Thursday, October 25, 2007

Chikungunya Fever and Elephantiasis

Thanks to Rachel Carson and her misguided, unscientific book Silent Spring, these two diseases continue to cripple and kill millions in developing countries, after having been virtually wiped out in the 1960s and 1970s. They used to be controlled by DDT. Chikungunya, a virus spread by mosquitoes, means "bent over and unable to walk upright" has turned up now in the Ravenna area of Italy. It is endemic in some areas of Africa, Southeast Asia, and the Indian subcontinent. It is spread by mosquitoes.

Elephantiasis is caused by a parasitic worm, and affects more than 120 million people in 80 countries, and more than 40 million of them are severely incapacitated and disfigured by the diseases. A team of scientists seem to be close to mapping the genome of the worm. [both stories from JAMA, October 17, 2007]
    "Some of the diseases controlled by DDT included typhus, plague, malaria, yellow fever, sleeping sickness elephantiasis, leishmanisasis, river blindness, Oroya fever, other fevers and dysentery (transmitted by domestic flies). Many kinds of animals were protected by DDT from envenomization and parasitism by arthropods. It also killed blood-sucking parasites of birds, thereby reducing deaths from avian malaria, encephalitis, and Newcastle disease. It also prevented the deaths of hundreds of millions of forest trees, by killing the caterpillars of the gypsy moths, Tussock moths, and other forest insects. In killing insects which destroyed crops, food shortages have been minimized and food prices held relatively affordable.

    Millions of trees were lost during the infestations of the gypsy moth and Tussock moths. Greens predictably opposed the use of DDT to save these trees. Political correctness and loyalty to their causes must never be challenged. The same crowd which once refused to save trees now supports saving the trees, the planting of trees, without embarrassment, without noticing the double standards." Hawaii Reporter


Ed Darrell said...

Your slam at Rachel Carson is quite unfortunate. She no more to do with the continuation of these diseases than you.

In point of fact, Carson noted that continued, unwise overuse of DDT on crops like cotton would lead to DDT's being ineffective against the mosquitoes that carry parasites. The phenomena you cite here are related to her predictions coming true. To blame her for sounding the trumpet is particularly cruel, since such games do nothing to ease the suffering of the victims of the disease, and nothing at all to stop the diseases' spread.

DDT has been available for vector control in Africa and Asia continuously since 1946, by the way. No "ban" has ever included use to control mosquitoes where DDT is the only effective tool.

The question then becomes, why isn't DDT used? The answer is much more complex. In the case of malaria, the parasites have become resistant to the drugs used to treat them directly. DDT never had any effect there. In other cases, governments have simply not been effective at carrying through the mosquito and disease abatement programs necessary. Uganda, for example, suffered many years under Idi Amin. His government's many failures played a much more direct role in the continued spread of disease in central Africa than any group of environmentalists' actions over the last 50 years. Rachel Carson played no role whatever in Amin's rise to power, and blaming her for the ill effects of such political events is especially misquided.

In the end, DDT is one tool in one front of the war against disease. Alone, DDT can offer temporary but extremely damaging respite (DDT sprayed in the wild also wipes out foods many people depend on; they don't suffer from malaria, but die of malnutrition instead). In conjunction with the netting and other barrier prophylaxis now being promoted in Africa, in conjunction with rapid and effective delivery of medical care to disease victims (who are pools of infection for some of these parasites when not treated), in conjunction with effective programs to eliminate breeding areas for vector insects around homes, DDT continues to be one of several effective tools against mosquitoes and flies, in the fight against disease.

In short, Rachel Carson was right. You should read her book sometime. I'm reading it again, and it holds up remarkably well. Prophets are often called "misguided," but that's more a function of ignorance among critics than it is a valid criticism, especially in this case.

Norma said...

I have read her book. I didn't say she caused all this death by herself, or that DDT was the only weapon against malaria or that it was never overused, or that insects wouldn't develop resistance. However, maybe one or two of the millions who have died from its hasty removal might have developed something else. There are unintended results from all medical discoveries and miracles. We had a polio epidemic in the 20th c. but it was mild in the 19th c. But we cleaned up the water supply lowering people's resistance. And there are lingering side effects from vaccines. But the benefits outweigh the risks.

However, I am not THIS callus, even if the end result has been to limit population growth in 3rd world countries: "Population control advocates blamed DDT for increasing third world population. In the 1960s, World Health Organization authorities believed there was no alternative to the overpopulation problem but to assure than up to 40 percent of the children in poor nations would die of malaria. As an official of the Agency for International Development stated, "Rather dead than alive and riotously reproducing." [Desowitz, RS. 1992. Malaria Capers, W.W. Norton & Company] Seen at the JunkScience page.

Although it does remind one of some of the pro-abortion arguments, doesn't it?

Ed Darrell said...

If you're callous enough to argue that WHO "blamed DDT for increasing third world population," an old hoax that is an insult to the hard working public health officials everywhere, you'd be callous enough to support AID -- the same agency which, in the Bush administration, has resisted the use of DDT even when Environmental Defense, the group that originally sued to stop DDT spraying in the U.S., asked them to spend the money.

JunkScience sells exactly what they advertise. They are not credible, and they hoax with abandon.

I figure, people who lie about how to fight malaria are among the most callous on Earth. That's JunkScience in a nutshell.

Ed Darrell said...

Looking at Rachel Carson's book again today, waiting for the younger son to finish the current sitting for the SAT, I read again the section where she documents that DDT was already ineffective against the vectors of elephantiasis -- in 1960.

The woman was an oracle. It's not too late to listen.