BOISE, Idaho — The Center for Disease Control says a multi-state salmonella outbreak that has sickened hundreds of people nationwide is linked to contact with backyard poultry. 

So far, 279 people in 41 states - including Idaho - have been infected with the outbreak Salmonella strain this year. According to the CDC, four of those cases were in Idaho.

RELATED: You Can Grow It: Raising backyard chickens

Forty people had to be hospitalized because of the illness, although no one has died. Those who became sick range in age from infancy to 92. 

Salmonella is a bacterial infection that causes diarrhea, fever and stomach cramps. Some people also experience nausea, vomiting and headaches.  

The illness can be life-threatening, especially in rare cases where the infection spreads into the patient's bloodstream. Young children, the elderly, and people with immune system problems are the most at risk for serious infections. 

According to the CDC, of 153 people interviewed as part of the current outbreak, 77 percent said they had contact with backyard poultry before they got sick. The patients reported buying the chickens from a range of sources, including agricultural stores, websites, and hatcheries. 

MORE: Food recalls increase due to foodborne illnesses and what you need to know about them

Those who have or handle backyard poultry should always wash their hands with soap and water immediately after touching the birds or anything in their area, including coops and equipment. In addition, people should not let chickens come inside the house, and should stay outdoors when cleaning cages, feeders, water dispensers or other equipment.

For more information on preventing illness, click here.