It is 8am on Monday morning, and already hot in Tréguine, a Red Cross-run refugee camp of 14,500 people in eastern Chad, near the border with Sudan.
A dozen women carrying small children sit on mats on the concrete floor of a large hangar. A merciful breeze ruffles their robes as they wait for the therapeutic nutrition clinic to open.
In a short time, nine volunteers, themselves refugees from the conflict in the Sudanese province of Darfur, set up a series of posts which the women and children will visit in turn. First, the volunteers register the children, all aged six months to five years, measure their upper arms, weigh them, check their height and take their temperature.
Then children who need them are given vitamins, minerals and high-energy food. Youngsters with other medical conditions are referred to the medical centre a few metres away.
It soon becomes clear that many children of the 70 children brought to the clinic on Monday need help. Most are too small and too light for their age.
"We know lots of children are malnourished," says Bernard Batsala, a nurse, nutritionist and social assistant who is overseeing the centre as a part of a Central African Regional Disaster Response Team (RDRT), whose members on this mission come from Red Cross societies in Congo, the Democratic Republic of Congo and Benin. This multi-disciplinary medical team has been in place since December 2004.
Many factors contribute to malnutrition, says Bernard, above the din of a dozen crying babies and toddlers: "People are poor and can't afford to buy much food. Often the mothers who are breast-feeding don't eat well themselves."
Refugees are given a narrow range of foods, with no fresh fruit or vegetables. The staple, boule, is a dumpling made of flour of sorghum. People are not used to eating fruit such as the mangoes and guavas that grow nearby.
Families often eat from the same big plate, with older children sometimes taking the lion's share of the food.
In addition, some deliveries of rations by the World Food Programme have been delayed due to administrative, military and customs formalities in other countries. In February, only half the usual ration of sorghum arrived, causing further hardship.
Supply problems have now been ironed out. But they might have had an effect on children's health.
To make matters worse, poor hygiene can lead to diarrhoea, which deprives the body of nutrients. Furthermore, some children have diseases that limit the absorption of vitamins and minerals.
Children registered at the clinic return every week until they gain weight. As they build a relationship with the mothers, Red Cross workers can pass on general messages about health and hygiene.
The day after the nutrition clinic, Djouma Ahamat Gamaradine, 28, a refugee and Red Cross volunteer, visits the homes of four children who are registered but failed to attend.
A father of four, including four-year-old twins, Djouma loves children.
"I myself am a refugee and I want to work to help mothers and fathers," he says. "Sometimes I think the mothers who bring their children to the centre suffer more than the children. But in a week or so, the babies can be much healthier. That's a good feeling."
Today he has a hard time with little Mahasine Adam, aged two. She sits passively on her mother's lap, breathing laboriously. When her mother, Khadidgé Souleman, lifts her, we can see her hip bones. Her upper arms, at just 10 centimetres' circumference, show that she is severely undernourished.
The best solution would be to take her to hospital for emergency feeding, says Djouma.
But Khadidgé is not convinced. She has been bringing Mahasine, her only child, to the nutrition centre for three or four weeks, without seeing any improvement. Mahasine won't eat the corn, soya and bean mix. And her mother's milk has now dried up.
Finally Djouma persuades Khadidgé and her husband to at least take Mahasine to the health centre. Perhaps they can find something to help her, such as baby formula.
Some children need more help than others. In Tréguine, over the past three months four mothers have died in childbirth, leaving their babies extremely vulnerable to malnutrition.
The oldest of these four children is now three months old, yet weighs just 2.5kg.
Sometimes a woman is found who is willing to breastfeed a motherless baby. In this case, it is important to support her so she can feed both her own child and the newcomer.
Another option is to provide cow's or sheep's milk for the motherless baby. However animals are not under the care of a veterinarian and could transmit diseases to the child.
Health workers also try to address the root cause of women dying in childbirth by urging women to get health care early if there are complications.
The Red Cross is sure there are other children in the 14,500-strong camp who need nutritional help. To track them down, members of the team will go out into the camp.
"We will be going from tent to tent, measuring every child," says International Federation community health delegate Carmen Rodriguez Escobar, a former nurse.
"This will give us a chance to ask mothers to bring their children to the clinic every week. In addition, the exercise will give us a much more accurate idea of children's nutrition."
The situation looks set to remain difficult for the refugees, since it is not yet safe for them to return to their homes in Darfur, some 50 km away. While they are staying in Chad, the refugees have few opportunities to improve their lot, says Bernard.
"No one has the land to cultivate vegetables or grow a fruit tree. There is just a small piece of land along the wadi (dry riverbed) for farming. Not everyone has a tree so there is not enough fruit. To eat a fruit is a luxury, you could say. Even the animals are thin."
Yet malnutrition is a risk for local people living in the dry villages around the camp too. In the nutrition clinic in Tréguine camp, Halima Brahim, 19, sits cross-legged on the floor while a Red Cross volunteer puts a thermometer under the armpit of her 11-month-old son, Zamzam.
Halima and her family live in Hadjer Hadid, the nearest town to the camp. Zamzam, who hides his face in his mother's dress when strangers come close, has had problems with his digestion and his eyes. But Halima has been bringing him to the clinic for several weeks, and says his health is improving.