6 ms·

Toxoplasmosis – A Global Threat (2014)

77 points by 0x456 5y ago

echelon 5y ago
Toxo is no joke. Apart from opening the door to other diseases and chronic inflammation, it also induces neurological changes we still barely understand. It might be a contributor to depression. What we do know is that it correlates positively with motorcycle deaths and risk taking behaviors [1]. Postmortem tests show this. (My old immunology professor used to say that toxoplasma indirectly leads to more organ donation.) Keep your cats indoors. Or get a dog instead. Toxo evolved to fuck with mice brains and make them not fear being eaten. Your brain operates on similar biochemistry. Be careful. [1] Not a direct citation, but similar claims : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC117239/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC117239/
- kossTKR 5y ago
  I don't get this. Just checked and about 30 percent of women have it when they give birth in Scandinavia - that's a number that keeps rising after that - so lets assume that 50 percent of the population has this at 50. If this is the case, that's half the population, and if above is true, why isn't "everyone" sounding the alarm? I have a few family members with cats, so i could pretty well have it. Doesn't sound like "avoiding" is in any way an option looking at the stats.
  - dwhit 5y ago
    Because the toxo doesn’t want us to sound the alarm
    - jes 5y ago
      Priceless!
  - kadoban 5y ago
    Part of why nobody is sounding the alarm is that we just get used to things. If this month, 2000 extra people die from Y, it's a huge story and everyone jumps on finding a solution. But if 2000 people have been dying per month from X for decades, no shits are given, it's just part of the background.
    - hallway_monitor 5y ago
      In the US it's 3,000 per month for car accidents and 4,000 per month for suicides, by way of example.
  - thaumasiotes 5y ago
    > Just checked and about 30 percent of women have it when they give birth in Scandinavia - that's a number that keeps rising after that You should see the rates in France.
    - edgeform 5y ago
      Can we, or can you only reference them sardonically?
    - greatpatton 5y ago
      The rate in France was 36.7% in 2010 (declining steadily year after year): http://www.bichat-larib.com/revue.presse/revue.presse.resume.affichage.php?numero_etudiant=&numero_resume=736 http://www.bichat-larib.com/revue.presse/revue.presse.resume...
  - dn3500 5y ago
    If this disease made your right hand fall off, everyone would be sounding the alarm. It doesn't. It might take someone who is in the bottom quartile for risk taking and move them up to the next quartile. Their behavior would still be within the bounds of normal, their friends might not even notice, but they might become say 50% more likely to die in a motorcycle crash. The point being we don't really know the consequences, and it's probably a good idea to study this some more.
    - alboy 5y ago
      >but they might become say 50% more likely to die in a motorcycle crash Or launch a startup.
  - echelon 5y ago
    We didn't have any idea about lead and mental illness, either. Many historians say it had a role to play in the downfall of Rome.
rubicon33 5y ago
I love studies like this. I believe that as science progresses, we're going to see a lot more conclusions like this that previously "benign" things were actually causing problems, or setting the body up for later issues, we just didn't know it. Toxo is a perfect example. Chicken pocks is another. HPV a third. Personally I believe "alergies" are actually the result of a viral infection probably from the common cold, that sets off a long term hyper reaction to airborn particles and pathogens. So things like pollen in the air sets off a huge response whereas for some people who never were infected with the virus, they don't get "alergies".
- joe-collins 5y ago
  What evidence do you have to back that assertion? Do you speak from a position of expertise?
- nkrisc 5y ago
  And the loads of people who have been infected with the common cold, the flu, and other viruses and never develop any allergies? Are you saying you think this only affects a subset of people? Out of curiosity, what lead you to this conclusion? Personally I've had countless colds and even the flu a few times, and no allergies. In fact, most people I know get a few colds every year and have no allergies. Actually, basically everybody I've ever met has had the common cold at some point. Maybe it's responsible for everything.
- chewbacha 5y ago
  Those are great examples! However, I’m not sure I agree with that allergy hypothesis. The histamine reaction is associated with IgE. This immunoglobulin is associated with parasitic response. A lack of childhood exposure actually higher correlates with higher incidence of allergies and asthma. The theory that has developed from this is that lack of stimulation leads to hyper reaction later when exposed to allergens. This is all posited by the “hygiene hypothesis”: https://en.m.wikipedia.org/wiki/Hygiene_hypothesis https://en.m.wikipedia.org/wiki/Hygiene_hypothesis There is a lot of supporting evidence to go along with it. As well as studies inspecting the impact of gut micro biome.
slumdev 5y ago
(2014) Definitely still a global threat in 2021, but not the disease that most people have on the brain right now. (Unless they own a cat.)
- young_unixer 5y ago
  Which one do they have?
- CrazyPyroLinux 5y ago
  > have on the brain I see what you did there...
- aaron695 5y ago
  Cats can catch SARS-CoV-2 from humans. Cats can catch SARS-CoV-2 from cats. It's reasonable to think we can catch it back (This has happened with minks) As the human population gets vaccinated it will be interesting to see what happens with cats.
adamnemecek 5y ago
The author of this paper, Jaroslav Flegr (https://en.wikipedia.org/wiki/Jaroslav_Flegr https://en.wikipedia.org/wiki/Jaroslav_Flegr), was considered a crackpot for a long time. There was a profile on him in the Atlantic in 2012 https://www.theatlantic.com/magazine/archive/2012/03/how-your-cat-is-making-you-crazy/308873/ https://www.theatlantic.com/magazine/archive/2012/03/how-you...
optimiz3 5y ago
Cats have the evolutionary benefit of being cute to humans. This allows them to be one of the most invasive species in the world. Case in point is Hawaii; attempts to bring the wild cat populations under control are immediately met with resistance from animal rights groups. This is in spite of the ongoing destruction to wild bird populations. One also has to be extremely careful about washing local vegetables, due to cats spreading toxoplasma.
- totetsu 5y ago
  I think Rattus Rattus might beat them to being the most invasive species in the world
- giantg2 5y ago
  I would think snails are the main reason for washing, but for a different pathogen.
- FooHentai 5y ago
  Same story in New Zealand. Even the SPCA here pursues a policy of trap, neuter, release for feral cats despite the overwhelming evidence that they absolutely decimate NZ's native bird populations, which evolved in the absence of such predators. It's very frustrating, folks can't acknowledge that 'cute and familiar' is causing enourmous ecological harm because it's out of sight, out of mind.
  - jephson 5y ago
    There isn't overwhelming evidence, though. Native bird life in New Zealand has dramatically increased in recent years, despite cats continuing to enjoy relative freedom and huge numbers.
    - soperj 5y ago
      From very low numbers, because they're controlling other predators (stoats)
    - AbrahamParangi 5y ago
giantg2 5y ago
Everyone is mentioning cats. 30% of the beef in the US contains toxoplasm gondii. Now, a deep freeze for more than 24 hours will kill it, but how many people eat fresh beef and less than well done? This is part of the reason they recommend pregnant women not eat beef that is cooked less than well done.
- argonaut 5y ago
  This study (https://pubmed.ncbi.nlm.nih.gov/16419752/ https://pubmed.ncbi.nlm.nih.gov/16419752/) failed to find infectious toxoplasma in any retail beef or chicken samples, and only <1% of pork samples (they tested this by feeding cats raw meat).
  - giantg2 5y ago
    FDA say about 50% of infections come from contaminated food. https://www.fda.gov/food/people-risk-foodborne-illness/toxoplasma-food-safety-moms-be https://www.fda.gov/food/people-risk-foodborne-illness/toxop... I remember a prior study said about 30% of beef and 24% of venison would test positive, but don't see it now. Also, that's just a positive test number. Transmission numbers could be lower, but likely rise over time with repeated consumption.
    - argonaut 5y ago
      They are likely referring to people that interact with cats and then contaminate their own food (fail to wash hands etc.)
      - giantg2 5y ago
        That seems extremely unlikely. It says 85% of pregnant women are at risk. Only half as many people own cats. Also, 3 out of the 4 vectors they list on there are food related and do not mention that contact with a cat is required. It mentions raw or undercooked meat several times, and even mentions that is the way that cats acquire it.
felixbraun 5y ago
It seems to be very unlikely that brain cysts (that might affect cognition) can form in immunocompetent people — a pathological study of AIDS patients showed cysts in ~20%; background seropositivity in France (where the study was conducted) is ~40%. Conclusion by the authors: the amount of toxoplasmic agents appeared to be related to the degree of deterioration of the immune status. > Neuropathological studies in the brains of AIDS patients with opportunistic diseases: https://pubmed.ncbi.nlm.nih.gov/8518200/ https://pubmed.ncbi.nlm.nih.gov/8518200/
beaner 5y ago
Does toxoplasmosis come up in a standard blood panel, or do you have to suspect it and test for it specifically?
- argonaut 5y ago
  There is an antibody test. I believe pregnant women are commonly screened with it.
  - beaner 5y ago
    If there are antibodies for it does that mean your body naturally fights and defeats it, like the cold? Or does it stick around until detected?
- drjasonharrison 5y ago
  You have to test for the antibodies or the DNA. https://labtestsonline.org/tests/toxoplasmosis-testing https://labtestsonline.org/tests/toxoplasmosis-testing
ck2 5y ago
Paper is from 2014, a few years later some scientists realized the answer is ironically, ivermectin. But good luck getting the NIH/CDC to mention that drug name right now.
dempsey 5y ago
This is remarkably similar to chronic lyme disease.
- dempsey 5y ago
  Why the downvotes? In chronic lyme, the purported issue is lyme hiding out in cysts and causing all sorts of difficult to trace calamity throughout one’s life.
jakubmazanec 5y ago
Please ignore this "study" and whatever Jaroslav Flegr says. At my university he was mocked for his misuse of statistics - he does it even in this article, giant models with huge sample sizes finding correlations everywhere with p < 0.1. Also, in this article https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-015-1290-7 https://parasitesandvectors.biomedcentral.com/articles/10.11... he says that "pathogen responsible for mood disorders in animals-injured subjects is probably not the protozoon Toxoplasma gondii but another organism; possibly the agent of cat-scratched disease – the bacteria Bartonella henselae." So did he discover yet another behaviour change inducing organism, or is he simply a shitty scientist? Let's have a look: he recruits respondents via Facebook, they take 4 psychological questionnaires (which are usually not very reliable and shouldn't be used in giant correlation tables) and finds effect sizes ranging from eta2 = 0.004 to eta2 = 0.045. Just look at this table - https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-015-1290-7/figures/1 https://parasitesandvectors.biomedcentral.com/articles/10.11... - results are significant because the sample size is 5000, but what are the practical differences? Barely 1 point on a scale that itself has reliability around 0.9 (which is good, but it still leads to standard measurement error greater than Flegr's effect sizes).

77 points by 0x456 5y ago

Toxo is no joke. Apart from opening the door to other diseases and chronic inflammation, it also induces neurological changes we still barely understand. It might be a contributor to depression. What we do know is that it correlates positively with motorcycle deaths and risk taking behaviors [1]. Postmortem tests show this. (My old immunology professor used to say that toxoplasma indirectly leads to more organ donation.) Keep your cats indoors. Or get a dog instead. Toxo evolved to fuck with mice brains and make them not fear being eaten. Your brain operates on similar biochemistry. Be careful. [1] Not a direct citation, but similar claims : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC117239/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC117239/

kossTKR 5y ago
I don't get this. Just checked and about 30 percent of women have it when they give birth in Scandinavia - that's a number that keeps rising after that - so lets assume that 50 percent of the population has this at 50. If this is the case, that's half the population, and if above is true, why isn't "everyone" sounding the alarm? I have a few family members with cats, so i could pretty well have it. Doesn't sound like "avoiding" is in any way an option looking at the stats.
- dwhit 5y ago
  Because the toxo doesn’t want us to sound the alarm
  - jes 5y ago
    Priceless!
- kadoban 5y ago
  Part of why nobody is sounding the alarm is that we just get used to things. If this month, 2000 extra people die from Y, it's a huge story and everyone jumps on finding a solution. But if 2000 people have been dying per month from X for decades, no shits are given, it's just part of the background.
  - hallway_monitor 5y ago
    In the US it's 3,000 per month for car accidents and 4,000 per month for suicides, by way of example.
- thaumasiotes 5y ago
  > Just checked and about 30 percent of women have it when they give birth in Scandinavia - that's a number that keeps rising after that You should see the rates in France.
  - edgeform 5y ago
    Can we, or can you only reference them sardonically?
  - greatpatton 5y ago
    The rate in France was 36.7% in 2010 (declining steadily year after year): http://www.bichat-larib.com/revue.presse/revue.presse.resume.affichage.php?numero_etudiant=&numero_resume=736 http://www.bichat-larib.com/revue.presse/revue.presse.resume...
- dn3500 5y ago
  If this disease made your right hand fall off, everyone would be sounding the alarm. It doesn't. It might take someone who is in the bottom quartile for risk taking and move them up to the next quartile. Their behavior would still be within the bounds of normal, their friends might not even notice, but they might become say 50% more likely to die in a motorcycle crash. The point being we don't really know the consequences, and it's probably a good idea to study this some more.
  - alboy 5y ago
    >but they might become say 50% more likely to die in a motorcycle crash Or launch a startup.
- echelon 5y ago
  We didn't have any idea about lead and mental illness, either. Many historians say it had a role to play in the downfall of Rome.

rubicon33 5y ago

I love studies like this. I believe that as science progresses, we're going to see a lot more conclusions like this that previously "benign" things were actually causing problems, or setting the body up for later issues, we just didn't know it. Toxo is a perfect example. Chicken pocks is another. HPV a third. Personally I believe "alergies" are actually the result of a viral infection probably from the common cold, that sets off a long term hyper reaction to airborn particles and pathogens. So things like pollen in the air sets off a huge response whereas for some people who never were infected with the virus, they don't get "alergies".

joe-collins 5y ago
What evidence do you have to back that assertion? Do you speak from a position of expertise?
nkrisc 5y ago
And the loads of people who have been infected with the common cold, the flu, and other viruses and never develop any allergies? Are you saying you think this only affects a subset of people? Out of curiosity, what lead you to this conclusion? Personally I've had countless colds and even the flu a few times, and no allergies. In fact, most people I know get a few colds every year and have no allergies. Actually, basically everybody I've ever met has had the common cold at some point. Maybe it's responsible for everything.
chewbacha 5y ago
Those are great examples! However, I’m not sure I agree with that allergy hypothesis. The histamine reaction is associated with IgE. This immunoglobulin is associated with parasitic response. A lack of childhood exposure actually higher correlates with higher incidence of allergies and asthma. The theory that has developed from this is that lack of stimulation leads to hyper reaction later when exposed to allergens. This is all posited by the “hygiene hypothesis”: https://en.m.wikipedia.org/wiki/Hygiene_hypothesis https://en.m.wikipedia.org/wiki/Hygiene_hypothesis There is a lot of supporting evidence to go along with it. As well as studies inspecting the impact of gut micro biome.

slumdev 5y ago

(2014) Definitely still a global threat in 2021, but not the disease that most people have on the brain right now. (Unless they own a cat.)

young_unixer 5y ago
Which one do they have?
CrazyPyroLinux 5y ago
> have on the brain I see what you did there...
aaron695 5y ago
Cats can catch SARS-CoV-2 from humans. Cats can catch SARS-CoV-2 from cats. It's reasonable to think we can catch it back (This has happened with minks) As the human population gets vaccinated it will be interesting to see what happens with cats.

adamnemecek 5y ago

The author of this paper, Jaroslav Flegr (https://en.wikipedia.org/wiki/Jaroslav_Flegr https://en.wikipedia.org/wiki/Jaroslav_Flegr), was considered a crackpot for a long time. There was a profile on him in the Atlantic in 2012 https://www.theatlantic.com/magazine/archive/2012/03/how-your-cat-is-making-you-crazy/308873/ https://www.theatlantic.com/magazine/archive/2012/03/how-you...

optimiz3 5y ago

Cats have the evolutionary benefit of being cute to humans. This allows them to be one of the most invasive species in the world. Case in point is Hawaii; attempts to bring the wild cat populations under control are immediately met with resistance from animal rights groups. This is in spite of the ongoing destruction to wild bird populations. One also has to be extremely careful about washing local vegetables, due to cats spreading toxoplasma.

totetsu 5y ago
I think Rattus Rattus might beat them to being the most invasive species in the world
giantg2 5y ago
I would think snails are the main reason for washing, but for a different pathogen.
FooHentai 5y ago
Same story in New Zealand. Even the SPCA here pursues a policy of trap, neuter, release for feral cats despite the overwhelming evidence that they absolutely decimate NZ's native bird populations, which evolved in the absence of such predators. It's very frustrating, folks can't acknowledge that 'cute and familiar' is causing enourmous ecological harm because it's out of sight, out of mind.
- jephson 5y ago
  There isn't overwhelming evidence, though. Native bird life in New Zealand has dramatically increased in recent years, despite cats continuing to enjoy relative freedom and huge numbers.
  - soperj 5y ago
    From very low numbers, because they're controlling other predators (stoats)
  - AbrahamParangi 5y ago

giantg2 5y ago

Everyone is mentioning cats. 30% of the beef in the US contains toxoplasm gondii. Now, a deep freeze for more than 24 hours will kill it, but how many people eat fresh beef and less than well done? This is part of the reason they recommend pregnant women not eat beef that is cooked less than well done.

argonaut 5y ago
This study (https://pubmed.ncbi.nlm.nih.gov/16419752/ https://pubmed.ncbi.nlm.nih.gov/16419752/) failed to find infectious toxoplasma in any retail beef or chicken samples, and only <1% of pork samples (they tested this by feeding cats raw meat).
- giantg2 5y ago
  FDA say about 50% of infections come from contaminated food. https://www.fda.gov/food/people-risk-foodborne-illness/toxoplasma-food-safety-moms-be https://www.fda.gov/food/people-risk-foodborne-illness/toxop... I remember a prior study said about 30% of beef and 24% of venison would test positive, but don't see it now. Also, that's just a positive test number. Transmission numbers could be lower, but likely rise over time with repeated consumption.
  - argonaut 5y ago
    They are likely referring to people that interact with cats and then contaminate their own food (fail to wash hands etc.)
    - giantg2 5y ago
      That seems extremely unlikely. It says 85% of pregnant women are at risk. Only half as many people own cats. Also, 3 out of the 4 vectors they list on there are food related and do not mention that contact with a cat is required. It mentions raw or undercooked meat several times, and even mentions that is the way that cats acquire it.

felixbraun 5y ago

It seems to be very unlikely that brain cysts (that might affect cognition) can form in immunocompetent people — a pathological study of AIDS patients showed cysts in ~20%; background seropositivity in France (where the study was conducted) is ~40%. Conclusion by the authors: the amount of toxoplasmic agents appeared to be related to the degree of deterioration of the immune status. > Neuropathological studies in the brains of AIDS patients with opportunistic diseases: https://pubmed.ncbi.nlm.nih.gov/8518200/ https://pubmed.ncbi.nlm.nih.gov/8518200/

beaner 5y ago

Does toxoplasmosis come up in a standard blood panel, or do you have to suspect it and test for it specifically?

argonaut 5y ago
There is an antibody test. I believe pregnant women are commonly screened with it.
- beaner 5y ago
  If there are antibodies for it does that mean your body naturally fights and defeats it, like the cold? Or does it stick around until detected?
drjasonharrison 5y ago
You have to test for the antibodies or the DNA. https://labtestsonline.org/tests/toxoplasmosis-testing https://labtestsonline.org/tests/toxoplasmosis-testing

ck2 5y ago

Paper is from 2014, a few years later some scientists realized the answer is ironically, ivermectin. But good luck getting the NIH/CDC to mention that drug name right now.

dempsey 5y ago

This is remarkably similar to chronic lyme disease.

dempsey 5y ago
Why the downvotes? In chronic lyme, the purported issue is lyme hiding out in cysts and causing all sorts of difficult to trace calamity throughout one’s life.

jakubmazanec 5y ago

Please ignore this "study" and whatever Jaroslav Flegr says. At my university he was mocked for his misuse of statistics - he does it even in this article, giant models with huge sample sizes finding correlations everywhere with p < 0.1. Also, in this article https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-015-1290-7 https://parasitesandvectors.biomedcentral.com/articles/10.11... he says that "pathogen responsible for mood disorders in animals-injured subjects is probably not the protozoon Toxoplasma gondii but another organism; possibly the agent of cat-scratched disease – the bacteria Bartonella henselae." So did he discover yet another behaviour change inducing organism, or is he simply a shitty scientist? Let's have a look: he recruits respondents via Facebook, they take 4 psychological questionnaires (which are usually not very reliable and shouldn't be used in giant correlation tables) and finds effect sizes ranging from eta2 = 0.004 to eta2 = 0.045. Just look at this table - https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-015-1290-7/figures/1 https://parasitesandvectors.biomedcentral.com/articles/10.11... - results are significant because the sample size is 5000, but what are the practical differences? Barely 1 point on a scale that itself has reliability around 0.9 (which is good, but it still leads to standard measurement error greater than Flegr's effect sizes).