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Robinson JM, Barnes AD, Fickling N, Costin S, Sun X, Breed MF. Food webs in food webs: the micro-macro interplay of multilayered networks. Trends Ecol Evol 2024:S0169-5347(24)00144-7. [PMID: 38960756 DOI: 10.1016/j.tree.2024.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 06/10/2024] [Accepted: 06/14/2024] [Indexed: 07/05/2024]
Abstract
Food webs are typically defined as being macro-organism-based (e.g., plants, mammals, birds) or microbial (e.g., bacteria, fungi, viruses). However, these characterizations have limits. We propose a multilayered food web conceptual model where microbial food webs are nested within food webs composed of macro-organisms. Nesting occurs through host-microbe interactions, which influence the health and behavior of host macro-organisms, such that host microbiomes likely alter population dynamics of interacting macro-organisms and vice versa. Here, we explore the theoretical underpinnings of multilayered food webs and the implications of this new conceptual model on food web ecology. Our framework opens avenues for new empirical investigations into complex ecological networks and provides a new lens through which to view a network's response to ecosystem changes.
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Affiliation(s)
- Jake M Robinson
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia; The Aerobiome Innovation and Research Hub, College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia.
| | - Andrew D Barnes
- School of Science, University of Waikato, Hamilton, New Zealand
| | - Nicole Fickling
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia; The Aerobiome Innovation and Research Hub, College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
| | - Sofie Costin
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
| | - Xin Sun
- The Aerobiome Innovation and Research Hub, College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia; Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Fujian Key Laboratory of Watershed Ecology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315830, China.
| | - Martin F Breed
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia; The Aerobiome Innovation and Research Hub, College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia.
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2
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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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Zerekidze A, Li M, Refisch A, Shameya J, Sobanski T, Walter M, Wagner G. Impact of Toxoplasma gondii and Human Microbiome on Suicidal Behavior: A Systematic Review. J Clin Med 2024; 13:593. [PMID: 38276099 PMCID: PMC10816148 DOI: 10.3390/jcm13020593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/10/2024] [Accepted: 01/16/2024] [Indexed: 01/27/2024] Open
Abstract
BACKGROUND Suicide remains a persistent global health challenge, resisting widespread prevention efforts. According to previous findings, toxoplasmosis is particularly associated with altered decision making, which could lead to risk-taking behavior, thereby increasing the likelihood for suicidal behavior (SB). In addition, discussion about the role of microbiome in psychiatric disorders has emerged lately, which also makes it relevant to investigate its role in the context of SB. Therefore, two systematic reviews are integrated in this paper, and the existing knowledge is comprehensively summarized regarding the association between microbial pathogens and SB. METHODS We conducted a systematic search with keywords including SB and Toxoplasma gondii (Suicid* AND Toxoplasm*) and microbiome (Suicid* AND Microbiome AND Microbiota) throughout PubMed and Scopus to retrieve related studies up to 9 November 2023, identifying 24 eligible records. The subjects of the included studies had to have fulfilled the criteria of an SB disorder as defined by DSM-5, and death cases needed to have been defined as suicide. RESULTS Most studies reported significant association between toxoplasmosis and SB, suggesting a higher likelihood of SB in the infected population. Regarding the microbiome, only very few studies investigated an association between SB and alterations in the microbiome. Based on six included studies, there were some indications of a link between changes in the microbiome and SB. CONCLUSION The cognitive aspects of decision making in T. gondii-infected individuals with SB should be further investigated to unravel the underlying mechanisms. Further sufficiently powered studies are needed to establish a link between SB and alterations in the microbiome.
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Affiliation(s)
- Ani Zerekidze
- Department of Psychiatry and Psychotherapy, Jena Center for Mental Health, Jena University Hospital, 07743 Jena, Germany
| | - Meng Li
- Department of Psychiatry and Psychotherapy, Jena Center for Mental Health, Jena University Hospital, 07743 Jena, Germany
- Circuits Underlying Mental Health (C-I-R-C), Jena-Magdeburg-Halle, 07743 Jena, Germany
| | - Alexander Refisch
- Department of Psychiatry and Psychotherapy, Jena Center for Mental Health, Jena University Hospital, 07743 Jena, Germany
- Circuits Underlying Mental Health (C-I-R-C), Jena-Magdeburg-Halle, 07743 Jena, Germany
| | - Justina Shameya
- Department of Psychiatry and Psychotherapy, Jena Center for Mental Health, Jena University Hospital, 07743 Jena, Germany
| | - Thomas Sobanski
- Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, Center for Mental Health, Thueringen-Kliniken “Georgius Agricola”, 07318 Saalfeld, Germany;
| | - Martin Walter
- Department of Psychiatry and Psychotherapy, Jena Center for Mental Health, Jena University Hospital, 07743 Jena, Germany
- Circuits Underlying Mental Health (C-I-R-C), Jena-Magdeburg-Halle, 07743 Jena, Germany
- German Center for Mental Health (DZPG), Partner Site Jena, 07743 Jena, Germany
| | - Gerd Wagner
- Department of Psychiatry and Psychotherapy, Jena Center for Mental Health, Jena University Hospital, 07743 Jena, Germany
- Circuits Underlying Mental Health (C-I-R-C), Jena-Magdeburg-Halle, 07743 Jena, Germany
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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: 0] [Impact Index Per Article: 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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Nava M, Corlatti L, Formenti N, Trogu T, Pedrotti L, Gugiatti A, Lanfranchi P, Luzzago C, Ferrari N. Parasite-mediated manipulation? Toxoplasma gondii infection increases risk behaviour towards culling in red deer. Biol Lett 2023; 19:20230292. [PMID: 37848050 PMCID: PMC10581775 DOI: 10.1098/rsbl.2023.0292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/27/2023] [Indexed: 10/19/2023] Open
Abstract
Parasites can modify host behaviour to increase their chances of survival and transmission. Toxoplasma gondii is a globally distributed protozoan whose ability to modify host behaviour is well known in taxa such as rats and humans. Less well known are the effects on the behaviour of wild species, with the exception of a few studies on primates and carnivores. Taking advantage of a culling activity conducted in Stelvio National Park (Italy), the serological status of T. gondii was studied in 260 individuals of red deer Cervus elaphus with respect to the risk of being culled. A temporal culling rank index was fitted as a response variable, and T. gondii serological status as the main explanatory variable in linear models, accounting for covariates such as sex, age, jaw length, bone marrow fat and culling location. The overall seroprevalence of T. gondii was 31.5%, and the selected models suggested that seropositive deer were culled earlier than seronegative ones, but this effect was only evident in females, in individuals with medium-good body condition, and in areas with greater human presence. Our results suggest that T. gondii may be involved in risk behaviour in large herbivores, supporting its role as a facilitator of predation risk.
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Affiliation(s)
- Matteo Nava
- Department of Veterinary Medicine and Animal Sciences, University of Milan, Lodi, Italy
| | - Luca Corlatti
- Stelvio National Park – ERSAF Lombardia, Bormio, Italy
- Chair of Wildlife Ecology and Management, University of Freiburg, Freiburg, Germany
| | - Nicoletta Formenti
- Experimental Zooprophylactic Institute of Lombardy and Emilia-Romagna ‘‘Bruno Ubertini’’, Brescia, Italy
| | - Tiziana Trogu
- Experimental Zooprophylactic Institute of Lombardy and Emilia-Romagna ‘‘Bruno Ubertini’’, Brescia, Italy
| | - Luca Pedrotti
- Stelvio National Park – ERSAF Lombardia, Bormio, Italy
| | | | - Paolo Lanfranchi
- Department of Veterinary Medicine and Animal Sciences, University of Milan, Lodi, Italy
| | - Camilla Luzzago
- Department of Veterinary Medicine and Animal Sciences, University of Milan, Lodi, Italy
- Wildlife Health Lab, University of Milan, Lodi, Italy
| | - Nicola Ferrari
- Department of Veterinary Medicine and Animal Sciences, University of Milan, Lodi, Italy
- Wildlife Health Lab, University of Milan, Lodi, Italy
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Hagen EH, Blackwell AD, Lightner AD, Sullivan RJ. Homo medicus: The transition to meat eating increased pathogen pressure and the use of pharmacological plants in Homo. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2023; 180:589-617. [PMID: 36815505 DOI: 10.1002/ajpa.24718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 01/31/2023] [Accepted: 02/08/2023] [Indexed: 02/24/2023]
Abstract
The human lineage transitioned to a more carnivorous niche 2.6 mya and evolved a large body size and slower life history, which likely increased zoonotic pathogen pressure. Evidence for this increase includes increased zoonotic infections in modern hunter-gatherers and bushmeat hunters, exceptionally low stomach pH compared to other primates, and divergence in immune-related genes. These all point to change, and probably intensification, in the infectious disease environment of Homo compared to earlier hominins and other apes. At the same time, the brain, an organ in which immune responses are constrained, began to triple in size. We propose that the combination of increased zoonotic pathogen pressure and the challenges of defending a large brain and body from pathogens in a long-lived mammal, selected for intensification of the plant-based self-medication strategies already in place in apes and other primates. In support, there is evidence of medicinal plant use by hominins in the middle Paleolithic, and all cultures today have sophisticated, plant-based medical systems, add spices to food, and regularly consume psychoactive plant substances that are harmful to helminths and other pathogens. We propose that the computational challenges of discovering effective plant-based treatments, the consequent ability to consume more energy-rich animal foods, and the reduced reliance on energetically-costly immune responses helped select for increased cognitive abilities and unique exchange relationships in Homo. In the story of human evolution, which has long emphasized hunting skills, medical skills had an equal role to play.
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Affiliation(s)
- Edward H Hagen
- Department of Anthropology, Washington State University, Pullman, Washington, USA
| | - Aaron D Blackwell
- Department of Anthropology, Washington State University, Pullman, Washington, USA
| | - Aaron D Lightner
- Department of Anthropology, Washington State University, Pullman, Washington, USA
- Department of the Study of Religion, Aarhus University, Aarhus, Denmark
| | - Roger J Sullivan
- Department of Anthropology, California State University, Sacramento, California, USA
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Meyer CJ, Cassidy KA, Stahler EE, Brandell EE, Anton CB, Stahler DR, Smith DW. Parasitic infection increases risk-taking in a social, intermediate host carnivore. Commun Biol 2022; 5:1180. [PMID: 36424436 PMCID: PMC9691632 DOI: 10.1038/s42003-022-04122-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 10/17/2022] [Indexed: 11/26/2022] Open
Abstract
Toxoplasma gondii is a protozoan parasite capable of infecting any warm-blooded species and can increase risk-taking in intermediate hosts. Despite extensive laboratory research on the effects of T. gondii infection on behaviour, little is understood about the effects of toxoplasmosis on wild intermediate host behavior. Yellowstone National Park, Wyoming, USA, has a diverse carnivore community including gray wolves (Canis lupus) and cougars (Puma concolor), intermediate and definitive hosts of T. gondii, respectively. Here, we used 26 years of wolf behavioural, spatial, and serological data to show that wolf territory overlap with areas of high cougar density was an important predictor of infection. In addition, seropositive wolves were more likely to make high-risk decisions such as dispersing and becoming a pack leader, both factors critical to individual fitness and wolf vital rates. Due to the social hierarchy within a wolf pack, we hypothesize that the behavioural effects of toxoplasmosis may create a feedback loop that increases spatial overlap and disease transmission between wolves and cougars. These findings demonstrate that parasites have important implications for intermediate hosts, beyond acute infections, through behavioural impacts. Particularly in a social species, these impacts can surge beyond individuals to affect groups, populations, and even ecosystem processes.
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Affiliation(s)
- Connor J. Meyer
- grid.454846.f0000 0001 2331 3972Yellowstone Wolf Project, Yellowstone Center for Resources, P.O. Box 168, Yellowstone National Park, WY 82190 USA ,grid.253613.00000 0001 2192 5772Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, W. A. Franke College of Forestry and Conservation, University of Montana, Missoula, MT 59812 USA
| | - Kira A. Cassidy
- grid.454846.f0000 0001 2331 3972Yellowstone Wolf Project, Yellowstone Center for Resources, P.O. Box 168, Yellowstone National Park, WY 82190 USA
| | - Erin E. Stahler
- grid.454846.f0000 0001 2331 3972Yellowstone Wolf Project, Yellowstone Center for Resources, P.O. Box 168, Yellowstone National Park, WY 82190 USA
| | - Ellen E. Brandell
- grid.454846.f0000 0001 2331 3972Yellowstone Wolf Project, Yellowstone Center for Resources, P.O. Box 168, Yellowstone National Park, WY 82190 USA
| | - Colby B. Anton
- grid.454846.f0000 0001 2331 3972Yellowstone Wolf Project, Yellowstone Center for Resources, P.O. Box 168, Yellowstone National Park, WY 82190 USA
| | - Daniel R. Stahler
- grid.454846.f0000 0001 2331 3972Yellowstone Wolf Project, Yellowstone Center for Resources, P.O. Box 168, Yellowstone National Park, WY 82190 USA
| | - Douglas W. Smith
- grid.454846.f0000 0001 2331 3972Yellowstone Wolf Project, Yellowstone Center for Resources, P.O. Box 168, Yellowstone National Park, WY 82190 USA
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Ngo P, Lignereux L, O'Handley R, Vyas A. An extended epiphenotype for an extended phenotype in
Toxoplasma gondii
infected feral house mice. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Philip Ngo
- School of Biological Science, Nanyang Technological University Singapore
| | - Louis Lignereux
- School of Animal and Veterinary Science, University of Adelaide Australia
| | - Ryan O'Handley
- School of Animal and Veterinary Science, University of Adelaide Australia
| | - Ajai Vyas
- School of Biological Science, Nanyang Technological University Singapore
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Rantala MJ, Luoto S, Borráz-León JI, Krams I. Schizophrenia: the new etiological synthesis. Neurosci Biobehav Rev 2022; 142:104894. [PMID: 36181926 DOI: 10.1016/j.neubiorev.2022.104894] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 08/25/2022] [Accepted: 09/25/2022] [Indexed: 10/31/2022]
Abstract
Schizophrenia has been an evolutionary paradox: it has high heritability, but it is associated with decreased reproductive success. The causal genetic variants underlying schizophrenia are thought to be under weak negative selection. To unravel this paradox, many evolutionary explanations have been suggested for schizophrenia. We critically discuss the constellation of evolutionary hypotheses for schizophrenia, highlighting the lack of empirical support for most existing evolutionary hypotheses-with the exception of the relatively well supported evolutionary mismatch hypothesis. It posits that evolutionarily novel features of contemporary environments, such as chronic stress, low-grade systemic inflammation, and gut dysbiosis, increase susceptibility to schizophrenia. Environmental factors such as microbial infections (e.g., Toxoplasma gondii) can better predict the onset of schizophrenia than polygenic risk scores. However, researchers have not been able to explain why only a small minority of infected people develop schizophrenia. The new etiological synthesis of schizophrenia indicates that an interaction between host genotype, microbe infection, and chronic stress causes schizophrenia, with neuroinflammation and gut dysbiosis mediating this etiological pathway. Instead of just alleviating symptoms with drugs, the parasite x genotype x stress model emphasizes that schizophrenia treatment should focus on detecting and treating possible underlying microbial infection(s), neuroinflammation, gut dysbiosis, and chronic stress.
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Affiliation(s)
- Markus J Rantala
- Department of Biology, University of Turku, FIN-20014 Turku, Finland.
| | - Severi Luoto
- School of Population Health, University of Auckland, 1023 Auckland, New Zealand
| | | | - Indrikis Krams
- Institute of Ecology and Earth Sciences, University of Tartu, 51014 Tartu, Estonia; Department of Zoology and Animal Ecology, Faculty of Biology, University of Latvia, 1004, Rīga, Latvia
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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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Contopoulos‐Ioannidis DG, Gianniki M, Ai‐Nhi Truong A, Montoya JG. Toxoplasmosis and Schizophrenia: A Systematic Review and Meta‐Analysis of Prevalence and Associations and Future Directions. PSYCHIATRIC RESEARCH AND CLINICAL PRACTICE 2022; 4:48-60. [PMID: 36254187 PMCID: PMC9558922 DOI: 10.1176/appi.prcp.20210041] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 12/15/2022] Open
Affiliation(s)
- Despina G. Contopoulos‐Ioannidis
- Department of Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, California, USA (D. G. Contopoulos‐Ioannidis); Department of Pediatrics, University Hospital, Athens, Greece (M. Gianniki); Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, California, USA (A. Ai‐Nhi Truong); Dr. Jack S. Remington Laboratory for Specialty Diagnostics, National Reference Center for the Study and Diagnosis of Toxoplasmosis Palo Alto Medical
| | - Maria Gianniki
- Department of Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, California, USA (D. G. Contopoulos‐Ioannidis); Department of Pediatrics, University Hospital, Athens, Greece (M. Gianniki); Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, California, USA (A. Ai‐Nhi Truong); Dr. Jack S. Remington Laboratory for Specialty Diagnostics, National Reference Center for the Study and Diagnosis of Toxoplasmosis Palo Alto Medical
| | - Angeline Ai‐Nhi Truong
- Department of Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, California, USA (D. G. Contopoulos‐Ioannidis); Department of Pediatrics, University Hospital, Athens, Greece (M. Gianniki); Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, California, USA (A. Ai‐Nhi Truong); Dr. Jack S. Remington Laboratory for Specialty Diagnostics, National Reference Center for the Study and Diagnosis of Toxoplasmosis Palo Alto Medical
| | - Jose G. Montoya
- Department of Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, California, USA (D. G. Contopoulos‐Ioannidis); Department of Pediatrics, University Hospital, Athens, Greece (M. Gianniki); Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, California, USA (A. Ai‐Nhi Truong); Dr. Jack S. Remington Laboratory for Specialty Diagnostics, National Reference Center for the Study and Diagnosis of Toxoplasmosis Palo Alto Medical
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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] [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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13
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Wilson AG, Wilson S, Alavi N, Lapen DR. Human density is associated with the increased prevalence of a generalist zoonotic parasite in mammalian wildlife. Proc Biol Sci 2021; 288:20211724. [PMID: 34666519 PMCID: PMC8527198 DOI: 10.1098/rspb.2021.1724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 09/23/2021] [Indexed: 01/24/2023] Open
Abstract
Macroecological approaches can provide valuable insight into the epidemiology of globally distributed, multi-host pathogens. Toxoplasma gondii is a zoonotic protozoan that infects any warm-blooded animal, including humans, in almost every ecosystem worldwide. There is substantial geographical variation in T. gondii prevalence in wildlife populations and the mechanisms driving this variation are poorly understood. We implemented Bayesian phylogenetic mixed models to determine the association between species' ecology, phylogeny and climatic and anthropogenic factors on T. gondii prevalence. Toxoplasma gondii prevalence data were compiled for free-ranging wild mammal species from 202 published studies, encompassing 45 079 individuals from 54 taxonomic families and 238 species. We found that T. gondii prevalence was positively associated with human population density and warmer temperatures at the sampling location. Terrestrial species had a lower overall prevalence, but there were no consistent patterns between trophic level and prevalence. The relationship between human density and T. gondii prevalence is probably mediated by higher domestic cat abundance and landscape degradation leading to increased environmental oocyst contamination. Landscape restoration and limiting free-roaming in domestic cats could synergistically increase the resiliency of wildlife populations and reduce wildlife and human infection risks from one of the world's most common parasitic infections.
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Affiliation(s)
- Amy G. Wilson
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
- Canadian Wildlife Health Cooperative, Abbotsford, British Columbia, Canada V3G 2M3
| | - Scott Wilson
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
- Environment and Climate Change Canada, Delta, British Columbia, Canada V4 K 3N2 0H3
| | - Niloofar Alavi
- Environment and Climate Change Canada, Ottawa, Ontario, Canada K1S 5B6
| | - David R. Lapen
- Ottawa Research Development Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada K1A 0C6
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14
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Carrillo-Bilbao G, Martin-Solano S, Saegerman C. Zoonotic Blood-Borne Pathogens in Non-Human Primates in the Neotropical Region: A Systematic Review. Pathogens 2021; 10:1009. [PMID: 34451473 PMCID: PMC8400055 DOI: 10.3390/pathogens10081009] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/29/2021] [Accepted: 08/05/2021] [Indexed: 01/17/2023] Open
Abstract
Background: Understanding which non-human primates (NHPs) act as a wild reservoir for blood-borne pathogens will allow us to better understand the ecology of diseases and the role of NHPs in the emergence of human diseases in Ecuador, a small country in South America that lacks information on most of these pathogens. Methods and principal findings: A systematic review was carried out using PRISMA guidelines from 1927 until 2019 about blood-borne pathogens present in NHPs of the Neotropical region (i.e., South America and Middle America). Results: A total of 127 publications were found in several databases. We found in 25 genera (132 species) of NHPs a total of 56 blood-borne pathogens in 197 records where Protozoa has the highest number of records in neotropical NHPs (n = 128) compared to bacteria (n = 12) and viruses (n = 57). Plasmodium brasilianum and Trypanosoma cruzi are the most recorded protozoa in NHP. The neotropical primate genus with the highest number of blood-borne pathogens recorded is Alouatta sp. (n = 32). The use of non-invasive samples for neotropical NHPs remains poor in a group where several species are endangered or threatened. A combination of serological and molecular techniques is common when detecting blood-borne pathogens. Socioecological and ecological risk factors facilitate the transmission of these parasites. Finally, a large number of countries remain unsurveyed, such as Ecuador, which can be of public health importance. Conclusions and significance: NHPs are potential reservoirs of a large number of blood-borne pathogens. In Ecuador, research activities should be focused on bacteria and viruses, where there is a gap of information for neotropical NHPs, in order to implement surveillance programs with regular and effective monitoring protocols adapted to NHPs.
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Affiliation(s)
- Gabriel Carrillo-Bilbao
- Research Unit of Epidemiology and Risk Analysis Applied to Veterinary Sciences (UREAR-ULiège), Fundamental and Applied Research for Animal and Health (FARAH) Center, Department of Infections and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium;
- Facultad de Filosofía y Letras y Ciencias de la Educación, Universidad Central del Ecuador, 170521 Quito, Ecuador
- Instituto de Investigación en Zoonosis (CIZ), Universidad Central del Ecuador, 170521 Quito, Ecuador;
| | - Sarah Martin-Solano
- Instituto de Investigación en Zoonosis (CIZ), Universidad Central del Ecuador, 170521 Quito, Ecuador;
- Grupo de Investigación en Sanidad Animal y Humana (GISAH), Carrera Ingeniería en Biotecnología, Departamento de Ciencias de la Vida y la Agricultura, Universidad de las Fuerzas Armadas—ESPE, 171103 Sangolquí, Ecuador
| | - Claude Saegerman
- Research Unit of Epidemiology and Risk Analysis Applied to Veterinary Sciences (UREAR-ULiège), Fundamental and Applied Research for Animal and Health (FARAH) Center, Department of Infections and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium;
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15
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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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16
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Egorov AI, Converse RR, Griffin SM, Styles JN, Sams E, Hudgens E, Wade TJ. Latent Toxoplasma gondii infections are associated with elevated biomarkers of inflammation and vascular injury. BMC Infect Dis 2021; 21:188. [PMID: 33602170 PMCID: PMC7890825 DOI: 10.1186/s12879-021-05882-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 02/09/2021] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Toxoplasma gondii is a protozoan parasite that infects cats as definitive hosts and other warm-blooded animals including humans as intermediate hosts. It forms infectious cysts in the brain, muscle and other tissues establishing life-long latent infection. Approximately 10% of the US population is infected. While latent infections are largely asymptomatic, they are associated with neurological deficits and elevated risks of neuropsychiatric diseases. METHODS This cross-sectional epidemiological study investigated associations of T. gondii infections with biomarkers of inflammation and vascular injury: soluble intercellular adhesion molecule 1 (ICAM-1), soluble vascular cell adhesion molecule 1 (VCAM-1), C-reactive protein (CRP), and serum amyloid A (SAA). Serum samples from 694 adults in the Raleigh-Durham-Chapel Hill, North Carolina metropolitan area were tested for IgG antibody response to T. gondii, and for the above biomarkers using commercially available assays. RESULTS T. gondii seroprevalence rate in this sample was 9.7%. Seropositivity was significantly associated with 11% (95% confidence limits 4, 20%) greater median levels of VCAM-1 (p = 0.003), and marginally significantly with 9% (1, 17%), and 36% (1, 83%) greater median levels of ICAM-1, and CRP, respectively (p = 0.04 for each) after adjusting for sociodemographic and behavioral covariates, while the 23% (- 7, 64%) adjusted effect on SAA was not statistically significant (p = 0.15). CONCLUSIONS Latent infections with T. gondii are associated with elevated biomarkers of chronic inflammation and vascular injury that are also known to be affected by ambient air pollution.
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Affiliation(s)
- Andrey I. Egorov
- United States Environmental Protection Agency, Office of Research and Development, EPA, MD 58-C, 109. T.W. Alexander Drive, Research Triangle Park, NC 27711 USA
| | - Reagan R. Converse
- United States Environmental Protection Agency, Office of Research and Development, EPA, MD 58-C, 109. T.W. Alexander Drive, Research Triangle Park, NC 27711 USA
| | - Shannon M. Griffin
- United States Environmental Protection Agency, Office of Research and Development, Cincinnati, OH USA
| | - Jennifer N. Styles
- United States Environmental Protection Agency, Office of Research and Development, EPA, MD 58-C, 109. T.W. Alexander Drive, Research Triangle Park, NC 27711 USA
- Gillings School of Global Public Health, Environmental Sciences and Engineering Department, University of North Carolina at Chapel Hill, Chapel Hill, NC USA
| | - Elizabeth Sams
- United States Environmental Protection Agency, Office of Research and Development, EPA, MD 58-C, 109. T.W. Alexander Drive, Research Triangle Park, NC 27711 USA
| | - Edward Hudgens
- United States Environmental Protection Agency, Office of Research and Development, EPA, MD 58-C, 109. T.W. Alexander Drive, Research Triangle Park, NC 27711 USA
| | - Timothy J. Wade
- United States Environmental Protection Agency, Office of Research and Development, EPA, MD 58-C, 109. T.W. Alexander Drive, Research Triangle Park, NC 27711 USA
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17
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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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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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Carrillo GL, Ballard VA, Glausen T, Boone Z, Teamer J, Hinkson CL, Wohlfert EA, Blader IJ, Fox MA. Toxoplasma infection induces microglia-neuron contact and the loss of perisomatic inhibitory synapses. Glia 2020; 68:1968-1986. [PMID: 32157745 PMCID: PMC7423646 DOI: 10.1002/glia.23816] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/25/2020] [Accepted: 02/26/2020] [Indexed: 12/17/2022]
Abstract
Infection and inflammation within the brain induces changes in neuronal connectivity and function. The intracellular protozoan parasite, Toxoplasma gondii, is one pathogen that infects the brain and can cause encephalitis and seizures. Persistent infection by this parasite is also associated with behavioral alterations and an increased risk for developing psychiatric illness, including schizophrenia. Current evidence from studies in humans and mouse models suggest that both seizures and schizophrenia result from a loss or dysfunction of inhibitory synapses. In line with this, we recently reported that persistent T. gondii infection alters the distribution of glutamic acid decarboxylase 67 (GAD67), an enzyme that catalyzes GABA synthesis in inhibitory synapses. These changes could reflect a redistribution of presynaptic machinery in inhibitory neurons or a loss of inhibitory nerve terminals. To directly assess the latter possibility, we employed serial block face scanning electron microscopy (SBFSEM) and quantified inhibitory perisomatic synapses in neocortex and hippocampus following parasitic infection. Not only did persistent infection lead to a significant loss of perisomatic synapses, it induced the ensheathment of neuronal somata by myeloid-derived cells. Immunohistochemical, genetic, and ultrastructural analyses revealed that these myeloid-derived cells included activated microglia. Finally, ultrastructural analysis identified myeloid-derived cells enveloping perisomatic nerve terminals, suggesting they may actively displace or phagocytose synaptic elements. Thus, these results suggest that activated microglia contribute to perisomatic inhibitory synapse loss following parasitic infection and offer a novel mechanism as to how persistent T. gondii infection may contribute to both seizures and psychiatric illness.
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Affiliation(s)
- Gabriela L. Carrillo
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA 24061
| | - Valerie A. Ballard
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016
- Roanoke Valley Governor’s School, Roanoke VA 24015
| | - Taylor Glausen
- Department of Microbiology and Immunology, University at Buffalo, Buffalo NY 14260
| | - Zack Boone
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061
| | - Joseph Teamer
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016
- FBRI neuroSURF Program, Roanoke, VA 24016
| | - Cyrus L. Hinkson
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016
| | | | - Ira J. Blader
- Department of Microbiology and Immunology, University at Buffalo, Buffalo NY 14260
| | - Michael A. Fox
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061
- Department of Pediatrics, Virginia Tech Carilion School of Medicine, Roanoke, VA 24016
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Fendt M, Parsons MH, Apfelbach R, Carthey AJ, Dickman CR, Endres T, Frank AS, Heinz DE, Jones ME, Kiyokawa Y, Kreutzmann JC, Roelofs K, Schneider M, Sulger J, Wotjak CT, Blumstein DT. Context and trade-offs characterize real-world threat detection systems: A review and comprehensive framework to improve research practice and resolve the translational crisis. Neurosci Biobehav Rev 2020; 115:25-33. [DOI: 10.1016/j.neubiorev.2020.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/28/2020] [Accepted: 05/03/2020] [Indexed: 12/21/2022]
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21
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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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22
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Robinson JM, Breed MF. The Lovebug Effect: Is the human biophilic drive influenced by interactions between the host, the environment, and the microbiome? THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 720:137626. [PMID: 32146404 DOI: 10.1016/j.scitotenv.2020.137626] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 02/27/2020] [Accepted: 02/27/2020] [Indexed: 06/10/2023]
Abstract
Psychological frameworks are often used to investigate the mechanisms involved with our affinity towards, and connection with nature--such as the Biophilia Hypothesis and Nature Connectedness. Recent revelations from microbiome science suggest that animal behaviour can be strongly influenced by the host's microbiome--for example, via the bidirectional communication properties of the gut-brain axis. Here, we build on this theory to hypothesise that a microbially-influenced mechanism could also contribute to the human biophilic drive - the tendency for humans to affiliate and connect with nature. Humans may be at an evolutionary advantage through health-regulating exchange of environmental microbiota, which in turn could influence our nature affinity. We present a conceptual model for microbially-influenced nature affinity, calling it the Lovebug Effect. We present an overview of the potential mechanistic pathways involved in the Lovebug Effect, and consider its dependence on the hologenome concept of evolution, direct behavioural manipulation, and host-microbiota associated phenotypes independent of these concepts. We also discuss its implications for human health and ecological resilience. Finally, we highlight several possible approaches to scrutinise the hypothesis. The Lovebug Effect could have important implications for our understanding of exposure to natural environments for health and wellbeing, and could contribute to an ecologically resilient future.
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Affiliation(s)
- Jake M Robinson
- Department of Landscape, The University of Sheffield, S10 2TN, UK; inVIVO Planetary Health, of the Worldwide Universities Network (WUN), NJ 10704, USA; The Healthy Urban Microbiome Initiative (HUMI), Australia.
| | - Martin F Breed
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia; The Healthy Urban Microbiome Initiative (HUMI), Australia
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23
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Coryell W, Wilcox H, Evans SJ, Pandey GN, Jones-Brando L, Dickerson F, Yolken R. Latent infection, inflammatory markers and suicide attempt history in depressive disorders. J Affect Disord 2020; 270:97-101. [PMID: 32339111 DOI: 10.1016/j.jad.2020.03.057] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/17/2019] [Accepted: 03/20/2020] [Indexed: 02/02/2023]
Abstract
BACKGROUND Numerous reports have described increased rates of exposure to Toxoplasma gondii levels in individuals with a history of suicide attempts in comparison with well controls, or psychiatrically ill individuals, with no suicide attempt history. Such findings suggest that the behavioral effects this parasite exerts on rodent hosts extends to humans though few studies have searched for underlying mechanisms. METHODS The present study compared 96 patients with an active depressive disorder and a history of at least two suicide attempts to 126 depressed patients with no history of suicide attempts by IgG and IgM levels of Toxoplasma gondii and cytomegalovirus (CMV). The groups were also compared by IL_1b, TNF-alpha, CRP, IL_6, and IL_1ra titers. RESULTS Toxoplasma gondii IgM levels were higher, and seropositivity more likely, in the suicide attempt group. CMV IgG levels were also higher among suicide attempters. Several of these immunoglobulin measures were more robustly associated with the number of suicide attempts than with the dichotomy of suicide attempter and non-attempter. These two antibody levels were also additive in their association with suicide attempter status. IL_1a levels were lower in suicide attempters and correlated negatively with levels of antibodies to Toxoplasma gondii and CMV. LIMITATIONS These include a sample size insufficient to explore differences across mood disorder diagnoses or demographic groupings. CONCLUSIONS These results indicate that exposure to common infectious agents such as Toxoplasma gondii and CMV are associated with increased risk of suicide attempts but the mechanism of association does not appear to involve the activation of cytokines. Elucidation of the mechanisms which define the relationship between infections and suicide attempts may lead to new methods for the prediction and prevention of suicide attempts.
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Affiliation(s)
- William Coryell
- Psychiatry Research, University of Iowa Carver College of Medicine, 500 Newton Road, 2-205 MEB, Iowa City, IA, 52242-1000, USA.
| | | | | | | | | | | | - Robert Yolken
- Stanley Division of Developmental Neurovirology, USA
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Fayard M, Dechaume-Moncharmont FX, Wattier R, Perrot-Minnot MJ. Magnitude and direction of parasite-induced phenotypic alterations: a meta-analysis in acanthocephalans. Biol Rev Camb Philos Soc 2020; 95:1233-1251. [PMID: 32342653 DOI: 10.1111/brv.12606] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 04/03/2020] [Accepted: 04/06/2020] [Indexed: 12/25/2022]
Abstract
Several parasite species have the ability to modify their host's phenotype to their own advantage thereby increasing the probability of transmission from one host to another. This phenomenon of host manipulation is interpreted as the expression of a parasite extended phenotype. Manipulative parasites generally affect multiple phenotypic traits in their hosts, although both the extent and adaptive significance of such multidimensionality in host manipulation is still poorly documented. To review the multidimensionality and magnitude of host manipulation, and to understand the causes of variation in trait value alteration, we performed a phylogenetically corrected meta-analysis, focusing on a model taxon: acanthocephalan parasites. Acanthocephala is a phylum of helminth parasites that use vertebrates as final hosts and invertebrates as intermediate hosts, and is one of the few parasite groups for which manipulation is predicted to be ancestral. We compiled 279 estimates of parasite-induced alterations in phenotypic trait value, from 81 studies and 13 acanthocephalan species, allocating a sign to effect size estimates according to the direction of alteration favouring parasite transmission, and grouped traits by category. Phylogenetic inertia accounted for a low proportion of variation in effect sizes. The overall average alteration of trait value was moderate and positive when considering the expected effect of alterations on trophic transmission success (signed effect sizes, after the onset of parasite infectivity to the final host). Variation in the alteration of trait value was affected by the category of phenotypic trait, with the largest alterations being reversed taxis/phobia and responses to stimuli, and increased vulnerability to predation, changes to reproductive traits (behavioural or physiological castration) and immunosuppression. Parasite transmission would thereby be facilitated mainly by changing mainly the choice of micro-habitat and the anti-predation behaviour of infected hosts, and by promoting energy-saving strategies in the host. In addition, infection with larval stages not yet infective to definitive hosts (acanthella) tends to induce opposite effects of comparable magnitude to infection with the infective stage (cystacanth), although this result should be considered with caution due to the low number of estimates with acanthella. This analysis raises important issues that should be considered in future studies investigating the adaptive significance of host manipulation, not only in acanthocephalans but also in other taxa. Specifically, the contribution of phenotypic traits to parasite transmission and the range of taxonomic diversity covered deserve thorough attention. In addition, the relationship between behaviour and immunity across parasite developmental stages and host-parasite systems (the neuropsychoimmune hypothesis of host manipulation), still awaits experimental evidence. Most of these issues apply more broadly to reported cases of host manipulation by other groups of parasites.
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Affiliation(s)
- Marion Fayard
- UMR CNRS 6282 Biogéosciences, Université de Bourgogne-Franche-Comté, 6 Bd Gabriel, 21000, Dijon, France
| | - François-Xavier Dechaume-Moncharmont
- UMR CNRS 6282 Biogéosciences, Université de Bourgogne-Franche-Comté, 6 Bd Gabriel, 21000, Dijon, France.,Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, F-69622, Villeurbanne, France
| | - Rémi Wattier
- UMR CNRS 6282 Biogéosciences, Université de Bourgogne-Franche-Comté, 6 Bd Gabriel, 21000, Dijon, France
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Santicchia F, Wauters LA, Piscitelli AP, Van Dongen S, Martinoli A, Preatoni D, Romeo C, Ferrari N. Spillover of an alien parasite reduces expression of costly behaviour in native host species. J Anim Ecol 2020; 89:1559-1569. [PMID: 32291765 DOI: 10.1111/1365-2656.13219] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/10/2020] [Indexed: 12/17/2022]
Abstract
Understanding the effects of invasive alien species (IAS) on native host-parasite relationships is of importance for enhancing ecological theory and IAS management. When IAS and their parasite(s) invade a guild, the effects of interspecific resource competition and/or parasite-mediated competition can alter existing native host-parasite relationships and the dependent biological traits such as native species' behaviour. We used a natural experiment of populations of native red squirrels Sciurus vulgaris that were colonized by the alien grey squirrel Sciurus carolinensis, comparing repeated measurements of red squirrel parasite infection and personality with those taken in sites where only the native species occurred. We explored two alternative hypotheses: (a) individual differences in personality traits (activity and/or sociability) of native red squirrel positively affect the probability of macroparasite spillover and thus the likelihood to acquire the alien's parasitic helminth Strongyloides robustus; (b) the combined effects of grey squirrel presence and parasite infection result in a reduction of costly personality traits (activity and/or exploration). Using data from 323 arena tests across three experimental (native species and IAS) and three control sites (only native species), we found negative correlations between native species' activity and infection with S. robustus in the sites invaded by the alien species. Activity was also negatively correlated with infection by its native helminth Trypanoxyuris sciuri but only when grey squirrels were present, while in the red-only sites there was no relationship of T. sciuri infection with any of the personality traits. Moreover, individuals that acquired S. robustus during the study reduced their activity after infection, while this was not the case for animals that remained uninfected. Our results show that parasite-mediated competition is costly, reducing activity in individuals of the native species, and altering the native host-native parasite relationships.
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Affiliation(s)
- Francesca Santicchia
- Environment Analysis and Management Unit "Guido Tosi Research Group", Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, Varese, Italy
| | - Lucas A Wauters
- Environment Analysis and Management Unit "Guido Tosi Research Group", Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, Varese, Italy.,Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Anna Pia Piscitelli
- Dipartimento di Biologia e Biotecnologie "Charles Darwin", Università "La Sapienza" di Roma, Rome, Italy
| | | | - Adriano Martinoli
- Environment Analysis and Management Unit "Guido Tosi Research Group", Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, Varese, Italy
| | - Damiano Preatoni
- Environment Analysis and Management Unit "Guido Tosi Research Group", Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, Varese, Italy
| | - Claudia Romeo
- Department of Veterinary Sciences and Public Health, Università degli Studi di Milano, Milan, Italy
| | - Nicola Ferrari
- Department of Veterinary Sciences and Public Health, Università degli Studi di Milano, Milan, Italy
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Desmettre T. [Toxoplasmosis and behavioural changes (French translation of the article)]. J Fr Ophtalmol 2020; 43:433-438. [PMID: 32248961 DOI: 10.1016/j.jfo.2019.08.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 07/29/2019] [Accepted: 08/20/2019] [Indexed: 11/26/2022]
Abstract
Nearly one-third of the planet's population is affected by T. gondii infection. In ophthalmology, toxoplasmosis is even considered to be the most common cause of posterior uveitis of infectious origin. Humans are only an intermediate host, and T. gondii needs to infect cats for its sexual reproduction. All the elements increasing the risk of predation by the definitive host are then favourable to the parasite. Numerous experimental animal model studies have shown that T. gondii infection is associated with predatory risk behaviours such as an attraction of infected mice to cat urine. Infection with the parasite is associated with a demethylation of the promoters of certain genes in the cerebral amygdala of the intermediate hosts, modifying dopaminergic circuits associated with fear. Similarly, T. gondii has been linked to behavioural changes in humans. Toxoplasma infection is classically associated with the frequency of schizophrenia, suicide attempts or "road rage." A more recent study shows that toxoplasma infection prevalence was a consistent, positive predictor of entrepreneurial activity. Fear of failure would be less important in infected individuals, who are more willing than others to start their own business. These elements shed interesting light on behaviours and their possible relationship with toxoplasmosis, which is generally considered benign in adults.
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Affiliation(s)
- T Desmettre
- Centre de rétine médicale, 187, rue de Menin, 59520 Marquette-Lez-Lille, France; Queen Anne Street Medical Centre, 18-22, Queen Anne Street, W1G 8Hun London, Royaume-Uni.
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27
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Xiao J. Toxoplasma-induced Behavioral Changes: An Aspecific Consequence of Neuroinflammation. Trends Parasitol 2020; 36:317-318. [PMID: 32191847 DOI: 10.1016/j.pt.2020.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 01/21/2020] [Indexed: 12/20/2022]
Abstract
A key strategy that many parasites use to facilitate transmission involves behavioral modification of their hosts. Toxoplasma gondii has been taken as an example for this strategy. A recent study by Boillat et al. reported that attraction to predator odor following Toxoplasma infection is not specific to felines.
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Affiliation(s)
- Jianchun Xiao
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
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28
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Desmettre T. Toxoplasmosis and behavioural changes. J Fr Ophtalmol 2020; 43:e89-e93. [PMID: 31980266 DOI: 10.1016/j.jfo.2020.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 10/16/2019] [Accepted: 01/04/2020] [Indexed: 11/25/2022]
Abstract
Nearly one-third of the planet's population is affected by Toxoplasma gondii infection. In ophthalmology, toxoplasmosis is even considered to be the most common cause of posterior uveitis of infectious origin. Humans are only an intermediate host and T. gondii needs to infect cats for its sexual reproduction. All the elements increasing the risk of predation by the definitive host are then favourable to the parasite. Numerous experimental animal model studies have shown that T. gondii infection is associated with predatory risk behaviours such as an attraction of infected mice to cat urine. Infection with the parasite is associated with a demethylation of the promoters of certain genes in the cerebral amygdala of the intermediate hosts, modifying dopaminergic circuits associated with fear. Similarly, T. gondii has been linked to behavioural changes in humans. Toxoplasma infection is classically associated with the frequency of schizophrenia, suicide attempts or "road rage". A more recent study shows that toxoplasma infection prevalence was a consistent, positive predictor of entrepreneurial activity. Fear of failure would be less important in infected individuals, who are more willing than others to start their own business. These elements shed interesting light on behaviours and their possible relationship with toxoplasmosis, which is generally considered benign in adults.
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Affiliation(s)
- T Desmettre
- Centre de rétine médicale, 187, rue de Menin, 59520 Marquette-Lez-Lille, France; Queen Anne Street Medical Centre, 18-22, Queen Anne Street, W1G 8Hun, London, United Kingdom.
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Taggart PL, Fancourt BA, Peacock D, Caraguel CGB, McAllister MM. Variation in Toxoplasma gondii seroprevalence: effects of site, sex, species and behaviour between insular and mainland macropods. WILDLIFE RESEARCH 2020. [DOI: 10.1071/wr19041] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Context Feral cats threaten wildlife conservation through a range of direct and indirect effects. However, most studies that have evaluated the impacts of feral cats on species of conservation significance have focussed on direct impacts such as predation; few studies have considered the indirect impacts of cat-borne disease. Toxoplasma gondii, a cat-borne parasite, causes both acute and latent disease in a range of wildlife species, and macropods are particularly susceptible. Kangaroo Island is Australia’s third largest island and supports a high density of feral cats and high seroprevalence of T. gondii in multiple species, relative to the mainland. This suggests that Kangaroo Island has a high environmental contamination with the parasite and a high risk of infection for other species. Aims We aimed to describe T. gondii seroprevalence in culled and road-killed macropods, so as to assess the effects of island versus mainland location, sex, species and behaviour. Methods Macropod sera were tested for T. gondii IgG antibodies using a commercially available modified agglutination test. Key results The seroprevalence of T. gondii in culled western grey kangaroos (Macropus fuliginosus) was significantly higher on the island (20%, 11/54 positive) than on the mainland (0%, 0/61 positive). There was no difference in T. gondii seroprevalence between culled and road-killed (21%, 21/102 positive) kangaroos from the island. The seroprevalence of T. gondii was significantly higher in female (32%, 12/38 positive) than in male (13%, 8/60 positive) kangaroos, but we observed no sex effect in tammar wallabies (Macropus eugenii), and no effect of species. Conclusions The higher T. gondii seroprevalence in insular macropods supports previous reports of higher T. gondii exposure in other Kangaroo Island fauna. The lack of difference in T. gondii seroprevalence between culled and road-killed kangaroos suggests that T. gondii-positive animals are not more vulnerable to road mortality, in contrast to that suggested previously. Implications Our findings suggest greater potential adverse conservation impacts owing to toxoplasmosis on the island than on the mainland. In light of a recent study demonstrating higher cat abundance on the island than on the mainland, the higher observed T. gondii seroprevalence in insular macropods is likely to be a consequence of higher cat density.
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Del Giudice M. Invisible Designers: Brain Evolution Through the Lens of Parasite Manipulation. QUARTERLY REVIEW OF BIOLOGY 2019. [DOI: 10.1086/705038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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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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Aguirre AA, Longcore T, Barbieri M, Dabritz H, Hill D, Klein PN, Lepczyk C, Lilly EL, McLeod R, Milcarsky J, Murphy CE, Su C, VanWormer E, Yolken R, Sizemore GC. The One Health Approach to Toxoplasmosis: Epidemiology, Control, and Prevention Strategies. ECOHEALTH 2019; 16:378-390. [PMID: 30945159 PMCID: PMC6682582 DOI: 10.1007/s10393-019-01405-7] [Citation(s) in RCA: 124] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 01/22/2019] [Accepted: 01/24/2019] [Indexed: 06/02/2023]
Abstract
One Health is a collaborative, interdisciplinary effort that seeks optimal health for people, animals, plants, and the environment. Toxoplasmosis, caused by Toxoplasma gondii, is an intracellular protozoan infection distributed worldwide, with a heteroxenous life cycle that practically affects all homeotherms and in which felines act as definitive reservoirs. Herein, we review the natural history of T. gondii, its transmission and impacts in humans, domestic animals, wildlife both terrestrial and aquatic, and ecosystems. The epidemiology, prevention, and control strategies are reviewed, with the objective of facilitating awareness of this disease and promoting transdisciplinary collaborations, integrative research, and capacity building among universities, government agencies, NGOs, policy makers, practicing physicians, veterinarians, and the general public.
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Affiliation(s)
- A Alonso Aguirre
- Department of Environmental Science and Policy, George Mason University, 4400 University Dr. MSN: 5F2, Fairfax, VA, 22030-4400, USA.
| | - Travis Longcore
- Spatial Sciences Institute, University of Southern California, 3616 Trousdale Parkway, AHF B55, Los Angeles, CA, 90089, USA
| | - Michelle Barbieri
- NMFS/PIFSC/PSD/Hawaiian Monk Seal Research Program, 1845 Wasp Boulevard, Building 176, Honolulu, HI, 96818, USA
| | - Haydee Dabritz
- Community Health Branch, Yolo County Health & Human Services Agency, 137 N Cottonwood St, Woodland, CA, 95695, USA
| | - Dolores Hill
- U.S. Department of Agriculture, Center Road Building 307-C Room 134, BARC East, Beltsville, MD, 20705, USA
| | - Patrice N Klein
- United States Department of Agriculture Forest Service, 201 14th Street, SW, Washington, DC, 20250, USA
| | | | - Emily L Lilly
- Virginia Military Institute, 303D Maury-Brooke Hall, Lexington, VA, 24450, USA
| | - Rima McLeod
- The University of Chicago, AMB N310, (MC 2114) 5841 South Maryland Avenue, Chicago, IL, 60637, USA
| | | | - Caroline E Murphy
- The Wildlife Society, 425 Barlow Place, Suite 200, Bethesda, MD, 20814, USA
| | - Chunlei Su
- M409 Walters Life Sciences, University of Tennessee, Knoxville, TN, 37996, USA
| | - Elizabeth VanWormer
- University of Nebraska-Lincoln, 406 Hardin Hall, 3310 Holdrege Street, Lincoln, NE, 68583, USA
| | - Robert Yolken
- Stanley Neurovirology Laboratory, Johns Hopkins School of Medicine, Baltimore, MD, 21287, USA
| | - Grant C Sizemore
- American Bird Conservancy, 4301 Connecticut Ave., NW, Suite 451, Washington, DC, 20008, USA
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Nakamura M, Hosaka K, Itoh N, Matsumoto T, Matsusaka T, Nakazawa N, Nishie H, Sakamaki T, Shimada M, Takahata Y, Yamagami M, Zamma K. Wild chimpanzees deprived a leopard of its kill: Implications for the origin of hominin confrontational scavenging. J Hum Evol 2019; 131:129-138. [PMID: 31182198 DOI: 10.1016/j.jhevol.2019.03.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 03/12/2019] [Accepted: 03/13/2019] [Indexed: 11/25/2022]
Abstract
This study reports the first observed case of wild chimpanzees (Pan troglodytes) obtaining animal prey freshly killed by a sympatric leopard (Panthera pardus) and scavenging it with the leopard still nearby. This observation has important implications for the emergence of confrontational scavenging, which may have played a significant role in human evolution. Many scholars agree that eating meat became important during human evolution, and hominins first obtained meat by scavenging. However, it is debatable whether scavenging behavior was "passive" or "confrontational (power)." The latter is more dangerous, as it requires facing the original predator, and it is thus considered to have been important for the evolution of several human traits, including cooperation and language. Chimpanzees do scavenge meat, although rarely, but no previous evidence of confrontational scavenging has hitherto emerged. Thus, it was assumed that they are averse to confrontation with even leopard-sized predators. However, in the observed case the chimpanzees frequently emitted waa barks, which indicated that they were aware of the leopard's presence but they nevertheless continued to eat the scavenged meat. In addition, we compiled and reviewed 49 cases of chimpanzee encounters with animal carcasses in the Mahale Mountains of Tanzania in 1980-2017. Chimpanzees scavenged meat in 36.7% of these cases, and tended to eat the meat when it was fresh or if the animal species was usually hunted by chimpanzees. However, no evidence indicated that carcasses were avoided when leopard involvement was likely. These results suggest that chimpanzee-sized hominins could potentially confront and deprive leopard-size carnivores of meat.
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Affiliation(s)
| | | | | | - Takuya Matsumoto
- The Research Institute for Humanity and Nature, Japan; JSPS Research Fellow
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Humphreys RK, Ruxton GD. Adaptive suicide: is a kin-selected driver of fatal behaviours likely? Biol Lett 2019; 15:20180823. [PMID: 30958139 PMCID: PMC6405458 DOI: 10.1098/rsbl.2018.0823] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 02/11/2019] [Indexed: 12/21/2022] Open
Abstract
While several manipulated host behaviours are accepted as extended phenotypes of parasites, there remains debate over whether other altered behaviours in hosts following parasitic invasion represent cases of parasite manipulation, host defence or the pathology of infection. One particularly controversial subject is 'suicidal behaviour' in infected hosts. The host-suicide hypothesis proposes that host death benefits hosts doomed to reduced direct fitness by protecting kin from parasitism and therefore increasing inclusive fitness. However, adaptive suicide has been difficult to demonstrate conclusively as a host adaptation in studies on social or clonal insects, for whom high relatedness should enable greater inclusive fitness benefits. Following discussion of empirical and theoretical works from a behavioural ecology perspective, this review finds that the most persuasive evidence for selection of adaptive suicide comes from bacteria. Despite a focus on parasites, driven by the existing literature, the potential for the evolution of adaptive suicidal behaviour in hosts is also considered to apply to cases of infection by pathogens, provided that the disease has a severe effect on direct fitness and that suicidal behaviour can affect pathogen transmission dynamics. Suggestions are made for future research and a broadening of the possible implications for coevolution between parasites and hosts.
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Affiliation(s)
- Rosalind K. Humphreys
- School of Biology, University of St Andrews, Dyer's Brae House, St Andrews, Fife KY16 9TH, UK
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Schlüter D, Barragan A. Advances and Challenges in Understanding Cerebral Toxoplasmosis. Front Immunol 2019; 10:242. [PMID: 30873157 PMCID: PMC6401564 DOI: 10.3389/fimmu.2019.00242] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 01/28/2019] [Indexed: 11/22/2022] Open
Abstract
Toxoplasma gondii is a widespread parasitic pathogen that infects over one third of the global human population. The parasite invades and chronically persists in the central nervous system (CNS) of the infected host. Parasite spread and persistence is intimately linked to an ensuing immune response, which does not only limit parasite-induced damage but also may facilitate dissemination and induce parasite-associated immunopathology. Here, we discuss various aspects of toxoplasmosis where knowledge is scarce or controversial and, the recent advances in the understanding of the delicate interplay of T. gondii with the immune system in experimental and clinical settings. This includes mechanisms for parasite passage from the circulation into the brain parenchyma across the blood-brain barrier during primary acute infection. Later, as chronic latent infection sets in with control of the parasite in the brain parenchyma, the roles of the inflammatory response and of immune cell responses in this phase of the disease are discussed. Additionally, the function of brain resident cell populations is delineated, i.e., how neurons, astrocytes and microglia serve both as target cells for the parasite but also actively contribute to the immune response. As the infection can reactivate in the CNS of immune-compromised individuals, we bring up the immunopathogenesis of reactivated toxoplasmosis, including the special case of congenital CNS manifestations. The relevance, advantages and limitations of rodent infection models for the understanding of human cerebral toxoplasmosis are discussed. Finally, this review pinpoints questions that may represent challenges to experimental and clinical science with respect to improved diagnostics, pharmacological treatments and immunotherapies.
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Affiliation(s)
- Dirk Schlüter
- Hannover Medical School, Institute of Medical Microbiology and Hospital Epidemiology, Hannover, Germany
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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Gabagambi NP, Salvanes AGV, Midtøy F, Skorping A. The tapeworm Ligula intestinalis alters the behavior of the fish intermediate host Engraulicypris sardella, but only after it has become infective to the final host. Behav Processes 2019; 158:47-52. [DOI: 10.1016/j.beproc.2018.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 11/06/2018] [Accepted: 11/09/2018] [Indexed: 11/28/2022]
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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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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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Petkova I, Abbey-Lee RN, Løvlie H. Parasite infection and host personality: Glugea-infected three-spined sticklebacks are more social. Behav Ecol Sociobiol 2018; 72:173. [PMID: 30369708 PMCID: PMC6182751 DOI: 10.1007/s00265-018-2586-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 09/20/2018] [Accepted: 09/24/2018] [Indexed: 01/04/2023]
Abstract
Abstract The existence of animal personality is now well-documented, although the causes and consequences of this phenomenon are still largely unclear. Parasite infection can have pervasive effects on hosts, including altering host behaviour, and may thus contribute to differences in host personality. We investigated the relationship between the three-spined stickleback and its common parasite Glugea anomala, with focus on differences in host personality. Naturally infected and uninfected individuals were assayed for the five personality traits activity, exploration, boldness, sociability, and aggression. If infected fish behaved differently from uninfected, to benefit this parasite with horizontal transmission, we predicted behaviour increasing interactions with other sticklebacks to increase. Infection status explained differences in host personality. Specifically, Glugea-infected individuals were more social than uninfected fish. This confirms a link between parasite infection and host behaviour, and a relationship which may improve the horizontal transmission of Glugea. However, future studies need to establish the consequences of this for the parasite, and the causality of the parasite-host personality relationship. Significance statement Parasite infection that alters host behaviour could be a possible avenue of research into the causes of animal personality. We studied the link between infection and personality using the three-spined stickleback and its parasite Glugea anomala. We predicted that infected individuals would be more prone to interact with other sticklebacks, since this would improve transmission of this parasite. The personality of uninfected and naturally infected fish was measured and we observed that Glugea-infected sticklebacks were more social. Our results confirm a link between parasitism and variation in host personality. Electronic supplementary material The online version of this article (10.1007/s00265-018-2586-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Irina Petkova
- Department of Physics, Chemistry and Biology, IFM Biology, Linköping University, SE-581 83 Linköping, Sweden
- School of Biological Sciences, Centre for Ecology, Evolution and Behaviour, Royal Holloway University of London, Egham, TW20 0EX UK
| | - Robin N. Abbey-Lee
- Department of Physics, Chemistry and Biology, IFM Biology, Linköping University, SE-581 83 Linköping, Sweden
| | - Hanne Løvlie
- Department of Physics, Chemistry and Biology, IFM Biology, Linköping University, SE-581 83 Linköping, Sweden
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Abstract
Information about responses to death in nonhuman primates is important for evolutionary thanatology. This paper reviews the major causes of death in chimpanzees, and how these apes respond to cues related to dying and death. Topics covered include disease, human activities, predation, accidents and intra-species aggression and cannibalism. Chimpanzees also kill and sometimes eat other species. It is argued that, given their cognitive abilities, their experiences of death in conspecifics and other species are likely to equip chimpanzees with an understanding of death as cessation of function and irreversible. Whether they might understand that death is inevitable-including their own death, and biological causes of death is also discussed. As well as gathering more fundamental information about responses to dying and death, researchers should pay attention to possible cultural variations in how great apes deal with death.This article is part of the theme issue 'Evolutionary thanatology: impacts of the dead on the living in humans and other animals'.
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Affiliation(s)
- James R Anderson
- Department of Psychology, Graduate School of Letters, Kyoto University, Kyoto 606-8501, Japan
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Egorov AI, Converse R, Griffin SM, Styles J, Klein E, Sams E, Hudgens E, Wade TJ. Environmental risk factors for Toxoplasma gondii infections and the impact of latent infections on allostatic load in residents of Central North Carolina. BMC Infect Dis 2018; 18:421. [PMID: 30139351 PMCID: PMC6108134 DOI: 10.1186/s12879-018-3343-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 08/17/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Toxoplasma gondii infection can be acquired through ingestion of infectious tissue cysts in undercooked meat or environmental oocysts excreted by cats. This cross-sectional study assessed environmental risk factors for T. gondii infections and an association between latent infections and a measure of physiologic dysregulation known as allostatic load. METHODS Serum samples from 206 adults in the Durham-Chapel Hill, North Carolina area were tested for immunoglobulin (IgG) responses to T. gondii using commercial ELISA kits. Allostatic load was estimated as a sum of 15 serum biomarkers of metabolic, neuroendocrine and immune functions dichotomized at distribution-based cutoffs. Vegetated land cover within 500 m of residences was estimated using 1 m resolution data from US EPA's EnviroAtlas. RESULTS Handling soil with bare hands at least weekly and currently owning a cat were associated with 5.3 (95% confidence limits 1.4; 20.7) and 10.0 (2.0; 50.6) adjusted odds ratios (aOR) of T. gondii seropositivity, respectively. There was also a significant positive interaction effect of handling soil and owning cats on seropositivity. An interquartile range increase in weighted mean vegetated land cover within 500 m of residence was associated with 3.7 (1.5; 9.1) aOR of T. gondii seropositivity. Greater age and consumption of undercooked pork were other significant predictors of seropositivity. In turn, T. gondii seropositivity was associated with 61% (13%; 130%) greater adjusted mean allostatic load compared to seronegative individuals. In contrast, greater vegetated land cover around residence was associated with significantly reduced allostatic load in both seronegative (p < 0.0001) and seropositive (p = 0.004) individuals. CONCLUSIONS Residents of greener areas may be at a higher risk of acquiring T. gondii infections through inadvertent ingestion of soil contaminated with cat feces. T. gondii infections may partially offset health benefits of exposure to the natural living environment.
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Affiliation(s)
- Andrey I Egorov
- United States Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, MD 58-C, 109. T.W. Alexander Drive, Research Triangle Park, NC, 27711, USA.
| | - Reagan Converse
- United States Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, MD 58-C, 109. T.W. Alexander Drive, Research Triangle Park, NC, 27711, USA
| | - Shannon M Griffin
- United States Environmental Protection Agency, National Exposure Research Laboratory, Cincinnati, OH, USA
| | - Jennifer Styles
- United States Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, MD 58-C, 109. T.W. Alexander Drive, Research Triangle Park, NC, 27711, USA.,Gillings School of Global Public Health, Environmental Sciences and Engineering Department, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Elizabeth Klein
- ORAU Student Services Contractor to US EPA, Chapel Hill, NC, USA
| | - Elizabeth Sams
- United States Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, MD 58-C, 109. T.W. Alexander Drive, Research Triangle Park, NC, 27711, USA
| | - Edward Hudgens
- United States Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, MD 58-C, 109. T.W. Alexander Drive, Research Triangle Park, NC, 27711, USA
| | - Timothy J Wade
- United States Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, MD 58-C, 109. T.W. Alexander Drive, Research Triangle Park, NC, 27711, USA
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Estato V, Stipursky J, Gomes F, Mergener TC, Frazão-Teixeira E, Allodi S, Tibiriçá E, Barbosa HS, Adesse D. The Neurotropic Parasite Toxoplasma gondii Induces Sustained Neuroinflammation with Microvascular Dysfunction in Infected Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 188:2674-2687. [PMID: 30121257 DOI: 10.1016/j.ajpath.2018.07.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 06/28/2018] [Accepted: 07/05/2018] [Indexed: 12/12/2022]
Abstract
Toxoplasmosis is one of the leading parasitic diseases worldwide. Some data suggest that chronic acquired toxoplasmosis could be linked to behavioral alterations in humans. The parasite infects neurons, forming immunologically silent cysts. Cerebral microcirculation homeostasis is determinant to brain functions, and pathologic states can alter capillarity or blood perfusion, leading to neurodegeneration and cognitive deficits. Albino mice were infected with Toxoplasma gondii (ME49 strain) and analyzed after 10, 40, and 180 days. Infected mice presented decreased cerebral blood flow at 10 and 40 days post infection (dpi), which were restored at 180 dpi, as shown by laser speckle contrast imaging. Intravital microscopy demonstrated that infection led to significant capillary rarefaction, accompanied by neuroinflammation, with microglial activation and increased numbers of rolling and adherent leukocytes to the wall of cerebral capillaries. Acetylcholine-induced vasodilation was altered at all time points, and blood brain barrier permeability was evident in infected animals at 40 dpi. Infection reduced angiogenesis, with a decreased number of isolectin B4-stained blood vessels and a decrease in length and branching of laminin-stained capillaries. Sulfadiazine reduced parasite load and partially repaired microvascular damages. We conclude that T. gondii latent infection causes a harmful insult in the brain, promoting neuroinflammation and microcirculatory dysfunction in the brain, with decreased angiogenesis and can contribute to a neurodegenerative process.
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Affiliation(s)
- Vanessa Estato
- Laboratório de Investigação Cardiovascular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil; Laboratório de Produtos Naturais, Departamento de Produtos Naturais, Farmanguinhos, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Joice Stipursky
- Laboratório de Neurobiologia Celular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fabiana Gomes
- Laboratório de Investigação Cardiovascular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Tally C Mergener
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Edwards Frazão-Teixeira
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Silvana Allodi
- Laboratório de Neurobiologia Comparativa e do Desenvolvimento, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Eduardo Tibiriçá
- Laboratório de Investigação Cardiovascular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Helene S Barbosa
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Daniel Adesse
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
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Libersat F, Kaiser M, Emanuel S. Mind Control: How Parasites Manipulate Cognitive Functions in Their Insect Hosts. Front Psychol 2018; 9:572. [PMID: 29765342 PMCID: PMC5938628 DOI: 10.3389/fpsyg.2018.00572] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 04/04/2018] [Indexed: 12/14/2022] Open
Abstract
Neuro-parasitology is an emerging branch of science that deals with parasites that can control the nervous system of the host. It offers the possibility of discovering how one species (the parasite) modifies a particular neural network, and thus particular behaviors, of another species (the host). Such parasite-host interactions, developed over millions of years of evolution, provide unique tools by which one can determine how neuromodulation up-or-down regulates specific behaviors. In some of the most fascinating manipulations, the parasite taps into the host brain neuronal circuities to manipulate hosts cognitive functions. To name just a few examples, some worms induce crickets and other terrestrial insects to commit suicide in water, enabling the exit of the parasite into an aquatic environment favorable to its reproduction. In another example of behavioral manipulation, ants that consumed the secretions of a caterpillar containing dopamine are less likely to move away from the caterpillar and more likely to be aggressive. This benefits the caterpillar for without its ant bodyguards, it is more likely to be predated upon or attacked by parasitic insects that would lay eggs inside its body. Another example is the parasitic wasp, which induces a guarding behavior in its ladybug host in collaboration with a viral mutualist. To exert long-term behavioral manipulation of the host, parasite must secrete compounds that act through secondary messengers and/or directly on genes often modifying gene expression to produce long-lasting effects.
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Affiliation(s)
- Frederic Libersat
- Department of Life Sciences and Zlotowski Center for Neurosciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Maayan Kaiser
- Department of Life Sciences and Zlotowski Center for Neurosciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Stav Emanuel
- Department of Life Sciences and Zlotowski Center for Neurosciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Abdulai-Saiku S, Tong WH, Vyas A. Sexual Transmission of Cyst-Forming Coccidian Parasites with Complex Life Cycles. CURRENT SEXUAL HEALTH REPORTS 2017. [DOI: 10.1007/s11930-017-0133-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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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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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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East-West Divide: temperature and land cover drive spatial variation of Toxoplasma gondii infection in Eurasian otters (Lutra lutra) from England and Wales. Parasitology 2017; 144:1433-1440. [DOI: 10.1017/s0031182017000865] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
SUMMARYToxoplasma gondii, a zoonotic parasite of global importance, infects all endothermic vertebrates, with extensive health implications. The prevalence of this parasite is seldom monitored in wildlife. Here, a semi-aquatic species, the Eurasian otter (Lutra lutra) was used as a model to assess the potential effect of climate, land cover and biotic factors on T. gondii seroprevalence in British wildlife. The Sabin–Feldman cytoplasm-modifying dye test identified T. gondii antibodies in 25·5% of blood samples from otters found dead, mainly as road kill, in England and Wales, between 2004 and 2010. Otters in the east of England were more likely to be infected with T. gondii than those in western regions. Land cover and temperature are key determinants of T. gondii infection risk, with more infection in arable areas and lower infection where temperatures are higher. The probability of T. gondii infection increased with host age, reflecting cumulative exposure with time, but there was no association between T. gondii seroprevalence and cause of host death.
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Riedmüller R, Müller S. Ethical Implications of the Mild Encephalitis Hypothesis of Schizophrenia. Front Psychiatry 2017; 8:38. [PMID: 28348532 PMCID: PMC5346578 DOI: 10.3389/fpsyt.2017.00038] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 02/27/2017] [Indexed: 02/02/2023] Open
Abstract
Schizophrenia is a serious mental disease with a high mortality rate and severe social consequences. Due to insufficient knowledge about its etiopathogenesis, curative treatments are not available. One of the most promising new research concepts is the mild encephalitis hypothesis of schizophrenia, developed mainly by Karl Bechter and Norbert Müller. According to this hypothesis, a significant subgroup of schizophrenia patients suffer from a mild, but chronic, form of encephalitis with markedly different etiologies ranging from viral infections, traumas to autoimmune diseases. This inflammatory process is thought to occur in the beginning or during the course of the disease. In this article, we investigate the consequences of the mild encephalitis hypothesis of schizophrenia for the scientific community, and evaluate these consequences ethically. The mild encephalitis hypothesis implies that schizophrenia would no longer be considered an incurable psychiatric disorder. Instead, it would be considered a chronic, but treatable, neurological disease. This paradigm shift would doubtlessly have significant consequences: (1) major reforms would be necessary in the theoretical conceptualization of schizophrenia, which would challenge the psychiatric diagnostic systems, Diagnostic and Statistical Manual of Mental Disorders version 5 and ICD-10. (2) Psychotic patients should be treated in interdisciplinary teams, optimally in neuropsychiatric units; additionally, specialists for endocrinology, diabetology, and cardiology should be consulted for the frequently occuring somatic comorbidities. (3) Current diagnostic procedures and (4) therapies would have to be modified significantly. (5) There might be repercussions for the pharmaceutical industry as well: first, because old drugs with expired patent protection could partly replace expensive drugs and, second, because there would be a demand for the development of new anti-inflammatory drugs. (6) Legal evaluation of compulsory treatment orders might have to be reconsidered in light of causal therapies; leading to increased legal approval and reduced need for compulsory treatment orders due to better patient compliance. (7) The social inclusion of patients might improve, if treatment became more effective regarding cognitive and social functioning. (8) The stigmatization of patients and their relatives might decrease.
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Affiliation(s)
- Rita Riedmüller
- Mind and Brain Research, Department of Psychiatry and Psychotherapy, CCM, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Sabine Müller
- Mind and Brain Research, Department of Psychiatry and Psychotherapy, CCM, Charité – Universitätsmedizin Berlin, Berlin, Germany
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Rushmore J, Bisanzio D, Gillespie TR. Making New Connections: Insights from Primate-Parasite Networks. Trends Parasitol 2017; 33:547-560. [PMID: 28279627 DOI: 10.1016/j.pt.2017.01.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/30/2017] [Accepted: 01/31/2017] [Indexed: 02/07/2023]
Abstract
Social interactions are important in everyday life for primates and many other group-living animals; however, these essential exchanges also provide opportunities for parasites to spread through social groups. Network analysis is a unique toolkit for studying pathogen transmission in a social context, and recent primate-parasite network studies shed light on linkages between behavior and infectious disease dynamics, providing insights for conservation and public health. We review existing literature on primate-parasite networks, examining determinants of infection risk, issues of network scale and temporal dynamics, and applications for disease control. We also discuss analytical and conceptual gaps that should be addressed to improve our understanding of how individual and group-level factors affect infection risk, while highlighting interesting areas for future research.
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Affiliation(s)
- Julie Rushmore
- Department of Biomedical Sciences, Oregon State University, Corvallis, OR, USA; College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Donal Bisanzio
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, UK
| | - Thomas R Gillespie
- Department of Environmental Sciences and Program in Population Biology, Ecology and Evolution, Emory University, Atlanta, GA, USA; Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
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Massa NM, Duncan E, Jovanovic T, Kerley K, Weng L, Gensler L, Lee SS, Norrholm S, Powers A, Almli LM, Gillespie CF, Ressler K, Pearce BD. Relationship between Toxoplasma gondii seropositivity and acoustic startle response in an inner-city population. Brain Behav Immun 2017; 61:176-183. [PMID: 27884623 PMCID: PMC5316358 DOI: 10.1016/j.bbi.2016.11.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 11/10/2016] [Accepted: 11/20/2016] [Indexed: 01/09/2023] Open
Abstract
Toxoplasma gondii (TOXO) is a neuroinvasive protozoan parasite that induces the formation of persistent cysts in mammalian brains. It infects approximately 1.1million people in the United States annually. Latent TOXO infection is implicated in the etiology of psychiatric disorders, especially schizophrenia (SCZ), and has been correlated with modestly impaired cognition. The acoustic startle response (ASR) is a reflex seen in all mammals. It is mediated by a simple subcortical circuit, and provides an indicator of neural function. We previously reported the association of TOXO with slowed acoustic startle latency, an index of neural processing speed, in a sample of schizophrenia and healthy control subjects. The alterations in neurobiology with TOXO latent infection may not be specific to schizophrenia. Therefore we examined TOXO in relation to acoustic startle in an urban, predominately African American, population with mixed psychiatric diagnoses, and healthy controls. Physiological and diagnostic data along with blood samples were collected from 364 outpatients treated at an inner-city hospital. TOXO status was determined with an ELISA assay for TOXO-specific IgG. A discrete titer was calculated based on standard cut-points as an indicator of seropositivity, and the TOXO-specific IgG concentration served as serointensity. A series of linear regression models were used to assess the association of TOXO seropositivity and serointensity with ASR magnitude and latency in models adjusting for demographics and psychiatric diagnoses (PTSD, major depression, schizophrenia, psychosis, substance abuse). ASR magnitude was 11.5% higher in TOXO seropositive subjects compared to seronegative individuals (p=0.01). This effect was more pronounced in models with TOXO serointensity that adjusted for sociodemographic covariates (F=7.41, p=0.0068; F=10.05, p=0.0017), and remained significant when psychiatric diagnoses were stepped into the models. TOXO showed no association with startle latency (t=0.49, p=0.63) in an unadjusted model, nor was TOXO associated with latency in models that included demographic factors. After stepping in individual psychiatric disorders, we found a significant association of latency with a diagnosis of PTSD (F=5.15, p=0.024), but no other psychiatric diagnoses, such that subjects with PTSD had longer startle latency. The mechanism by which TOXO infection is associated with high startle magnitude is not known, but possible mechanisms include TOXO cyst burden in the brain, parasite recrudescence, or molecular mimicry of a host epitope by TOXO. Future studies will focus on the neurobiology underlying the effects of latent TOXO infection as a potential inroad to the development of novel treatment targets for psychiatric disease.
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Affiliation(s)
- Nick M Massa
- Atlanta Veterans Affairs Medical Center, 1670 Clairmont Rd, Decatur, GA 30033, United States; Department of Epidemiology, Rollins School of Public Health, Emory University, 1518 Clifton Rd., Atlanta, GA 30322, United States
| | - Erica Duncan
- Atlanta Veterans Affairs Medical Center, 1670 Clairmont Rd, Decatur, GA 30033, United States; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - Tanja Jovanovic
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - Kimberly Kerley
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - Lei Weng
- Department of Epidemiology, Rollins School of Public Health, Emory University, 1518 Clifton Rd., Atlanta, GA 30322, United States
| | - Lauren Gensler
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - Samuel S Lee
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - Seth Norrholm
- Atlanta Veterans Affairs Medical Center, 1670 Clairmont Rd, Decatur, GA 30033, United States; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - Abigail Powers
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - Lynn M Almli
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - Charles F Gillespie
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - Kerry Ressler
- Department of Psychiatry, Harvard School of Medicine, 25 Shattuck St, Boston, MA 02115, United States
| | - Bradley D Pearce
- Department of Epidemiology, Rollins School of Public Health, Emory University, 1518 Clifton Rd., Atlanta, GA 30322, United States.
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