A virus is a small infectious agent that replicates only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.
It really depends on you and your preferences. If you're okay with getting fit in a longer time frame and if by get fit you mean lose weight, then I would suggest do some cardio exercises each day, ideally for an hour or so (running, walking, exercise machines like elliptical or treadmill). Also, make sure to have a balanced diet. Try to limit bad carbs (bread, pasta, etc. ) when possible and eat lots of protein and vegetables. But it is okay to not follow your diet all the time; you can have some cheat days.
Hope this helps