Cat scratch fever
There's one thing I hate about the Internet. Anyone can become an authority on any topic and people read it and take it as fact. Since working on my master's, I've learned the value of hard research based on fact. I'm always amazed to hear "facts" coming out of people's mouths. "Did you know that deodorant causes breast cancer?" A while ago, I would have thrown out my deodorant but I've become wise enough to know that I have to search further to find the real facts. In the case of the deodorant/breast cancer link, what I found was there is no evidence to support this claim so my armpits remain dry and BO-free.
I was sent this link from my son (I have three cats who sleep on my head each night). The weblogger made some statements that highly exaggerated the facts, and even worse, eluded to the suggestion that maybe people shouldn't keep domestic cats around. Forget the fact that dogs eat their own shit then lick you in the face but nowhere did he mention the facts surrounding dogs and their despicable hygiene habits.
Speaking of dogs, humans, especially small children, can contract a zoonotic infection from their dog. For example, roundworms and hookworms live in a dog's intestine and are spread through contact with contaminated dog feces or soil. Generally, children are more likely to contract zoonoses than adults since they may neglect to wash their hands before putting them in their mouths after playing in contaminated sand or dirt. Even a simple barefoot walk through a park can put you at risk since hookworms can penetrate through the skin-especially the soles of the feet.
For anyone with any misconceptions about cats and toxoplasmosis, I will post some facts here which I found in the journal, "Diagnostic Microbiology and Infectious Disease," through the University of Nebraska-Lincoln library on the topic of toxoplasmosis and cats (I would link it, but you need a code to access). In a nutshell:
Outdoor cats and stray kittens and cats can carry the parasite, while it's almost impossible for an indoor cat to contract the parasite. Toxoplasmosis is caused by a parasite called toxoplasma gondii, it is found in raw meat, in cats who eat raw meat and in cat feces. In only about 30-40% of people who catch toxoplasmosis during their pregnancy will the infection pass to the unborn baby, and only 1 in 1,000 to 1 in 10,000 babies contract the disease in this country. To avoid catching toxoplasmosis you should ensure that all meat is thoroughly cooked before you eat it and that you use seperate cutlery and surfaces for raw meat and other food stuff. Also get someone else to empty out the cat litter tray, or wear gloves and thoroughly wash your hands afterwards. You should also wear gloves when you do any gardening. If you stick to these guidelines the chances of catching toxoplasmosis is very small.
For more information, you can go to the March of Dimes website which contains some good info on the topic. Again, please note the statistics: Between 1 in 1,000 and 1 in 10,000 babies contract the disease in this country (and you can bet these babies are not ones that were born from a vegetarian home with indoor cats).
To clear another matter up: There isn't a single verified case of a cat smothering a baby, this is entirely myth. However, there are several cases of parents accidentally smothering babies in their sleep.
When Summer was a baby, our cat, Spyder, sat in her crib by her side and guarded her. If you were someone new you had to pass his smell test to even touch her. So snuggle your cats and fear nothing. You have a far greater chance of catching a serious disease from a human, or from eating in a restaurant.
Posted at November 5, 2003 7:58 AM
Comments
Toni, thanks for your comments. I would have responded sooner, but it's been a hectic day.
I think you're ascribing claims to me that I haven't made. For example, I made no normative comparison between cats and dogs, made no specific arguments based on the rate of Toxoplasmosis infection, and certainly said nothing about cats smothering babies.
As to my reaction to my friends' hygiene, I did not have to rely on aggregate rates of infection; I had observed a specific pathway from litter box to our food, with a young, formerly stray, outdoor cat as the vector. Being rather risk averse in this regard, I viewed this as serious threat. While I knew that the aggregate rate could not be high — because most babies do not have a problem — and that rather specific timing is required for infection, I did not know the likelihood of infection (or of course other problems) upon eating residual cat feces. I was unwilling to take a chance. Take your odds on that if you like, but we avoided it. I do see how my phrase “serious threat” suggests a high likelihood of aggregate infection, but that was not my intended meaning.
Now, regarding the facts. Based on the medical sources I read, I wrote "about 40%" for transmission rate; you write 30-40%. I don't see the former as misleading. On the source of infection, your suggestion that raw meat is the problem is incomplete. The parasite uses the cat as primary host and can use a variety of secondary hosts (e.g., rats, mice, rabbits, people, even birds). Raw meat can be infected as a secondary effect of this lifecycle, for instance because the parasites are in the muscle tissue of the meat animal or because of fecal matter deposited on the meat during processing. (Infection can come from rabbits too, and it seems dogs as well.) But the original pathway is still relevant: If a cat eats an infected rat (or presumably mouse?), then it can get infected. I do not know much about the habits of indoor cats, but I have seen indoor cats eat mice and rats in the basement, which makes me skeptical of the claims that it is nearly impossible for indoor cats to be infected.
I did say "most domestic cats are or will be infected over time". This was not arbitrary, as you suggest, but was based on similar claims from several sources I read while investigating the background. Nonetheless, I agree that I should have made clearer the uncertainty in this statement since I did not have any empirical support for this second-hand assertion. If it is much less likely for indoor cats to be infected, then that is an important qualification as well. Note, however, that "most" does not mean all, and given the high infection rate among secondary hosts in many countries, it seems likely that the infection rate among primary hosts will also be high.
My post was not an argument to panic over toxoplasmosis or to ditch your cat. The main point of my post was to evaluate the statistical claims for infection-induced personality change. Though I remain skeptical of these claims, if it were shown that T. gondii infection had serious neuropsychological implications, then given the high stated infection rates in many countries, this would be a serious public health issue. If it comes to that — and note I never said it has — I think it would be reasonable to consider a correspondingly serious response.
Thanks for your response. My point was simply that your post was an alarmist view of toxoplasmosis. I can find equally alarming literature on everything from aspirin to milk consumption. When you said, "On first glance, their house seemed immaculate: every surface polished and shiny, no paper out of place, tasteful knick-knacks thoughtfully positioned. But the surface tidiness masked deeper sanitation horrors. I still shudder when I think about it," all I could think of was, "Man, has this guy ever used a public bathroom or slept on a hotel bed?" There are horrors that exist everywhere around us. If we dwell on the remote possiblity of catching diseases in every day places, we will quickly become Felix Unger.
Chris- one more thing- I wasn't responding to your post when I mentioned the myth surrounding cat smothering. I was just addressing another misconception about cats and babies.
I just heard that same thing about deodorant a few days ago! I also heard (from a professor) that abortions can cause breast cancer. I looked it up...not true.
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Toni, thanks for your comments. I would have responded sooner, but it's been a hectic day.
I think you're ascribing claims to me that I haven't made. For example, I made no normative comparison between cats and dogs, made no specific arguments based on the rate of Toxoplasmosis infection, and certainly said nothing about cats smothering babies.
As to my reaction to my friends' hygiene, I did not have to rely on aggregate rates of infection; I had observed a specific pathway from litter box to our food, with a young, formerly stray, outdoor cat as the vector. Being rather risk averse in this regard, I viewed this as serious threat. While I knew that the aggregate rate could not be high — because most babies do not have a problem — and that rather specific timing is required for infection, I did not know the likelihood of infection (or of course other problems) upon eating residual cat feces. I was unwilling to take a chance. Take your odds on that if you like, but we avoided it. I do see how my phrase “serious threat” suggests a high likelihood of aggregate infection, but that was not my intended meaning.
Now, regarding the facts. Based on the medical sources I read, I wrote "about 40%" for transmission rate; you write 30-40%. I don't see the former as misleading. On the source of infection, your suggestion that raw meat is the problem is incomplete. The parasite uses the cat as primary host and can use a variety of secondary hosts (e.g., rats, mice, rabbits, people, even birds). Raw meat can be infected as a secondary effect of this lifecycle, for instance because the parasites are in the muscle tissue of the meat animal or because of fecal matter deposited on the meat during processing. (Infection can come from rabbits too, and it seems dogs as well.) But the original pathway is still relevant: If a cat eats an infected rat (or presumably mouse?), then it can get infected. I do not know much about the habits of indoor cats, but I have seen indoor cats eat mice and rats in the basement, which makes me skeptical of the claims that it is nearly impossible for indoor cats to be infected.
I did say "most domestic cats are or will be infected over time". This was not arbitrary, as you suggest, but was based on similar claims from several sources I read while investigating the background. Nonetheless, I agree that I should have made clearer the uncertainty in this statement since I did not have any empirical support for this second-hand assertion. If it is much less likely for indoor cats to be infected, then that is an important qualification as well. Note, however, that "most" does not mean all, and given the high infection rate among secondary hosts in many countries, it seems likely that the infection rate among primary hosts will also be high.
My post was not an argument to panic over toxoplasmosis or to ditch your cat. The main point of my post was to evaluate the statistical claims for infection-induced personality change. Though I remain skeptical of these claims, if it were shown that T. gondii infection had serious neuropsychological implications, then given the high stated infection rates in many countries, this would be a serious public health issue. If it comes to that — and note I never said it has — I think it would be reasonable to consider a correspondingly serious response.
Posted by: Chris Genovese at November 5, 2003 7:41 PM