Which are the mutations involved in the adaptation of the H5N1 avian influenza virus to humans?
• Prof Dra. Rita Catarina Medeiros Souza. Tropical Medicine Core / Federal University of the State of Pará and Respiratory Virus Laboratory / Evandro Chagas Institute /Ministry of Health. The species barrier for the type A influenza virus is established by many viral genes, involving not only the coded genes of the glycoproteins of the viral surface, hemagglutinin (HA) and neuraminidase (NA), but also internal genes like the PB2 of the polymerase complex. The influenza virus has a segmented RNA genome, which favors the accumulation of mutations, in addition to the possibility of rearrangements of the many segments when one cell is co-infected with two or more genetically different viruses. The viruses introduced in the human population during the 1957 and 1968 pandemics, caused respectively by viruses A (H2N2) and A (H3N2), were the result of a rearrangement between segments of the genome of a virus of avian origin with viruses that had already been circulating for some time in the hum
