FYI- don't worry about devolving symptoms at all.

Single Player -> Main Game -> Simian Flu ->

Genetic Code:

• Metabolic Hijack
  
• ATP Overdose
  
• Aquacyte
  
• Extremophile
  
• Together Strong
  
  On Casual,
  Start in Greenland.

As soon as you can,

Evolve:

• Simian Neuro-Genesis
  
• Ape Colonies
  
• (Then Place Colony In Greenland)
  
• Social Cohesion
  
• Cognitive Shift
  
• Education

Move Onto:

• Fomites 1
  
• Air 1
  
• Water 1
  
• Drug Resistance 1
  
• Fomites 2
  
• Fomites 3
  
• Blood 1
  
• Air 2
  
• Water 2
  
• Extreme Bioaerosol
  
• Heat 1

Some Symptoms to Evolve:

• Joint Pain
  
• Hydrocephalus
  
• Meningitis
  
• Blindness
  
• Subconjunctival Haemorrhage
  
• Subconjunctival Bleed
  
• Photophobia
  
• Coma

Keep an eye out for your plague killing people faster than it is spreading, and devolve/reload if needed.

If drones target your colony, go ahead and purchase "Organized Travel" and move your colony out of reach.

Last But Not Least, Evolve:

• Hypocoagulability
  
• Haemorrhagic Shock
  
• Genetic Hardening 1
  
• Genetic Reshuffle 1

Wait for the game to finish :)