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Emergency: requires immediate attention
Avian influenza
See also in: Pulmonary
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Emergency: requires immediate attention

Avian influenza

See also in: Pulmonary
Print Images (8)
Contributors: Neil Mendoza MD, Paritosh Prasad MD
Other Resources UpToDate PubMed

Synopsis

Avian influenza viruses (also known as avian flu and bird flu) are influenza A viruses that are generally found in the intestines of wild birds.

Migratory wild birds, asymptomatic carriers of the virus, can infect domestic birds such as chickens, ducks, and turkeys. Infection makes the domestic birds sick, and most die.

Humans acquire avian influenza viruses primarily through direct contact of the mucous membranes with infectious secretions and excreta from infected birds or contaminated poultry products. The major portal of entry appears to be the upper respiratory tract. Although human-to-human transmission has been suggested in several household clusters, so far, there has been no sustained human-to-human transmission. Much remains to be learned about the exact mode of transmission. Most human illness from avian influenza has resulted from infection with Asian lineage H7N9 and H5N1 viruses.

The incubation period is generally between 2-5 days, but an upper limit of 8 days is possible. Most patients have headache, malaise, high fever, sore throat, cough, shortness of breath, and myalgia. Conjunctivitis, watery diarrhea, abdominal pain, vomiting, pleuritic pain, and bleeding from the nose have also been reported. Respiratory distress, tachypnea, and inspiratory crackles are present on physical examination. Lymphopenia and thrombocytopenia are commonly present. The frequency of milder illnesses, subclinical infections, and atypical presentations such as encephalopathy is not known. Pregnant women are at increased risk for severe illness from influenza.

Atypical presentations of avian influenza have been reported. Patients have developed nausea, vomiting, and diarrhea preceding acute respiratory failure. Progression to acute respiratory distress syndrome (ARDS) and respiratory failure is common. Complications have included bacterial sepsis, pulmonary hemorrhage, and multi-organ failure. The mortality rate of hospitalized patients has been high due to progressive respiratory failure.

Codes

ICD10CM:
J09.X2 – Influenza due to identified novel influenza A virus with other respiratory manifestations

SNOMEDCT:
55604004 – Avian influenza

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Therapy

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References

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Last Reviewed: 04/13/2017
Last Updated: 09/08/2017
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Emergency: requires immediate attention
Avian influenza
See also in: Pulmonary
Print 8 Images
View all Images (8)
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Avian influenza : Abdominal pain, Cough, Fever, Headache, Rhinorrhea, Dyspnea, Myalgia, RR increased
Imaging Studies image of Avian influenza
Copyright © 2018 VisualDx®. All rights reserved.