Infectious Disease Book

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Avian Influenza

Aka: Avian Influenza, Avian Influenza A, Bird Flu, Asian H5N1, H5N1
  1. See Also
    1. Influenza
  2. Background
    1. Historical Avian Influenza Outbreaks
      1. Spanish Flu (H1N1): 1918-1919 (40-100 Million deaths)
      2. Asian Flu (H2N2): 1957 (2 million deaths)
      3. Hong Kong Flu (H3N2): 1968 (1 million deaths)
    2. Recent strains
      1. Asian strain (H9N2): 1998
      2. Netherlands (H7N7):2003
    3. Avian Influenza A (H5N1, Bird Flu)
      1. Currently active Avian Influenza Strain
      2. Expected to be next Influenza pandemic
      3. 1997: 18 cases (6 deaths) in Hong Kong
      4. 2004-5: 137 cases (70 deaths) Southeast Asia, China
        1. Outbreak associated with more virulent Z-strain
      5. 2006: 228 cummulative cases and 130 deaths
        1. Total cases thought to be much higher
        2. Mild cases are likely underestimated
  3. Pathophysiology
    1. Life-cycle of Avian Influenza A
      1. Avian Influenza A shed in waterfowl (esp. ducks)
      2. Poultry and pigs become infected
      3. Animal handlers become infected
        1. Exposure to infected animals is primary source
        2. Human-to-human transmission requires high exposure
    2. Virulence
      1. Immune reaction to virus is intense
      2. Results in cytokine storm
  4. Risk Factors: Exposures
    1. Asian poultry animal handlers
    2. Asian animal markets, poultry farms, cock fights
    3. Cleaning up areas with poultry feces present
    4. Contact with fertilizer contaminated with bird feces
  5. Symptoms: Onset 2-5 days after exposure
    1. Fever
    2. Cough
    3. Respiratory distress (associated with Viral Pneumonia)
    4. Watery Diarrhea
  6. Diagnosis: Pharyngeal swab for H5-Specific RNA
    1. Preferred over nasal swab
    2. Detection by Reverse transcriptase PCR
  7. Labs
    1. Complete Blood Count with Leukopenia
  8. Imaging
    1. Chest XRay
      1. Nonspecific infiltrates by 7 days post-fever onset
  9. Management
    1. Tamiflu
      1. See Neuraminidase Inhibitors (also Relenza)
      2. Treatment: 75 mg PO bid for 5 days
        1. Must be started within 48 hours of onset
        2. Reduces illness severity by 40%
      3. Post-exposure prophylaxis: 75 mg PO qd x7-10 days
      4. Resistance rates are currently low
    2. Other anti-viral agents
      1. Amantadine and Ramantadine resistance is high
    3. Other experimental agents
      1. Statins
        1. May reduce cytokine storm reaction
        2. Improves survival in septic shock
        3. Only effective if started prior to infection
  10. Prevention
    1. Avoid exposure
      1. See Risk Factors above
    2. H5N1 Vaccine
      1. Undergoing human trials
      2. Not expected to be available for several years
  11. Resources
    1. CDC Avian Flu Information
      1. http://www.cdc.gov/flu/avian/gen-info/facts.htm
    2. WHO Avian Influenza information
      1. http://www.who.int/csr/don
    3. U.S. Department of Health and Human Services
      1. http://www.pandemicflu.gov
  12. References
    1. Fauci (2006) Emerg Infect Dis 12:73-7
    2. Juckett (2006) Am Fam Physician 74(5):783-90
    3. Monto (2005) N Engl J Med 352:323-5

Influenza in Birds (C0016627)

Definition (MSHFRE) Infection virale des volailles domestiques et sauvages ainsi que d'autres oiseaux par le virus influenza aviaire de type A. Habituellement, la grippe aviaire ne rend pas malades les oiseaux sauvages mais elle peut être hautement pathogène et mortelle chez les volailles domestiques.
Definition (MEDLINEPLUS)

Birds, just like people, get the flu. Bird flu viruses infect birds, including chickens, other poultry and wild birds such as ducks. Most bird flu viruses can only infect other birds. However, bird flu can pose health risks to people. The first case of a bird flu virus infecting a person directly, H5N1, was in Hong Kong in 1997. Since then, the bird flu virus has spread to birds in countries in Asia, Africa and Europe.

Human infection is still very rare, but the virus that causes the infection in birds might change, or mutate, to more easily infect humans. This could lead to a pandemic, or a worldwide outbreak of the illness.

During an outbreak of bird flu, people who have contact with infected birds can become sick. It may also be possible to catch bird flu by eating poultry that is not well cooked or through contact with a person who has it. Bird flu can make people very sick or even cause death. There is currently no vaccine.

Definition (MSH) Infection of domestic and wild fowl and other BIRDS with INFLUENZA A VIRUS. Avian influenza usually does not sicken birds, but can be highly pathogenic and fatal in domestic POULTRY.
Definition (CSP) infection caused by influenza A viruses that occur naturally in birds; wild birds can carry the viruses, but usually do not get sick from them; some domesticated birds, including chickens, ducks, and turkeys, can become infected, often fatally; one strain of avian influenza, the H5N1 virus, may infect various types of animals, including wild birds, pigs, and tigers; symptoms in birds and other animals vary, but virulent strains can cause death within a few days; human H5N1 infection was first recognized in 1997 in Hong Kong.
Concepts Disease or Syndrome (T047)
MSH D005585
ICD10 J09.0
SnomedCT 55604004
English Plague, Fowl, Avian flu, Bird flu, H5N1, Bird Flu, Influenza in Birds [Disease/Finding], fowl plague, Fowl plague, Avian influenza, Avian influenza (disorder), Fowl Plague, Avian Influenzas, Avian Influenza, Influenzas, Avian, Avian Flu, Flu, Avian, Influenza, Avian, Influenza in Bird, avian flu virus, avian flu, avian influenza, bird flu virus, bird flu, Influenza in Birds
Dutch vogelpestvirus
Portuguese Gripe aviária, Peste Aviária, Gripe Aviária, Gripe do Frango, Influenza A Aviária, Influenza Aviária, Praga Aviária, Gripe das Aves
Spanish Influenza aviar, gripe aviaria, Gripe de las Aves, Gripe Aviaria, influenza aviaria (trastorno), influenza aviaria, peste de las aves de corral, Peste Aviar, Gripe Aviar, Gripe del Pollo, Influenza A Aviar, Influenza Aviar, Plaga Aviar
German Geflügelgrippe, Geflügelseuche, Vogelgrippe, Geflügelpest
Swedish Fågelinfluensa
Japanese トリインフルエンザ, インフルエンザ-トリ, 家禽ペスト, 鳥インフルエンザ, トリインフルエンザ, 鳥のインフルエンザ, トリペスト, ニワトリペスト, ペスト-家禽, 鳥ペスト, 鶏ペスト
Czech drůbeží mor, chřipka ptačí, ptačí chřipka u ptáků, ptačí chřipka, Ptačí chřipka
Finnish Lintuinfluenssa
French Grippe chez les oiseaux, Grippe aviaire, Peste aviaire vraie, Grippe du poulet, Influenza aviaire
Russian GRIPP PTITS, PTITS CHUMA, CHUMA PTITS, SINUSIT UTOK, ПТИЦ ЧУМА, СИНУСИТ УТОК, ЧУМА ПТИЦ, ГРИПП ПТИЦ
Polish Pomór ptaków właściwy, Pomór ptaków klasyczny, Grypa ptasia, Ptasia grypa
Hungarian madárinfluenza
Italian Peste aviaria, Influenza aviaria, Influenza dei polli
Sources
Derived from the NIH UMLS (Unified Medical Language System)


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