Campylobacter bacteria have infected 39 people in seven states, and puppies sold at one chain of pet stores in Ohio are likely to blame. As NPR reports, a federal investigation is currently underway as to the exact cause of the outbreak of the intestinal infection.

The symptoms of Campylobacter include fever, diarrhea, and abdominal pain, and in rare cases it can lead to death in victims with weakened immune systems. About 1.3 million people fall ill to it each year, but the bacteria can also infect animals like dogs.

Of those hit by the latest outbreak, 12 are employees of the national chain Petland in four states, according to the CDC. The other 27 have either bought a puppy from a Petland store recently or live with or visited someone who has. Eighteen cases have been reported in Ohio, and the rest have appeared in Florida, Kansas, Missouri, Pennsylvania, Tennessee, and Wisconsin. While no deaths have been reported, nine victims have been hospitalized.

Puppies, like humans babies, are more likely to get sick than full-grown dogs, which may explain how the Petland animals caught the illness in the first place. But even apparently healthy adult dogs may be harboring the bacteria and spreading it through their feces. To avoid catching it from your canine companion at home, the CDC recommends washing your hands whenever you make physical contact. This also applies when handling their food and especially when picking up and throwing away their poop (with disposable gloves of course).

For the small percentage of people who do contract the infection each year, the best course of action is to wait it out if you're healthy otherwise: Symptoms take about a week to clear up.

[h/t NPR]