Influenza in Orange County
Epidemiology & Assessment

Influenza Surveillance Information

Eye on Influenza Current summaries of seasonal influenza activity and updates on avian and pandemic influenza are found in the Eye on Influenza newsletter.

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Influenza Surveillance Information (last updated 4/18/07)
Annual influenza epidemics follow a winter seasonal pattern in the United States with typical activity peaking during late December to early February. Surveillance of influenza activity is important to guide prevention and control activities, vaccine strain selection, and patient care. In addition, surveillance activities help to monitor and prepare for the impact of influenza on the healthcare system. Influenza surveillance in California is particularly important to monitor for importation of novel strains of influenza due to our coastal location with several ports of entry for flights and shipping from Asia.  

Surveillance for influenza activity in Orange County includes the monitoring of the following components year-round:

• influenza viruses:  specimens are submitted from participating hospitals, physicians, and laboratories for tracking and strain-typing
• influenza-like illnesses:  sentinel providers (physicians, nurse practitioners, physician assistants) report outpatient influenza-like illnesses and submit specimens
• pneumonia and influenza deaths:  death certificates are reviewed for deaths from pneumonia or influenza
• emergency room saturation:  the hours that emergency rooms are “on diversion” or closed to new patients because of saturation
• severe influenza and deaths in children:  are reported by health care providers and hospital infection control professionals
• outbreaks of respiratory illness:  are investigated and control measures are instituted.
• enhanced surveillance for avian influenza:  health care providers are requested to report any patients with fever and respiratory symptoms who traveled to Asia in the 10 days prior to symptom onset

In addition, data on hospital admissions for pneumonia and influenza from one Orange County hospital is included in the California Department of Public Health weekly influenza report. Data from all these components are analyzed weekly, summarized, and compared with state and national trends.

We are actively recruiting physicians and other health care providers to participate as sentinel providers for influenza surveillance. For more information, please email: EPI@ochca.com. To receive our influenza newsletter, please email EPI@ochca.com.

For information on statewide influenza activity, see ww2.cdph.ca.gov/programs/vrdl/Pages/CaliforniaInfluenzaSurveillanceProject.aspx.

For information on national influenza activity, see www.cdc.gov/flu/weekly/fluactivity.htm.