I contracted malaria many times in PNG over a period of 12 years The types I have were vivax at least ten times and falciparum twice. A thing to remember is that recommended anti malarials work in certain areas and not in others.After recovering from malaria you can get plenty of false warnings, as if you have malaria but nothing shows in the blood tests. I have used doxycycline and it worked but you can sunburn easily. The advice I was given in Rabaul was, if planning a long term stay in malaria affected area to take no antimalarials. The reasoning given by the doctor was there are good treatments available that work fast.