HomeHuman to cat relationshipToxoplasmosisScientifically Reviewing the Link between Feline Toxoplasmosis and Human Schizophrenia


Scientifically Reviewing the Link between Feline Toxoplasmosis and Human Schizophrenia — 19 Comments

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  3. What I find ironic is that, far from presenting a contradictory argument, Galen T is actually agreeing with what I’ve said: with toxo present in the environment and oocysts dispersed in several ways, close contact with cats is not necessary in order to become infected.

  4. Cats can be reinfected multiple times, but most cats have immunity after the first infection and they do not shed oocysts on subsequent reinfections. Antibodies prevent toxo from completing its lifecycle in the cat.

    Galen T undermines his own claim of “removing infected rodents eliminates the parasite” (in a localised area) by mentioning aerosolised toxo can blow the parasite in from neighbouring areas. He also undermines his arguments be resorting to ad hominems in his first post. And he still misses the point that the studies (including my analysis of them) are not denying the link between cats and T gondii, they are looking at a specific link between childhood close contact with cats and mental illness.

    I could resort to personal attacks, but that adds nothing to a scientific argument and only shows the individual to have nothing of substance to add to the debate (except comments that are outside of the focus of the debate).

    • Thanks Sarah for taking the time to present a counter argument. There are people like this person (who I believe is Woody, the notorious troller) but I believe we need to argue with them rather than delete everything they write provided it is not too rude.

  5. You also downplay the FACT that cats can become reinfected many times during their lives, even from their own feces, even when their antibody counts are high.

    Again, do your homework, instead of wallowing in that bliss of self-inflicted ignorance.

    And not even washing your hands and garden-vegetables in bleach nor hydrochloric acid will destroy the oocysts. Again, do your homework before you infect a billion more people with your brain-hijacking parasite — ALL just because “cats make you feel good”. What a great reason to do it.

  6. I see that you fail to mention that infection also occurs just by breathing any air that passes over soils where the oocysts have become dessicated and airborne too. You can contract T. gondii just from a neighbor’s yard with cats in it just by breathing the air that passes over their yard on a dry day.

    Do your homework before you spread some more of your biased misinformation and outright deceptive lies. Google for: Toxoplasma gondii aerosolized

    • Look Galen, you cannot just pluck information from the thin ear without supporting it with hard science. You’ll note that Sarah supported her article with references. All you can do is demonstrate your hatred for the domestic cat! Pathetic. Give us chapter and verse and if you can’t, shut up.

  7. Medical Microbiology. 4th edition.
    Chapter 84Toxoplasma Gondii – J. P. Dubey.

    ” the definitive hosts are members of the family Felidae, including domestic cats. Various warm-blooded animals serve as intermediate hosts. Toxoplasma gondii is transmitted by three known modes: congenitally (from mother to foetus), through the consumption of uncooked infected meat, and via fecal matter.”

    Note it says “INCLUDING domestic cats” In countries with indigenous wildcats, they are also hosts and spread it into the environment. This publication is candid that it only looks in detail at tissue cysts as a mode of transmission. It does mention congenital toxo that is passed from mother to infant without needing feline intervention. This is most common in rodents and seems to be a “back-up plan” for toxo to perpetuate itself in the population of a prey species.

    “Toxoplasma gondii infection in humans is widespread throughout the world. Approximately half a billion humans have antibodies to T gondii. The incidence of infection in humans and animals may vary in different parts of a country. The cause for these variations is not yet known: environmental conditions, cultural habits, and animal species are among factors that may determine the degree of natural spread of Toxoplasma gondii. Only a small proportion (less than 0.1 percent) of people acquire infection congenitally. Immunocompetent mothers of congenitally infected children do not give birth to infected children in subsequent pregnancies. However, repeated congenital infection can occur in mice, rats, guinea pigs, and hamsters without reinfection from outside sources.”

    “Invertebrates such as flies, cockroaches, and earthworms can spread oocysts mechanically.”

    “at any given time as little as 1 percent of the domestic cat population in the United States is shedding oocysts.” (another factor needed in any study of a link between childhood pets and mental illness – was the family cat shedding oocysts or had it already acquired immunity?)

    • Guess what? Removing all cats from an environment effectively sterilizes this parasite from reproducing ever again. Without cats this parasite ceases to exist within the lifetime of one herbivore that some cat has infected with it, or the lifetime of one infected herbivore + one carnivore that ate that infected herbivore. You can candy-coat the problem and try to lay blame elsewhere with your “intermediate hosts” all you want, but T. gondii is here because of your cats and no other reason.

      • And as for your congenital “backup plan” in rodents, once all rodents from any area are removed (or eaten by predators), 1 to 2 populations worth, and rodents free from being infected by any more cats repopulate the area, then the parasite is also gone. Zero cats = zero Toxoplasma gondii.

  8. While cats are the definitive host for T gondii (i.e. the one in which in reproduces), many mammals and birds are intermediate hosts. It is contracted by humans through a variety of routes without needing close contact with a cat. The oocysts can even be transported into cat-free areas e.g. when turf is moved from one area to another or when plants are moved in pots of unsterilised garden soil. The reports are specifically discussing cat ownership/close contact with cats while ignoring the other vectors such as the intermediate hosts or the environment. These media’s take on these studies is “your pet cat may make you ill” and that is what I have addressed. I haven’t denied that cats are hosts, but I’ve pointed out that you don’t need any one-to-one contact with cats in order to get toxo, so blaming mental illness on a childhood pet is looking at only one vector out of many. In addition, purely indoor cats may be completely free of toxo and, as mentioned, healthy cats usually only shed oocysts the first time they are infected.

  9. It’s difficult to take anything seriously from a person who doesn’t even realize that all those “other” ways that people can contract T. gondii were originally infected by oocysts direct from cats. The whole article now meaningless from this clear and blatant misinformation bias.

    This author wouldn’t know “science” if even their own life depended on it. But you go ahead and swallow it, because it helps you to wrongly believe what you already wrongly believe.

    • Sarah Hartwell is not biased. She has a very good brain. I would suggest that it is you who is biased because you hate it when people defend the cat and try and put everything that is said about the cat and toxoplasmosis into context and in a more truthful way.

      For example, please describe to me how oocysts from cats end up in raw meat in kitchens from livestock? Raw meat is the biggest source of toxoplasmosis in humans according to the reference works that I have. Let’s just focus on that one aspect of it for the time being. Please provide a full answer. I require chapter and verse if I am to believe what you write.

      I will also ask Sarah to respond to your comment.

      • You might like to know that more than 60% of all deer across the USA are now infected with T. gondii from cats contaminating all the soils and waters across the lands. Even rare marine mammals are dying off from T. gondii from run-off from the land. And then you wonder how all our livestock can become infected from cats just roaming around stockyards and farms? Tighten those ignorance-is-bliss blinders a little more.

        • Here’s a clue for you: Herbivores (and seed-eaters, like most rodents and birds) can contract T. gondii in NO OTHER WAY than directly from cat-shat oocysts. Or is your comprehension and knowledge of this parasite’s life-cycle too far beyond you? Do you even know what an herbivore is? Or must this be explained to you as well.

          • Galen (Woody) if you insult Sarah again. I’ll delete and ban you. You are a rude, aggressive, arrogant, unpleasant American.

        • Stop insulting people. All you can do is insult people. You can’t resist can you? Such arrogance. Your comment is worthless without support from a proper scientific study. I said I need chapter and verse. And if you respond and insult me you’ll be banned and the comment deleted.

    • Hello Woody.

      If you had any knowledge of Ms Hartwell’s credentials, you’d realise you’re just embarrassing yourself with comments like “This author wouldn’t know “science” if even their own life depended on it.”

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