The flu is responsible for millions of deaths worldwide each year. Scientists watch carefully for crossover viruses – transmission between hosts belonging to different species – as part of the quest to determine how best to contain harmful outbreaks. As more are infected, more become a threat to pass it on to others. And illness can spread exponentially and rapidly, exacting considerable death and crippling financial chaos.
It becomes critical to be proactive, using considerable resources to determine the variables that allow for the transmission and addressing them accordingly in the effort to prevent the devastating outbreaks. Outbreaks such as those we are witnessing presently with COVID-19, and the scores of diseases we have experienced many times in the past. Viruses are sneaky and adaptable, changing their makeup ever so slightly. Containment approaches must be constantly re-evaluated to address ongoing mutations. The links directly below provide overviews from the CDC of some past pandemics.