Valley visitors may have taken home more than souvenirs from their action-packed weekend of golf and football.
As the tourists were winging their way home Monday, the state Department of Health Services declared Arizona in a widespread influenza outbreak, the highest designation for flu activity.
Confirmed flu cases more than doubled in some counties this past week, spreading from what had been mostly urban illnesses to virtually every corner of the state.
"There's no safe haven anymore," said Will Humble, assistant director of public health preparedness for the state health department. "It's still on the increase. The peak may be ahead of us."
The official numbers - 954 lab-confirmed cases statewide, including 488 in Maricopa County - don't begin to tell the story.
On the front lines, hospitals and schools are seeing thousands of coughing, sneezing, feverish people who feel like they've been hit by a bus.
Some of it is influenza, but there's lots of other crud going around, doctors and nurses said.
"We just got bombarded with kids - with colds, coughs, wheezing," said Dr. Amy Shoptaugh, a Tempe pediatrician.
East Valley hospitals are juggling to keep beds open. Shoptaugh said she had to keep a child in her office for five hours before she found a spot at Banner Desert Medical Center's Children's Hospital.
The hospital has opened overflow pediatric beds to handle a 50 percent increase in ER admissions in the past week, said emergency services director Kevin Craven.
About 300 people crammed the emergency department last week, Craven said, and roughly one in five were diagnosed with the flu or flu-like symptoms, including dehydration.
"A lot of it is upper respiratory. Body aches, headache, sore throat, bronchitis," he said. "And if they're having upper respiratory stuff, they're not eating or drinking right."
Scottsdale Healthcare Osborn was extra busy this weekend treating locals and visitors with fever, coughing and vomiting.
Nurse manager Betty McCarter said most patients were released after treatment, and few tested positive for the flu, though fevers registered as high as 103 degrees.
Chandler Unified schools are sending children home and fielding plenty of phone calls to the attendance line. Symptoms include sore throats and fevers, with different schools specializing in different illnesses, said district nurse June Carson.
Teachers and custodians are keeping bleach spray and antibiotic gel handy, wiping down tables and drinking fountains, and reminding children throughout the day to wash their hands.
Last season was a mild one for the state and the country, and public health officials had warned that this could be a bad year. The virus is right on schedule for Arizona, with the peak typically hitting in late January or early February.
As it happens this year, the Super Bowl in Glendale and the FBR Open in Scottsdale gave locals and tourists plenty of reason to come together in close quarters and share their germs. With an incubation period of three to 14 days, influenza could be percolating around here for some time to come.
"The holiday parties are a good kickoff to sort of get the ball rolling," Humble said.
"Then there's a big introduction of people from all across the country," he said. "They came into this town with a bunch of stuff, and they're going to leave some of it here and go home."
Either way, you can protect yourself and your family. Wash your hands regularly. Sneeze and cough into your sleeve. Stay home if you're sick.
"The good news is, people can take matters into their own hands," Humble said. "You're not an automatic victim of this."