Got a light-colored horse—white, gray, palomino, dun, or buckskin? All the more reason to make sure you keep him adequately vaccinated against the mosquito-borne West Nile virus.

Results of a 2008 study indicate that light-colored horses infected by WNV are 4.4 times more likely to die of it or be euthanized than their darker counterparts. The study was conducted at the Western College of Veterinary Medicine in Saskatchewan, Canada.
Although reason for the difference remains unknown, the researchers suggested that immune response in horses might be linked genetically to coat color.