Plague is caused by a bacterium (Yersinia pestis) transferred by flea bites or through direct contact with an infected animal (including transmission to humans). Plague is now commonly found in rock squirrels, prairie dogs, wood rats, and other species of ground squirrels and chipmunks. Other animals in the plague cycle include mice, fox squirrels, tree squirrels, swift fox, wild rabbits, and domestic pets.
In humans, symptoms may include sudden fever and chills, severe headache, muscle aches, nausea, vomiting, and a general feeling of illness. If detected early, antibiotics can be effective; otherwise, life-threatening complications may follow.
View the New Mexico Department of Health's Plague Brochure.