Originally posted at Dean’s World here.
Last week scientists met to discuss the eradication of Malaria. This comes just after the appearance of two articles in popular science magazines New Scientist and Scientific American.
How the World Left Malaria Off the Hook, by Fred Pearce documents the failure of the world community to stop the malarial parasite during the 1950s and 1960s. He attributes the failure to a combination of aid cuts by the US congress, overconfidence over the control of the disease and its vectors, and the demonization of DDT by environmentalist groups. Pearce notes, "environmentalists were as determined to ban DDT as doctors had once been to banish malaria. In 2001, the pesticide appeared on a list of 12
toxic industrial chemicals that were to be banned worldwide under the Stockholm Convention on Persistent Organic Pollutants." Fears that DDT would breed resistance were unfounded because DDT not only killed mosquitoes, it repelled them. "Roberts has also now shown that DDT is uniquely effective in banishing malaria not because it kills mosquitoes but because it repels them. He published these findings in August this year – but notes that the observations were first made in 1953 by the entomologist Robert Muirhead-Thomson. (link)"
Jeffrey Sachs takes a more political correct view of malaria, writing DDT’s "function as an insecticide in open fields (which is environmentally
unsafe and promotes resistance) also curtailed use of the chemical," while ignoring the fact that countries banned the pesticide and refused to fund its use at all in the developing world.
His solution? Free bed nets and cheap drugs. While both are part of the solution, cheap drugs such as chloroquine have been in use for decades. The result? Most malaria parasites have some degree of chloroquine resistance. While artemisinin therapy is relatively cheap, there is already concern about the development of resistance to the wormwood-based drug, so the WHO and CDC recommend its usage in combination with other anti-malarials in order to minimize resistance.
Treatment is $1/day – which doesn’t sound like much until you realize that in many regions that’s a day’s pay for a worker. However treatment consists of six doses – so that’s six days of wages for one person. If the average worker is supporting 4 people, chances are that one of them will be sick with malaria at any given time – so that theoretically leaves the worker broke after paying for malarial treatments. Jeffrey Sachs is an economist. He should have known better.
Here’s another problem. Have you ever slept under a bed net in the tropics? The holes are tiny but effective at keeping out any breeze, thereby making sleep under one uncomfortable. Since the mosquitoes that carry malaria are most active at night, insecticide-treated bed nets have been proven to significantly reduce morbidity in children. They are an important part of the fight against malaria, but they are only one weapon in an arsenal that we must deploy against a disease that kills 1,000,000 children a year and sickens as much as a tenth of the world’s population.
In Tanzania, people are extremely social and tend to meet and congregate outside at night. Burning mosquito coils and citronella candles as well as wearing repellents and protective clothing would go a long way to cutting down the incidence of malaria. Other weapons include environment management strategies that seek to change the conditions the mosquito needs in order to pass along the malaria parasite. These strategies involve the local people organizing to removing weeds from irrigation canals and clean up debris that could fill with water and provide mosquitoes places to breed: "In Kampala, brick pits, tire ruts and puddles were the predominant
sites favored by the major malaria vector, Anopheles gambiae s.l.." In Malawi, a Habitat for Humanity project where mud and thatched roof huts were replaced with houses made from brick and tile not only cut the incidence of malaria, but also respiratory illness and diarrhea in children. A study conducted jointly by Boston and Harvard Universities in conjunction with the Ethiopian Ministry of Health and Ethiopian Institute for Agricultural Resources found that changes in the maize cultivation practices can control the mosquito population based on the discovery that mosquito larvae prosper on maize pollen.
All of these grassroots efforts involve the local people actively participating in their own protection instead of passively relying upon aid from the national government or international relief organizations. Because the locals are involved in their own security, they are much more likely to continue these practices after the aid money and has dried up and the attention of the international community has shifted elsewhere.
A vaccine is the Holy Grail for those fighting malaria. Currently the best candidate is RTS.S, a vaccine funded by GlaxoSmithKline and the Gates Foundation’s Malaria Vaccine Initiative. While this vaccine is only 50% effective for children under the age of 18 months, it is the first vaccine to show any significant promise at fighting the disease. As GSK CEO JP Garnier points out in an article in The Times of London, the task is complicated by the disease’s multi-stage life cycle as well as its endemicity in regions with few medical resources and riven with linguistic and religious divides.
There is a lot of finger pointing at the environmental movement and Rachel Carson’s book Silent Spring that became its manifesto for succeeding in banning DDT, but Carson herself cannot be blamed for the DDT bans since she was not calling for a ban on its use in the fight against malaria, only on its use as a general pesticide for crops. While environmental groups have a responsibility to recognize their hand in the resurgence of malaria from the brink of eradication, and those who continue to call for the ban without scientific evidence to back up their claims should be held accountable for their positions, we must recognize that malaria is not really a single problem that will fall to a single solution. Instead, like cancer, it is a complex system that will only fall to a systematic and thorough approach involving all of the resources at our disposal.
Bed nets. DDT. Cheap Drugs. Grassroots efforts. A vaccine. All of these weapons and more must be brought to bear against a disease that kills a child every 30 seconds. To that end I am pleased to see Bill Gates take a personal interest in this fight. I’ll remember that the next time Windows blue-screens on me.