The number of confirmed measles cases in Washington County has jumped by about 60 percent in the past week, Southwest Utah Public Health Department officials say.

Approximately 90 measles cases were confirmed in the county as of Tuesday, said Gary Edwards of the Southwest Utah Public Health Department. Last week, the Utah Department of Health confirmed 56 cases in the county.About half of the confirmed cases were contracted by teen-agers between 15 and 19 years of age, but the disease has affected adults and a handful of infants, Edwards said.

Edwards says the new cases were confirmed by blood tests or, in those who refuse to have blood drawn, by symptoms coupled with a high possibility of exposure.

Symptoms include fever, cough, red and watery eyes and runny nose, followed by a red blotchy rash that lasts for at least three days.

Southern Utah health officials saw a lull in the outbreak last week, but then another wave of reports arrived late in the week and over the weekend.

The hiatus is not unusual, considering the 10- to 14-day incubation period for measles, said Hugh Mainzer, one of four doctors from the Centers for Disease Control in Atlanta working on the St. George outbreak.

"Assuming we have the susceptible individuals immunized, it would still be two generations, two 10- to 14-day periods, until we start to see a decrease in new cases," Mainzer said. "It's not a surprise. It's just unfortunate. It's a hard thing to contain."

State officials were awaiting test results that were to confirm whether a 14-year-old St. George boy who attended a weeklong basketball camp at Brigham Young University was infected with measles.

Some 350 teenagers from throughout Utah and several other states attended the camp, said Ross Martin, public information officer for the Utah Department of Health.

State law requires children to be adequately immunized - which includes one vaccination for measles, mumps and rubella - before entering school. Health officials advise a second vaccination, Martin said.

Martin refused Tuesday to say how many confirmed cases of measles the state and Washington County have reported. He said he would release the numbers Wednesday.