Due to their cryptic nature, very little is known about the northward-creeping and vector-borne pathogens that cause malaria (Plasmodium odocoilei), babesiosis (Babesia odocoilei), or theileriosis (Theileria cervi) in cervids. These pathogens are moving north along with their mosquito and tick vectors and white-tailed deer hosts due to climate and land use changes. These pathogens pose a threat to northerly-distributed and declining moose, reindeer, and caribou populations.