By Jake Rossen
By Jesse Marx
By Michelle LeBow
By Alleen Brown
By Maggie LaMaack
By CP Staff
By Jesse Marx
No insect registers high on the ish scale with Moon. Bedbugs? He downs the dregs of his coffee and chuckles with anticipation: "We have three bedbugs living in our office. This afternoon I'm going to prick my finger so that I can see them in action, sucking blood." Box-elder bugs? "When we moved into our house, there was a bag of box-elder seeds in the porch. It attracted bugs into our house. I was fascinated. But others in my house weren't so happy, so the bag went outside." Plagues of locusts? "In the bicentennial year, I went to Washington, D.C., when they had an overabundance of cicadas. I was in seventh heaven. These are the things we live to see. If there's an outbreak of anything, I think, Give me more. I want to see insects in the range of conditions that they can occur in."
This summer Moon will travel to Kazakhstan and Russia, looking for beneficial insects to pit against flies. "The housefly and stable fly evolved in that area; they've only been [in North America] a couple of centuries. Over there in the Old World, natural enemies have had more time to evolve. It's classic biological control: reuniting old enemies."
"Biological control" is a big word in the bug-fighting universe these days: The idea is that for each bug there's another bug that will eat it--or a scent that will lure it, or a microbe that will kill it. The Bti granules Pennuto spreads around metro-area swamps qualify as biological controls; so do the hormone-baited traps used to capture gypsy moths (see "Bugs Without Borders," p. 21). It's more expensive than the heavy-hitting insecticides that gave birth to mosquito-control districts after World War II (in the 1960s, the MMCD routinely sprayed the now-banned DDT in the Twin Cities). But for insect fans like Moon, it's the best of all possible worlds--not to mention a fascinating challenge: "The better you know a bug," he beams, "the better chance you have at finding its enemy."
If Kurt Pennuto looks at the mosquito with a hunter's admiration for his prey, and Moon studies it with a researcher's passion for detail, Mike Osterholm sees it with a mix of clinical detachment and parental anguish. Minnesota's state epidemiologist for 15 years, Osterholm is an internationally known authority on infectious diseases. He is also the father of an 18-year-old who three years ago came down with a case of LaCrosse encephalitis, one of the diseases carried by some metro-area mosquitoes.
Osterholm doesn't dwell on the illness, from which his son recovered. But he will talk, long and often, about his contention that given the right set of circumstances, mosquitoes could once again become a major health threat in the area. "Just a century ago," he notes, "malaria was a major problem in Minnesota." According to a recent report by Mayo Clinic epidemiologist L. Joseph Melton, European immigrants brought the disease with them and mosquitoes spread it around; in 1852, nearly every resident of Winona contracted it. The epidemic began to subside in the 1870s as housing and sanitation improved, the use of quinine increased, and the number of infected immigrants declined. But there were sporadic outbreaks in Minnesota until 1952, when malaria was eradicated nationwide. Visitors have kept the specter looming, however: Tens of thousands of cases were brought into the country by returning Vietnam War vets, and subsequent years have seen cases among immigrants, missionaries, migrant workers, tourists, and Peace Corps volunteers.
On the other hand, says Osterholm, "LaCrosse encephalitis outbreaks are very localized. It's spread by Aedes triseriatus, the treehole mosquito, which has trouble crossing the road from where it's hatched." Another variant of the disease, Western encephalitis, is carried by Culex tarsalis, a long-distance flyer whose range extends from the western edge of the metro area to the West Coast. In 1983, after several cases of the disease cropped up in the state, then-governor Rudy Perpich issued an emergency proclamation and sent out planes--including C-125 Air Force jets whose use had to be approved by the White House--to spray the insecticide malathion across Minnesota.
Osterholm, who served as state epidemiologist during the unprecedented effort, says he has sometimes wondered: "Was the bang worth the buck?" We have no doubt that we reduced the risk of Western encephalitis. But would we embark again on a statewide spraying?" These days, Osterholm says, he would prefer localized spraying along with public-education campaigns urging people to stay inside at night, when Culex tarsalis bites.
But encephalitis and its carriers are known entities to public-health experts, Osterholm says. Not so the Asian tiger mosquito, Aedes albopictus. The insect, native to Japan, Southeast Asia, and China, can transmit not only encephalitis, but malaria, dengue fever, and yellow fever. It often breeds inside tires, including the thousands shipped each year from Japan--where thread standards are extremely rigorous--to the United States. Asian tiger mosquitoes were first found in 1985 near Houston, Texas; by 1997 they had been documented in nearly 700 counties in 25 states. In 1992 MMCD inspectors found tiger-mosquito females near a tire-recycling facility in Savage. They've since had two more sightings, most recently in 1997 near Delano.