The Centers for Disease Control and Prevention asked local and state health officials Tuesday to maintain flu surveillance operations at peak-season levels over the summer in a bid to remain watchful for any signs of human-to-human spread of the H5N1 bird flu virus.
Flu surveillance activity is generally conducted at low levels during the late spring and summer months, in recognition of the fact that as temperatures rise, transmission of seasonal flu viruses drops to minimal levels in the Northern Hemisphere.