Avian Influenza and the Threat of an Impending Pandemic Eden V. Wells, MD, MPH Michigan Department of Community Health

Influenza Strains Type A –Infects animals and humans –Moderate to severe illness –Potential epidemics/pandemics Type B Type B –Infects humans only –Milder epidemics –Larger proportion of children affected Type C –No epidemics –Rare in humans Source: CDC

A’s and B’s, H’s and N’s Classified by its RNA core –Type A or Type B influenza Further classified by surface protein –Neuraminidase (N) – 9 subtypes known –Hemagluttin (H) – 16 subtypes known Only Influenza A has pandemic potential

Influenza Virus Structure A/Moscow/21/99 (H3N2) Neuraminidase Hemagglutinin Type of nuclear material Virus type Geographic origin Strain number Year of isolation Virus subtype

Differentiating Influenza  Seasonal –Caused by influenza A or B strains circulating in humans –~36,000 human deaths annually in USA  Avian –Caused by Influenza A –Shorebirds and water fowl are the reservoir and rarely see outbreaks, except in current H5N1 strain –Domestic poultry (chickens and turkeys), causes morbidity and mortality with outbreaks annually worldwide  Pandemic –When new virus strain occurs –Humans lack immunity –Simultaneous epidemics worldwide –Disease easily transmitted between people –Significant number of illness and deaths

Influenza A: Antigenic Drift and Shift Hemagglutinin (HA) and neuraminadase (NA) structures can change Drift: minor point mutations –associated with seasonal changes/epidemics –subtype remains the same Shift: major genetic changes (reassortments) –making a new subtype –can cause pandemic

Seasonal Influenza October to April People should get flu vaccine Children and elderly most prone ~36,000 deaths annually in U.S.

Seasonal Effects

Seasonal Influenza Surveillance

Avian Influenza The “Bird Flu” Images from:

Avian Influenza Infection can be in two forms –“low pathogenic” (LPAI) - causes mild illness and may go undetected –“highly pathogenic” (HPAI) - affects multiple organs, spreads rapidly among birds, causes high mortality very quickly

Avian Influenza and Domestic Poultry Virus is shed in saliva, nasal secretions, and feces of infected birds Virus can survive for long periods in feces, water, and even on the ground, especially when environmental temperatures are low Avian influenza is a reportable disease in Michigan

The Role of Animals in Influenza A Infection Shore Birds and Wild Waterfowl Domestic Birds Mammals Humans

Countries with H5N1 in Poultry (OIE, 8/22/06) AfghanistanAlbaniaAzerbaijan Burkina Faso CameroonCambodiaChina Cote d’ Ivoire CyprusDenmarkDijboutiEgyptFranceGermany HungaryIndiaIndonesiaIraqIsraelJapanJordanKazakhstanLaosMalaysiaMyanmarNigerNigeria North Korea Pakistan Palestian Aut. Territories Romania Russia Serbia and Montenegro South Korea Sudan Sweden Thailand Turkey Ukraine Vietnam

Domestic Poultry Surveillance Michigan veterinarians are responsible for overall livestock and poultry reportable disease programs They conduct investigations into reports of diseases such as: –Avian influenza –Rabies –Eastern equine encephalitis –Equine infectious anemia –Tuberculosis –Psittacosis

H5N1 in Poultry and Wild Birds (WHO, 8/2/06)

Countries with H5N1 in Wild Birds (OIE, 8/22/05) Afghanistan Austria Azerbaijan Bosnia and Herzegovina Bulgaria Cambodia Cameroon China Cote d’ Ivoire Croatia Czech Republic Denmark Egypt France Georgia Germany Greece Hungary Indonesia Iran Italy Japan Kazakhstan Kuwait Mongolia Nigeria Poland Russia Serbia and Montenegro Slovakia Slovenia South Korea Spain Sweden Switzerland Thailand Turkey Ukraine United Kingdom Vietnam

Wildlife biologist monitor diseases of wild birds at the population level Sick or Dead Wildlife website reporting Bird Banding Hunter Surveillance Wild Bird Surveillance

H5N1 Influenza in Humans- Risk Transmission from birds to humans does not occur easily –Contact with feces or secretions from infected birds –Risk with butchering, preparing, defeathering of infected birds –NOT transmitted through cooked food

Implications for Human Health Asian Strain H5N1 in humans more aggressive than seasonal flu strains –Severe clinical course –Rapid deterioration –High fatality –Low transmissibility human-to-human Incubation may be longer than seasonal influenza –Seasonal influenza: 2-3 days –H5N1: possibly up to 10 days More studies needed

Confirmed Human Cases of H5N1 (WHO, 8/23/06) Country H5N1 Cases Fatalities Mortality Rate (%) Azerbaijan8563 Cambodia66100 China Djibouti100 Egypt14643 Indonesia Iraq22100 Thailand Turkey12433 Vietnam Total

(July 7, 2006)

What is the H5N1 Pandemic Risk? Three conditions must be met for a pandemic to start: –Emergence of a new influenza subtype –The strain infects humans causing serious illness serious illness –Spreads easily between humans Each new H5N1 human case gives the virus a chance to mutate into a highly transmissible form, increasing the risk of a pandemic

MDCH Pandemic Influenza Plan 2005 Revision of 2002 plan Released November 2005 Appendix to MDCH All-Hazards Response Plan Pandemic plan updated as needed

Leads for Public Health International: World Health Organization United States: Centers for Disease Control and Prevention, DHHS Michigan: Michigan Department of Community Health County: Local Health Department/Jurisdiction

Current WHO Risk Assessment

20 th Century Influenza Pandemics 1918 – 1919, “Spanish Flu” (H1N1) –Influenza A H1N1 viruses still circulate today –US mortality: approx. 500, , “Asian Flu” (H2N2) –Identified in China (February 1957) with spread to US by June –US mortality: 69, , “Hong Kong Flu” (H3N2) –Influenza A H3N2 viruses still circulate today –First detected in Hong Kong (early 1968) and spread to US later that year –US mortality: 33,800

Estimated Impact of a Future Pandemic in Michigan (*Michigan figures developed with Flu-Aid 2.0 software, CDC) Characteristic Moderate (1957 / ‘68-like) Severe (1918-like) Illness3.4 million Outpatient2.5 million1.5 million Hospitalization51,000420,000 Deaths15,000125,000

Influenza Surveillance Michigan Disease Surveillance System Sentinel Surveillance Syndromic –Pharmacy –ER LaboratoryNationalInternational LHD’s/MDSS Non-MDCHLabs WHO Data CDC Data LHD’s/Healthcareproviders Pharmacy OTC OTC SentinelPhysicians ERSyndromic Hospitals MDCHLabs Mi-Flu Focus

Treatment Options Antiviral Medications –Neuraminidase Inhibitors OseltamivirZanamivir Pandemic strain vaccine –Minimum 5 month production time –Need chicken eggs and viral seed stock Source: CDC

Oseltamivir- Not a Panacea Limited availability (one manufacturer) Personal stockpiling could lead to: –Inappropriate use –Increased resistance by the virus (already one documented case) –Decreased availability for the critically ill For prophylaxis, multiple courses may be needed throughout flu season

Human Vaccine for Avian H5N1 Effective vaccine is not yet available –Small batches of vaccine are undergoing clinical trials –Not ready for mass production US has advance-ordered 20,000,000 doses May not match strain that causes pandemic Seasonal influenza vaccine does not protect against H5N1 strain

Public Health:Non- Pharmaceutical Interventions Social distancing –Schools –Business practices –Public gatherings Respiratory/Cough Etiquette Hand Hygiene

Influenza Control Measures Education to encourage prompt self- diagnosis Hand hygiene Consider masks, if possible, for symptomatic persons (then send them home!) Cancellation of school/social gatherings Quarantines

Have a Plan! DevelopExerciseUpdateReviewExerciseUpdate…. CDC/EOC-PHIL

Current U.S. Status No current evidence in U.S. of highly pathogenic H5N1 in –Wild birds –Domestic poultry –Humans Images from:

Conclusion Many unknowns Simple precautions go a long way Education is critical to your COOP Get employees involved in the process

Health Advice Good Now, Good in a Pandemic Get your annual flu shot –Won’t protect against a pandemic strain Stay at home if you have a fever Wash hands with soap or hand sanitizers when you sneeze or cough Get adequate sleep, eat healthy, stay hydrated

References pandemicflu.gov Michigan Department of Community Health ( Local Health Department Chamber of Commerce