Confronting Malaria and Drug Resistance on the Thai-Cambodia Border

It is in the remote villages carved out of forests along Cambodia’s border with Thailand that you get a keen sense of the challenge in containing the malaria parasite, which has withstood numerous attempts at eradication over the decades.

It now threatens to outfox medicine’s last line of effective drugs.

A NewsHour crew accompanied a team from Cambodia’s National Malaria Control Program to Ochrab village, two bumpy hours from the nearest public health center in Thasanh.

Here, after asking around about those who might be ill, we found a gaunt 23-year-old Pin Sreymom. Too weak to tend the family’s patch of land with her parents, she sat outside the family home, a one-room wood structure perched a few feet above ground on stilts.

Inside, her 19-year-old brother Pin Vantim lay bedridden by the searing fever that is a hallmark of malaria. He had rejected all offers to address his declining health. Meanwhile, his sister took some medicines bought from a neighbor.

With cajoling, the siblings agreed to be tested for plasmodium falciparum, the most lethal malaria parasite, which kills hundreds of Cambodians each year. A health worker mixed the blood specimens with a blue fluid, spread them on glass slides and set a timer for 30 minutes — time enough to set up a microscope and probe their hosts’ reticence to seek free treatment offered at the regional center.

Her brother is afraid of drugs and injections, explained Sreymom. For her part, leaving their house unattended was simply out of the question, she said. The journey would take too long, imperiling their modest livelihood and belongings and the motorcycle taxi ride is both unaffordable and uncomfortable.

So Sreymom made do with a sachet of pills from a neighbor. The label suggested it contained a full four-day course of the government-approved combination therapy for malaria. Sreymom decided to take only some of the cocktail of tablets, a common practice, often done to conserve a precious commodity.

Her case deeply worries doctors like Darapiseth Sea, of Cambodia’s malaria control program. For one thing, Sea could not certify the authenticity of the drugs. Counterfeits are widespread here. Imported mostly from China they may contain none of the drug’s active ingredients or – worse – only a portion of what’s required. Even in cases where the drugs are genuine, patients often stop taking them once they feel better. However it occurs, such partial dosing means the parasite may not be eliminated from the body and can begin to develop resistance to the drug.

That’s what happened with earlier antimalarials, like Chloroquine and Mefloquine. New studies show a similar pattern, a small but disturbing decline in the efficacy of artemisinin, modern medicine’s last effective weapon against P. falciparum, says Mark Fukuda, co-author of one of the recent studies, published in the New England Journal of Medicine.

Fukuda is a Bangkok-based lieutenant colonel in the U.S. Army, one of several international agencies launching a concerted joint effort to contain the problem here.

Cambodia’s health officials must coax patients to take only the approved drug combinations, which mix in a portion of artemisinin with older anti-malarial drugs, which are far less effective by themselves. Doctors want to preserve the potency of artemisinin and use it as a solo drug for only the most severe cases.

The government must make it easier and cheaper for patients to get unadulterated drugs — the most effective way to put knock-off drug sellers out of business. And health workers must convince patients to take the full dosage, even after they feel better.

The goal is to get information and medicines to vulnerable people, along with treated bed nets that can shield them from mosquitoes, which spread the parasite as they pierce the skin of one human victim after another.

It is a daunting task in a region still suffering the legacy of decades of brutal warfare. Roads are poor to non-existent in a landscape where signs warning of unexploded mines are common.

And the government must find more efficient ways to deliver care, such as training local volunteers to conduct surveillance. That may become easier with the advent of promising new rapid test kits. The stop at the Pin residence alone took almost an hour for the malaria team we followed, a tedious rate of productivity.

When the timer went off, the microscope confirmed what seemed obvious to the visiting team. Pin Sreymom’s blood samples showed some parasites. However, her brother’s levels were life-threatening and required immediate intervention.

Still, Vantim adamantly refused to travel for treatment – an intravenous course of pure artemisinin for his advanced case. In the full glare of an international news crew backing up the malaria team, he finally agreed to take a less-optimal course of pills. The team could only hope he would complete the dosage. There are no resources yet to follow up on his case.

It was a long morning’s work in the farthest reaches of the global malaria pandemic. The stakes are huge. Resistant malaria would spell catastrophe if it spread to sub-Saharan Africa, where the disease already kills 3,000 children every day. With the ease of global travel, Fukuda says, we’re one plane ride away from that epidemiologic leap.