The objective of this study was to review the literature related to avian influenza A (H5N1). The bibliographic research was conducted using the Medline, MD Consult, HighWire, Medscape and Literatura Latinoamericana y del Caribe en Ciencias de la Salud (LILACS, Latin American and Caribbean Health Sciences Literature) databases, as well as through direct research, limiting the scope to articles published within the past 10 years. We selected 31 original articles addressing the recent outbreaks of infection with the H5N1 subtype of avian influenza A in domesticated birds in Asia, which have resulted in significant economic losses and repercussions for public health, as well as some cases of human infection presenting high lethality. In most cases, infection has been associated with direct exposure to infected birds or contact with surfaces infected with bird excrement. However, cases of human-to-human transmission have been confirmed. In those cases, the incubation period varied from 2 to 4 days. The clinical manifestations range from asymptomatic infection to mild upper airway disease, pneumonia and multiple organ failure. Chest X-rays may reveal bilateral interstitial infiltrate, lobar collapse, focal consolidation and air bronchogram without pleural effusion. Lymphopenia is indicative of a poor prognosis. Supportive care appears to be the only acceptable treatment. Risk factors for poor prognosis include advanced age, delayed hospitalization, lower airway involvement, low white blood cell count or lymphopenia upon admission. Controlling outbreaks in domestic fowl and limiting contact between humans and infected birds must be the priorities in the management of this disease at the public health level. In addition, techniques and knowledge regarding the disease should be widely disseminated.

Keywords: Influenza A virus, avian /pathogenicity; Influenza; Disease outbreaks; Disease vectors; Clinical trials