Wednesday, October 03, 2007

Animal myths part 2

This is the second installment of my "myths" series... We'll see how long I can keep it going!

Myth #4: Giardia comes from beavers.

Every good Boundary Waters camper knows that you don't drink water from anywhere near a beaver dam, lest you contract "beaver fever", or Giardia. Giardia is a protozoan parasite that, in humans, causes GI symptoms like painful gas and diarrhea- not a ton of fun under normal circumstances, but especially not fun when roughing it in the BWCA. Before you go blaming the beavers for giving humans Giardia, though, think again. Giardia doesn't originate from beavers- beavers pick up Giardia from humans. So if humans wouldn't go around pooping near beaver dams, the poor beavers wouldn't get infected in the first place. Beavers don't really get sick from Giardia, so unlike humans, beavers have (and shed) Giardia for a long time. That's the real reason that beavers infected with Giardia are dangerous. The number one source to pick up Giardia today is not beaver-tainted lake water, but daycares and nursing homes.
  • Myth #5: Cats pose a significant risk to pregnant women due to the potential for Toxoplasmosis infection.
Like beavers, cats got blamed for spreading Toxoplasma to humans when it was discovered that they were a host for the parasite, even though there are other sources more likely to spread the parasite to humans. Toxo is a scary disease not for your normal adult human, but for pregnant women. Women infected with the Toxoplasma parasite during pregnancy can pass the parasite on to their unborn baby, who has no immunity to it. It goes on to cause congenital malformations, mental retardation, or blindness in the baby. Toxo can also cause problems in immunocompromised individuals, like people with AIDS. Because cats are the main host for the Toxo parasite, many people now believe that pregnant women should not come in contact with cats, or at least should not handle the cat litter during pregnancy. While the litter thing is a great idea, getting rid of the cat is unnecessary. Even if they have Toxo, cats only shed the parasite for 2 weeks of their entire lives. The major source of Toxo in humans is actually eating undercooked beef, because cows are part of the life cycle of the parasite, too. Somehow human doctors always want to blame the cat (although they are getting better about acknowledging raw meat as another potential source of Toxo). So, be careful around the kitty, but also cook your meat thoroughly!!

1 comment:

Bjorn said...

So, cook your kitty throughly, and don't mess with cow litter? And keep away from beavers who hang out with old people who poop on babies? Myths are hard.