In a startling development for 2025, three confirmed cases of the plague—commonly known as the Black Death—have emerged in the United States, reviving concerns over a disease often thought to belong solely to medieval history. The latest case involves a 43-year-old man from New Mexico who was recently discharged from hospital after treatment. Prior to this, a resident of South Lake Tahoe, California, tested positive following a camping trip, and in July, a man from Arizona died from pneumonic plague—the most severe and contagious form of the disease—marking the first fatality in that county since 2007.
Health officials have traced the likely source of these infections to contact with infected wild animals or flea bites, particularly in rural and forested areas. The New Mexico patient had camped in Rio Arriba, near the Colorado border, where he may have encountered the pathogen. The bacterium responsible, Yersinia pestis, is typically transmitted via fleas that infest wild rodents such as squirrels, chipmunks, and field mice. These fleas can jump to humans or pets when their original hosts die or become ill.
The plague manifests in three forms: bubonic, pneumonic, and septicaemic. Bubonic plague—the most well-known—causes sudden fever, chills, headaches, fatigue and swollen lymph nodes. Pneumonic plague, which proved fatal in the Arizona case, affects the lungs and can spread through respiratory droplets, making it especially dangerous. If left untreated, the disease can escalate rapidly, but modern antibiotics significantly improve recovery rates when administered early.
According to the Centers for Disease Control and Prevention (CDC), the US sees an average of seven plague cases annually. Despite its rarity, the recent cluster has prompted a renewed public health advisory, especially for those spending time in the wilderness. Authorities urge people to avoid contact with wild animals—particularly those that appear sick or are found dead—and to use flea prevention on pets when hiking or camping. Handling rodents, whether alive or dead, is strongly discouraged, as they are primary carriers of the bacteria.
In the recent incidents, links to wildlife were confirmed. In California, the infection likely occurred via a flea bite during camping, while in Arizona, the deceased had reportedly handled an infected dead animal.
