Comments on: There’s just something about him…

By: The social network of solitary lizards | Australian Science

The social network of solitary lizards | Australian Science — Thu, 03 May 2012 00:59:14 +0000

[...] to great lengths to change the behaviour of their hosts. The Tom & Jerry dynamic witnessed in Toxoplasma gondii, and zombie ants are the more popular [...]

By: Geack

Geack — Mon, 07 Nov 2011 16:14:06 +0000

Q,
I don’t follow your logic. Why would an increase in sexual attractiveness require a loss of some beneficial genetic trait? There’s no reason to believe the increased attraction is a result of a mutation that would be passed to offsrping; it simply appears to be a consequence of the infection.

I’m hoping that answering your question a) is part of the ongoing research. They can’t leave us hanging like this

By: Q

Mon, 07 Nov 2011 15:45:16 +0000

I wonder what the mechanism could possibly be? I mean, I’m not saying evolution produces perfection in all cases, but I do think there’s a pretty strong evolutionary incentive to increase sexual attractiveness. So, I would imagine, in a normal rat, there’s not a whole lot that can be done to increase sexual attractiveness without significantly reducing some other important ability (otherwise, a mutation that causes this increase would very, very quickly spread through the whole population).

So, I wonder a) how exactly the infected rats become more attractive, and b) what the infected rats have to give up to do so?

By: David B. Benson

David B. Benson — Mon, 07 Nov 2011 04:21:44 +0000

Harrow — That research, of course, will never be published.

By: Harrow

Harrow — Mon, 07 Nov 2011 00:01:23 +0000

In a related story, graduate students at Johns Hopkins University are on the trail of a related species of Toxoplasma that conceals itself by infecting and modifying the behavior of medical journal referees to make them less likely to publish articles containing evidence of its existence.

-Harrow.

By: christopher

christopher — Sun, 06 Nov 2011 17:39:29 +0000

when my sister was pregnant with her first child, i warned her about this, but her dr said it wasn’t dangerous to the fetus. iwas soo pissed! not to mention that the worthless sperm-donor was too lazy and self-absorbed to clean the litter box for her…luckily,all went well. even go rid of the ‘father’ eventually.

By: linkfest – 11/06/11 « hbd* chick

linkfest – 11/06/11 « hbd* chick — Sun, 06 Nov 2011 17:02:02 +0000

[...] There’s just something about him… – the latest on the wonderfully weird Toxoplasma gondii from carl [...]

By: Brian Schmidt

Brian Schmidt — Sun, 06 Nov 2011 05:52:56 +0000

Seems like it wouldn’t be too hard to find a large-enough sample of young, recently-married human couples where the women grew up in cat-free environments (maybe allergic to cats) while the men had extensive exposure to cats, and then test the women.

One thing I’ve wondered about is how long, really, will the most of the parasites remain alive in people following exposure (and potentially affecting personalities). I would assume there’d by some kind of half life, that these things designed to live a rodent with a two-year lifespan can’t last forever, even if a few do last decades.

By: Murr Brewster

Murr Brewster — Sun, 06 Nov 2011 02:09:29 +0000

I could use a boost. I’m going to go eat a dead rat.

By: Felix

Felix — Sat, 05 Nov 2011 08:31:49 +0000

If you want to hear more about Toxoplasma Gondi listen to this great podcast:

http://www.virology.ws/2010/06/18/twip-12-toxoplasma-gondii/

By: Avi B

Avi B — Sat, 05 Nov 2011 06:13:43 +0000

Hi Carl, this is kind of off-topic but I wanted to bring it to your attention, in case you found it worth promoting: http://rockethub.com/projects/3737-support-zombie-research
She’s raising funds to do further research into zombies (also known as fish brain infecting parasites).
Oh, and the latest radiolab segment was really wonderful. Thank you for sharing such a personal story.

By: Jada Urquharat

Jada Urquharat — Fri, 04 Nov 2011 21:35:49 +0000

Maybe the parasite in a human makes that human like cats. Especially female humans. Think of all the human females who crave ownership of multiple cats; acquire ridiculous numbers of cats; melt, babbling, at icanhascheesburger.com pictures of cats. Thus, those human females are unwittingly spreading Toxoplasmosa, tra la, tra la, far and wide. (I did, in fact, test positive during pregnancy and, only with great self-denial, keep my personal cat population in single digits, but am non-libidinous, probably already having inadvertently infected my own offspring, who have multiple cats of their own. Never ending.)

By: Susan Durham

Susan Durham — Fri, 04 Nov 2011 21:19:59 +0000

So many reasons not to have a cat-box. Or a cat. Let alone hundreds of cats! Do you suppose humans who have been infected may have a tendency to hoard cats?

By: Daniel Engblom

Daniel Engblom — Fri, 04 Nov 2011 17:48:12 +0000

Does T. gondii also reproduce sexually in larger cats (tigers, lions, pumas, cheetas etc, and perhaps dead species like the saber-toothed tiger)? I was thinking that if so, then there’s the possibility that, since people are infected by T. gondii, and they have some symptoms (not quite clear on what has been definitely established, slow motor function?), there could have been active selection on T. gondii to manipulate people as well to be better preyed upon by larger cats.

Have you Carl found any repeated efforts to collect data on these?

By: Mike Lewinski

Mike Lewinski — Thu, 03 Nov 2011 20:59:17 +0000

There’s a possibility of a parasite becoming more of a symbiont over time, right?

It seems like the bacteria discussed here are a possible example:

http://blogs.discovermagazine.com/notrocketscience/2008/05/17/aphids-get-superpowers-through-sex/

By: Cathy

Cathy — Thu, 03 Nov 2011 17:14:27 +0000

Is there a regular test or screening process to check for infections in humans?

[CZ: There are tests, but they're not regular.]

By: Acleron

Acleron — Thu, 03 Nov 2011 13:13:27 +0000

And now we know why we keep cats

By: Mcs

Mcs — Thu, 03 Nov 2011 05:35:36 +0000

Very cool.

Does the Toxoplasma replicate in the rats? If not, how does it get a steady supply of cysts into the semen?

Have they confirmed that it can pass from females to males, or just males to female?

By: so-so

so-so — Thu, 03 Nov 2011 04:51:13 +0000

I thought lowered sexual inhibitions and greater sex drive were part of the symptoms of neurosyphilis.

By: OmegaMom

OmegaMom — Thu, 03 Nov 2011 02:45:40 +0000

Ahhh, but then, if you get too much Toxoplasma, then you turn into a Crazy Cat Lady (or Guy), and the sex appeal goes *poof*. It would be interesting to see what would happen with a T. sample from a cat hoarder versus a T. sample from a “normal” cat lover.

By: Scicurious

Scicurious — Thu, 03 Nov 2011 02:18:55 +0000

WOW. The god parasite. More amazing every day!!

By: Paul Raeburn

Paul Raeburn — Thu, 03 Nov 2011 00:59:14 +0000

Carl,

This came up this year at the science writers’ meeting, in the talk by Rob Knight, I think. And Robert Sapolsky talked about it a few years ago when we were at Stanford. He was devoting a lot of time to the study of rats and cats then, and he might well have some new stuff, the next time you visit Toxoplasma.

[CZ: Thanks, Paul. Sapolsky is Vyas's co-author on this new study.]

By: aimee w

aimee w — Thu, 03 Nov 2011 00:50:35 +0000

I’m sure I remember hearing (somewhere) years ago that people infected with Toxoplasma were friendlier and, well, hornier than before the infection…

Good to know it may _not_ have been true