Last month, a 16-year-old girl from Crook County, Oregon, was hospitalized with an illness many of us thought died out in the Dark Ages: the bubonic plague. And while incidents of the plague in the United States are far from reaching epidemic proportions, the number of plague cases has been increasing in recent years. Time reported that there have been 16 cases so far in 2016 – six more than in all of 2015. And this year the disease has been responsible for four deaths, including that of a teenager.

The plague is spread through a bacteria called Yersinia pestis, which is associated with rodents. Transmission to humans usually occurs via a flea bite or through contact with an infected animal.

Symptoms of the bubonic plague generally appear within a week of exposure and include fever, chills, weakness and painfully swollen lymph nodes. In addition, some people develop black pustules. With antibiotics, the bubonic plague can usually be treated successfully. (Two other types of the plague – septicemic and pneumonic – can be tougher to treat.) According to the CDC, before antibiotics the plague had a fatality rate of 66 percent in the United States.

Since 1970, incidents of the bubonic plague have been almost entirely confined to rural areas of the western half of the United States, particularly the Southwest.

To decrease your chances of contracting the bubonic plague, the CDC recommends wearing gloves when handling or skinning animals that may carry the disease and using insect repellent (like DEET) to prevent flea bites. Use flea-control products to keep your pets free from fleas. In addition, make your home as rodent-unfriendly as possible by eliminating brush piles and keeping pet food in closed containers.

Are you likely to contract bubonic plague? The short answer is no. Sixteen cases is still a very, very small number. But if you live or hunt in the rural West, a few simple precautions can ensure that you won’t have to deal with this medieval killer.