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Splicing the Sting Out of Bugs

Health: Genetic altering of insects and bacteria could prevent them from transmitting diseases such as malaria. But ultimate effects are unpredictable.

April 09, 2001|AARON ZITNER | TIMES STAFF WRITER

ATLANTA — Charles Beard's recipe for stopping the kissing bug, a tropical pest that kills 50,000 people each year, calls for ammonia, ink and guar gum. The result is an odorous goop that resembles the bug dung that, unpleasant as it may seem, happens to be a vital meal for young kissing bugs.

But Beard adds something else to his faux feces that could prove to be even more noxious. It is genetically engineered bacteria that, once ingested, render the kissing bug unable to pass along its deadly disease.

Now, a world that is already debating the safety of gene-spliced foods is about to meet a new class of genetically engineered organisms: modified bugs. Beard's creation is just one in a series of plans to turn insects and bacteria into warriors against disease and crop pests.

This summer, scientists hope to start the first U.S. field tests on a gene-spliced insect--a version of a moth that chews through $24 million worth of U.S. cotton plants each year. Researchers are also trying to create mosquitoes that cannot carry malaria, which still kills 1 million a year, or West Nile fever, which is spreading across the United States. On the drawing board are ticks that cannot carry Lyme disease or Rocky Mountain spotted fever. Although the work is advancing quickly, questions remain about which U.S. agencies would monitor the new organisms.

If released in the wild, scientists say, a properly engineered bug would spread its disease-defusing trait to its wild cousins, protecting a whole community or region. Public health officials say the bugs could be a crucial new weapon against often-deadly diseases such as malaria, which has built resistance to drugs and pesticides and has reemerged in places where it was once defeated.

"The situation is awfully bleak out there," said Barry Beaty, an insect specialist at Colorado State University. "A lot of people are dying. We need new ways to respond to the problem."

But if much of the world is anxious about genetically engineered foods, then modified bugs are sure to set off alarms as well. "Once you release an insect, it flies, and you can't control its distribution in the environment," cautioned Svata Louda, a University of Nebraska plant ecologist. "That's just one of the things that makes ecologists apprehensive about new versions of an insect."

Critics also ask whether an engineered bug gene might mutate over time into something dangerous, or whether it would jump to an unintended insect species. Another question: Given that bugs travel freely, how many people in an area would have to give consent before gene-spliced bugs were released?

Scientists say they have kept these questions well in mind over the last decade. But it is only now, thanks to funding from such heavyweights as the U.S. government and the World Health Organization, that they have accomplished enough in the lab to start thinking about conducting field tests that would produce some answers.

In London this June, researchers from around the world will hash out basic scientific questions about field trials--where they might be conducted, what data should be collected and how they should be monitored. The meeting is sponsored by the WHO, the National Institutes of Health and London's Imperial College.

At the same time, U.S. officials say they are taking some early, tentative steps to sort out which agency should make sure that the new bugs pose no harm to people or the environment.

In some cases, jurisdiction seems clear. In July, for example, scientists from the U.S. Department of Agriculture and UC Riverside hope to start the first field test of a gene-spliced insect, the pink bollworm moth, a bane to cotton growers. Because the Agriculture Department itself has authority over plant pests, it has claimed jurisdiction over the field trial.

The scientists want to place 2,350 gene-altered moths in a large mesh cage in an Arizona cotton field. Their long-term plan is to insert a lethal gene into the moth that would be passed to their offspring, wiping out the next generation of insects. But in their first field trial, the scientists will use only a marker gene and watch how it affects moth behavior.

Robert Rose, a USDA official charged with assessing the scientists' plan, said he is considering the stability of the mesh cage and the fitness of altered moths to survive in the wild. Only sterile moths would be put into the cage, he said, a step that aims to diminish their effect on the environment if they escape.

Federal jurisdiction is less clear over other bugs now being developed. A "talking points" document by the NIH says "there are gaps" in the existing law covering field tests.

An antimalaria mosquito, for example, would not be considered a plant pest and therefore would probably not fall under USDA jurisdiction, Rose said. But officials at the Environmental Protection Agency say it is not clear that they would oversee the mosquitoes, either.

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