By Tim Bonfield
The Cincinnati Enquirer

Among the maps and charts and books about bugs and disease that clutter his office, a sheet of paper tacked to the wall above Dr. Richard Berry's desk reads: "It's the mosquitoes, stupid!"

As chief of the Ohio Department of Health's vector-borne disease unit, Dr. Berry has been "eating, sleeping and breathing" data about West Nile virus for the past three years - ever since the first outbreak occurred in New York.

Dr. Berry is the state government's resident mosquito expert. From his point of view, understanding and controlling the spread of West Nile is all about getting to know the feeding and breeding habits of blood-sucking pests that have spread disease among humankind since prehistoric times.

There's a reason public health officials have urged property owners to eliminate sources of stagnant water - mosquitoes can multiply quickly.

In addition to rapid breeding, the spread of West Nile virus also is related to the types of mosquitoes involved. Dr. Berry's lab has found West Nile virus in 17 different species of mosquito.

Some mosquitoes prefer bird blood. Some prefer mammals, including people. And some "opportunistic" species don't care what they bite, Dr. Berry says.

The biggest West Nile carrier in Ohio has been the culex species, believed to feed almost exclusively on birds. Of 1,411 positive "pools" of mosquitoes tested through Oct. 4, culex mosquitoes accounted for 1,197.

Of increasing concern to Dr. Berry are signs of the West Nile virus in a mosquito species known to regularly feed on birds and people.

The season's second highest number of infected mosquitoes (47 positive pools) have occurred among Ochlerotatus triseriatus, also known as the "tree hole mosquito." This bug is known to live in suburban areas, where it lays eggs in small containers.