PHOENIX - The influenza virus is spreading quickly and doctors say it's rare that it happens this late in the season.
"This year flu reports started late," a spokesperson for the Arizona Department of Health Services said in a news release.
"Approximately 30 percent (338) of all the cases (1,159) we've had this season were reported last week."
ADHS said that those numbers might actually be too small, stating that many people don't go to the doctor when they have the flu.
Dr. Eric Katz with Maricopa Medical Center told ABC15 that it's normal to see a sudden rush of patients, but that it usually happens much earlier in the season.
"Once it hits a few people in the area," Dr Katz said, "it spreads very, very rapidly."
ADHS recommends that people who have not received the flu vaccine and have not yet been sick this season get the shot when possible.
A list of flu shot providers is available at the Arizona Department of Health Services or by calling Community Information and Referral at (602) 236-8856 or (800) 352-3792.