“West Nile is coming. Bring Back DDT,” the sign on campus said. I surveyed it with a dirty look, suppressed an equally dirty epithet and kept walking.
The West Nile virus is spreading, the death tolls in America are reaching the hundreds this year and there have been thousands of reported cases of infection. California’s first case of West Nile was confirmed on Sept. 13 in Los Angeles. The disease is transmitted by mosquitoes and is closely related to yellow fever. Not surprisingly, it has done well in the damp Southern states and in states with high populations of crows – common blood donors to mosquitoes.
Roughly one out of every 200 people bitten by a West Nile-infected mosquito becomes infected themselves. The virus may also be transmitted by blood transfusions and organ transplants. West Nile genetic material was recently found in the breast milk of an infected mother, although it is unclear whether the disease can be transmitted in this way. The disease mainly attacks older males, in part because their immune systems are weaker. By the same token, it could be particularly harmful to children.
In most cases though, the infection is mild and the symptoms merely flulike. In more extreme cases, paralysis and encephalitis can occur, making the disease fatal. Spokespeople for the Centers for Disease Control and Prevention (CDC) have begun to use the loaded term “epidemic” when talking about West Nile.
In any case, people are getting nervous. According to the National Post, a popular Canadian newspaper, some Canadians have proposed sending out trucks to fumigate urban neighborhoods with the mosquito larvacide malathion. The U.S. Environmental Protection Agency claims a child could stand in a shower full of the stuff for upward of 20 minutes with no adverse effects.
OK, a couple things are obvious at this point: 1) The EPA is good at choosing really, really creepy thought experiments to make a point, and 2) Before hosing down an urban neighborhood with insecticide, you should do some more research. So here are a few facts about malathion.
In 1979, the CDC published a report, “The Toxicological Properties of Impurities in Malathion,” which cited the use of the pesticide in Pakistan as cause for concern:
“During a malaria eradication program in Pakistan in 1976, out of 7,500 spray men, 2,800 became poisoned and five died. The major determinant of the poisoning has been identified as isomalathion present as an impurity in the malathion. It seems almost certain that the isomalathion was produced during storage of the formulated malathion.”
A study in the Jan. 1992 issue of Epidemiology reported that children exposed to malathion during the second trimester of gestation face a 150 percent increase in the risk of being born with a gastrointestinal disorder.
Various studies tentatively link malathion to blood disorders, kidney failure, brain damage, genetic damage and immune disorders in humans, as well as a host of other disorders in various animals.
Other mosquito pesticides are also suspect. Exposure to resmethrin can cause coughing, wheezing, shortness of breath, a runny or stuffy nose, chest pains, difficulty breathing, rashes, itching, blisters and eye irritation. Exposure to sumithrin produces similar side effects, and can also lower sperm counts in men and produce abnormal breast cells in women because of its tendency to mimic estrogen.
It’s not the kind of stuff you want to be gassing urban neighborhoods with. At any rate, none of these pesticides stays very long in the environment, which means that they will not prevent mosquitoes for any length of time. Some people advocate more extreme measures.
Steven Milloy recently wrote in the Washington Times that he favors the re-introduction of DDT because of its staying power in the environment. He believes that it could potentially wipe out West Nile-carrying mosquitoes by virtue of its lasting effects.
The problem with Milloy’s argument is that DDT will also wipe out plenty of birds and wreak havoc on the nation’s ecosystems. Milloy claims the pesticide has no adverse health effects, so it shouldn’t matter if it sits around for awhile. “No harm, no foul,” he says.
“Are you sure he didn’t mean, ‘no fowl,'” asks my friend, Sarah. Between the years 1959 and 1966, DDT nearly wiped out pelicans on the West Coast and brought several endangered species of birds to the very brink of extinction.
Even if you are not environmentally conscious, there is reason to be concerned. A recent study by researchers at the National Institute of Environmental Health Sciences drew a strong statistical link between DDT and premature births in the 1960s, when the pesticide was widely used. Of roughly 2,400 children selected as the sample group, 351 were born prematurely and 221 were significantly underweight. Premature birth is a leading cause of infant mortality. I’m not so eager to “bring back DDT.”
So, what to do? Wait it out. Throwing pesticides around seems a bit rash. The first screenings for West Nile will be introduced at blood banks in 2003 and will initially be voluntary. Mandatory screenings will most likely follow in a few years.
More importantly, Acambis, Inc., a biotech company, has created a vaccine for West Nile that has shown a nearly 100 percent success rate in animal subjects. Human trials will begin in 2003. The vaccine was created by inserting West Nile genetic material into the existing yellow fever vaccine, which means most of the work was done over 60 years ago. The yellow fever vaccine is widely considered to be one of the safest known vaccines, so a slightly modified version shouldn’t have much trouble clearing the Food and Drug Administration.
My point is that we can wait a year or two before we start using pesticides indiscriminately. It’s disconcerting to hear “hundreds of deaths” or “thousands of infections,” but people need to maintain some perspective: According to the CDC, 20,000 deaths and 114,000 hospitalizations per year result from the flu in the U.S. alone – and yet most people don’t even bother to get a flu shot.
Josh Braun is the Daily Nexus science and environment editor. Don’t worry, he won’t bite – and if he does, there’s a very low risk of infection.
