Signal + Noise: Cat Got Your Brain?
I thought this was an interesting bit of discussion on cat toxoplasmosis. Toxoplasmosis is something I know a little bit about since I recently researched it for the cat lovers website. The post at the link above references an article concerning a study on cat toxoplasmosis and human behavior modification. In short, it basically says that having toxoplasmosis alters your personality. Interesting concept.
The personality altering possibilities of cat toxoplasmosis were discussed here as well, so I thought I'd respond to both posts.
Part of my response is in my page on toxoplasmosis and also my page concerning the toxoplasmosis pregnancy issue.
My concern for the safety of our personalities aside, I was interested to see how much misinformation there still seems to be out there about toxo, so I thought I'd add some comments in addition to my toxoplasmosis pages on my website. Below is my collective response to the various posts that I have seen in some of the blogs discussing this topic...
The facts and conclusions of the study about the effect of the parasite in question aside, here are some points about cats and toxoplasmosis...
- The primary means by which humans contract toxoplasmosis is NOT cats - it is by eating raw or undercooked meat. This is exemplified by the extremely high rate of infection in France. It also may be through contaminated soil, although this is more likely in developing countries.
- According to the Virginia Beach (VA, USA) SPCA, a study published in the New England Journal of Medicine showed that there is no correlation between cat ownership and toxoplasmosis infection.
- Cats have become the number one pet in the United States, eclipsing dogs, with an estimated 30% of all US households having at least one cat. Let's assume, that some have claimed here, that cats ARE responsible in a large way for infecting humans with toxo. Let's further assume that there have been no substantial measures taken by the cat owning public to prevent toxoplasmosis infection (there haven't - in fact, people who used to give cats away during pregnancies because of misinformation by medical professionals now keep them). Then over the years, as more and more people adopted cats, the rate of toxoplasmosis infection should have gone up.
According to the Centers for Disease Control, this is not the case. In fact, toxoplasmosis infections are decreasing!
- Hygiene for your cat does play a role here. Cats commonly get toxoplasmosis from eating raw meat, just as humans do. That is one reason why the so called "raw meat diets" are not a good idea for your cat. They also can contract toxoplasmosis from contaminated soil, and from catching infected prey (rodents and birds). Keep your cat safe and indoors.
- Cats typically only shed the infective form of the disease (oocysts) for about 2 to 3 weeks after their first infection. This is a small window of opportunity. For example, if your cat has not been fed undercooked meat or allowed to roam outside in the last 4 weeks, then your chances of getting infected from your cat are almost 0!
- The oocysts need 24 hours or more to "ripen" - until then, they are not infective. If you clean the litterbox daily, you dramatically reduce the window of opportunity even more.
- The risk during pregnancy is not the only risk for women. Some sources tell us that an initial infection occuring up to six months prior to pregnancy can also be damaging.
- People who are immunocompromised are at high risk as well. Toxoplasmosis is the number one opportunistic infection in AIDS patients. But, the majority of these cases are prior infections that resurface due to a compromised immune system.
All that having been said, you should follow the links to the precautions stated on the websites that I recommend you use for toxoplasmosis resources.
Update: In researching cat toxoplasmosis as well as other zoonotic diseases, I came across the following information published by the American Association of Feline Practicioners (AAFP):
Source of Infection
"ingestion of undercooked meat, transplacental, ingestion of oocysts after 1-5 days of sporulation"
Relative human risk from cats
"Rare; common in people but not usually associated with individual cats becasue of short term oocyst shedding and sporulation period"
In addition, they recommend certain precautions for preventing the spread of zoonotic diseases, such as toxoplasmosis from cat to cat and cat to human. Among those are only feeding cats cooked or commercially processed food, and cooking meat for human consumption medium-well.
