An outbreak of whooping cough has been reported among 14 employees at the VA Pittsburgh Healthcare System's Oakland location.

After two employees came down with the illness, the hospital began an investigation on Aug. 23 and found more cases.

All who had confirmed or suspected cases have been treated with a five-day course of an antibiotic found effective against Bordetella pertussis, the bacteria that causes the respiratory illness, and placed on sick leave, according to the VA's announcement.

The statement said as of yesterday, no patients were found ill with pertussis. The VA is continuing to investigate patients and employees who may have been exposed. It said that 52 patients have been offered a protective dose of antibiotic and 222 employees, residents, interns and medical students have been contacted to get a protective dose because they may have been exposed to the bacteria.

Allegheny County Health Department spokesman Guillermo Cole said the VA is doing what it should to treat the employees and protect the others.

"Fortunately, it's a mild illness in adults," Mr. Cole said. "Our greatest fear is an adult would pass it to an infant who has not yet received the pertussis vaccine." For an infant, pertussis is very serious and can be life-threatening.

The illness spreads through contact with mucus discharges from the nose and from coughing.

Cases of pertussis occur regularly in Allegheny County, Mr. Cole said. In 2005, 41 cases were reported; in 2006, 12 people had it; and last year there were 27 cases reported. Although now the number is higher, only seven cases were reported in the first half of 2008.

Concerns about adults losing immunity from infant vaccinations rose after 2004, Mr. Cole said, when 107 cases were reported. He said one reason for that large number is Children's Hospital was testing for pertussis in family members of their patients with the illness. The testing found adults who had mild pertussis, but didn't know it.

The county this year requires, with some exemptions allowed, students in grades 7 through 12 have a tetanus-diphtheria-pertussis booster, to extend immunity for those three diseases into adulthood.

Once adequately treated with antibiotics, Mr. Cole said, people with pertussis can return to work.