Laboratory-based surveillance for influenza: role of the Wisconsin State Laboratory of Hygiene.

Influenza poses a significant threat to public health worldwide. In the United States alone, mortality attributed to annual epidemics of influenza is estimated at 36,000 deaths per year. Influenza viruses also cause pandemics, during which the rates of illness and death can be expected to be much higher. In order to optimize prevention and control strategies for influenza, a variety of surveillance activities are carried out year-round internationally, nationally, and at the state level. This article summarizes relevant features of influenza and the surveillance activities carried out at each of these levels to monitor influenza activity. Particular emphasis is given to the state's laboratory-based surveillance network, developed and coordinated by the Wisconsin State Laboratory of Hygiene, that features strong and productive partnerships with private sector clinicians and laboratories and that provides a solid foundation for surveillance directed at other public health threats such as Severe Acute Respiratory Syndrome and bioterrorism.