THE world is losing the fight against malaria. That is the grim picture painted by a series of reports on the disease鈥檚 social and economic burden. What鈥檚 more, countries are failing to switch quickly enough to the best treatments as the parasite develops resistance to widely used drugs.
But despite the grave news, some experts believe we are better placed to tackle the disease than ever. With a better understanding of malaria鈥檚 costs and the best ways to combat it, researchers believe they can provide more accurate advice to governments.
鈥淲e are learning from history,鈥� says Melinda Moree of the Program for Appropriate Technology in Health, based in Seattle, Washington. 鈥淭here is long-term horizon planning going on that I haven鈥檛 seen before,鈥� she says.
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The analyses are published in a supplement of the American Journal of Tropical Medicine and Hygiene (vol 71, supplement 2). They claim that more than half of the world鈥檚 population is exposed to malaria, an increase of nearly 10 per cent in the past decade. This will cut economic growth in malarial regions by more than 1 per cent per year.
Mortality from the disease in Africa alone may be approaching 3 million annually, almost three times World Health Organization estimates. The discrepancy is partly the result of the WHO using government figures that are often not based on effective monitoring or are understated for political ends. Nigeria in 2000, for example, only reported 58 deaths from malaria. Neighbouring Niger with one-tenth the population reported over 1000 deaths.
In many African countries only a little over half the children with suspected malaria receive treatment. And of those, 84 per cent get chloroquine, even though resistance is rife. 鈥淚n many parts it is practically ineffective, no better than a sugar pill,鈥� says Ramanan Laxminarayan of Resources for the Future an independent research institute in Washington DC. Chloroquine treatment is ineffective in around half of cases.
Some places with chloroquine resistance are considering altering official guidelines to recommend sulfadoxine-pyrimethamine (S/P) drugs as first-choice treatments. At 20 to 25 cents per dose these are only around twice as expensive as chloroquine. But resistance is already developing and the WHO now recommends artemisinin combination therapy (ACT).
However, ACT is much more expensive ($1 to $2.50 per dose) and some governments doubt that an early shift is worth the extra cost. But analyses of the social and economic burden of malaria suggest that delaying the switch is ultimately a false economy. Laxminarayan, for example, created a mathematical model to compare the economic impact of switching directly to ACT with moving first to S/P drugs (supplement 2, p 187).
He factored in the burden of disease, including lost working time, learning time and deaths, plus the cost of administering ineffective drugs. Laxminarayan says the costs of failing to switch immediately to ACT are huge because many will die as resistance grows.
Even where resistance to chloroquine is initially low, an early switch would still be cost-effective in the long term, according to an analysis by Anne Mills, an economist at the London School of Hygiene and Tropical Medicine and her team (supplement 2, p 179).
But artemisinin treatments may also fail if the drug is not used properly. Worryingly, artemisinin is currently being given widely on its own because only one combination therapy in a single pill has been licensed. 鈥淭his would really jeopardise the effectiveness of this valuable drug,鈥� says Laxminarayan. 鈥淚t has a very high chance of developing resistance.鈥�
Even when experts agree on the best course of action, making it happen is another question. For example, the WHO-sponsored Roll Back Malaria Partnership pledged in Abuja, Nigeria, in 1998 that 60 per cent of African children should be sleeping under mosquito nets by 2005. But in 2001 (the best available data) only 2 to 15 per cent of children were using nets. 鈥淚t is not that likely the Abuja target will be met,鈥� says Eline Korenrompe of the Roll Back Malaria group at the WHO in Geneva.
