Since then, outbreaks of the H5N1 highly pathogenic avian influenza strain have been identified in birds, wild and domestic poultry, in several countries, particularly in Vietnam, Indonesia, Thailand, China, Cambodia and, more recently, in Turkey and Iraq. In Italy, no human cases have been reported and two epidemics occurred in poultry causes by avian influenza virus H5 and H7 subtypes. Alongside these massive avian outbreaks, the World Health Organization (WHO) reported more than 300 confirmed human cases of avian influenza A (H5N1), approximately two thirds of whom have subsequently died [4] . Nearly all of these cases are traceable to exposure to infected poultry or birds, but there has not yet been a mutation allowing the H5N1 and H7N7 viruses to spread efficiently in human [5] .