Brain Parasites and Suicide

In a sample of 17 European nations, the prevalence of the brain parasite Toxoplasma gondii and the percentage of Finno-Ugrians in the populations were significantly associated with national suicide rates for men and women.

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Toxoplasma Gondii and Homicide

Psychological Reports ◽

10.2466/12.15.16.pr0.111.4.196-197 ◽

2012 ◽

Vol 111 (1) ◽

pp. 196-197 ◽

Cited By ~ 12

Author(s):

David Lester

Keyword(s):

Toxoplasma Gondii ◽

Positive Association ◽

Homicide Rates ◽

Suicide Rates ◽

Causal Mechanisms ◽

The Brain

In a sample of 20 European nations, the prevalence of the brain parasite Toxoplasma gondii was positively associated with national homicide rates, amplifying previous research indicating a positive association of Toxoplasma gondii with suicide rates. Possible causal mechanisms were proposed.

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Estrogen Actions in the Brain and the Basis for Differential Action in Men and Women: A Case for Sex-Specific Medicines

Pharmacological Reviews ◽

10.1124/pr.109.002071 ◽

2010 ◽

Vol 62 (2) ◽

pp. 155-198 ◽

Cited By ~ 357

Author(s):

Glenda E. Gillies ◽

Simon McArthur

Keyword(s):

Men And Women ◽

The Brain ◽

Differential Action

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Insights into the molecular basis of host behaviour manipulation by Toxoplasma gondii infection

Emerging Topics in Life Sciences ◽

10.1042/etls20170108 ◽

2017 ◽

Vol 1 (6) ◽

pp. 563-572 ◽

Cited By ~ 1

Author(s):

Pierre-Mehdi Hammoudi ◽

Dominique Soldati-Favre

Keyword(s):

Toxoplasma Gondii ◽

Stress Responses ◽

Molecular Mechanisms ◽

Brain Regions ◽

Intermediate Hosts ◽

Toxoplasma Gondii Infection ◽

Host Parasite ◽

Host Behaviour ◽

The Brain ◽

Brain Homeostasis

Typically illustrating the ‘manipulation hypothesis’, Toxoplasma gondii is widely known to trigger sustainable behavioural changes during chronic infection of intermediate hosts to enhance transmission to its feline definitive hosts, ensuring survival and dissemination. During the chronic stage of infection in rodents, a variety of neurological dysfunctions have been unravelled and correlated with the loss of cat fear, among other phenotypic impacts. However, the underlying neurological alteration(s) driving these behavioural modifications is only partially understood, which makes it difficult to draw more than a correlation between T. gondii infection and changes in brain homeostasis. Moreover, it is barely known which among the brain regions governing fear and stress responses are preferentially affected during T. gondii infection. Studies aiming at an in-depth dissection of underlying molecular mechanisms occurring at the host and parasite levels will be discussed in this review. Addressing this reminiscent topic in the light of recent technical progress and new discoveries regarding fear response, olfaction and neuromodulator mechanisms could contribute to a better understanding of this complex host–parasite interaction.

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Toxoplasma gondii injected neurons localize to the cortex and striatum and have altered firing

10.1101/2021.02.18.431839 ◽

2021 ◽

Author(s):

Oscar A. Mendez ◽

Emiliano Flores Machado ◽

Jing Lu ◽

Anita A. Koshy

Keyword(s):

Toxoplasma Gondii ◽

Single Neuron ◽

Latent Infection ◽

Ex Vivo ◽

Medium Spiny Neurons ◽

Patch Clamping ◽

Spiny Neurons ◽

The Brain ◽

Mapping Program

AbstractToxoplasma gondii is an intracellular parasite that causes a long-term latent infection of neurons. Using a custom MATLAB-based mapping program in combination with a mouse model that allows us to permanently mark neurons injected with parasite proteins, we found that Toxoplasma-injected neurons (TINs) are heterogeneously distributed in the brain, primarily localizing to the cortex followed by the striatum. Using immunofluorescence co-localization assays, we determined that cortical TINs are commonly (>50%) excitatory neurons (FoxP2+) and that striatal TINs are often (>65%) medium spiny neurons (MSNs) (FoxP2+). As MSNs have highly characterized electrophysiology, we used ex vivo slices from infected mice to perform single neuron patch-clamping on striatal TINs and neighboring uninfected MSNs (bystander MSNs). These studies demonstrated that TINs have highly abnormal electrophysiology, while the electrophysiology of bystander MSNs was akin to that of MSNs from uninfected mice. Collectively, these data offer new neuroanatomic and electrophysiologic insights into CNS toxoplasmosis.

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Will the COVID-19 pandemic lead to a tsunami of suicides? A Swedish nationwide analysis of historical and 2020 data

10.1101/2020.12.10.20244699 ◽

2020 ◽

Author(s):

Christian Rück ◽

David Mataix-Cols ◽

Kinda Malki ◽

Mats Adler ◽

Oskar Flygare ◽

...

Keyword(s):

Negative Impact ◽

Annual Data ◽

Short Term ◽

Death Rates ◽

Men And Women ◽

Influenza Pandemics ◽

Suicide Rates ◽

Distributed Lag ◽

The Media

ABSTRACTBackgroundVarious surveys have documented a negative impact of the COVID-19 pandemic on the population’s mental health. There is widespread concern about a surge of suicides, but evidence supporting a link between global pandemics and suicide is very limited. Using historical data from the three major influenza pandemics of the 20th century, and recently released data from the first half of 2020, we aimed to investigate whether an association exists between influenza deaths and suicide deaths.MethodsAnnual data on influenza death rates and suicide rates were extracted from the Statistical Yearbook of Sweden from 1910-1978, covering the three 20th century pandemics, and from Statistics Sweden for the period from January to June of each year during 2000-2020. COVID-19 death data were available for the first half of 2020. We implemented non-linear autoregressive distributed lag (NARDL) models to explore if there is a short-term and/or long-term effect of increases and decreases in influenza death rates on suicide rates during 1910-1978. Analyses were done separately for men and women. Descriptive analyses were used for the available 2020 data.FindingsBetween 1910-1978, there was no evidence of either short-term or long-term significant associations between influenza death rates and changes in suicides. The same pattern emerged in separate analyses for men and women. Suicide rates in January-June 2020 revealed a slight decrease compared to the corresponding rates in January-June 2019 (relative decrease by −1.2% among men and −12.8% among women).InterpretationWe found no evidence of short or long-term association between influenza death rates and suicide death rates across three 20th century pandemics or during the first six months of 2020 (when the first wave of COVID-19 occurred). Concerns about a substantial increase of suicides may be exaggerated. The media should be cautious when reporting news about suicides during the current pandemic.

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Microglia and macrophages as innate producers of interferon-gamma in the brain following infection with Toxoplasma gondii

International Journal for Parasitology ◽

10.1016/j.ijpara.2004.10.020 ◽

2005 ◽

Vol 35 (1) ◽

pp. 83-90 ◽

Cited By ~ 75

Author(s):

Yasuhiro Suzuki ◽

Jennifer Claflin ◽

Xisheng Wang ◽

Andrea Lengi ◽

Takane Kikuchi

Keyword(s):

Toxoplasma Gondii ◽

Interferon Gamma ◽

The Brain

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Seropathological Diagnosis of Toxoplasma gondii in Stray Cats in Baghdad Province

The Iraqi Journal of Veterinary Medicine ◽

10.30539/iraqijvm.v38i1.260 ◽

2014 ◽

Vol 38 (1) ◽

pp. 92-98

Author(s):

Mohammed J. Alwan

Keyword(s):

Toxoplasma Gondii ◽

Alveolar Space ◽

Internal Organs ◽

Blood Samples ◽

Pathological Lesions ◽

Stray Cats ◽

Significant Difference ◽

Adult Cat ◽

The Brain ◽

Local Necrosis

The current study was performed an investigation in seropositive stray cats with Toxoplasma gondii and to correlate the results of pathological lesions with seropositive results of the cats. To achieve these goals, fifty blood samples and specimens from internal organs (liver, spleen, brain, kidney, intestine and lung) of stray cats were collected from different area of Baghdad Province during the period 1.10.2011-1.10.2012. Seropositive ELISA-IgG was demonstrated that 66 % of stray cats while female expressed (75 %) of seropositive ELISA-IgG were higher than male (30% ) and animals with average age 2months showed high percentage of seropositive ELISA-IgG (100%) as compared with age (adult cat) that expressed( 63.82 %) of seropositive. There was a significant difference (P≤0.01) among positive cases to anti-Toxoplasma ELISA-IgG. Severe pathological lesions were noticed in the lungs ,livers and intestines of animals that expressed high (optical density) (OD) of anti-Toxoplasma IgG ,in addition ,tachyzoits intracytoplasm of alveolar macrophages and hepatocytes as well as free zoites in alveolar space of the lung, were reported. Local necrosis with tachyzoites was seen in the brain of the cats, in addition to mineralization. On bases of the presence of pathological lesions in cats that expressed seropositive anti-Toxoplasma antibodies, it can be conclude that T.gondii is responsible for the appearance of inflammatory reaction in the internal organs of cats and there is a correlation between seropositive and pathological lesions of T.gondii infection and this parasite is highly distributed in Baghdad stray cats and it may be an important cause of abortion in the women.

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Tissue cyst tropism in Toxoplasma gondii: a comparison of tissue cyst formation in organs of cats, and rodents fed oocysts

Parasitology ◽

10.1017/s0031182097008949 ◽

1997 ◽

Vol 115 (1) ◽

pp. 15-20 ◽

Cited By ~ 52

Author(s):

J. P. DUBEY

Keyword(s):

Toxoplasma Gondii ◽

Cyst Formation ◽

Tissue Cyst ◽

Intermediate Hosts ◽

Mesenteric Lymph Nodes ◽

Marked Contrast ◽

Mesenteric Lymph ◽

Time Period ◽

Rats And Mice ◽

The Brain

The persistence of Toxoplasma gondii tissue cysts in organs of cats (definitive host) and rodents (intermediate hosts) was studied. Nine cats, 12 rats, and 12 mice were fed T. gondii oocysts and their organs were digested in pepsin and then bioassayed for bradyzoites in mice. Of 9 cats killed 37 or 51 days after feeding 102 (2 cats), 103 (3 cats) or 104 (4 cats) oocysts of the VEG strain, tissue cysts were found in each cat; in the tongue of 9, in the heart of 5, in the brain of 4, and in the eyes of 1 cat. The dose had no effect on the distribution of tissue cysts in cats. Twelve rats were each fed 105 oocysts of the VEG strain of T. gondii and killed 21, 29, 64 or 237 days later. At each time-period, 11 tissues of 3 rats were pooled and bioassayed in mice. Tissue cysts were found in the brain, skeletal muscle, heart and kidneys of rats at each killing time; in the lungs, intestines, and mesenteric lymph nodes in 3 of 4 instances; in the tongue, liver, and eyes in 2 instances and in the spleen in 1 instance. Also, using the same procedures and sampling the same 11 tissues as used for rats, tissue cysts were seen in all organs except in the tongue and liver of 3 mice killed on day 82 after feeding the VEG strain. In 9 mice (3 with each strain) fed oocysts of the ME-49, GT-1, or P89 T. gondii strain and killed 62–130 days later, tissue cysts were found consistently only in the brain. Thus, in rats and mice, most tissue cysts were found in the brain and rarely in the tongue. This was in marked contrast to the distribution of tissue cysts in cats.

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