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The DDT Miracle
As far as we know, the type of malaria that infects humans does not infect wildlife, which means that the malaria parasite needs human hosts to survive. Accordingly, if human transmission could be prevented the malaria parasite would die off. This is unlike the West Nile virus which appeared in the United States in 1999. West Nile also infects birds and other species, and mosquitoes can then transmit the disease between humans and these species. Accordingly, West Nile can reside in wildlife for years without human transmission and then reappear among humans sporatdically. Because humans serve as the malaria parasite’s host species through which they reproduce and spread, efforts to prevent human exposure not only benefit the individuals employing such tools, they help in the larger battle to eradicate malaria.
The pesticide DDT—which is short for Dichloro-Diphenyl-Trichloroethane—have proven to be a critically important tool in reducing malaria transmission, practically eradicating malaria in some areas of the world. Paul Herman Muller discovered DDT’s insecticidal properties in 1939, which earned him the 1948 Nobel Prize in Medicine because his discovery provided a highly effective and affordable way to manage major public health risks carried by mosquitoes, lice, and other vectors. DDT has saved millions of lives around the world. It helped cleanse Nazi war victims of disease-ridden lice, and it was embeded in the uniforms to protect allied troops from vermin and typhus.
DDT was used to largely eradicate malaria from the United States and other Western nations, and was used with some success in developing nations as well. In 1955, the World Health Organization launched a global campaign to use DDT along with anti-malaria drugs to fight malaria in developing nations. One report in the Bulletin of the World Health Organization notes: "As a result of the Campaign, malaria was eradicated by 1967 from all developed countries where the disease was endemic and large areas of tropical Asia and Latin America were freed from the risk of infection. The Malaria Eradication Campaign was only launched in three countries of tropical Africa since it was not considered feasible in the others.”
In 1970, the National Academy of Sciences reported: “To only a few chemicals does man owe as great a debt as to DDT. It has contributed to the great increase in agricultural productivity, while sparing countless humanity from a host of diseases, most notably, perhaps, scrub typhus and malaria. Indeed, it is estimated that, in little more than two decades, DDT has prevented 500 million deaths due to malaria that would otherwise have been inevitable. Abandonment of this pesticide should be undertaken only at such time an in such places that it is evident that the prospetive gain to humanity exceeds the consequent losses. At this writing, all available substitutes for DDT are both more expensive per crop-year and decidedly more hazardous to those who manufacture and utilize them in crop treatment for other, more general purposes.”
In 1975, Barron’s magazine (November 10, 1975, p. 3) pointed out the great benefits that DDT brought to public health, including reducing India’s death rate from 750,000 to 1,500 a year, helping eradicate malaria in the United States (where it was endemic in 26 states) and Europe. In addition, DDT helped control typhus, yellow fever, and sleeping sickness—all deadly diseases transmitted by insects. “ Perhaps the most remarkable success story,” note Richard Tren and Roger Bate, is Sri Lanka, where within 10 years of DDT use, malaria cases dropped from about 3 million a year to 7,300 eventually reaching just 29 in 1964.
DDT is still effectively used by some nations for malaria control. For example, Ecuador, which has increased its use of DDT since 1993, has the largest reduction of malaria rates in the world. South Africa relied on DDT until 1996, but then suffered from serious malaria outbreaks after it discontinued use because of environmentalist pressure. Amir Attaran and Rajendra Maharaj report that after DDT was discontinued in one province, “malaria cases then promptly soared, from just 4,117 cases in 1995 to 27,238 cases in 1999 (or possibly 120,000 cases, judging from pharmacy records.) Other provinces experienced similar catatrophes.”
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