The volunteer farmers who bare their skin throughout the night and offer their blood to the mosquitoes of Pailin are taking grave risks for a good reason. Armed with a flashlight, some cotton wool and a test tube each, and with their trouser legs rolled up, it is their low-tech duty to wait until an insect, attracted mostly by the carbon dioxide in perspiration or breath, alights on their skin, and then to capture it for the laboratories of Phnom Penh, where its disease-bearing parasite levels can be assessed. In this remotest district of Cambodia, tight up against the Thai border on the northern slopes of the Cardamom mountains where the Khmer Rouge fought their final battles, and where some of their cadres are now senior figures in the administration, the mosquitoes are among the world's most deadly. A single bite and any of these eight human baits, working in four-hour shifts, could become the bone-aching, haemorrhaging victims of dengue fever, which is at its most virulent during this season of monsoons and which, though not normally lethal except for children and the very old, is incurable. According to Richard Veerman, my Médecins Sans Frontières (MSF) host and its head of mission in Cambodia, who has himself only just recovered from the fever, "You can do nothing about it but sit out the pain and hope not to die."
But it is not dengue that should worry me most, when I sit down on the boggy ground in the tiny village of Pang Rolim to join the volunteers and bare my own leg to the mosquitoes. Nor is it the deadly russell's vipers or the cobras that are common in the soya-bean fields behind us. Nor is it even the undetected and undetonated landmines that, according to a recent Unicef report, make these farmlands "one of the most dangerous places in the world". What should have kept our legs covered is the knowledge that the anopheles mosquitoes of Pailin or, more specifically, the single-cell Plasmodium falciparum malaria parasites that live in them and us, were the first in the world to develop (through over-prescribing and incomplete dosing) a resistance to chloroquine. This is the drug which for decades has been humankind's main defence against malaria. I have suffered from malaria before, in Sudan, and I got through with little more than a debilitating fever, but that was the less deadly P vivax strain, which has yet to develop resistance to drugs.
Yet my fellow volunteers and I are not being foolhardy. We can be confident that whatever the parasite-load of the vectors filling their abdomens with our blood, we are unlikely to contribute to the worldwide toll of 2.7m malaria deaths each year (out of the at least 350m almost exclusively poor people who, according to a UN report of May 2005, sicken with the disease). In this fortunate village at least, there is a new and readily available treatment for P falciparum, a cocktail based on artemisinin, an extract from sweet wormwood. But it has to be administered swiftly. All the locals understand, from the too recent and bitter experience of neighbours, that to contract this strain of malaria in Pailin and leave it to its own devices is to invite a rapid and painful death. After a week or more, we could expect fever, muscle pains and headaches, explains Bart Janssens, MSF's medical co-ordinator. For any victims beyond the reach of artemisinin, however, diarrhoea, nausea and anaemia might develop. And finally, in a third to a half of all cases, there would be "severe complications", including brain damage, multiple organ failure and coma. "You could be dead in 10 days," he warns.
Our job that night, under the scrutiny of an entomologist, Dr Tho Sochantha, from the Centre for Malariology, is to help verify what
the rapidly falling P falciparum prevalence and death toll has been suggesting: that MSF's volunteer-based, rapid-treatment programme for malaria in these forest-edge villages, where conditions are perfect for breeding mosquitoes, is "breaking the pathways of transmission" between female insects, parasites and humans.
My own contribution to the insect survey is only modest. I seem at first to be more attractive to ants than to mosquitoes. But finally, in the pitch-blackness, I learn to recognise the weightless, fussy probing of anopheles on my shins, and I begin to fill a test tube with my captives. At the end of my shift, Dr Sochantha holds my tally up to his magnifier and, much to the delight of a crowd that has abandoned a blaring, battery-powered television set to watch a European make a meal of himself, declares my specimens to be "from a vector that normally prefers to feed on cows". He would be happy to offer me a trapper's job at any time, though. "You are a good hunter," he says. "Their abdomens are not bloated. You have captured them before they could feed." What I do not mention is that, though my leg has not been pierced, the back of my neck is already itchy and lumpy from a dozen uninterrupted bites.
Over the next few days, in the straw-roofed stilt villages of Treng Leu and Phnom Reang (or Tree Mountain), accessible to only the toughest off-road vehicles, the MSF mobile malaria team and its dignified and gentle Thai co-ordinator, Raden Srihawong, meet up with some of their 40 trained community volunteers to "mass-screen" every inhabitant for malaria. Their simple purpose is "to reduce malaria morbidity by finding more patients". The villagers, in their mixture of traditional blouses, fake Nike or Puma T-shirts and an eclectic array of hats, are queuing in the mud at the temporary canvas-and-bamboo tents that MSF has erected for its medical inspection.
They are the strongest-looking buildings in the village. There is some crying from the children, who seem alarmed by the presence of so many strangers. But the adults are delighted to have so much free medical attention. These are some of the poorest communities in Asia. Not one has a school, electricity, sanitation, or water for washing or cooking, other than that provided by the heavens. At this time of the year, the heavens have provided more than generously. A week of monsoons has turned the countryside into one great puddle. But for most of the year, the land is dry. "There are three harvests a year in Thailand," observes Bart Janssens. "But in Pailin there is probably only a half. Most farmers can produce enough food for six months, but then they have to catch insects and make soup from wild plants."
They have, too, to deal with the presence of unexploded ordnance. Amputees are a common sight, and signs warning "Danger! Mines!!" can be encountered every 20 yards, even on the narrowest of pathways. It is said that Pailin will not be entirely cleared for a further 80 years. Chea Doeurn, whose 18-year-old daughter, Chek Dany, is a malaria volunteer in the virtually unreachable village of Bor Thmei, has found many mines in his soya-bean fields. Three of their neighbours have died. Ten have lost limbs. Their home is between "confirmed minefields" and "residual minefields" in the most mined area in the world, and is at the end of Route 10, where, as late as 1999 and eight years after the official ceasefire, the final skirmishes were exchanged between government troops and the last few Khmer Rouge insurgents. It is reached on foot by a newly cleared corridor that is barely a yard wide in places. Most of his neighbours are "retired" Khmer Rouge soldiers and may well have planted many of the mines themselves.
But they have no idea where. The landscape has changed so much. The district of Pailin, like much of Cambodia, was almost entirely forested 10 years ago. Now Pailin is mostly fields. The hardwoods have been felled and exported, mostly illegally. The thoughtless destruction of the forests (together with gem and petrol smuggling, bribery and unofficial taxes) has made government, police and army officials in Pailin, many of whom were the henchmen of Pol Pot's Brother Number Three, Ieng Sary, immensely rich. Even the most modest of cafes in town are furnished with timber tables that would be worth a fortune in Europe. The villagers have not benefited, though, from the regime's sanctioned lawlessness. "Cambodia exports its wood and imports its toothpicks," one of them comments drily. All the farmers have to show for the rape of the landscape are semi-fertile fields, rotting trees stumps, and mines.
Chea Doeurn, who is one of the many new immigrants who have come to these remote and risky borders because there is no shortage of smallholdings to squat and farm, recounts the story of a near neighbour who lost his right leg incrementally — ankle, knee, thigh — in three separate explosions. His daughter, Chek Dany, shudders to hear of it. "Malaria is not our most frightening problem," she says, though she has suffered from the disease four times in the five years since her family arrived in Pailin, probably because as an outsider she has little immunity to it. On one occasion, she was so ill that she reached what she calls "a staring coma". Now, as MSF's "village face", she offers malaria advice, diagnosis and treatment to most of the 370 inhabitants within her district. But she has yet to dare to visit some of her nearest neighbours because the ground between them is so full of landmines. "I think a lot about the danger when I am working," says Chea Doeurn, sitting on the decking of his house-cum-shop where he sells vegetables and glasses of home-brewed rice spirit which — as I can verify — must have caused some "staring comas" of its own, "but I have to farm the fields because I am a poor man. I am more frightened of hunger than I am of the mines."
The good news is that thanks to the work of MSF and its village volunteers, at least the killer form of malaria is retreating from their lives. The 2003 prevalence survey found 7.8% of these rural populations positive for P falciparum (and showed that 5% of the countless millions of mosquitoes were carriers). In 2004 the "positive" figure was down to 3.7%. Already the 2005 surveys are indicating a heartening prevalence of less than 1.4%. Certainly, in the two communities of the mass screening, those few villagers reporting malaria-like symptoms on this occasion and judged symptomatic when examined physically are few and far between. Most people are marked by ink pen on their arms with an ID number and a blue A for Asymptomatic (clear of disease). Of this overwhelming majority, only those pregnant women needing iron tablets, or children who require deworming, or anyone with a rash, an infection or an abrasion is sent to Raden Srihawong for treatment. But the few who are sporting the red S of Symptomatic proceed to another set of blood tests and Parachecks. Among them is No 191, an 11-year-old boy called Phan Mol who suffers from malnutrition. He weighs a little over three stone, less than a healthy five-year-old. He is stoical when Raden examines him. But Phan Mol, like most of those marked S, is lucky. He has the less dangerous P vivax. Raden dispenses the chloroquine there and then.
No 67, Uong Virakk, is less fortunate. As the red PF(+) mark on his forearm indicates, he has P falciparum and is very ill. He lies on his back under yet another battery-driven television set. He is nauseous, shivering, struggling to breathe. No 82, a three-year-old girl, is PF(+) also. So are numbers 107 (a pregnant 22-year-old), 149 (a young farmer), and 26 (an elderly woman, recently widowed, who has come to the village to live with her daughter and has not been exposed to malaria before). Out of almost 600 villagers tested, only these five have been in any danger from fatal malaria. In three days' time, after their courses of artemisinin, they will be cured.
Here, for once, is evidence of a medical success story. Indeed, I myself have cause to be grateful to MSF and its efficient strategies. Two weeks after my exposure to the mosquitoes of Pailin and back home in Birmingham, I begin to sweat and shiver. Every muscle in my body aches. I prick my fingertip and carry out the simple Paracheck that all the village volunteers offer to their symptomatic patients. I show negative for P falciparum. It's vivax again. Raden Srihawong has sent me home with all the treatments and I am well again within a few days.
