Widespread use of insecticide-treated mosquito nets and state-of-the-art drugs has succeeded in cutting malaria deaths in half in two countries most heavily affected by the disease, the World Health Organization is reporting today.
The findings from Rwanda and Ethiopia are the first to show a greater than 50 percent reduction in malaria mortality nationwide in "high burden" countries. Such dramatic reductions had been achieved previously only in smaller regions or in countries where the disease is less pervasive.
The results suggest what may be possible in dozens of other countries, and they are likely to spur efforts already underway to roll out the relatively low-cost measures.
Malaria is responsible for 2 percent of all deaths worldwide and 9 percent of deaths in Africa. Each year, about 1.1 million deaths — almost all in children — are directly attributable to the disease, and at least a million more occur from complications such as severe anemia. In Africa, where most cases occur, malaria costs $12 billion a year in medical expenses and lost productivity.
"This is the first time we have seen these results with the new tools," said Arata Kochi, head of malaria programs for WHO.
‘A genuinely historic achievement’
"This is a genuinely historic achievement," said Richard G.A. Feachem, former director of the Global Fund to Fight AIDS, Tuberculosis and Malaria who is now the director of the Global Health Group at the University of California at San Francisco. "This is not theoretical. We do not have to wait for a vaccine or new drugs. If we implement today's technologies aggressively on a national scale, we will have a big impact."
Two key items in the current "tool kit" are bed nets treated with insecticide that lasts as much as five years, and treatment with at least two drugs, one of them artemisinin, a compound derived from a Chinese herbal medicine.
The nets repel or kill mosquitoes and work even if they have holes in them. When used by 80 percent of households, the nets can reduce infections in African villages even among people who do not have them, a phenomenon similar to the "herd immunity" provided by vaccines. Artemisinin-containing therapies (ACTs) are oral drugs that work quickly and are often life-saving when the brain is infected by the malaria parasite.
WHO epidemiologists looked at the effect of nets and medicine in Rwanda, Ethiopia, Zambia and Ghana. Those countries' success in implementing the measures varied, and the drops in cases and deaths differed accordingly.
The most striking results were seen in Rwanda, in Central Africa, where an unplanned "natural experiment" unfolded in 2006.
That September, 3 million nets were given to households with children younger than 5 or pregnant women. The next month, artemisinin-based therapies were stocked in all public hospitals and clinics, where more than three-quarters of Rwanda's more than 9 million people get medical care.
Within two months, malaria cases and deaths were falling steeply. By 2007, the number of hospitalized children younger than 5 was 64 percent lower than in comparable periods in 2005, and deaths were 66 percent lower.
In Ethiopia, the drugs and nets were introduced in 2005, with each household getting one net for every two people. Hospitalized malaria cases in young children fell 60 percent and deaths 51 percent.
Indoor spraying with DDT or other insecticides — used in Rwanda at the end of the study period, and before and during it in Ethiopia — did not appear to be a factor in the steep, sudden declines.
Improvements were less dramatic in Ghana, where cases fell 13 percent and deaths 34 percent. That country could afford to give nets only to households with children younger than 2. It also had a new medical insurance program that had already given more people access to medical care, possibly dampening the decline in malaria deaths compared with previous years.
Zambia, where cases fell 29 percent and deaths 33 percent, did not finish distributing nets until late last year, and hospitals and clinics there frequently ran out of the artemisinin-containing drugs.
Data on cases and deaths came from the records of hospitals and outpatient clinics. The sites studied were widely scattered throughout the countries but not chosen at random. In Rwanda, for example, the researchers sampled two districts in each province, examining a total of nine hospitals and 10 clinics.
Benefits from striking quickly
Overall, the differences in results "reflect the scale of coverage of the intervention," said Wilson Were, a WHO researcher. "If we do this rapidly, we can save more lives than doing it slowly," he added.
The study was done at the request of the Global Fund, an independent organization headquartered in Geneva that collects money from governments, foundations and individuals, and distributes it to needy countries.
Since its founding in 2002, the fund has provided $3.6 billion for malaria programs in 85 countries. It commissioned the research to learn the effects of some of the interventions it financed. Its officials deferred commenting on the findings until they have studied them further.
While cheap, the items in the malaria tool kit are still out of reach for many high-burden countries, which are among the world's poorest. The insecticide-treated nets cost about $5.50 each, plus $2 to $3 for shipping and distribution. Artemisinin-containing drugs — generally taken twice a day for three days — cost about $2.50 for a course of treatment. The common alternative, chloroquine, costs about 20 cents but is less effective.
Consensus for widespread use
For a while, ACTs were reserved for severe cases, because of expense and fear that resistant strains of the parasite would emerge. There is now consensus that the drugs should be used in virtually all cases. Resistance to artemisinin is reportedly emerging on the Thailand-Cambodia border — the historical nursery for drug-resistant malaria strains — and WHO is looking into the matter.
Cutting malaria mortality by 50 percent is a goal of the President's Malaria Initiative, started by the Bush administration in 2006. As with its global AIDS program, the administration is targeting specific countries with its malaria effort, starting with three the first year, adding four more last year (including Rwanda) and eight more this year. It plans to spend $1.2 billion between 2005 and 2010.
Worldwide, spending on malaria has tripled in the past three years, according to the New York-based nonprofit group Malaria No More. WHO estimates that about $4.5 billion a year is needed to control and treat the disease. At the moment, about $1 billion is spent yearly by donor countries and about $600 million by countries where malaria is prevalent.