Dr. Aun Pyae Phyo examines a baby at the Whampa malaria clinic on the Thailand-Myanmar border.

MELISSA BLOCK, HOST:

This is ALL THINGS CONSIDERED from NPR News. I'm Melissa Block.

ROBERT SIEGEL, HOST:

And I'm Robert Siegel.

Drug-resistant parasites are a growing threat to the global fight against malaria. And the World Health Organization is focusing especially on Thailand. In Thailand's border regions with Myanmar and Cambodia, parasites have become resistant to one of the most powerful anti-malarial drugs. If that drug resistance were to spread, it would be a big setback. NPR's Jason Beaubien traveled to the Thai-Myanmar border for this first report in our series Malaria Pushing Back.

JASON BEAUBIEN, BYLINE: At 8 in the morning, people flow into the dirt courtyard of a health clinic in Mae Sot on Thailand's western border with Myanmar. Some people arrive on foot, some on bicycles, others come in motorized rickshaw taxis. Many of the women have traditional Burmese sunscreen, an earthy-yellow powder spread across their cheeks.

UNIDENTIFIED WOMAN: (Foreign language spoken)

BEAUBIEN: In the malaria room at the clinic, 17-year-old Moo Gay Paw is slumped over the nurse's desk. She wearily rests her cheek on her forearm. Beads of sweat glisten across her forehead. The nurse has just told Gay Paw that she has the potentially fatal disease, but she looks too exhausted to care.

UNIDENTIFIED WOMAN: (Foreign language spoken)

BEAUBIEN: This teenager represents the huge challenges of controlling malaria in the porous border region between Thailand and Myanmar, also known as Burma. Over the last decade, Thailand slashed its malaria rate by more than 50 percent. Thailand's aggressive malaria control program has eliminated the disease from most of its own territory. But those efforts have been less successful along the border with Myanmar, which has the highest rate of malaria in the region. Gay Paw arrived here earlier in the morning because she says the medical care in Myanmar is terrible.

MOO GAY PAW: (Foreign language spoken)

BEAUBIEN: The government health clinics in Myanmar give out malaria pills, she says, but the drugs don't work. The muddy Moi River separates this part of Thailand from Myanmar. Each day, people shuttle back and forth in small skiffs unhindered by any governmental oversight. Some Burmese come for medical care or to shop. Others come to work as day laborers in the rice and sugarcane fields. Still, others are fleeing the turmoil in their home country. It's here in this bustling border region that one of the most powerful anti- malaria drugs currently on the market, artemisinin, is starting to fail.

APITYA NIRAMITANTIPONG: It's a big deal problem. It's a big problem in this area.

BEAUBIEN: Apitya Niramitantipong, a malaria specialist with the Thai Ministry of Health, says before this resistance emerged, Thailand was talking about attempting to eliminate malaria entirely. But now that's changed.

NIRAMITANTIPONG: Now, the story is focused on how to contain drug-resistant malaria parasite not to spreading to any other area.

BEAUBIEN: To try to contain resistance, Thailand recently started having health care workers watch patients take their malaria medication to make sure it's taken properly. The country has also started using Malarone as a substitute for artemisinin in some provinces. Malarone is an extremely expensive drug used primarily by Western tourists vacationing in swampy tropical locales. Drug resistance can develop when the parasite is exposed to an inadequate dose of a drug, a dose that's not strong enough to kill it.

Dr. Khin Maung Lwin says this is happening all the time on the Myanmar side of the border, where questionable malaria drugs are openly sold in grocery stores.

DR. KHIN MAUNG LWIN: You can buy freely in the market inside Burma easily.

BEAUBIEN: Just across the river, you can buy them?

MAUNG LWIN: Yes.

BEAUBIEN: Maung Lwin works for the Shoklo Malaria Research Unit, which helps run 14 malaria clinics in Eastern Burma. He says Burmese shopkeepers also offer a local remedy called ya chut. It's a small satchel containing a mishmash of medicines. It might have malaria medicine in it or it might be just a couple of aspirin tablets. Another problem he says is that malaria drugs are distributed at illegal logging camps by foremen who want to make sure their laborers stay on the job.

MAUNG LWIN: Logging, woodcutting, charcoal thing is - they are not legally allowed.

BEAUBIEN: This makes it nearly impossible for groups like his to provide appropriate medical services to the workers, he says. Researchers don't know for sure what's causing drug resistance to emerge here, but this ad hoc use of malaria drugs is a prime suspect. What's also worrying researchers is that drug resistance to two other leading anti-malarial drugs, chloroquine and Fansidar, also started in this region decades ago. That resistance then spread to the rest of the world. Arjen Dondorp, the deputy director of the Mahidol-Oxford Tropical Medicine Research Unit in Bangkok, says the amount of resistance to artemisinin right now is still low, but it could get much worse.

ARJEN DONDORP: There is a fear that if this problem increases, malaria will become again like it was in the '90s: very, very difficult to treat. And then the fear is that malaria will increase again.

BEAUBIEN: Part of the problem is that there are very few other drugs available right now that are as cheap and as effective as artemisinin has been. Jason Beaubien, NPR News.

SIEGEL: Jason has more about the world of counterfeit drugs in the fight against malaria tomorrow on NPR's MORNING EDITION. Transcript provided by NPR, Copyright NPR.