Plague — the bacterial disease caused by Yersinia pestis and responsible for the Black Death that killed roughly one-third of Europe's population in the 14th century — has not gone away. It circulates in wild rodent populations throughout the American Southwest and kills people every year. On June 11, 2026, the New Mexico Department of Health announced that a Santa Fe County woman had died from plague, making her the state's first human plague fatality in 2026. The Department has contacted her close contacts and launched an environmental assessment to evaluate ongoing risk.
"We extend our heartfelt condolences to the friends and family of the woman who passed away due to plague," said Erin Phipps, state public health veterinarian for NMDOH. "This tragedy emphasizes the need for heightened community awareness and for taking measures to prevent plague infections."
The human death comes after three dogs in New Mexico were diagnosed with plague in 2026. In 2025, New Mexico recorded three human cases, and the state saw a fatal case in 2024. Approximately half of all human plague cases in the United States occur in New Mexico — a state with a long history of Y. pestis enzootic circulation in rodent populations and a landscape of rocky terrain, pinyon-juniper woodland, and prairie dog colonies that form the primary reservoir.
June, July, and August are the highest-risk months for human plague exposure in the United States. Peak flea activity, peak outdoor recreation, and peak rodent activity all converge in the summer months. Anyone hiking, camping, hunting, or working outdoors in the Southwest needs to understand the basics of plague prevention right now.
How Plague Infects Humans — and Why It Can Kill Rapidly
Plague is caused by Yersinia pestis, a bacterium that primarily circulates in wild rodent reservoirs — including wood rats, rock squirrels, prairie dogs, ground squirrels, mice, chipmunks, and marmots — and the fleas that feed on them. The bacteria are transmitted to humans most commonly through the bite of an infected flea that has fed on an infected rodent. Less commonly, humans are infected through direct contact with infected animal tissues (hunters skinning infected animals, veterinarians treating sick pets) or through inhalation of respiratory droplets from an infected animal.
There are three forms of plague in humans. Bubonic plague — the most common form — occurs when the bacteria multiply in the nearest lymph node to the flea bite, causing the swollen, painful lymph node (called a bubo) that has defined the disease's historical appearance. Without treatment, bubonic plague typically kills between 30 to 60 percent of patients. Septicemic plague occurs when the bacteria enter the bloodstream directly — either from a flea bite or from untreated bubonic plague — and can cause widespread blood vessel damage, disseminated intravascular coagulation, skin discoloration, and death. The Santa Fe County woman had both bubonic and septicemic plague. Pneumonic plague — the rarest but most dangerous form — occurs when the bacteria infect the lungs, either by inhalation or by spread from untreated bubonic or septicemic plague. It is the only form that spreads person to person, and it can be fatal within 24 hours.
The critical clinical fact about modern plague is that it is almost always curable with antibiotics when treatment begins early. Gentamicin and fluoroquinolones are the most effective current treatments. Doxycycline and ciprofloxacin are also used. The window of opportunity is narrow — delay in diagnosis leads directly to preventable deaths.
What New Mexico Residents and Visitors Must Do Right Now
The New Mexico Department of Health provides specific guidance for preventing plague during peak season. Key recommendations include: avoid handling sick or dead rodents, rabbits, and their nests or burrows; use DEET-based insect repellent on skin and permethrin on clothing when outdoors; keep dogs and cats on veterinarian-recommended flea prevention; do not allow pets to roam unsupervised in areas with rodent populations; eliminate rodent habitat around homes by removing woodpiles, brush piles, and debris; and seek immediate medical care for any unexplained sudden fever, chills, headache, weakness, or swollen, painful lymph nodes following outdoor activity in the Southwest.
Physicians in New Mexico and neighboring states (Arizona, Colorado, Utah, California, Oregon) should have a high clinical index of suspicion for plague in any febrile patient with recent outdoor exposure or animal contact in rural or semi-rural settings, particularly between May and September.
Frequently Asked Questions
Q: How many people die from plague in the United States each year?
A: Historically, the U.S. reports an average of 7 human plague cases annually, with fatalities occurring in some years. About half of all US cases occur in New Mexico. One person died in New Mexico in 2024 and another in 2026.
Q: How do people get plague in the United States?
A: Most commonly through the bite of infected fleas from wild rodents. Less commonly through direct contact with infected animal tissues or, rarely, inhalation. Person-to-person transmission occurs only with pneumonic plague and has not been documented in the US since 1924.
Q: What are the warning signs of plague that require immediate medical attention?
A: Sudden high fever, chills, severe headache, extreme weakness, and swollen painful lymph nodes (buboes), especially in the groin, armpit, or neck, following outdoor exposure in the Southwest. These require same-day emergency evaluation.
Q: Is plague treatable?
A: Yes, when caught early. Gentamicin, fluoroquinolones, doxycycline, and ciprofloxacin are all effective treatments. Early diagnosis is the most important factor in survival.
Q: What states are most at risk for plague?
A: New Mexico (about half of all US cases), Arizona, Colorado, Utah, California, and Oregon. Peak season runs from May through September.
