(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 cats 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 cancer, non-Hodgkin's lymphoma. They also note the plethora of studies that have been undertaken that show that pet ownership 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 brain cancer.
Both teams conclude that it's time to stop blaming cats for mysterious maladies as most of the supposed evidence is suspect at best.
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