Liem The Mosquito Man at center of controversy

Thursday, August 11, 2005

Science is not politics.

Born in Indonesia and educated as a teenager in Holland, Dr. Khian Liem, 64, would eventually become the first director of the South Cook County Mosquito Abatement District.

For most of his 31 years in that post, Liem eradicated bugs in obscurity.

But since the West Nile virus outbreak of 2002, when more people died in south Cook County than any other region of Chicago, Liem has found himself at the center of a political controversy.

Until this week, he simply refused to use insecticide sprays to kill adult mosquitoes.

"I made that decision back in 1974, when I first became director of the South Cook County Mosquito Abatement District," Liem told me.

"I conducted an experiment in the Cook County Forest Preserves. I laid bed sheets out on the forest floor. They covered about a quarter of a square mile.

"Then we sprayed insecticide. We found butterflies, moths, beetles dead on the bed sheets. Some mourning doves got dizzy and fell out of trees.

"But we didn't find a single dead mosquito. The results of that experiment have stayed with me my entire life."

I asked Liem if the mosquitoes might have simply been blown away by the wind.

"I stayed there the entire time," Liem said. "No mosquitoes fell."

It still doesn't explain why butterflies and moths would die, but mosquitoes would not.

In Liem's opinion, there is no scientific proof that spraying or fogging for adult mosquitoes is effective.

"All the studies that have been done have taken place in a controlled environment," Liem said. "They spray mosquitoes in a glass-enclosed case. They die. Well, that's like shooting prison inmates in their cells. It doesn't prove anything."

Yet, the Centers for Disease Control recommends spraying in areas where adult mosquitoes are found to be carrying the West Nile virus.

Other mosquito abatement districts in the Chicago region spray.

The Cook County Department of Public Health paid for spraying out of its own budget in south Cook County when Liem refused to use money from his budget to spray the area south of 87th Street in Chicago to the Indiana line, which is his responsibility.

This week, under threat of being fired, Liem relented.

"My (mosquito abatement board) was under so much pressure, I agreed to spray," Liem said. "It was for politics. It won't help anything."

Liem, whose five siblings all became medical doctors, became fascinated by the study of bugs at an early age.

In the 1970s, he chose to attend the University of Illinois to study entomology under Dr. William Horsfall, who was considered one of the world's greatest experts on mosquito control.

While most experts at the time focused on the use of pesticides to reduce adult mosquito populations, Horsfall developed a theory of bionomics that concentrated on eliminating the habitats where the mosquitoes lived and applying larvicides to kill their offspring.

Although his theories were originally considered radical, they eventually became accepted practice among entomologists.

It was his idea to create mosquito abatement districts in Illinois, Liem said.

"He was the greatest expert in the world," Liem said. "And I became convinced through my studies under him and my own work that insecticides often do more to harm the environment then they do to control insects."

Yet, the U.S. Environmental Protection Agency approves the use of insect sprays to combat mosquitoes.

"I am a man of science," Liem said. "The science shows the insecticides do have an impact on the environment. There is no science that proves that spraying is effective in controlling adult mosquito populations."

Indeed, even Liem's critics admit that the scientific studies are at best "mixed."

But they contend in areas where adult mosquitoes are found to be carrying the West Nile virus, the only way to reduce their number is to spray.

Mike Siska, director of the Northeast Mosquito Abatement District, said, "Just look at the figures from 2002. The areas that sprayed for adult mosquitoes had fewer human deaths."

Liem believes other factors were at work.

"In the south suburbs, in places like Harvey, Ford Heights, there are people living in homes without screens," he said.

"They live with mosquitoes in their households."

The South Cook abatement district, at 340 square miles, is also nearly one-third larger than the other mosquito abatement districts.

It also contains 47 square miles of forest preserves, along with more landfills and cemeteries than other areas.

"We treat the areas where the mosquitoes lay their eggs," Liem said. "That's the most effective way to keep their population down."

But people like to see trucks fogging and their tax money at work.

To the average person, that's better than doing nothing.

"It's politics and not science," Liem said. "But we're going to do it."

Phil Kadner may be reached at or (708) 633-6787


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