Tips.

[kajomc72]

With all diseases but Virus and Nano-Virus, I found this strategy works decently, if you have some patience (I got 4/5 biohazard symbols in the final score using this with a parasite on brutal)
Start in Australia (the 2 ports and airport allow it to reach most islands very quickly, and the kissing festival gives you a good starting boost if it occurs), buy Drug resist I (to increase spread in Australia), Water Transmission 1 (to start infecting boats), Air transmission 1 (to infect planes), and Avian transmission 1 (to increase mutations and land transmission once it hits landfall). I also recommend trying to get all the other transmission types to 1 as well to increase infection rates across the globe. Wait as it spreads (it will spread rapidly, so be ready to click a lot of bubbles) and sell all mutations until every country is infected (you may need cold resistance II to be effective in Greenland and Canada). Once that occurs, start getting basic symptoms leading up to either internal hemorrhaging/hemorrhagic shock or total organ failure (cysts/anemia and coughing respectively, but only one to reduce the severity) to increase infection rate and wait for around 50-70% of all countries population to be infected. Then, rapidly mutate the hyper lethal symptoms before they can fight back, killing them to quickly for a cure to be researched with any efficiency. If you have DNA left over, you can increase you're score by buying genetic scrambling perks and research inhibiting evolution to reduce what little research will have taken place (max on mine was 25%). Then sit back and watch as humanity desolves