Climate change could exacerbate the threat posed by toxoplasmosis, a tiny pathogen that can cause serious illness and damage to organs, in northern Canada, where human infection rates are already among the highest in the world. Researchers are investigating the presence of toxoplasma gondii in wildlife and water supplies, and are seeking ways to reduce the risks of infection. Possible measures include treating drinking water using multiple barrier treatment, removing parasites from water tanks and inactivating them using ultraviolet disinfection. The pathogen is usually spread by cats, but in the Arctic it appears to be spread by migratory birds and Arctic foxes.