The Peace Corps Doc from Nigeria had all of us switch over to mefloquine about 6 months into our 18 month tour after plasmodium falciparum bug became resistant to chloroquine. The meth dreams were something else...

In a small detachment it was easy to keep track and make sure that the Marines took the prescribed prophylaxis, in larger line units, it was difficult but not impossible.

Our biggest problems in Central Africa, Middle East or Central America was the various forms of gardia.