The Black Death is silently spreading in the US, experts are warning, with cases now confirmed in three states.
A 43-year-old man from Valencia County, New Mexico has become the latest patient to be hit by the plague, following cases in California, and Arizona.
Health officials said the man was hospitalized and has since been discharged.
He recently spent time camping in Rio Arriba County, and it is believed he was exposed to the plague during this time.
It is unclear how he contracted the infection but the plague – which is a bacterial disease caused by the bacterium Yersinia pestis – is spread mainly by fleas and it affects both humans and animals.
In the US, it is known to circulate among wildlife throughout the western areas of the country.
But human cases are very rare, with around seven Americans falling ill with it each year. Half of the cases involve people aged 12 to 45 years. Deaths are even rarer, with 14 deaths in the past 25 years in the US.
The bacteria can cause major damage to the body when it takes hold. It can infect your lymph nodes (bubonic plague), causing large swellings called buboes. If it gets in your blood (septicemic plague), it can damage your organs and if it spreads to the lungs (pneumonic plague), it can cause severe inflammation and respiratory failure.
A 43-year-old man from Valencia County, New Mexico (shown above in stock image) has become the latest patient to be hit by the plague, following cases in California and Arizona
The New Mexico plague case marks the first in the state for 2025, following another report last year.
California last week reported a plague case involving a South Lake Tahoe resident who, like the New Mexico patient, is thought to have been exposed to a flea bite while camping.
They are also currently recovering from the infection. It was the first report of the human plague in California in a decade.
Meanwhile, an Arizona resident died in July from the plague, marking the first recorded death in the state since 2007 from the disease.
In all of the cases, there were no details given around patient ages, their state of health at the time and how the disease impacted them.
In light of the most recent patient in New Mexico, the state’s public health veterinarian Erin Phipps said: ‘This case reminds us of the severe threat that can be posed by this ancient disease.
‘It also emphasizes the need for heightened community awareness and for taking measures to prevent further spread.’
Just seven cases of the plague, which once wiped out up to half of the population in medieval Europe, are reported on average in the US each year, according to the CDC
Untreated plague has a mortality rate of 30 to 60 percent.
The above CDC map shows confirmed plague cases in the US from 1970 to 2023
Plague is an infectious disease caused by the bacterium Yersinia pestis, which is carried by fleas and transmitted between animals. The picture above is a 3D illustration of the bacterium
But if it spreads to the lungs or bloodstream, it’s nearly 100 percent deadly.
It tends to crop up most often in areas like California and New Mexico due to having more rodents prone to Yersinia pestis, the bacterium that causes plague.
Human-to-human transmission is possible but it is extremely rare.
Plague symptoms strike within one to eight days, with fever, chills, and debilitating fatigue.
It’s often accompanied by painful, swollen lymph nodes (buboes) in the groin or armpits. Left untreated, it can ravage the bloodstream and travel to the lungs, causing deadly infections.
Once the disease enters cells, it kills them by releasing deadly toxins.
Infection can arise from handling infected cats, rodents, or their fleas.
In cats and dogs, plague symptoms are fever, lethargy and loss of appetite. There may also be swelling in the lymph node under the jaw.
According to the California Department of Health, there were 45 ground squirrels or chipmunks with evidence of exposure to the plague bacterium in the Lake Tahoe Basin from 2021 to 2025.
The plague, sometimes referred to as the Black Death, wiped out 25 to 50million people in Europe between 1346 and 1353.
This was thought to be 30 to 50 percent of the population.
It was first introduced into the US in 1900, from rat–infested steamships that had sailed from affected areas.
Epidemics occurred in port cities and the last urban plague epidemic in America occurred in Los Angeles from 1924 through 1925.
Today, cases mostly occur as scattered cases in rural areas.
The above CDC graph shows both fatal and non-fatal US plague cases from 2000 to 2023
Most human cases in the US are acquired in two regions: Northern New Mexico, northern Arizona, and southern Colorado and California, southern Oregon, and far western Nevada.
The CDC notes that the plague has occurred in people of all ages, from infants up to patients aged 96, though 50 percent of cases occur in people ages 12 to 45.
Modern antibiotics and hygiene have drastically reduced deaths, but the disease remains endemic in wildlife. Health officials urge caution in high-risk areas.
Health officials in affected states have urged residents and visitors to avoid exposure to rodents or ticks.
They recommended wearing long pants tucked into boots and using a bug repellent with DEET.
Additionally, people in infected areas should never feed or touch wild rodents and refrain from camping new animal burrows or dead rodents.
