It's not an answer per se but note that if you evolve symptoms, you are supposed to get more DNA points as the game progresses to reward you for being daunty and challenge humans in curing you. I don't know if it's still actual though.
Back when i started, i used the silent strategy often to win scenarios but soon found out that getting level1 and level2 symptoms that increase infectivity to be much better than using transmissions. Sure, transmissions are necessary but not off the start. My setup of choice is:
- Metabolic Hijack (Cause i'm lazy)
- Aerocyte (I always felt planes were more ubundant and varied in destinations compared to boats)
- Ionised Helix (To slow down cure)
- Base oxydisation (It's good to automatically mutate transmissions as transmissions help automatically mutate symptoms)
- Extremophile (Better to be accustomed to many places than just one)
Then i use the following pattern, it's not the best but it works fine for me:
- Start in Saudi Aradia
- Get Coughing symptom
- Get Pneumonia symptom
- Get air 1 transmission
- Get Bacterial resistance 1 ability
- Get Nausea symptom
- Get Vommit symptom
- Get Bacteria resistance 2 ability
- Get Cold resistance 1 ability
- Get Drug resistance 1 ability
From that point on, get more abilities based on where your disease is going and take more and more infective symptoms, transmissions will mutate by themselves. Worst, to help you, take Water transmission and bird transmission but thats all...
It usually works fine!