To get this achievement, I did a casual run with bacteria. It's probably not the best strategy but it worked :
- Metabolic jump
- Darwinist
- Aquacyte
- Xerophile
- Trans-Stasis
Egypt start. I bought the following as soon as i had enough DNA:
- Air 1 and 2
- Water 1 and 2
- Bacterial Resistance 1, 2 & 3
Then, as soon as possible, i bought every symptom that increased infectivity without increasing lethality.
Once every country has been infected by at least 1 person, buy what brings most lethality asap.