Friday, February 27, 2009

How to Get Toxoplasmosis From Your Cat

To become infected with toxoplasmosis, there are several conditions that must be met. Of course, no one wants to become infected, but I present it this way to demonstrate how much effort is needed to do it.

First, you must own or obtain a cat that is infected with the organism, Toxoplasma gondii. It's not a bacterium, it's not a fungus, and it's not a virus. It's what is known as a protozoan, a tiny, one-celled parasite... kind of like an amoeba, but crescent-shaped, if you have a microscope and want to look at one.

To find out if your cat has it, have a veterinarian test for it. However, this involves doing a blood test called an "antibody titer," but it's not diagnostic unless a series of tests can be performed over time. If the titer is positive, it means the cat is pretty much immune, as antibodies are present to fight off current and future infections. This is true of humans as well. Therefore, a pre-pregnancy antibody test that yields a positive result means mom is immune, too.

However, if you're not immune, the next thing to do to become infected is to make contact with the parasite's eggs. But not just a touch... you have to eat them. Ugh. How does that happen? During the only two weeks in the cat's life when the parasite is shedding its eggs into the host cat's feces, a human must touch them, then somehow get the infectious material into their own mouth. But not right away. If you do it too soon, the eggs won't mature and you won't be infected. You must wait 1 - 4 days, when the feces are dried enough for the eggs to be "potent." Scientifically, it's called "sporulated."

Consequently, if you are cleaning the litter box every day, this can't even happen.

But there's more. Other conditions must be met at the same time.

"Ideally," this must be your first cat, preferably a kitten, since they haven't had a chance to develop immunity from several exposures yet. If you've ever owned cats before, or have one now that's been in the family a long time, the chances of infection are actually negligible. Why?

Because you will be immune by now... and so will the cat. Since exposure is rather common, both you and your cat will have had time to develop some immunity to it.

Also, this infection is a one-time thing, so no treatment has been invented, except for humans. Once the parasite has run through its life cycle, it's over. The cat must become infected again to be infectious again. But the cat's own immune system will be stronger, and spreading the condition to others is even less likely. In fact, repeated infection, as by cats who hunt and eat infected mice (the most prevalent host), leads to a form of "natural vaccination," eventually rendering the cat non-infectious. However, this doesn't mean it's OK to let the cat keep getting infected. They could actually become sick from the disease state of Toxoplasmosis and die.

Now, if you really want to scare yourself and take a chance that the infection will harm your fetus, you must become infected during your second or third trimester of pregnancy. This is the time when you might have some transplacental transmission of the parasite into the baby's bloodstream, and on to the small intestine, where the "oocysts" (the parasite's eggs) can hatch and grow. However, even with such infection, the odds are still greatest that the baby will be born normally and totally healthy.

Just when you thought you were through, there is yet another condition to be met. It's called immunity. Just in case you have a very poor immune system, the chance of infection, though small, is still there.

However, while the incidence of toxoplasmosis is extremely low among healthy humans, it actually is quite high among AIDS victims, who have little or no immune strength left at all. Those who have pet cats and come into close contact with them are more than likely to become infected. But pregnancy has nothing to do with it. Companionship is more important at such times, and so it's best to leave these happy relationships alone, offering support by relieving them of those cleanup chores that present the most risk.

But there is yet ONE MORE condition to consider, and it has nothing whatsoever to do with a cat! Just eating undercooked meat can do it, too.

The main thing you don't have to do is get rid of your cat.

Sources: The Cornell Book of Cats, Cornell University; The Merck Veterinary Manual, Merck & Co.

Feel free to download a brochure on this subject at my website: The Problem Cat

Look through the center column of Free Reports. In fact, download anything there that looks interesting to you.


Anonymous said...

Cat Bert,

Thank you, thank you, thank you for posting this!! As a current nursing student AND having worked in veterinary medicine for nearly 10 years, I'm still appalled by the number of my preggers friends whose OBs tell them they have to get rid of their cat or have someone else "deal" with the litter box...I'm only one person, and I can only educate so many people before I'm just too dog-gone tired!


Cat Bert said...

Thank you for your comment on this. I was beginning to think no one was reading these things. I can't seem to get the message out either. As a rescuer, I was inundated with people surrendering their beloved cats because their big honcho doctor told them they had to. I simply could not convince them of this "non-risk." I'm a doctor, too, but I'm not THEIR doctor. And it's also surprising (maybe not) how doctors hold their patients hostage by threatening not to treat them if they don't follow orders. Anyway, thanks for your comments. That means a lot to me.

Anonymous said...

Thank you so much for this article - the first one that actually makes sense and puts my mind at ease!
My cat(9 yr old who was homeless) had titres in her blood which showed positive antibodies to a previous infection of toxoplasmosis somewhere along the line between 0-5yrs ago, i have been worrying myself sick recently as we have been trying to conceive and i've been considering gettting pre-pregnancy antibody test incase i currently had any active infection. We already have another cat who is 9 yr old, do you think i am being overly cautious? p.s and i am using disposable gloves whilst cleaning the litter tray!

Cat Bert said...

Thanks for finding my article on toxoplasmosis. I hope it helps you to relax and feel more confident that you are doing the right thing to keep your cats. As for being "overly cautious," there is nothing wrong with being as careful as possible. The only problem I've seen with that has been when it leads to almost neurotic measures, causing harm either to you, family members, or the cat! It's typical of doctors to demand that all family pet cats be disposed of when mom gets pregnant. Now, THAT's overboard. Totally unnecessary. Though the risk is small-to-none from your description of your situation, I see nothing wrong with using disposable gloves! It's a distasteful job anyway. It sounds like you love your cats, so why not keep them? I've run a shelter for 7 years and saw too many cats die unnecessarily because they were removed from the families they loved and could not adjust to it. Cats are very sensitive.

The next issue you may encounter is that of a cat "stealing a baby's breath" once your new baby arrives. That is, of course, pure hogwash. Cats love babies and have no nefarious motives about it. Perhaps the baby smells great to them, certainly they are warm and soft, and the cat may feel an immediate bond to a new family member, just as we do. Don't discount that.

Thanks for writing!

Cat Bert said...

Oh, one more thing: Just as a reminder, please note that having a positive antibody titer after a blood test does NOT mean you are infected. It means, rather, that you have been exposed to the organism, BUT you now are immune because you have the antibodies in your blood. Same goes for the cat. Hope that puts your mind at ease. I did a lot of research on this...