The U.S. flu season has arrived earlier than typical and is intensifying rapidly, with the South and West seeing the strongest activity so far.

The Centers for Disease Control and Prevention released its latest FluView report on Friday showing seven states reporting high flu activity for the week ending November 7. That figure rose from two states the prior week. More than 3 percent of doctors' office visits involved flu-like illness, a clear signal the season is underway.

Louisiana has been hit hardest initially, though several other states are close behind. The affected states include California, Louisiana, Oregon, South Carolina, Tennessee, Texas, and Washington. Activity began climbing in late summer in western states before spreading.

CDC data indicate at least 2.6 million illnesses, 36,000 hospitalizations, and 2,100 deaths tied to flu so far this season. The hospitalization rate in mid-October reached the highest level seen that early in more than 15 years. Influenza A, specifically the H1N1pdm09 strain, dominates laboratory detections.

Experts note the early onset stems in part from a mutated variant that evades some existing immunity. Hospitalizations and emergency visits are forecast to keep climbing through late November.

Public health officials continue to recommend vaccination, hand hygiene, and staying home when sick to limit spread. The season's early start means peak activity could arrive sooner than in recent years.