The US Centers for Disease Control and Prevention (CDC) has urged people to refrain from kissing live poultry amid an outbreak of salmonella.

The CDC and public health officials are investigating salmonella outbreaks after 163 people were reported ill in 43 states.

The infections have been linked to contact with backyard poultry.

“Don’t kiss or snuggle the birds, as this can spread germs to your mouth and make you sick,” the health agency said.

It warned that poultry, like chicken and ducks, can carry salmonella germs even if they look healthy and clean, and these germs can easily spread in areas where they live and roam. Infection can cause fever, diarrhea, stomach pain and vomiting. Most people recover without treatment, but more severe cases can cause death.

According to the CDC, one-third of the people reported ill in the recent outbreaks have been under the age of five. Some 34 people have been taken to hospital since mid-February, but no deaths have been reported.

The CDC’s advice also includes washing hands after coming into contact with poultry, and preventing children from touching the birds. It estimates that salmonella bacteria – which can be found in raw or undercooked meat, eggs or other food products – causes about 1.35 million infections in the US every year, and 420 deaths.