A familiar bacterial foe has reared its head in the ugliest of ways: According to the Utah Department of Health, the death of an elderly resident earlier this August is now confirmed to have been caused by plague. It is the fourth such death, out of 12 confirmed cases of plague in seven states since April 1.

Known as a frequent harbinger of infection and death throughout much of human history — most infamously as the Black Death, a pandemic that may have killed as many as 200 million people from 1346 to 1353 — plague has since become a rarity in the modern world.

Caused by the bacterium Yersinia pestis, the plague is normally and commonly found in the fleas that feed on rodents and other small mammals. It often spreads to humans via a wayward bite from a flea that has been infected by an animal host already infected by an earlier flea — not the easiest of transmission routes. It can also be transmitted via contact with an infected dead animal (or person, presumingly).

Ordinarily, the infection takes hold in the lymph nodes of a victim, causing bubonic plague (bubos being the discolored and swollen lymph nodes that arise as a result). Rarely though, the plague can manifest as a more fatal respiratory illness that can spread from person to person, then called pneumonic plague, or end up in the bloodstream, as septicemic plague (other, even rarer, forms exist as well, depending on where the plague infects the body). While the three main forms of plague are life-threatening without antibiotic treatment, septicemic plague is almost always fatal without immediate care. With treatment, the mortality rate can lower to 16 percent.

Aside from swollen lymph nodes, other common symptoms can include fever, headache, chills, and weakness.

The Centers for Disease Control this Tuesday released a report announcing that the number of plague cases seen this year in America is especially high compared to previous years (a median of three cases from 2001 to 2012).

According to health officials, it still isn’t known how the Utah resident ended up encountering plague, since there isn’t any evidence that they traveled anywhere where plague is commonly seen — Yosemite Park being the suspected source of plague in two of the other cases. Their death is the first plague case to hit the state since 2009.

They also explained that plague largely originates in rural and semi-rural areas, especially from campsites and homes that provide food and shelter for various ground squirrels, chipmunks and wood rats. For that reason, they warned residents to avoid touching wild animals without gloves on, using repellants in places where rodent fleas may be common, and not allowing pets who roam freely outside to sleep on the bed.