Tough Choices – DDT or Malaria?
The organochlorine compound DDT (Dichloro-Diphenyl-Trichloroethane) was first synthesized in 1874, but its insecticidal properties were not discovered until 1939 by the Swiss scientist Paul Muller, who was awarded the 1948 Nobel Prize in Physiology and Medicine for his efforts. DDT kills by opening sodium ion channels in insect neurons, causing the neuron to fire spontaneously. This leads to spasms and eventual death. Insects with mutations in their sodium channel gene or with up-regulation of genes expressing cytochrome P450 may become resistant to DDT and similar insecticides.
In the early years of World War II DDT was used with great effect to combat mosquitoes spreading malaria, typhus, and other insect-borne human diseases among both military and civilian populations. After the war, DDT was made available as an agricultural insecticide, and its production and use skyrocketed.
In 1955 the World Health Organization began a program to eradicate malaria worldwide, relying largely on DDT. Though this effort was initially highly successful (reducing mortality rates from 192 per 100,000 to a low of 7 per 100,000), resistance soon emerged in many insect populations as a consequence of the widespread agricultural use of DDT. In the 1960s, the environmental impacts of indiscriminate spraying of DDT became known. As a persistent organic pollutant, DDT accumulated in the food chain and had severe effects on fish, amphibians, birds, and rather less well known impacts on mammals, including humans. DDT can still be found in the fat reserves of polar bears, penguins, and possibly you, thousands of miles away from where it was ever sprayed. In 1987 the US EPA classified DDT as a probable human carcinogen. DDT is also known to be an endocrine disruptor and to cause developmental problems in infants.
In the 1970s and 1980s, agricultural use of DDT was banned in most developed countries, in 1970 in Scandinavia, 1972 in the USA, but not until 1984 in the UK. The Stockholm Convention which came into effect in 2004 outlawed several persistent organic pollutants, and restricted the use of DDT to the control of insect vectors of human diseases. After these bans, the populations of many severely threatened species, such as the American bald eagle, rebounded.
In September 2006, the World Health Organization announced that DDT will be used as one of the three main tools against malaria, and recommended indoor spraying in epidemic areas and places with high malaria transmission. USAID now funds the use of DDT overseas. DDT sprayed inside a home provides protection from mosquitoes for up to six months. New studies show that despite mosquito resistance to DDT, it also acts as a powerful insect repellent.
Malaria afflicts between 300 million and 500 million people each year. The World Health Organization estimates that around 1 million people die of malaria and malaria-related illness every year, with 90% of these deaths in Africa, mostly in children under the age of five. To put that in perspective, that is equivalent to the death toll of around ten of the nuclear bombs dropped on Hiroshima during World War II. Malaria also weakens the economies of poor countries. People who become infected cannot work or die. Infected children can suffer brain damage. The World Bank estimates that malaria costs Africa more than US$100 billion annually and this cost is growing by 1.3 per cent each year. In 2004, when Uganda publicly contemplated reintroducing DDT to fight malaria, the European Union made threats that the country’s US$32 billion agriculture exports could be at risk if tough new measures were not taken to ensure DDT residues did not find their way into food crops.
As a result of the WHO program, the number of African countries spraying DDT inside houses has exploded. Eritrea, Madagascar, Ethiopia, Swaziland, Senegal, Ghana, Angola, South Africa, Mauritius, Mozambique, Zimbabwe, Namibia, Zambia and Burkina Faso are all using the chemical. Uganda, where more than 100,000 people died from malaria in 2006, began spraying it this year in a pilot project, and Tanzania and Malawi may follow. But Rwanda, Burundi and Kenya (a major producer of pyrethrum, the main alternative to DDT) are so far refusing to adopt the use of the chemical. In 1995, South Africa stopped spraying DDT to control malaria, citing international pressures, but as soon as the ban started, the incidence of malaria rose.
DDT is cheap. Safer pyrethrum-based insecticides are 20 times more costly, often too expensive for developing countries. The price of controlling malaria in Africa has been estimated at US$1 billion per year, but foreign aid targeting the disease has never topped US$200 million.
So my question to you is this: imagine you are the president of the world, but with a limited budget. What would you do?
Related:
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- Malaria is a continuing danger to UK travellers
- Africa Malaria Day 2007
- Malaria: now you see me, now you don’t
Tags: Africa, American bald eagle, amphibians, Angola, birds, Burkina Faso, Burundi, cytochrome P450, DDT, diseases, endocrine disruptor, Eritrea, Ethiopia, fish, foreign aid, Ghana, Hiroshima, humans, insect, insecticide, Kenya, Madagascar, Malaria, Malawi, mammals, Mauritius, Mozambique, Namibia, neurons, Nobel Prize, organochlorine, penguins, polar bears, pyrethrum, resistance, Rwanda, Senegal, sodium ion channels, South Africa, Stockholm Convention, Swaziland, Tanzania, Uganda, USAID, World Health Organization, Zambia, Zimbabwe
I’d listen to the environmentalists who preserved the usefulness of DDT by stopping its overuse, and I’d pay attention to the public health people who point out that DDT is not so effective as you claim, and who argue that we need mosquito nets for people to sleep under.
An effective malaria control program needs first, an effective health care system that can treat malaria victims quickly and completely — much of Africa and Asia lack such health care. Second, it requires that mosquito abatement programs be used appropriately, for the species of mosquito, for the species of the malaria parasite, and for the area. Mostly this involves time-consuming but inexpensive programs to drain water traps around homes where people live. Third, there needs to be a lot of education, to educate people to stay indoors and away from mosquito-infested areas at times the bugs are active, to train them how to avoid getting bitten, to teach them to seek effective medical care if they get infected. And fourth, an effective program generally requires effective barriers to biting mosquitoes — walls, windows, doors, screens and mosquito netting over beds.
DDT can be a part of an effective fight against malaria. Most often, there will be other chemicals used instead, or in addition.
DDT is no panacea. It doesn’t fight malaria. It kills some mosquitoes, sometimes. DDT alone is ineffective and destructive. DDT carefully and wisely used, in an integrated program of pest control, can be a good tool.
Free mosquito nets would be the single best, cheapest thing to do to stop malaria. DDT would not even be in the ballpark.
I live in a Middle Eastern country where most people neither sleep under mosquito nets, nor use screens (although screen “material” is easily and cheaply available here. But people don’t like how screens “look” on their windows, and I even find the same prejudice from my European friends (I’m American). If they use anything at all, richer people here use chemical repellents that they plug in electrically, that dispense something into the air which has a “knock-down” effect on mosquitoes. (I never saw anything like this in America.) DEET repellents are completely banned in Europe,nor are they available in North African countries (who generally follow Europe). When I visited South Africa in 1980, DEET-based repellents were available there–I don’t recall if they were available in Central and East Africa when I visited there, but I’m thinking that they were.
Madame Monet
winewriter.wordpress.com
I live in Burkina Faso, where malaria is a big big problem seasonally. For a long time I was against DDT but have changed my opinion now, and believe that, if used discretely as part of a multi-pronged approach, its benefit outweighs the potential harm (I wrote on this in 2005 <a href=”http://www.voiceinthedesert.org.uk/keith/archives/2005/04/africa_malaria.html” here.
While I appreciate Ed’s suggestions, most are impractical in Burkina in the lifestyle that people live. I agree that treated mosquito nets are the biggest positive thing that can be done, but that they should be used as part of a co-ordinated strategy at different levels.
cheers
I read all these writting, I am afraid about my country and all the countries suffering from this malaria. I don’t understand Africans government program malaria. The only solution for Malaria is to avoid mosquitoes sucking.How to avoid it? It is ease, destroy mosquitoes by spraying the DDT in the first time, and then involve the community to control the settings where the mosquito is developing.Finally, sanitation is provided by government for each citizen, and each citizen where he lives, must surveille the outbreak of mosquitoes. Collaboration between population and local authorities must be straight for the malaria fighting.International Organizations must be take its own responsabilities to tell the truth at these developing countries.
fEW COMMENTS.
Some of developed countries have eliminated malaria in their country. The first idea which become in my mind, is International organization know this.It knowns the process that permitts to eliminate the mosquitoes, Why couldn’t apply this process in africa? In the second time, African government known very well that others countries could eliminate the mosquitoes, Not Bed nets and so many drug using.Why actually,they want to use bed nets and toxic drug to fight malaria? Understanding when these DEVELOPING COUNTRIES will use DDT, they are polluting Environment.
Make the balance Died by the mosquitoes and …. these countries continue to use DDT, Last outbreak mosquitoes in USA,What US used DDT or WHAT?
BE SERIOUS MY friends, tell us the TRUTH. how did you fight mosquitoes.
[...] Tough Choices – DDT or Malaria? [...]
[...] Tough Choices – DDT or Malaria? [...]
[...] Tough Choices – DDT or Malaria? [...]
Alright I’ve read the article and the responses to the articles. However, having read the last Kabore Talato I realize that it’s important for someone to understand simple things mainly geography. You see I live in America and I can tell you that if we had a mosquito problem our method for treating it would be different than one effective in Africa because of weather and over all climate differences. Finally, it bothers me a bit that the international community looks to America for solutions and in many cases(not all) we aren’t given any credit. We do help the world and give more than any other country in the world, but still we are looked upon like a baby sitter whose life revolves around solving other people’s problems. In short, America helps as much as possible but we can not just stop and focus on curing the world. After all we must also survive!