Stories tagged DDT

Researchers at the University of South Florida recently found that the fungicide chlorothalonil, in the same family as DDT, killed almost 90% of the frogs exposed to it. They tested several species of frogs, and all had the same reaction. They are now testing the chemical's mortality rate for other organisms, including bees.


So I'm surfing the web and I come across an item about DDT use in Africa. If it's true, then this is the kind of thing that really frosts my shorts. But, as the blogger notes, the item has only appeared in a couple of fringe outlets. Not that I consider the MSM the font of credibility. But I've already been taken to task for the Space Camp Barbie post, so it would be nice to have verification.

Anyway, according to this report, a Dutch textile firm is refusing to buy cotton from parts of Uganda which use the chemical DDT to combat malaria. Malaria kills up to 100,000 Ugandans every year. DDT effectively controls the mosquitoes that spread the disease.

But DDT has a downside -- it gets into the environment and poisons fish, birds and other wildlife. For this reason, it has been banned in the US and other Western countries for more than 30 years.

Countries that use DDT today don't spray food crops. They use small, safe amounts and generally confine its use to indoors, protecting people from malaria-ridden mosquitoes.

But this apparently is not good enough for the Dutch. According to the report, the company is refusing to buy cotton from areas that use DDT, claiming the crop is no longer "organic." As a result, farmers from those areas cannot sell their cotton at full price, and are losing money.

Basically, European eco-purists are giving African farmers a choice: avoid DDT and die of malaria, or use DDT and die of starvation. The Euro-elites, of course, face neither of these fates.

Like I said, this is based on just one report. It would be nice to get independent confirmation.


Red blood cells infected with Plasmodium falciparum: This thin film Giemsa stained micrograph reveals ring-forms, and gametocytes of Plasmodium falciparum.
Red blood cells infected with Plasmodium falciparum: This thin film Giemsa stained micrograph reveals ring-forms, and gametocytes of Plasmodium falciparum.Courtesy cdc

  • Malaria is both preventable and curable.
  • A child dies of malaria every 30 seconds.
  • More than one million people die of malaria every year, mostly infants, young children and pregnant women and most of them in Africa.

A recent article in the NY Times discussed if it is possible to eliminate malaria. They need more money, better health systems and a vaccine. Some experts feel the big push to eradicate malaria is counterproductive or even dangerous. Dr. Arata Kochi, the W.H.O. malaria chief stated in the article that, “… enough money, current tools like nets, medicines and DDT could drive down malaria cases 90 percent. But eliminating the last 10 percent is a tremendous task and very expensive.” He doesn’t want people to have false hope.

A new vaccine
In spite of the debate, research is progressing to reach the goal of eliminating malaria. The Seattle Biomedical Research Institute (SBRI) is home to one of the largest malaria research programs in the United States. SBRI's Malaria Program is focused on vaccine discovery for malaria during pregnancy, severe malaria in children and liver-stage malaria. SBRI scientists are working on a vaccine that uses genetic engineering to render malaria parasites harmless. According to an article in the Seattle Times SBRI is looking for volunteers to be bitten by malaria-infected mosquitoes to aid in the quest for new vaccines and drugs. Scientists will analyze blood from the human volunteers to learn more about the body's immune response to the disease.

What do we do?
Economists believe that malaria is responsible for a ‘growth penalty’ of up to 1.3% per year in some African countries. When compounded over the years, this penalty leads to substantial differences in GDP between countries with and without malaria and severely restrains the economic growth of the entire region. Malaria costs Africa $12 billion every year in lost productivity alone.

What do you think? Where should we be putting our resources?

  • Developing a vaccine (the Bill and Melinda Gates foundation alone has spent $258 million
  • More money to distribute long-lasting insecticidal nets (each net costs $5-7)
  • Mosquito control with indoor residual spraying like DDT (costs nearly $4 per person)
  • Getting effective drug treatments to the infected (effective therapy costs $2.40 for a round of treatment)

Rachel Carson, inspiration for the modern environmental movement: Photo from US Fish & Wildlife Service
Rachel Carson, inspiration for the modern environmental movement: Photo from US Fish & Wildlife Service

Today is the 100th anniversary of the birth of Rachel Carson, whom many credit as the inspiration for the modern environmental movement. Her 1962 book Silent Spring warned the world of the dangers of environmental degradation, especially due to the overuse of chemical pesticides. The book stirred millions of people worldwide to take action. In the United States, we saw the passage of the Clean Air Act, the Endangered Species Act, and the establishment of the Environmental Protection Agency – all the result of the movement Carson inspired.

Today, our air and water are cleaner thanks to these actions, and dangerous chemicals are more closely regulated. But some people are re-evaluating Carson’s legacy, especially with regards to the pesticide DDT. Carson explained how insects absorbed the poisonous chemical. Birds which ate enough insects often died themselves, or would have trouble hatching eggs. Carson promoted restricting the use of DDT.

However, some of her followers went further, pushing for a total ban of DDT in many countries. Unfortunately, DDT is extremely effective at killing mosquitoes that spread malaria – a disease that kills some one million people each year. Responsible, limited use of DDT could save millions of lives.

(Science Buzz has discussed malaria here and here,and the possible effects of preventative measures such as mosquito nets, drugs, and genetic engineering.)

Carson’s legacy reminds us not only of the importance of protecting our environment, but also that one person can have a tremendous impact. It also reminds us that even the best ideas can have unintended consequences, and any major changes need to be undertaken in a balanced, rational and flexible manner.