Toxoplasma gondii is a parasite found in cat poop that can make both people and cats ill. It can infect any warm-blooded animal, including reportedly 60 million Americans. People infected with T. gondii typically have flu-like symptoms. Dr. David J Bzik in the Department of Microbiology and Immunology at Dartmouth recently said, "We know biologically this parasite has figured out how to stimulate the exact immune responses you want to fight cancer." Cells in the body that are activated by T. gondii include natural killer cells and cytotoxic T cells, both known to fight cancer.
In research studies Dr. Bzik's team have provided evidence that a modified version of the parasite that is unable to replicate, termed "cps", effectively kills melanoma and ovarian cancer cells in mice with aggressive forms of these cancers leading to high survival rates. The special trick is the ability for the parasite to reprogram the immune system to wipe out tumor cells.
The researchers also discovered that even if cancer has depressed the immune system of the host, cps can activate the immune response to wipe out the cancer cells. The hope is to eventually test this treatment in humans by infecting the patient's own cells with the mutated version of the parasite, which is predicted to ramp up the cancer-fighting ability of the immune system and may offer long-term protection from that specific cancer.
So the epidemiologists should be comparing rates of various types of cancers and the correlation with -- what?
Presence of a cat in the household?
Past history of being around a cat? Over what time span?
There's already the work done on autoimmune/allergy correlation with overly clean animal-free households.
Big data, waiting to be looked into, I hope.