Antigenic shift is the process by which two or more different strains of a virus, or strains of two or more different viruses, combine to form a new subtype having a mixture of the surface antigens of the two or more original strains. The term is often applied specifically to influenza, as that is the best-known example, but the process is also known to occur with other viruses, such as visna virus in sheep.[1] Antigenic shift is a specific case of reassortment or viral shift that confers a phenotypic change.
Many antibiotics, which we have taken for granted since the 1950's, are now becoming ineffective because bacteria have developed ways of acquiring resistance. The development of new antibiotics is lagging behind the loss of the old ones in this race to combat infectious disease. Simultaneously, there is an increase in infectious diseases around the world due to over population, globalization and urbanization. This results in a lethal combination of emerging diseases and loss of effective antibiotics. Multiple factors have contributed to this escalating scenario. The world is now a global village, there is a loss of control of national borders, there are significant populations of aging and immuno-compromised people, there are drastic chnges in global ecology, and migration pathways of animal and insect vectors are changing due to urbanization and global warming. Large networks of epidemiologists and scientists worldwide are now working to coordinate detection, diagnosis and treatment of infectious disease flare-ups in order to contain the threat of epidemics
When you get the flu, viruses turn your cells into tiny factories that help spread the disease. In this animation, NPR's Robert Krulwich and medical animator David Bolinsky explain how a flu virus can trick a single cell into making a million more viruses.
This animation illustrates how directing monoclonal antibodies to the influenza virus prevents a conformational change in the protein that is necessary for viral entry into the host cell
Seth Berkley explains how smart advances in vaccine design, production and distribution are bringing us closer than ever to eliminating a host of global threats -- from AIDS to malaria to flu pandemics.
