The children, 6 months and 2 years old, are in the same family, have received medical treatment and are doing well, said Belle Shepherd, public health director, in a news release this morning.

Two Grants Pass children have pertussis, better known as whooping cough, the Josephine County Public Health department has announced.

The children, 6 months and 2 years old, are in the same family, have received medical treatment and are doing well, said Belle S. Shepherd, public health director, in a news release this morning.

The disease can be fatal to infants.

The new cases are the third and fourth of pertussis this year in Josephine County, up from a single case last year.

Shepherd noted that children who have not been vaccinated against the disease are more likely to come down with it. She did not say whether the children with the new cases had been vaccinated.

Health workers often identify "presumptive" cases of pertussis on the basis of symptoms such as the deep, rasping, persistent cough that persists for weeks or even months after the original cold-like symptoms have faded.

Pertussis is most contagious during its cold-like early phase. Most otherwise-healthy adults can eventually overcome the bacterium, but they can spread it to others. This "adult reservoir" of bacteria is often the source of new cases among youngsters.

Oregon last had a major pertussis outbreak in 2004, when cases reached an all-time high of 14.9 per 100,000, or twice the national average.