DDT and Malaria

Published April 1, 2001

Malaria is a devastating global problem, with 300 to 500 million cases and 3 million deaths occurring annually, mostly in children. In the United States, the 1,167 cases reported in 1995 represented a 15 percent increase over 1994, Worldwide, only AIDS and tuberculosis cause more deaths.

Disarming ourselves

Despite decades of ingenious effort, malaria fighters are in some ways “worse off than we were in the 1950s,” stated Louis Miller, a leader of the anti-malaria effort at the National Institute of Allergic and Infectious Diseases (NIAID), because effective pesticides like DDT are less available.

The use of pesticide-soaked bed nets, for example, has produced “a substantial reduction in child mortality” in western Kenya, where a single child may experience 300 infective mosquito bites every year. “Few other interventions have produced such credible evidence of effectiveness,” noted Richard Skeketee, chief of the CDC’s malaria branch, in Science. The “U.N.-backed push to phase out DDT’,” he wrote, makes efforts such as the genetic manipulation of the mosquito more urgent.

Once focused on the nuclear disarmament of the American military, Physicians for Social Responsibility (now billed as “a group concerned with environmental health”) is working for the disarmament of the malaria fighters, through a comprehensive ban on their most effective weapon, DDT. Their ally, the World Wildlife Fund, is pressing for a total global ban by 2007.

At least one expert, Dr. Donald R. Roberts of the Uniformed Services University of the Health Sciences, has challenged the environmentalists’ plan. “DDT is the best insecticide we have for controlling malaria,” he told the New York Times in August 1999. “We have got to stop pressuring countries to ban DDT. It is immoral.”

With only three countries still manufacturing DDT–Mexico, China, and India–lack of a reliable supply has forced some African nations to resort to more expensive methods.

Malaria research underway

Money is pouring into malaria research. Funding through the National Institutes of Health increased five-fold and should reach $50 million in 2001. The Bill & Melinda Gates Foundation plans to disburse $115 million, $50 million through its Malaria Vaccine Initiative. The hope is to find a vaccine that will be 95 percent effective for at least six months.

The malaria parasite is becoming resistant to every cheap drug that works–chloroquine is ineffective nearly everywhere–and even to newer drugs like mefloquine. Drugs designed with the aid of genome sequencers are probably a decade away. Fortunately, artemisinins, used as herbal remedies in China for 2,000 years, look promising. Clinical trials were delayed, however, because the World Health Organization expressed concern about neurotoxicity in animals. Some observers say the biggest roadblock was lack of the right regulatory “credentials, which people seem to regard almost as religious edicts.”

Science has also reported that efforts are underway to engineer a mosquito that is refractory–“stubbornly defiant”–to the malaria parasite, and get it to replace the native population.

Malaria and global warming

A wider range for mosquitoes that carry the disease is one of the predicted consequences of catastrophic global climate change, a favorite threat of Physicians for Social Responsibility and their allies, who strive to make “advocacy and activism regarding the link between the environment and patient health become the responsibility of health professionals.” That link, however, has always been a stretch.

Even proponents of global warming theory now concede there would be remarkably few changes in mosquito distribution, even under the most extreme scenarios. That admission came an issue of Science magazine, in an article titled to suggest the opposite conclusion: “The Global Spread of Malaria in a Future, Warmer World,” by D.J. Rogers and S.E. Randolph.

While malaria “has been included in most predictions about the impact of climate change on the future distribution of vector-borne diseases, these studies . . . generally use only one or at most two climatic variables to make their predictions.” Models do not accurately describe the current distribution of malaria, Rogers and Randolph conclude, and “cannot be used to give reliable predictions about the future.”

A global energy-rationing regime, such as that proposed to address global warming, will not stop malaria. Poverty, which would be exacerbated by energy restrictions, is “a particularly recalcitrant contributor to and consequence of infectious diseases,” reported S. Binder and colleagues in “Emerging Infectious Diseases: Public Health Issues for the 21st Century,” published in Science in 1999.

DDT polluting oceans?

U.S. District Judge Manuel L. Real has entered the fray against DDT, ruling that DDT pollution on the ocean floor is responsible for decades of injury to bald eagles and peregrine falcons. The U.S. Department of Justice was seeking $150 million for damage to natural resources, plus about $10 million to compensate for past cleanup costs. In Los Angeles County, 150 municipalities and three companies agreed to pay $67 million in damages for their role in the pollution. It is alleged that 100 tons of DDT lies on the Palos Verdes Shelf and is continuing to contaminate the ocean.

“Most experts say it breaks down slowly, remaining in ocean sediments for decades if not centuries,” noted an October 2000 story in the Los Angeles Times.

Montrose Chemical Company, once the world’s largest manufacturer of DDT, the most widely used pesticide in history, is now defunct except for the lawsuit. It has agreed to settle the case for an undisclosed amount.

Dr. J. Gordon Edwards of San Jose State University, who never received any money from Montrose, writes: “I had heard that they may be reaching a settlement, rather than seeking a victory, because it costs too much to compete with the government attackers, who have unlimited funds.”

A key piece of incriminating evidence is the amount of DDT in the Montrose sewer line. Noted Edwards, “Dr. Risebrough took his remarkable sample by opening a manhole cover near the coast and dipping some water out. He analyzed it in a lab at Berkeley, using unreliable methods. Dr. Alice Ottoboni visited his lab and told me he couldn’t possibly have made an accurate analysis because it was such a mess. AND the lighting consisted of fluorescent light tubes (the ballast of which throw off PCBs, which, at that time, gave GLC readings identical to DDT).”

Additionally, Edwards writes: “My naive view was that the EPA conclusion that DDT in sea water was short-lived (with 92 percent of it gone in 38 days, along with its breakdown products) would make it obvious that the ridiculous claim of tons of DDT still in the bay after over 25 years of breaking down in sea water would at least force the attackers to provide samples of the sediment for scientific analysis by the defense. It is obvious that DDT cannot still be in the sediment.”

Dr. Jane Orient is executive director of Doctors for Disaster Preparedness.