DALLAS — Whooping cough is a growing public health threat. State health officials recently re-launched a campaign in the fight against the coughing disease.

Part of the problem, according to health experts and patients, is that many doctors aren't paying attention to the signs.

Playing on the floor with her son still isn't easy for Danielle Slaybaugh, considering she has a broken rib.

She cracked the rib while she was coughing. "I was coughing so hard I sometimes threw up," she said. "I went to the doctor and he said it was allergies."

Slaybaugh was sent home, where she sufferred for weeks.

When her son and other family members started coughing, Slaybaugh started searching the Internet for causes.

"Whatever I have, it's not allergies, because my son got it," she said.

But the youngster's pediatrician failed to link the chronic, choking cough to pertussis, the clinical name for whooping cough.

Whooping cough is on the rise everywhere. Last year, four North Texas counties accounted for nearly one-fifth of the 954 confirmed cases in Texas:

80 — Dallas County
52 — Denton County
37 — Collin County
26 — Denton County

Health authorities say many doctors miss the diagnosis because patients don't fit a stereotypical profile for pertussis—poor and unimmunized.

"It's basically people that live in crowded conditions, so it's often big families," said Dr. Karine Lancaster of Dallas County's preventive health division.

Dr. Lancaster said it's time for doctors to readjust their thinking about pertussis. "It needs to go further up the list of possible diagnoses," she said.

Danielle Slaybaugh is a single mother who doesn't fit the profile for pertussis. "I have no idea where I got it from," she said. "No idea."

Slaybaugh remains concerned that two doctors missed the signs of a disease most dangerous for babies like her son.

"You'd think they'd be more apt to know what it is."

E-mail jstjames@wfaa.com