New Mexico health officials have urged residents to take precautions after a wild rat found on private property in Santa Fe County tested positive for plague. The test result marks the state's first confirmed wildlife case of the disease this year.
The New Mexico Department of Health (NMDOH) announced the finding on Monday, saying the dead rodent had been submitted for testing by a local resident. It is the fifth confirmed animal case of plague recorded in New Mexico in 2026, following four earlier infections in domestic dogs.
In a public advisory shared on Instagram, the department reminded residents that plague remains a naturally occurring disease in parts of the American Southwest and can spread from infected animals to humans.
The latest detection comes weeks after a Santa Fe woman died from plague-related illness in June, underscoring the continuing public health concern despite the disease's rarity in the United States.
Officials Stress Humans and Pets Remain At Risk
According to the NMDOH, the newly identified infected rat is the first wild animal in New Mexico to test positive this year. Earlier confirmed cases involved three dogs in Santa Fe County and one dog in Bernalillo County.
State epidemiologists say domestic animals can become infected after being bitten by fleas carrying the plague bacterium or by hunting and eating infected wildlife. Pets can also transport infected fleas into homes, increasing the risk of human exposure.
'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,' said Dr. Chad Smelser, deputy state epidemiologist for NMDOH.
'Pets can be infected with plague if they eat an infected animal or are bitten by infected fleas.'
Plague is caused by the bacterium Yersinia pestis, the same pathogen responsible for the medieval Black Death pandemic. Today, however, modern antibiotics make the disease highly treatable when diagnosed early.
The US typically records only a handful of human cases each year, with most occurring in rural areas of New Mexico, Arizona, Colorado, California and Oregon, where the bacteria circulate naturally among wild rodent populations and their fleas.
Recognising Symptoms and Preventing Infection
Although human plague infections remain uncommon, early treatment is critical. Initial symptoms often resemble influenza and can include sudden fever, chills, headache, weakness and swollen, painful lymph nodes, a form known as bubonic plague.
Without prompt medical care, the infection can spread to the bloodstream or lungs, where it becomes significantly more dangerous. Veterinarians are also urging pet owners to remain vigilant.
Infected cats and dogs may develop fever, lethargy, swollen lymph nodes, reduced appetite and general signs of illness. Cats are considered particularly susceptible and can sometimes transmit the infection directly to humans through respiratory droplets or bites, although such cases are rare.
State health officials continue to recommend year-round flea prevention for pets, avoiding contact with wild rodents and their carcasses, and seeking immediate medical or veterinary attention if symptoms appear after possible exposure. Authorities say these simple precautions remain the most effective way to reduce the risk of infection as plague continues to occur naturally in parts of New Mexico.
