reporter: to comb the read of resistance, the bil and minda gates foundation is unding a campaign prect adminisred by cam beaa's governmt and the world health organization. the key to its success is findingut how and why the parasite are deloping a tolance to the a.c.t. a trip to the local market provides clues. shoppers come here not onlyor uit and vegetles, but also for medication fromrivate pharmacies that have be here for years. >> this drug is correct, a it's gotlear instruction inside as to how to take the drug in ththree days that you have to take it. but it's possile that patients already cut it up and only take it until they're fling better. is is the whole poblem that we find in the priva sector that patients arenot getting the correct dose, not getting the correct combation, and this is going to le to drug sistance developing very rapidly, unless it c be controlled. >> reporter: the cbodian governmt is awe of the problems in the private sector. it has banned the sale o monotherapies, sile drugs that are easy for parasites to apt to. but they are stilleadily available on the o