Researchers say it's time to stop blaming cats for brain cancer in people

August 23, 2012 by Bob Yirka, Medical Xpress report
Cat

(Medical Xpress)—Two groups of researchers have published articles in the journal Biology Letters, suggesting that it's time we stop blaming cats for making people crazy or for a certain type of brain cancer that other researchers have linked to a parasite in cat feces. The first group, with the Tour du Valat research center, say that after looking at all the current research findings they can find no evidence linking cats and brain cancer in people. The second team from Oxford University's Cancer Epidemiology Unit, after conducting what they call the "Million Woman Survey" have found among many other things, that there was no more incidence of brain cancer in women who owned cats than in those who did not.

For many years, rumors have been floating around accusing common housecats of causing insanity and other ailments in their human "owners" not the least of which is brain cancer. Then, last year a team of researchers in France found that a parasite called Toxoplasma gondii, found in cat guts and feces could perhaps be linked to brain cancer in humans, after discovering that countries with higher incidences of brain cancer also reported higher incidences of the parasite being found in people.

The researchers from Tour du Valat say there is no basis for correlating cat ownership with a higher incidence of T. gondii and thus no real evidence that living with raises the risk of brain cancer. Instead they say other studies have shown that most instances of parasitic infestation in humans is via eating foods or dinking beverages that have been contaminated with the parasite. Instead they say, other studies have shown that cat (and dog) owners tend to have less risk of another type of , . They also note the plethora of studies that have been undertaken that show that provides mental and emotional health benefits.

The Tour du Valat team's findings were backed up by those of the team from Oxford who report that after conducting extensive surveys with over 600,000 women all across Britain, eighteen percent of whom owned cats, they found zero evidence to suggest that those who own cats wind up more often with .

Both teams conclude that it's time to stop blaming cats for mysterious maladies as most of the supposed evidence is suspect at best.

Explore further: Study finds risk factors for cat cancer, could have human implications

More information: Cat ownership is neither a strong predictor of Toxoplamsa gondii infection nor a risk factor for brain cancer, Biol. Lett. rsbl20120625; published ahead of print August 22, 2012, doi:10.1098/rsbl.2012.0625 1744-957X

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3 comments

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TheGhostofOtto1923
3.6 / 5 (18) Aug 23, 2012
"Instead they say other studies have shown that most instances of parasitic infestation in humans is via eating foods or dinking beverages that have been contaminated with the parasite."

-Which necessarily originated in cats. The organism can only reproduce in their digestive tracts.
http://joomla.wil...toxo.pdf

"Both teams conclude that it's time to stop blaming cats for mysterious maladies as most of the supposed evidence is suspect at best."

-Fine. But it still appears that t gondii causes brain cancer, schizophrenia, suicidal tendencies, and who knows what else. So we need an effective vaccine and a cure.

J_Goudy
5 / 5 (2) Aug 23, 2012
I had some doubt about the validity of this study due to toxoplasmosis spreading through the ingestion of raw or undercooked meat. If you consider only domesticated cats fed commercial food, the likelyhood of toxoplasma gondii ingestion is close to 0. Not that there aren't mice in that region just that this data seems inconclusive. Looking at the full text of the study I found:
"Information on current ownership of cats, dogs, birds and fishes was obtained from a postal survey of study participants during 2006–2007: the respondents to this survey form the baseline cohort for these analyses."
and
"Information on T. gondii positivity or consumption of undercooked meats was not available."

If I am reading that right, this was a postal survey with no follow up testing or viable information on what the cats ate. These facts do not make me confident that their conclusion was obtained in an exhaustive manner.
mrlewish
5 / 5 (2) Aug 23, 2012
Caption on cat should say. "I am staring brain cancer into you"

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