DES MOINES, Iowa — Luke Gabriele was a healthy 14-year-old football player in Pennsylvania when he began to feel soreness in his chest that grew increasingly painful. After his breathing became difficult, doctors detected what appeared to be a tumor.

For a week, Dan and DeAnna Gabriele thought their son was dying until tests identified the cause: not cancer, but chickens – the ones he cared for at home. They had infected him with salmonella that produced a severe abscess.

The popular trend of raising backyard chickens across the U.S. is bringing with it a soaring number of illnesses from poultry-related diseases, at least one of them fatal.

Since January, more than 1,100 people have contracted salmonella poisoning from chickens and ducks in 48 states, according to the Centers for Disease Control. Almost 250 were hospitalized and one person died. The toll was four times higher than in 2015.

The CDC estimates that the actual number of cases from contact with chickens and ducks is likely much higher.

“For one salmonella case we know of in an outbreak, there are up to 30 others that we don’t know about,” CDC veterinarian Megin Nichols said.

A “large contributing factor” to the surge, Nichols said, comes from natural food fanciers who have taken up the backyard chicken hobby but don’t understand the potential dangers. Some treat their birds like pets, kissing or snuggling them and letting them walk around the house.

Poultry can carry salmonella bacteria in their intestines that can be shed in their feces. The bacteria can attach to feathers and dust and brush off on shoes or clothing.

But illnesses can be prevented with proper handling. The CDC recommends that people raising chickens wash their hands thoroughly after handling the birds, eggs or nesting materials, and leave any shoes worn in a chicken coop outside.

Salmonella is much more common as a food-borne illness. More than 1 million people fall ill each year from salmonella contamination in food, resulting in more than 300 deaths, according to the CDC.