Flu patient spikes cause Texas school district closure, tents at California hospital A Texas school has taken extreme measures to combat the flu.

 -- A deadly flu epidemic sweeping the nation has triggered one Texas school district to cancel classes for the week and one California hospital has set up a triage tent outside an emergency room for flu patients.

The U.S. Centers for Disease Control and Prevention has identified a particular strain of influenza A, H3N2, as the culprit affecting thousands from coast to coast.

"I think this is the first time we've had 49 of 50 states reporting widespread activity at the same time, at least in the last 13 years," Lynnette Brammer, an epidemiologist with with the CDC's influenza division, told ABC News on Wednesday. Hawaii is the only state where the flu is not widespread.

Brammer said this flu season is on par with the 2014-2015 season, when more than 700,000 people were hospitalized with the flu and nearly 130 died.

California has been the hardest hit state with at least 42 people under the age of 65 dying from flu-related symptoms, according the the state's public health department. At least 3,269 people in the state have tested positive for the flu, the agency reported.

Even otherwise healthy people, across age groups, have succumbed to this year's flu.

Katie Oxley Thomas, a 40-year-old mother of three and a marathon runner from San Jose, California, died 15 hours after being admitted to an emergency room with influenza, her family told ABC station KGO in the San Francisco Bay Area.

"I know that she could hear us and we're saying, 'Katie you can fight this, you can beat it,'" said Thomas' stepmother, Adrienne Oxley.

She said the family had a hard time accepting that she died from the illness.

"We just didn't believe it," Oxley said. "We were in total shock. It's still hard to believe."

Nico Mallozzi, 10, of New Canaan, Connecticut, died Sunday after his family took him to a hospital to be treated for flu symptoms while he was at a hockey tournament in Buffalo, New York.

"Nico was a very lively, vibrant, spirited kid," Bryan Luizzi, superintendent of the New Canaan Public School District, told ABC News.

At Loma Linda Medical Center in San Bernardino Count, California, the medical staff has erected a triage tent outside the emergency room to handle the influx of flu patients.

"This seems to be the worst flu season we've had here in the last 10 to 15 years," Dr. Adrian Cotton, chief of medical operations at the Southern California hospital, told ABC's "Good Morning America." "We're seeing a lot more patients for the flu and the patients we're seeing are a lot sicker than usual."

In Texas, the influenza outbreak is so severe that the Bonham Independent School District, which has about 2,000 students, canceled classes through Tuesday.

"As the number of confirmed cases of influenza grows, it is important to increase health and safety protocols for each campus, including disinfection of all buses and spaces," the school district wrote in a letter to parents. "Local health officials have recommended a full seven days to stop the cycle of spreading influenza."

The flu epidemic is also taking a toll on the nation's blood supply.

Jodi Sheedy, a spokeswoman for the American Red Cross blood services, told ABC News that nearly 500 blood drives have been canceled in the past week due to bad weather. Sheedy said the organization suspects that the flu is keeping people home as well. The Red Cross supplies about 40 percent of the blood used in hospitals across the nation.

"If you're not feeling well, you should not be giving blood," Sheedy said.

"Right now we're doing everything we can to make sure hospitals have enough blood on their shelves," she added. "We haven't had any indication that surgeries have been postponed."

She encourage healthy people, especially those who have gotten flu shots, to donate blood, and particularly platelets.

"We're asking people to go out and donate blood as soon as possible," Sheedy said. "All blood types are needed."

Brammer said it's not too late for people to get flu shots and the CDC continues to recommend them.

"The best way to prevent the flu is to get vaccinated, even if we are at the peak of flu season," she said. "There's still weeks to go."