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Avian Influenza Avian Influenza in 2005 Joann M Schulte DO

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Avian Influenza Avian Influenza in 2005 Joann M Schulte DO Powered By Docstoc
					Avian Influenza
in 2005
     Joann M. Schulte, DO, MPH
     Richard Hopkins, MD, MSPH
Carina Blackmore, MS, Vet. Med., PhD
     Florida Department of Health
             April 4, 2005
     Etiology

• Viral disease, member of Orthomyxoviridae
  – Type A viruses

• Subtypes
  – Hemagglutinin: 15 subtypes
  – Neuraminidase: 9 subtypes

• Highly Pathogenic Avian Influenza (HPAI)
  – H5 and H7
  – Human case fatality estimated to be as high has 50%,
    but not definitely known
       Epidemiology - Birds
• Natural Hosts
   – Domestic fowl, ducks, geese, turkeys, guinea fowl,
     quail, and pheasants

• Source of Infection
   – Generally not ascertained
   – Direct/indirect contact with migratory waterfowl

• Spread
   – Rapid in flocks by direct contact
   – Viral shed in feces and nasal and ocular discharges
  Clinical Symptoms - Birds
• Virulence
   – Dependant on virulence of virus, species affected and
     other environmental conditions

• HPAI
   – Often no clinical signs other than sudden death

• Possible signs of illness
   – Soft-shelled eggs              – Depression
   – Cyanosis of wattle and combs – Diarrhea
   – Loss of appetite               – Respiratory distress
        Cycle of Avian Influenza
         Viruses in Animals &
                Humans

                                                                       Direct bird to human
                                                                  T ranmi ssi on
                                                                  to p eop le.
                                                                                                al so   d




                                                                       transmission is also
                                                                       common.
                                            Domestic birds



               Natural avian                 Pandemic
              influenza cycle               disease cycle

Shore birds                     Waterfowl                        Mammals
                                                             (primarily swine)




                                                                                       Humans
   Epidemiology - Humans

• Confirmed AI in Humans Since 1997
  – 1997 Hong Kong (H5N1)
     •   1st time transmitted birds to humans
     •   18 hospitalized, 6 died
     •   1.5 million chickens killed within 3 days
     •   Rare person-to-person infection considered possible
  – 1999 Hong Kong (H9N2)
     • 2 children, both recovered
     • Poultry source of infection
     • Additional H9N2 cases reported mainland China 98-99
   Epidemiology - Humans

• Confirmed AI in Humans Since 1997 – (cont)
  – 2003 Hong Kong (H5N1)
     • 2 family members who traveled to China
     • 1 recovered, 1 died; 1 unknown cause of death
  – 2003 Netherlands (H7N7)
     •   Among poultry workers and their families
     •   84 cases reported, 1 death was veterinarian
     •   Symptoms mostly eye infections and some respiratory
     •   Some evidence of person-to-person transmission
  – 2003 Kong Kong (H9N2)
     • 1 child, hospitalized and recovered
Clinical Symptoms - Humans

• Typical influenza-like symptoms
   – Fever         – Sore throat
   – Cough         – Muscle aches

• Eye infections
• Pneumonia
• Acute Respiratory Distress (ARDS)
• Other severe and life-threatening complications
        World Health Organization:
        Cumulative Cases of H5N1
          Avian Flu, 2003-2005*
County                  Total Cases   Deaths

Cambodia                1             1

Thailand                17            12

Viet Nam                51            33

Total                   69            46
*As of February 2005.
        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
       Historic Pandemics

• 1918-1919 Spanish Flu
  – A (H1N1)
  – 20-50 million deaths worldwide
  – 500,000 deaths in the United States
  – Nearly half were young, healthy adults
 Historic Pandemics – cont.

• 1957-1958 Asian Flu
  – A (H2N2)
  – 1st identified in China Feb. 1957
  – Spread to U.S. by June 1957
  – 70,000 deaths in the United States
 Historic Pandemics – cont.

• 1968-1969 Hong Kong Flu
  – A (H3N2)
  – 1st detected in Hong Kong early 1968
  – Spread to U.S. later that year
  – Approx 34,000 deaths in the United States
  – Virus still circulating today
Map of Current Outbreak
                *As of February 11, 2004




   FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
 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
Map of Current Outbreak
 and Poultry Livestock
        Density




  FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
     H5N1 Outbreak in Asia
• Began mid-December 2003
• Countries Affected (confirmed in poultry)
   – Cambodia      China         Indonesia   North Korea
   – Hong Kong      Laos         Japan
   – South Korea   Thailand      Vietnam

• January 2004 in humans, Vetnam and Thailand
• All genes are of bird origin
• Slight variations in circulating H5N1 virus
 Avian Influenza 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
    What is Florida DOH Doing
        about Avian Flu?

• Protocol for testing in place between DOH labs
  and Bureau of Epidemiology; approval required
• Protocol requires detailed history of travel,
  avian exposure & other risks
• No avian flu testing without clinical history and
  testing for other respiratory diseases
• Close coordination with CDC; testing not
  available at private reference labs
What About Bird Flu in Florida?

• Department of Agriculture and Consumer
  Services monitors poultry flocks in
  Florida
• Avian surveillance by veterinarians is
  ongoing
• No avian outbreaks currently detected

				
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