Question: If a disease does jump from one thing to another, does the disease need to change or evolve in anyway or does it stay exactly the same

Alexandra Kamins answered on 21 Jun 2010:

Usually some level of change is needed for a disease to survive in a new species, because pathogens tend to be very specific. Fortunately (for the pathogens), viruses and bacteria have very short generations (a new offspring as fast as every 20 minutes!) so they can change a lot, and very quickly. Sometimes, one just happens to change in the right way AND get the chance to be passed into a new species. And voila, you have an emerging disease!