A Common Parasite Reveals Its Strongest Asset: Stealth

The New York Times ^ | June 20, 2006 | Carl Zimmer

[ConservativeMind]

On paper, Toxoplasma gondii looks as if it ought to be the most famous parasite on earth. This single-celled pathogen infects over half the world's population, including an estimated 50 million Americans. Each of Toxoplasma's victims carries thousands of the parasites, many residing in the brain. As if that were not enough of an accomplishment, Toxoplasma is equally adept at infecting all other warm-blooded animals, as disparate as chickens and kangaroos.

Scientists are now discovering some of the secrets of Toxoplasma's success. Researchers in Sweden report that the parasite fans out through the body by manipulating mobile cells that are part of the immune system. Toxoplasma hijacks these so-called dendritic cells and makes them race around the body and ignore commands from other immune cells to commit suicide. The dendritic cells sneak the parasites into the brain and other organs, acting much like a Trojan horse.

Strategies like this one have made Toxoplasma incredibly widespread and incredibly obscure. Mention the parasite to most people and chances are you will draw a blank. Pathogens that infect far fewer people, like the Ebola and West Nile viruses, are far more famous.

[ConservativeMind]

There are studies from Eastern Europe that suggest personality shifts among men and women once infected. Women become somewhat more personable and men become more jealous.

Regardless, a parasite like this could be doing a lot of bad and is simply able to cover it up.

There's no telling how many fewer colds or how much faster our bodies could respond to stresses without this pathogen hijacking our cells.

I grew up on a farm with many cats. Since reading about T. Gondii over the years, I will not ever let my kids have a cat.

[A CA Guy]

[ConservativeMind]

More on dendritic cells and their importance:

http://en.wikipedia.org/wiki/Dendritic_cells

[A CA Guy]

Stuff like this can be dangerous.

Do you remember about three years ago when they did research into people who had to get Kidney dialysis?
They took blood samples of everyone and found out like 90% of people on dialysis had a disease of the blood related to contact with rodents/rats.

Rats are nocturnal and different creatures than we are.
They are toxic as are their droppings.

If you ever see their droppings, it is mask and gloves time before you clean.

Lots of nasties out there.

[non-anonymous]

If your kids aren't pregnant and don't have AIDS, I wouldn't worry.

[Pontiac]

Since T. Gondii infects nearly all warm blooded animals can be transmitted by the eating of meat and finds its way to the brain could it be possible that T. Gondii is the cause of Mad Cow disease and not prions?

[neverdem]

Graphic: A Ubiquitous Pathogen That Keeps Its Host Healthy

Top, Henrik Lambert and Anette Hofmann/Karolinska Institute; Above, Niclas Hitziger/Karolinska Institute
PARASITE'S PROGRESS Toxoplasma gondii, the smaller organism at top, hijacks cells of the immune system. Scientists used mice to monitor the movement of Toxoplasma, highlighted above. Dendritic cells help the parasite spread faster than it could alone.

[neverdem]

ping

[cricket]

The dendritic cells sneak the parasites into the brain and other organs, acting much like a Trojan horse

Toxoplasma gondi. . .

'As above; so below'. .

. . ..have long mused as to the synchroncity in the similar 'waves of terror' that threaten us.

Finally, we have definitive evidence and as well a name/classification. ..origin perhaps of the terror species who live, attack and kill in the 'above' world. Terrorists, terror cells. . .who challenge description in human terms

Beyond the metahor. . . a 'naming' of that viral terror; speaks as well to the 'above'. ..sharing similar attributes. . .dendritic cells, stealth parasites. . .trojan horse MO; all which cause fear, panic and death.

And for survivial; a warring response. . .

Toxoplasma gondi. . .if one thinks about it and with the smallest stretch. . .seems to resonate with Liberals and 'stealth Liberalism' as well. . .

[cricket]

ahh...that should be 'Beyond the metaphor (of course). . . a 'naming' of that viral terror; speaks as well to the 'above'. ..sharing similar attributes. . .dendritic cells, stealth parasites. . .trojan horse MO; all which cause fear, panic and death.

(and hence. . .our 'WOT').

[cricket]

Beyond the metaphor. . . a 'naming' of that viral terror; that speaks as well to the 'above'. . .

. . . our current threat of various named terror cells as in the differing; but similar. . . 'bird. ..ebola. .West Nile. . .so mentioned. . .and those 'et als' virus names not included.

[AngelesCrestHighway]

sounds like the Democratic Party in America....

[leadhead]

It's:

Pick one:

1.Bush's fault

2.Because of Global warming

3.The end of life as we know it

4.B******t

[thoughtomator]

...personality shifts among men and women once infected. Women become somewhat more personable...

A Rare Case of Complete Immunity

[Blueflag]

Bear in mind that a healthy human body has, by numeric count, far more non-human organisms living in it than it has cells alltogether.

But read this quote from wikipedia, ESPECIALLY THE LAST LINE!

"Toxoplasma gondii is a species of parasitic protozoa whose definitive host is cats but can also be carried by the vast majority of other warm-blooded animals including humans. It causes the disease toxoplasmosis which is usually minor and self-limiting but can have serious or even fatal effects, particularly in cats, or for a foetus when first contracted during pregnancy. It belongs to the Apicomplexa and is the only known member of the genus Toxoplasma.

Human prevalence

The U.S. NHANES (1999-2000) national probability sample found that 15.8% of U.S. persons above 12 years of age had Toxoplasma-specific IgG antibodies, indicating that they had been infected with the organism. This prevalence had not significantly changed from the 1988-1994 data.[4]

It is estimated that up to 50% of all people worldwide are infected with Toxoplasma gondii. The incidence of infection is highly specific to each nationality with ranges such as 22% infected in the UK to over 88% in France.[5]

[vetvetdoug]

Thanks for the ping. I had the dubious honor of having submitted the serum from a cat that had the highest titer ever recorded by Dr. Dubai at the National Center for Infectious Diseases at Maryland. It is commonly found in dogs and cats in this area and we are very aware of its implications in families that have members that are immunocompromised.

[ConservativeMind]

Looking between the CIA Factbook population for France and the top ten country cat populations show that there would be roughly 1.3 cats for every man, woman, and child in that country.

If there are any personality or mental problems to be had, France is the place to study. The US, by comparison, has merely 1 cat for every four people.

[ConservativeMind]

The website used to garner cat populations was pawsonline.info.

[Blueflag]

fascinating epidemiologically ...

[Route797]

Keep your cats indoors.