I liked the different bio items and energy as a concept to grow the disease. Maybe you could introduce reproducing/creating copies of self and then we would have to build around them too. You could also introduce some meter like detection scale which would tell whether the immune system is being aware that a virus is present in the system or not. This would be detected only once you reach a certain size or something.
Good concept. I can see it begin expanded upon. Maybe art style can also be improved. Tried my best but I couldn't reach the wall everytime xD Good game!