This is also the guide for beating the Neurax Worm on Mega-Brutal difficulty. So, feel free to choose that difficulty and you'll get the Neurax Master achievement as well.
Gene Setup:
Metabolic Jump
Genetic Mimic
Native Biome
Extremophile
Trans-Stasis.
1. Start in India
2. Evolve
ALL the transmissions, but evolve these five Transmissions and this Ability first:
Genetic Swap
Corpse Feeder 1 and 2
Mutative Regeneration 1 and 2
Trojan Planes 1
3. From here on out, send the planes to any island (you'll see a plane icon pop up from Trojan Planes, click it then select the country to infect) if they haven't been infected yet. Start in Greenland, then Iceland, then Caribbean. You choose the islands after that. If all the islands are infected, then go after healthy countries next. If every country is infected, go after the biggest research contributor.
4. Evolve Cold Resistance 1 & 2, then Drug Resistance 1 & 2
5. Evolve these Symptoms if they haven't mutated yet (the first two are basically always mutated by this time):
Neural Breach
Cerebral Tendrils
Frontal Mesh
Immaturity
Mania
Obsession
Devotion
Adoration
Transcendence
6. Rest of the DNA can go to whatever you choose. I prefer going after the evolutions that increase infectivity, though.
NOTE: There is a luck factor in this game. If this doesn't work for you, try again or change some slight details to fit your preference. This method worked for me 1st try.
Credit: Unknown author, from
http://icspicy.blogspot.ca/2014/09/plague-incsubmitted-guide...