Well there alot of challenges faced by biologist researchers during the research of infectious disease, however major of those include the followings:1- Defining and measuring the fitness for pathogens across the scales2- Developing models to capture the impact of co-infection on the evolutionary process3- Modeling how pathogen characteristics shape the evolution of hose immune diversity4- Understanding the maintenance of pathogen diversity5- Developing the better models for the impact of genetic systems on pathogen evolution .
Hope this helps!
-Payshence xoxo