A very poor study, they did not prove, or even made plausible, any causal relationship between the parasite and the cancer.
If they had found proof of (higher) exposure in individuals who developed cancer, I would say they had a case.
The higher incidence of the parasite might just as well be a sign of lower hygiene standards in general, or of a greater population of rabbits, or of a higher incidence of FIV-positive cats, or of a certain type of climate.......
In which case both the brain cancer and the higher incidence of toxoplasmosis may well be due to a common cause.
