[Bird flu: what the intensivist must know]

In the last century, humankind has faced 3 major pandemics of influenza virus infections. The first one occurred in 1918 and caused a significant amount of deaths. It was also capable of crossing over species barrier and affecting mammals, and most worrisome, humans. Since then several outbreaks have been reported in the Southeast of Asia. Many patients with the flu-like illness have a severe course and the patient develops pneumonia and in some cases multiorgan failure involving liver, kidneys, brain and lungs. Since the virus lacks regulatory control of genetic division it undergoes constant mutations leading to new subtypes and, sometimes, new strains. The only drugs that have shown some protection are oseltamivir and zanamivir. It is crucial to develop effective and non-expensive vaccines to prevent the virus spread and infection not only in humans but in birds too.