Fifty-two people in 21 states have contracted salmonella from backyard poultry, the Centers for Disease Control and Prevention has announced.

Five patients have been hospitalized, and 28% of those sickened by these home-based chicks and ducklings are children under age 5.

"Epidemiologic and laboratory evidence indicate that contact with backyard poultry from multiple hatcheries is the likely source of these outbreaks," the CDC said. "People reported obtaining chicks and ducklings from several sources, including agricultural stores, websites and hatcheries."

The issue is that chickens and ducks with salmonella look healthy and clean, so people touch them or the areas where the birds live and then get infected.

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A person who gets sick from the salmonella bacteria will have diarrhea, fever and abdominal cramps within 12 to 72 hours afterward and remain sick for four to seven days, the CDC said. Most patients recover on their own.

Backyard poultry, especially chickens, have become popular pets in the U.S. Many owners continue to use them as a source for eggs and meat, too.

The state with the most cases in this outbreak is Ohio with nine, followed by Missouri with six, Pennsylvania with five, Tennessee and Virginia with four each and Mississippi with three. Alabama, Arkansas, Colorado, Illinois, Kansas and Texas have two cases each, while Arizona, Idaho, Kentucky, Maryland, Michigan, Nebraska, Utah, West Virginia and Wyoming have one each.

The CDC's tips for avoiding getting sick from salmonella include:

Always wash your hands with soap immediately after touching backyard chickens and ducks or the places where they live. If you can't do that, use hand sanitizer instead.

Prohibit backyard poultry from coming into your house, especially places where you store, prepare and consume food and drinks.

Designate one pair of shoes to wear when taking care of the birds and then never wear them inside.

Don't let children under age 5, adults over 65 and people with weakened immune systems touch the poultry.

Don’t kiss or snuggle backyard poultry or let them touch your face.

Only clean your backyard poultry equipment, such as cages and feed, outdoors.

According to the CDC, approximately 1.2 million people in the U.S. are infected with salmonella each year. An estimated 23,000 need to be hospitalized and 450 die.

Follow USA TODAY reporter Zlati Meyer on Twitter: @ZlatiMeyer