Infectious Disease Book


Avian Influenza

Aka: Avian Influenza, Avian Influenza A, Bird Flu, Asian H5N1, Influenza A 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
    2. WHO Avian Influenza information
    3. U.S. Department of Health and Human Services
  12. References
    1. Fauci (2006) Emerg Infect Dis 12:73-7 [PubMed]
    2. Juckett (2006) Am Fam Physician 74(5):783-90 [PubMed]
    3. Monto (2005) N Engl J Med 352:323-5 [PubMed]

Influenza in Birds (C0016627)

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, the Middle East, 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, 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 or eggs that are not well cooked or through contact with a person who has it. Bird flu can make people very sick or even cause death. Antiviral medicines may make the illness less severe, and may help prevent the flu in people who were exposed to it. 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.X
SnomedCT 55604004
English Plague, Fowl, Avian flu, Bird flu, Influenza in Birds [Disease/Finding], avian influenza, fowl plague, Bird influenza, H5N1, Bird Flu, H7N9, 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, bird flu virus, bird flu, Influenza in Birds
Dutch vogelpestvirus, vogelgriep
Portuguese Gripe aviária, Peste Aviária, Gripe das Aves, Influenza A Aviária, Gripe Aviária, Gripe do Frango, Influenza Aviária, Praga Aviária
Spanish Influenza aviar, gripe aviaria, Gripe Aviaria, Gripe aviar, Influenza A Aviar, Peste Aviar, Gripe de las Aves, influenza aviaria (trastorno), influenza aviaria, peste de las aves de corral, Gripe Aviar, Gripe del Pollo, 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 des oiseaux, Grippe du poulet, Influenza aviaire
Polish Pomór ptaków właściwy, Pomór ptaków klasyczny, Grypa ptasia, Ptasia grypa
Hungarian madárinfluenza, Madárinfluenza
Norwegian Influensa A(H5N1), Fugleinfluensa
Italian Peste aviaria, Influenza aviaria, Influenza dei polli
Derived from the NIH UMLS (Unified Medical Language System)

Influenza A Virus, H5N1 Subtype (C1613950)

Definition (MSH) A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 5 and neuraminidase 1. The H5N1 subtype, frequently referred to as the bird flu virus, is endemic in wild birds and very contagious among both domestic (POULTRY) and wild birds. It does not usually infect humans, but some cases have been reported.
Concepts Virus (T005)
MSH D053124
SnomedCT 421264001
English Influenzavirus type A, avian, H5N1 strain (organism), Influenzavirus type A, avian, H5N1 strain, Avian Influenza A H5N1 Virus, H5N1 Viruses, H5N1 Virus, Influenza A Virus, H5N1 Subtype, Virus, H5N1, Viruses, H5N1, H5N1 virus
Spanish virus influenza tipo A, aviar, cepa H5N1 (organismo), virus influenza tipo A, aviar, cepa H5N1, virus influenza aviar A H5N1, Virus de la Influenza A Subtipo H5N1, Subtipo H5N1 del Virus de la Influenza A, Virus H5N1
Portuguese Vírus H5N1, Virus da Influenza A Subtipo H5N1, Subtipo H5N1 do Vírus da Influenza A
Italian Sottotipo H5N1 del virus influenzale A, Virus H5N1
German Influenza-A-Virus, Subtyp H5N1, H5N1-Virus
French Virus H5N1, Virus A(H5N1), Sous-type H5N1 du virus de la grippe A, Virus de la grippe A(H5N1), Virus grippal A(H5N1), H5N1 subtype influenza A virus
Swedish Influensa A-virus, subtyp H5N1
Czech virus H5N1, virus chřipky A - podtyp H5N1
Finnish Influenssa A -virus, alatyyppi H5N1
Japanese H5N1型インフルエンザウイルス, H5N1ウイルス, インフルエンザウイルスA型H5N1亜型
Polish Wirus grypy A podtyp H5N1
Derived from the NIH UMLS (Unified Medical Language System)

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