"Fortunately, now we can synthesize the hormone, so we don't have to use 100,000 ovaries for each batch anymore," Borovsky said.

The synthesized hormone is inexpensive, as is chlorella, which is found and produced worldwide. Chlorella, in fact, turns out to be the perfect ride for the mosquito hormone, because it can be freeze-dried and stored for long periods and then brought back to life as the deadly diet pill.

The mosquito fen-phen is benign environmentally. Unlike DDT and some other pesticides, it does not alter the environment in any way, except for poisoning the larval lunch. Mosquitoes that feed on the hormone-laced chlorella starve to death within 72 hours.

"This is a natural bullet that we can use in the environment because the hormone doesn't stay in the environment," Borovsky said. "The chlorella stops producing the hormone within three weeks."

That's by design, Borovsky said. If the hormone were incorporated into the chlorella genome and chlorella continued to produce the hormone, making it omnipresent in the environment, mosquitoes could become resistant to it. But the hormone sits outside the genome, and after the third division of the chlorella it no longer can be detected.

Of course, Borovsky points out, if mosquitoes become resistant to their own reproductive hormone that could have unknown adverse consequences for them as well.

"We have to stay a step ahead of them or outsmart them all over again," Borovsky said.

In the decade since he began work on the pill, Borovsky has made believers out of even the most ardent doubters.

"Ten years ago, everybody was laughing at us, but now they are taking us seriously," Borovsky said. "Eight years ago, at a Vancouver meeting, a colleague harshly criticized this work. He just did not believe it."

The next step, Borovsky says, is to develop diet pills for infamous agricultural pests. Curren
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Contact: Cindy Spence
crsp@gnv.ifas.ufl.edu
352-392-1773
University of Florida
2-Dec-1997