Denton County reported its first fatal case of swine flu Thursday.

A 49-year-old Lewisville woman died from the swine flu virus during the overnight hours Wednesday, said Dr. Bing Burton, Denton County Health Department director.

The woman had an underlying medical condition that contributed to her death, Burton said.

“It confirms what we’ve known all along,” he said. “The disease continues to be mild to moderate for most people, but it can be fatal for those with underlying medical conditions.”

No additional information about the death was available Thursday evening.

Denton County has had thousands of reported swine flu cases; however, this was the first reported death, Burton said.

“It’s everywhere,” he said. “It just happens that now we’ve had the first fatal case.”

Earlier this week, Dallas County reported its 14^th swine flu-related death.

While swine flu is a disease everyone should be concerned about, Burton said, the regular seasonal flu is by far more serious.

Over the last five years, Denton County has averaged 55 deaths from seasonal flu per year, he said.

Residents should take precautions, such as frequently washing their hands, staying home if they are sick and getting medical providers involved at the onset of the illness, Burton said.

Residents should get a seasonal flu shot and a swine flu shot when larger quantities become available, he said.

Recently, Denton County schools noted increases in sick students, including the Aubrey school district, which closed campuses earlier this month to prevent the spread of the virus.

Most of the 1,400 doses of the swine flu vaccine Denton County has received over the last few weeks have been administered, Burton said.

Burton ordered 20,000 doses, but the vaccine likely won’t be available in large quantities in Denton County until the end of November or early December, he said.

The Dallas Morning News contributed to this report.

CANDACE CARLISLE can be reached at 940-566-6889. Her e-mail address is ccarlisle@dentonrc.com.