Disease Prevention Has a worldwide ban on the use of DDT helped to spread AIDS? And can a resumption of its use help curb two plagues on mankind simultaneously? A new study says yes.
When a worldwide ban led by the U.S. on the use of the insecticide DDT began in the early 1970s, it may have contributed not only to a resurgence of an old killer, malaria, but also to the spread of a new and deadly plague, AIDS.
A study by researchers at the University of Washington's Fred Hutchinson Cancer Research Center in Seattle and published in the journal Science documents how malaria and HIV have a deadly symbiotic relationship, one helping to spread the other, making both more deadly.
Scientists at the center have discovered that when someone with HIV has a bout of malaria, it can cause the virus levels to surge as much as sevenfold, an increase that lasts after the malaria ends. Because HIV affects the immune system, the likelihood of getting malaria increases.
In regions where both diseases are common, malaria may be responsible for almost 5% of HIV infections, and HIV may be behind 10% of malaria episodes, said lead researcher Laith Abu-Raddad.
The group paid particular attention to Kisumu, Kenya, where both diseases are prevalent and good tracking data are available. In Kisumu, the relationship between the diseases resulted in about 8,500 extra HIV infections and 980,000 additional cases of malaria over several decades.
"We have always known the relationship (between malaria and HIV/AIDS), but we did not know the impact it had on the spread; now we have a reference point," said Ayub Manya, an epidemiologist with the Kenya National Malaria Control Program.
"It's a substantial impact," said Abu-Raddad, adding that it helps explain the explosive spread of AIDS in southern Africa. Malaria sickens about 500 million people each year, killing more than a million, mostly children, and mostly in Africa. Sub-Saharan Africa has about 24.7 million HIV-infected people with the U.N. putting 2005 deaths from AIDS in Africa at 2 million.
"It's an important paper," said Dr. Anthony Fauci of the National Institutes of Health. "We really need to be much more serious about what we do about malaria at the same time we're serious about what we do about HIV."
It would be a double tragedy if millions of people died needlessly over the past three decades from both AIDS and malaria due to environmental hysteria over DDT. The dangers ascribed to DDT use were based on its heavy use in agriculture, which is no longer necessary in this age of biotechnology and other advances. But the fear remains.
Spraying indoors to control mosquitoes is not, and never was, dangerous. "DDT presents no health risk when used properly indoors," said Dr. Arata Kochi, director of the World Health Organization's malaria program. "Well-managed indoor spraying programs using DDT pose no harm to wildlife or humans."
The World Health Organization recently reversed its 30-year-old opposition to the use of DDT, deciding that saving African lives is as important as saving the environment. Speaking before the National Press Club, Kochi gave DDT a "clean bill of health," saying it is safe for humans and is "remarkably effective" when a small amount is sprayed on the indoor walls of houses and huts.
Dr. Elizabeth Whelan, president of the American Council on Science and Health, said DDT prevented more human death and disease during its less than 30 years of widespread use (1944-72) than any other artificial chemical in recorded history.
The National Academy of Sciences said that in those years DDT saved more than 500 million lives. In India there were a million deaths from malaria in 1945, and DDT reduced that number to only a few thousand by 1960.
And now we know it can also slow the spread of and reduce the death toll from AIDS. Unless the fear-mongers get in the way.
