Dr. Cort Lohff, assistant state epidemiologist, said Thursday the state routinely sees a smattering of cases but doesn't usually have as many at once.

He urged doctors who suspect it to send samples to the University of Iowa Hygienic Laboratory for testing.

None of the outbreaks is considered widespread, but officials asked parents and doctors to be on the lookout for the bacterial disease, formally called pertussis. The illness is marked by severe coughing, often accompanied by a gasping "whoop" as victims struggle to catch their breath.

The most dramatic Iowa outbreak in recent years came last fall and winter, when 120 cases were reported in Johnson County.

State officials said they have no indication such a large outbreak was starting this fall.

Cases are reported this fall in children in Black Hawk, Clinton, Dallas, Iowa, Keokuk, Linn, Madison and Polk counties.
Eight of the 11 cases were school-age children, said state officials.

Pertussis used to be a common killer of young children, but its impact has been reduced by widespread vaccinations starting when babies are 2 months old. The vaccinations begin wearing off in teenagers. The illness isn't usually as serious for them, but Lohff said, "They could spread it to a really young child who hasn't been vaccinated."

Some parents have avoided the vaccine because of questions about its safety. Lohff said he doesn't believe Iowa is heavily affected by those fears, which most doctors believe the fears are unfounded.

Whooping-cough patients are treated with antibiotics, as are people with whom they've had close contact.