Avian influenza, or bird flu, was first recognized as a potential world health threat in 1997 through an outbreak in Hong Kong. This illness is caused by several subtypes of influenza A virus. Normally affecting chickens, turkeys and ducks, the virus can be transmitted to humans who inhale aerosolized bird feces or respiratory secretions. Bird handlers are especially at risk for infection from direct contact. Avian flu, especially the subtype H5N1, has caused serious illness and death in humans in Asia. To date human-to-human transmission appears to be quite rare. However growing concern exists that avian and human influenza viruses may be capable of recombining to form more virulent subtypes that could potentially spreading from person to person. The organism’s new pathogenicity could indeed cause a global pandemic.
Would you recognize someone suffering from avian flu? The initial presentation of symptoms is typically two to five days after exposure. Symptoms are very similar to other influenza illnesses, and include fever, myalgias, sore throat, cough, conjunctivitis, and watery diarrhea. Leukopenia or lymphopenia is typically present. Chest X-ray frequently detects infiltrates resulting from viral pneumonia. Patients may progress to respiratory distress and multi-organ failure. Distinguishing avian flu from other forms of influenza or pneumonia is aided by a history of direct or indirect contact the birds. Definitive diagnosis is made by viral isolation or identification of the H5-specific RNA from nasal or pharyngeal swabs.
While the chances may seem remote that avian influenza would appear in the US, it is just this line of reasoning that will cause us to misdiagnose the first cases. International travel makes it possible that an outbreak in the Far East could indeed affect us within hours. A basic understanding of the disease coupled with clinical vigilance could prepare you to nail the diagnosis. To gain more expertise in threats to global health, please take advantage of the INMED International Self-Paced Courses.