Counterfeit drugs are a growing scourge around the world. They're generating millions of dollars in revenue for organized crime and fueling the rise of drug-resistant parasites.

Anti-malarials are among the most popular drugs to fake. But these faux pharmaceuticals are particularly dangerous because malaria can kill a person in a matter of days.

"Someone comes with malaria," says Stephane Proux, a researcher at the Shoklo Malaria Research Unit in Thailand, setting up a scenario. A seller will say, " 'Here you go, and take those tablets.' But there's nothing in there. ... It's very dangerous, potentially fatal for the patient."

SMRU helps to set up and run malaria clinics across the Thai border in Myanmar, also known as Burma. Myanmar has the highest level of malaria transmission in Southeast Asia, and it has been flooded with phony malaria drugs.

A lengthy civil war in Myanmar fueled both malaria and the counterfeit drug problem. Soldiers and villagers were pushed into mosquito breeding grounds. The conflict devastated health clinics, and it allowed smugglers to move with relative ease in and out of the country.

In Myanmar, malaria drugs and many other medications are sold openly without a prescription in markets and small shops. Proux says counterfeiters are playing with people's lives by selling useless medicines.

"That's a deadly trade. Those people are not only crooks, they are criminals, definitely criminals," he says.

Sometimes the fake drugs are nothing more than repackaged sugar pills or chalk. But at times, they contain small amounts of anti-malarial drugs.

That causes another major public health problem. When the malaria parasite is exposed to an insufficient dose of a drug, resistance can start to develop. And that appears to be happening now in Southeast Asia with one of the most powerful anti-malarials, artemisinin.

Drugmakers put holograms on drug packaging to authenticate the contents. "In the early days, it was quite easy to tell the fake from true because the hologram[s] were really badly done and very rough, and you could see straight away that it was fake," Proux says.

He says that started to change around 2004 or 2005. The malaria drugs for sale in eastern Myanmar became almost indistinguishable from the authentic ones. The packets even had hologram stickers that were nearly identical to the stickers from the factory.

"They are champion counterfeiters those guys. They are really, really well crafted holograms," Proux says.

Oxford University epidemiologist Paul Newton, who is based in Laos, has studied the trade in fake malaria drugs for more than a decade. He says shoddy and counterfeit medications have been a major problem for at least 10 years, and they're responsible for reducing the efficacy of malaria drugs throughout Southeast Asia.

But the problem isn't limited to that region of the world.

Economist Roger Bate, from the American Enterprise Institute, just wrote the book Phake: The Deadly World of Falsified and Substandard Medicines about the rise of phony pharmaceuticals around the globe. He says fake malaria drugs are a favorite among counterfeiters.

"It's impossible to know the exact scale of the problem of fake anti-malarials," he says. "But in some markets, it's as low as single-digit percentages, and in the worst markets half the market is fake."

For instance, he says, in Lubumbashi, the most southern city in Congo, 48 percent of malaria drugs sampled didn't work.

Even if they're worthless against malaria, these phony drugs can generate millions of dollars for organized criminals.

Yet global efforts to attack the counterfeit malaria drug trade remain weak.

Bate says part of the problem is that malaria mainly affects people in developing nations where pharmaceutical regulation is weak. Drug regulatory agencies in malaria-endemic countries, he says, simply aren't strong enough to take on the counterfeiters.

Copyright NPR 2018.