Widespread distribution of mosquito nets and a new medicine sharply reduced malaria deaths in several African countries, World Health Organization researchers reported Thursday.
The report was one of the most hopeful signs in the long battle against a disease that is estimated to kill a million children a year in poor tropical countries.
"We saw a very drastic impact," said Dr. Arata Kochi, chief of malaria for the W.H.O. "If this is done everywhere, we can reduce the disease burden 80 to 85 percent in most African countries within five years."
There have been earlier reports of success with nets and the new medicine, artemisinin, a Chinese drug made from wormwood. But most have been based on relatively small samples; this is the first study to compare national programs.
"This is extremely exciting," said Dr. Michel Kazatchkine, executive director of the Global Fund to Fight AIDS, Tuberculosis and Malaria. "If we can scale up like this everywhere, we should be able to eliminate malaria as a major public health threat in many countries."
The report was done by a team from the World Health Organization for the Global Fund, the chief financing agency for combating malaria. It looked at programs in four countries that tried to distribute mosquito nets to the families of every child under 5, and medicines containing artemisinin to every public clinic.
In Ethiopia, deaths of children from malaria dropped more than 50 percent. In Rwanda, they dropped more than 60 percent in only two months.
Zambia, Dr. Kochi said, had only about a 33 percent drop in overall deaths because nets ran short and many districts ran out of medicine. But those areas without such problems had 50 to 60 percent reductions, he said.
Ghana was a bit of a mystery, according to the report. It got little money from the Global Fund, Dr. Kochi said, and so bought few nets and had to charge patients for drugs. Malaria deaths nonetheless fell 34 percent, but deaths among children for other reasons dropped 42 percent.
Holding drives to distribute insecticide-impregnated nets is a growing trend, now that the Global Fund, the President's Malaria Initiative, United Nations agencies, the World Bank and private fund-raisers like AgainstMalaria.org have offered hundreds of millions of dollars. Such drives must be continuous because "permanent" nets wear out after three to five years.
The report, finished in December, was an effort to find hard data, which has long been a problem with malaria, especially in rural Africa, where anyone with fever is often presumed to have malaria and medical records scribbled in school notebooks are rarely forwarded to the capital. For this study, researchers tallied only hospitalized children whose diagnoses were confirmed.
Rwanda, a small country that handed out three million nets in two months in 2006, had 66 percent fewer child malaria deaths in 2007 than in 2005.
Ethiopia, much larger, took almost two years to hand out 20 million nets; it cut deaths of children in half.
In Africa, malaria is a major killer of children, but so are diarrhea and pneumonia, which have multiple causes, as well as measles, which has been declining as the Global Alliance for Vaccines and Immunization has expanded.
Until the recent infusions of money from international donors and the reorganization of malaria leadership at the W.H.O., the fight against malaria had been in perilous shape, with nets scarce, many countries using outdated or counterfeit medicines, spraying programs dormant and diagnoses careless.
Even the most commonly cited mortality figure — one million deaths of children a year — has always been no more than an educated guess.