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Pandemic Influenza: What Occurred in Wisconsin? Spring and Summer 2009. Shaun Truelove Bachelor of Science, Biology Master of Public Health Candidate University of Wisconsin-Madison Graduate Intern Bureau of Communicable Disease Wisconsin Division of Public Health. Overview. Background
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Pandemic Influenza: What Occurred in Wisconsin?Spring and Summer 2009 Shaun Truelove Bachelor of Science, Biology Master of Public Health Candidate University of Wisconsin-Madison Graduate Intern Bureau of Communicable Disease Wisconsin Division of Public Health
Overview • Background • Significance • Methods • Findings • Discussion • Conclusion
Background:2009 H1N1 Influenza Outbreak Outbreak in the U.S. • April 15: First confirmed case in U.S. • April 25: WHO declares “Public Health Emergency” • April 15-July 31: 9,000 to 21,000 hospitalizations in U.S. Outbreak in WI • April 23: First confirmed hospitalization (Milwaukee) • July 15: Outbreak peaks in WI • >6,000 confirmed or probable cases through July 31 • April 23-August 15: 253 hospitalizations in WI
Significance of Hospitalized Patient Surveillance 2009 H1N1 Surveillance • Emerging pandemic due to novel influenza virus • Symptoms, risk factors, and severity of illness • Poor historical surveillance of influenza outbreaks and seasonal Hospitalized Patients • Effective measure of the disease • Consistent testing and confirmation • Accurate depiction of illness severity • Most reliable sources of illness info in this pandemic
Project Methods Study Type • Prospective surveillance of WI / Case series Data collection • 16-page CDC case report form • Collaboration with Infection Control Practitioners Subjects • 253 Hospitalized WI Residents • Hospitalized due to H1N1 virus • RT-PCR confirmed 2009 H1N1 Influenza A infection • ≥24 hour hospitalization
Findings Demographics • 57% Female • 37% of patients <18 yr old • 89% of cases from Madison or Milwaukee • 48% African American, 29% non-Hispanic white, 16% Hispanic, and 8% Asian Symptoms • Fever - 79% • Influenza-like illness - 66% • Nausea, vomiting, or diarrhea - 35% Diagnostics • 11% with positive bacterial cultures • 54% with abnormal radiographic imaging, suggestive of pneumonia
Discussion Limitations • Surveillance-based data • Only hospitalized cases • Lack of laboratory data Strengths • Prospective study • Statistically significant findings • Influenza outbreak data • Use of standardized case report forms and guidelines • Substantial laboratory testing capacity • Complete data for the state
Conclusion • Highly concentrated outbreak in WI • Epidemiologic shift in age of patients • Traditional risk factors highly prevalent in 80% • Importance of effective and accurate surveillance • Early empiric antiviral treatment • Additional antiviral therapy for critically ill patients needed
Acknowledgments • Amit Chitnis, MD, MPH • Richard Heffernan, MPH • Jeffrey Davis, MD • Jeannie Druckenmiller, SM(NRM), CIC • WI Division of Public Health • All of the ICPs who made this surveillance possible
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