Arniyuki--disasters effect the rate of spread of your disease or other things.
Earthquakes-disrupt hospitals, slowing the rate at which your number infected goes down and the rate at which the vaccine is developed.
Drought-Increases the rate at which any disease with the "insect" transmission vector infects new people
Flood-increases the rate at which a disease with the "waterborne" transmission vector infects new people
Hurricanes-Temporarily shut down public transit, airports, and schools
Riots-negate the effect of curfews.
If you're just in it to win (not go for the under 100 days thing) and have a LOT of patience, go for parasite. Best place to start is anywhere that doesn't have any borders (so, regions completely surrounded by water.) Sell your starting symptom and buy waterborne transmission. Unlock all the tiers (you shouldn't get any symptoms for buying tiers with parasite, if you do sell them) and buy 1-1-1-3 resistances. Wait until all the regions are infected. This will take a LONG time, but once it happens it'll go pretty quick. After all regions are infected, buy moisture resistance 2, cysts, and vomiting. Wait until every single person is infected. Then get necrosis, Pulmonary Edema, sores, insanity and then from there just watch as everyone dies. To expedite this process buy a new symptom that increases lethality every time you build up enough points.
If you're just in it to win (not go for the under 100 days thing) and have a LOT of patience, go for parasite. Best place to start is anywhere that doesn't have any borders (so, regions completely surrounded by water.) Sell your starting symptom and buy waterborne transmission. Unlock all the tiers (you shouldn't get any symptoms for buying tiers with parasite, if you do sell them) and buy 1-1-1-3 resistances. Wait until all the regions are infected. This will take a LONG time, but once it happens it'll go pretty quick. After all regions are infected, buy moisture resistance 2, cysts, and vomiting. Wait until every single person is infected. Then get necrosis, Pulmonary Edema, sores, insanity and then from there just watch as everyone dies. To expedite this process buy a new symptom that increases lethality every time you build up enough points.
You also have to know what you're doing with parasite, i suppose. :P I guess I kind of take it for granted that other people do because I play this so much. ^^;;
 "Kongai"){kind=icon}
 "Pandemic 2"){kind=icon}