Several diseases affect black-footed ferrets, the most serious being canine distemper and sylvatic plague. Canine distemper is thought to always be fatal to ferrets and is spread by other animals that frequent prairie dog towns, such as coyotes and badgers. Sylvatic plague, spread by fleas, is akin to the bubonic plague that devastated humans in Europe in the Middle Ages. Both ferrets and prairie dogs are highly susceptible to plague, and entire dog towns can be eliminated quickly. Ferrets are also susceptible to other diseases, including rabies, tularemia and human influenza, but these are not considered serious threats.
Loss of habitat is the primary reason black-footed ferrets remain near the brink of extinction.
Conversion of grasslands to agricultural uses, widespread prairie dog eradication programs and plague have reduced ferret habitat to less than 2 percent of what once existed. Remaining habitat is now fragmented, with prairie dog towns separated by great expanses of cropland and human development. Many other sensitive species such as burrowing owls, mountain plovers, golden eagles, swift fox, and ferruginous hawks are strongly linked to this habitat for their survival. Many of these species are following the ferret's fate, and may soon require further conservation efforts to ensure their survival. View this page in non-frames for easy printing.