As the rainy season took hold, the illnesses spread. Jeanne Mbwisha saw children in her village with fevers. She saw children vomiting. She became afraid for her own six children.
Then her daughter, Seraphine, fell sick. She took her to the village clinic for treatment, but the illness deepened, week after week. At last she scraped together some money and took her daughter to the city. Only an emergency blood transfusion saved her life.
Doctors confirmed that Seraphine had severe malaria. Like thousands of other Congolese children, she had fallen victim to a massive resurgence of malaria that has baffled scientists and raised doubts about the global fight against the deadly scourge.
Bad news on malaria has been mounting worldwide this year. A new study concluded that the global malaria toll is much higher than previously believed. Malaria-carrying mosquitoes were found to be showing greater resistance to insecticide in 64 countries. And in parts of Southeast Asia, the malarial parasite has developed resistance to the main treatment drug, artemisinin.
At a time when malaria was believed to be in decline, the number of malaria patients has soared by a stunning 250 per cent in the Democratic Republic of the Congo since 2009, according to statistics at clinics run by Médecins sans frontières (Doctors Without Borders).
Malaria is already the single biggest killer in Congo, with nearly 200,000 people dying annually, and now the trend is worsening. At one clinic in Katanga province alone, nearly 25,000 people were treated for malaria last year – more than triple the number in 2009.
In another district of the same province, MSF set up an emergency centre for malaria treatment this year, expecting 1,000 patients a week. Instead the clinic has been flooded with 3,000 patients a week since the end of March – in a district of just 218,000 people. It had to airlift medicine into the district to cope with the outbreak.
"It's completely shocking," said Andrew Mews, head of the mission in Katanga for MSF Holland. "We were overwhelmed by the sheer numbers."
Malaria outbreaks are normally worst in the rainy season, when mosquitoes breed in the water. But this year, with southern Congo already several weeks into the dry season, there is no sign of a slowdown in the malaria surge.
Nobody knows why the malaria rate has skyrocketed. Some of the increase is due to population displacement: refugees fleeing from wars and economic migrants in search of jobs. Often they move unwittingly into malarial zones, unprepared for the risks. In eastern and southern Congo, where fighting has increased this year, many people are forced to take refuge in swamps and forests where mosquitoes breed.
But this explains only some of the increase. The other causes are unknown and MSF is planning several studies to investigate. There is speculation that drug resistance could be rising.
"The truth is, we really don't know," Mr. Mews said. "Are there more mosquitoes? Maybe the mosquitoes are more virulent? Are people becoming more susceptible to the disease? Malaria is a very old disease, but we still don't fully understand it."
For years, the world seemed to be making progress against malaria, with a reduced death rate and a recent breakthrough on a potential vaccine. But based on his own observations in several African countries, Mr. Mews is skeptical of the official claims. He has seen dramatic increases in malaria in countries such as Congo and the Central African Republic.
A study published this year in The Lancet, the British medical journal, concluded that the malaria toll has been hugely underestimated. It calculated that 1.2 million people worldwide are dying from malaria annually – far higher than previous estimates of 655,000. More than 90 per cent of the deaths are in Africa.
Despite decades of research on how to treat and prevent malaria, there are still barriers in many poor countries. Some Christian sects in Congo, for example, are strongly opposed to blood transfusions, which are crucial for saving lives in severe malaria cases. This has led to the deaths of many children, experts say.
There are also financial barriers. The $3 cost of a mosquito net can be a deterrent to poor families that earn only $1 a day. "If they have to choose between food and a mosquito net, they choose food," said Kalil Sagno, head of child survival for UNICEF in Katanga and two other provinces.
Even when they receive a bed net, some families don't understand how to use them. Jeanne Mbwisha, for example, decided that her family's sole bed net should be used to protect her and her husband – even though her children were far more vulnerable. "People don't realize how important the nets are," said Mutombo Musau, head of pediatrics at a hospital in Lubumbashi, where 11 of the 12 children in his wards had malaria.
To combat the disease, 13.7 million mosquito nets will be distributed across Congo this year by UNICEF and other groups. It will be a massive task, involving planes, trains, boats, trucks, bicycles and workers on foot. Television and radio messages will educate villagers on how to use the nets properly.
It's the first time anyone has attempted a universal bed-net distribution in Congo – one of the biggest, poorest and most chaotic countries in Africa. "We didn't invest enough in malaria in the past," Mr. Sagno said.