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Learn about the H5N1 "Bird Flu" outbreak, its impact on humans and animals, transmission methods, treatment options, pandemic risks, and preparedness measures recommended by the CDC and WHO.
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Avian Influenza A (H5N1)“Bird Flu”TRCPANovember 18, 2005 Charles W. Mackett III, MD FAAFP Executive Vice Chair Department of Family Medicine University of Pittsburgh Medical Center
Etiology • Viral disease • Avian Influenza (HPAI) • H5 and H7 – highly pathogenic • Human case fatality estimated to be as high has 50%, but not definitely known
Domestic birds Natural avian influenza cycle Pandemic disease cycle Shore birds Waterfowl Mammals (primarily swine) Humans Cycle of Avian Influenza viruses in animals & humans Direct bird to human transmission is also common
How is bird flu monitored? • WHO and CDC maintain regional labs that test both bird and human specimens • Periodic updates are provided • The lab surveillance permits implementation of control measures if needed • Vaccine trials are underway for the H5N1 strain, but are in early phases
FOODAND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Map of current outbreak
Bird flu by the numbers *Source: World Health Organization
Previous avian flu in the U.S. • Delaware (H7N2) • Reported February 6, 2003 • 12,000 chickens • Low pathogenicity • Texas (H5N2) • Reported February 23, 2004 • 1st such case in U.S. in 20 years • 7,000 chickens • Highly pathogenic • No H5N1
Human H5N1 • Incubation: 3-5 days • Few URI symptoms • Severe viral pneumonia picture • Fever • Lymphopenia • Pulmonary infiltrates • Hypoxia • Diarrhea (50%) • Time to death: 10 days (mean)
Transmission • Respiratory droplets vs. aerosol • Hand to hand • Fomites • Viral shedding starts 24 hours before clinical illness and lasts 5-7 days
Prerequisites for a pandemic • Novel virus with no immunity • Able to cause significant disease in humans • Efficient human to human transmission • Re-assort during co-infection with H3N2 • Evolve in a human by spontaneous mutation
Common pandemic features • Herald wave (warning): up-tick in mortality at end of prior year • Increased mortality • Mortality shift to younger ages • Multiple waves of increased mortality for several years
Potential for influenza pandemics • All influenza viruses can mutate • Avian flu can cause illness in humans • Little to no herd immunity to avian strains among humans • If avian viruses acquire human genes • Facilitate efficient person-to-person transmission • H5N1 of particular concern • No one can predict when a pandemic might occur
How is bird flu in humans treated? • The H5N1 virus currently infecting birds in Asia that has caused human illness and death is resistant to amantadine and rimantadine • Neurominidase inhibitors • oseltamavir (Tamiflu) • zanamavir (Relenza) inhaled, not stocked in house • Resistance can develop • Additional studies are needed to prove the effectiveness of these medicines.
Defenses • Vaccination • Prophylaxis • Rapid diagnosis • Treatment • Infection control • Respiratory etiquette • Hand washing • Disinfection • Droplet precautions in hospitals
CDC recommendations • Enhanced surveillance in the U.S. of H5N1. • Travelers to countries with known outbreaks of influenza A (H5N1) should avoid: • Poultry farms • Contact with animals in live food markets • Surfaces that appear to be contaminated with feces from poultry or other animals. • CDC does not recommend any travel restrictions to affected countries at this time. • For more information, visit Travelers' Health
CDC pandemic preparation Providing leadership and working with: • National Pandemic Influenza Preparedness and Response Task Force, created in May 2005 by the Secretary of the U.S. Department of Health and Human Services • Association of Public Health Laboratories on training workshops for state laboratories • Council of State and Territorial Epidemiologists and others to help states with their pandemic planning efforts • Department of Defense and the Veterans Administration on antiviral stockpile issues • World Health Organization (WHO) and Vietnamese Ministry of Health to investigate influenza H5N1 in Vietnam and provide help in laboratory diagnostics and training
CDC pandemic preparation • Offering laboratory testing for H5N1 viruses • Funding a $5.5 million initiative to improve influenza surveillance in Asia • Holding or taking part in training sessions to improve local capacities to conduct surveillance for possible H5N1 human cases • Developing and distributing reagents kits to detect the currently circulating influenza A H5N1 viruses • Working together with WHO and the National Institutes of Health (NIH) on safety testing of vaccine seed candidates and to develop additional vaccine virus seed candidates for influenza A (H5N1) and other subtypes of influenza A virus
UPMC Avian Flu Task ForceUnder the Direction of Loren Roth, MD, MPH Sr. V.P., Quality Care & Chief Medical Officer • Comprised of experts in : • infectious disease -virology • critical care -epidemiology • emergency management -emergency medicine • pathology -mental health • medical laboratory -medical logistics • human resources -public affairs • corporate security -Center for Biosecurity of UPMC; • The Task Force works closely in cooperation with the Allegheny County Health Department and Region 13 emergency management in facilitating and guiding UPMC’s preparations • Preparation for a possible pandemic has been ongoing since early this year
Thank You! Many thanks to : UPMC Avian Flu Task Force Center for Biosecurity of UPMC Questions?