 staining were not due to decreased expression but rather to a change from GAD67 clustering at presynaptic termini to a more diffuse localization throughout the neuropil. Consistent with a loss of GAD67 from the synaptic terminals, Toxoplasma-infected mice develop spontaneous seizures and are more susceptible to drugs that induce seizures by antagonizing GABA receptors. Interestingly, GABAergic protein mislocalization and the response to seizure-inducing drugs were observed in mice infected with type II ME49 but not type III CEP strain parasites, indicating a role for a polymorphic parasite factor(s) in regulating GABAergic synapses. Taken together, these data support a model in which seizures and other neurological complications seen in Toxoplasma-infected individuals are due, at least in part, to changes in GABAergic signaling. IMPORTANCE Infections of the central nervous system can cause seizures. While inflammation in the brain has been proposed to initiate the onset of the seizures, relatively little is known about how inflammation impacts the structure and function of the neurons. Here we used a parasite called Toxoplasma gondii that infects the brain and showed that seizures arise due to a defect in signaling of GABA, which is the neurotransmitter primarily responsible for preventing the onset of seizures.
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48
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Flegr J. Neurological and Neuropsychiatric Consequences of Chronic Toxoplasma Infection. CURRENT CLINICAL MICROBIOLOGY REPORTS 2015. [DOI: 10.1007/s40588-015-0024-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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49
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Sutterland AL, Fond G, Kuin A, Koeter MWJ, Lutter R, van Gool T, Yolken R, Szoke A, Leboyer M, de Haan L. Beyond the association. Toxoplasma gondii in schizophrenia, bipolar disorder, and addiction: systematic review and meta-analysis. Acta Psychiatr Scand 2015; 132:161-79. [PMID: 25877655 DOI: 10.1111/acps.12423] [Citation(s) in RCA: 292] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/17/2015] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To perform a meta-analysis on studies reporting prevalence of Toxoplasma gondii (T. gondii) infection in any psychiatric disorder compared with healthy controls. Our secondary objective was to analyze factors possibly moderating heterogeneity. METHOD A systematic search was performed to identify studies into T. gondii infection for all major psychiatric disorders versus healthy controls. Methodological quality, publication bias, and possible moderators were assessed. RESULTS A total of 2866 citations were retrieved and 50 studies finally included. Significant odds ratios (ORs) with IgG antibodies were found in schizophrenia (OR 1.81, P < 0.00001), bipolar disorder (OR 1.52, P = 0.02), obsessive-compulsive disorder (OR 3.4, P < 0.001), and addiction (OR 1.91, P < 0.00001), but not for major depression (OR 1.21, P = 0.28). Exploration of the association between T. gondii and schizophrenia yielded a significant effect of seropositivity before onset and serointensity, but not IgM antibodies or gender. The amplitude of the OR was influenced by region and general seroprevalence. Moderators together accounted for 56% of the observed variance in study effects. After controlling for publication bias, the adjusted OR (1.43) in schizophrenia remained significant. CONCLUSION These findings suggest that T. gondii infection is associated with several psychiatric disorders and that in schizophrenia reactivation of latent T. gondii infection may occur.
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Affiliation(s)
- A L Sutterland
- Department of Psychiatry, Academic Medical Centre (AMC), Amsterdam, the Netherlands
| | - G Fond
- AP-HP, DHU Pe-PSY, Pôle de Psychiatrie et d'addictologie des Hôpitaux Universitaires H Mondor, INSERM U955, Eq 15 Psychiatrie Translationnelle, Université Paris Est-Créteil, Créteil, France.,Fondation Fondamental, Créteil, France
| | - A Kuin
- Department of Psychiatry, Academic Medical Centre (AMC), Amsterdam, the Netherlands
| | - M W J Koeter
- Department of Psychiatry, Academic Medical Centre (AMC), Amsterdam, the Netherlands
| | - R Lutter
- Departments of Experimental Immunology and Respiratory Medicine, Academic Medical Centre (AMC), Amsterdam, the Netherlands
| | - T van Gool
- Department of Parasitology, Academic Medical Centre (AMC), Amsterdam, the Netherlands
| | - R Yolken
- Stanley Neurovirology Laboratory, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - A Szoke
- AP-HP, DHU Pe-PSY, Pôle de Psychiatrie et d'addictologie des Hôpitaux Universitaires H Mondor, INSERM U955, Eq 15 Psychiatrie Translationnelle, Université Paris Est-Créteil, Créteil, France.,Fondation Fondamental, Créteil, France
| | - M Leboyer
- AP-HP, DHU Pe-PSY, Pôle de Psychiatrie et d'addictologie des Hôpitaux Universitaires H Mondor, INSERM U955, Eq 15 Psychiatrie Translationnelle, Université Paris Est-Créteil, Créteil, France.,Fondation Fondamental, Créteil, France
| | - L de Haan
- Department of Psychiatry, Academic Medical Centre (AMC), Amsterdam, the Netherlands
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50
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Parlog A, Schlüter D, Dunay IR. Toxoplasma gondii-induced neuronal alterations. Parasite Immunol 2015; 37:159-70. [PMID: 25376390 DOI: 10.1111/pim.12157] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 10/31/2014] [Indexed: 12/13/2022]
Abstract
The zoonotic pathogen Toxoplasma gondii infects over 30% of the human population. The intracellular parasite can persist lifelong in the CNS within neurons modifying their function and structure, thus leading to specific behavioural changes of the host. In recent years, several in vitro studies and murine models have focused on the elucidation of these modifications. Furthermore, investigations of the human population have correlated Toxoplasma seropositivity with changes in neurological functions; however, the complex underlying mechanisms of the subtle behavioural alteration are still not fully understood. The parasites are able to induce direct modifications in the infected cells, for example by altering dopamine metabolism, by functionally silencing neurons as well as by hindering apoptosis. Moreover, indirect effects of the peripheral immune system and alterations of the immune status of the CNS, observed during chronic infection, might also contribute to changes in neuronal connectivity and synaptic plasticity. In this review, we will provide an overview and highlight recent advances, which describe changes in the neuronal function and morphology upon T. gondii infection.
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Affiliation(s)
- A Parlog
- Institute of Medical Microbiology and Hospital Hygiene, Otto-von-Guericke University, Magdeburg, Germany
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