The FluView report, produced each week by the Centers for Disease Control and Prevention during flu season, said visits to doctors for influenza-like illness remained below the national baseline last week. All parts of the United States reported influenza-like illness activity below region-specific baseline levels as well.
No states reported widespread, regional or local influenza activity, while sporadic influenza activity was reported by 19 states the District of Columbia and Puerto Rico.
However, 31 states -- a decrease from 32 states from the previous week -- Guam and the U.S. Virgin Islands reported no influenza activity, the report said.
Nationally, the percentage of specimens testing positive for influenza in the United States was 0.9 percent an increase from last week of 0.8 percent.
Though very few viruses have been submitted so far this season, those confirmed were: 2009 H1N1 viruses, influenza A (H3N2) viruses and influenza B viruses. These viruses remain susceptible to the antiviral drugs oseltamivir and zanamivir.
Two reports of human infection with swine origin influenza A (H3N2) virus are being reported this week.
Of the 1,804 specimens tested by U.S. World Health Organization and National Respiratory and Enteric Virus Surveillance System collaborating laboratories 17, or 0.9 percent, were positive for influenza.