Toxoplasma gondii: a parasite pollutant in the Arctic.

It is enigmatic, but important, to understand how Toxoplasma gondii, with felids as the ultimate source, enters and circulates among wildlife, people, and the environment of the Arctic, where felids are rare. Informed by studies in the last 15 years, we opine that: (i) marked regional differences in human seroprevalence across the North American Arctic are supported by more numerous animal sentinel studies; (ii) tissue cysts in migratory geese and oocysts shed by felids travel north as 'parasite pollutants' into Arctic ecosystems, moving from land to sea and back again; and (iii) exposure to T. gondii is increasing in polar bears, linked to increased time on land and climate change in the most rapidly warming region of the globe.