Health officials in New Mexico say a wild rat has tested positive for plague, marking another animal case after four dogs in the state were diagnosed with the disease earlier this year.
The infected rodent was found dead by a homeowner on private property in Santa Fe County and was later submitted for laboratory testing, according to the New Mexico Department of Health.
Officials said it is the first confirmed wild animal case of plague in Santa Fe County in 2026. The illness is caused by the bacterium Yersinia pestis.
The discovery comes after four confirmed plague cases in dogs this year, including three in Santa Fe County and one in Bernalillo County.
“While this is an animal case of plague, it’s important to remember humans can get plague from flea bites or direct contact with infected animals, including rodents, wildlife and even pets,” Dr. Chad Smelser, deputy state epidemiologist for NMDOH, said in a statement.
Smelser also warned that pets may become infected if they eat an infected animal or are bitten by fleas carrying the bacteria.
Human plague infections remain uncommon, but New Mexico accounts for about half of the cases reported in the United States each year, according to the health department.
Officials said the disease can be life-threatening if left untreated, though early diagnosis and antibiotics are effective in treating it.
Symptoms in humans include sudden high fever, chills, headache, nausea, and swollen lymph nodes.
Infected pets similarly suffer from fever, low energy, loss of appetite, and swollen lymph nodes, experts added.
The New Mexico Health Department cautioned residents to take several steps to prevent themselves and their contracting the plague — including cleaning up areas near homes such as woodpiles, brush piles, junk and abandoned vehicles, where rodents could live.
Pet food and water should be kept away from where rodents and wildlife can get to them, and people should stay away from sick or dead rodents and rabbits.
Pets should use veterinarian-approved flea control products and be promptly taken to a veterinarian if they are sick.
Last year, a man in Arizona and a domestic cat in Colorado died of the bubonic plague.
A 43-year-old man from Valencia County in New Mexico was also hospitalized with the disease in 2025.
