SAN DIEGO -- Local doctors said a six-month-old baby might be the latest whooping cough case in San Diego County.

Martina Alcantar Gonzales said she started to notice her son Emmanual's heavy breathing and coughing two weeks ago, and she took him to get medical care. She said two days ago he was having trouble breathing and was turning blue.

Nurses said the baby had a runny nose, and his heavy breathing was a sign he could have whooping cough, also known as pertussis.

Whooping cough is now considered a statewide epidemic, and it has already claimed the life of an infant in San Diego. The whooping cough-related death was the first in 9 years in the county.

Ana Noceda, a pediatric nurse practitioner at San Diego Family Care, said, "There is a cause for concern because children under six months, if they're not immunized there is a high mortality rate."

So far this year, there have been 266 cases of whooping cough in San Diego County, with 15 infants having been hospitalized.

In 2009, there were a total of 143 cases in the county, and local health officials believe it's possible the total could surpass the 2005 record of 371.

"I feel nervous because I don't know if he has it," said Gonzales.

Gonzales said her family members were feeling sick and it's possible her child got it from them.

He got his shots ten days ago, but doctors said a series of shots are needed for the vaccinations to work.

Right now, the infant is stable and is being treated with antibiotics.

Noceda said he is being held under close watch.