It was just a hollow rubber squirrel nailed to a tree.

Who would have thought such an innocent garden decoration could pose a public health risk? Yet sure enough, mosquito larvae were growing last summer in the stagnant water that had collected inside that squirrel.

And when mosquitoes multiply, they increase the risk of spreading West Nile virus.

"I've been doing this for 27 years. And I've seen an awful lot of backyard breeding sites for mosquitoes. But this was a first," said Bob Restifo, chief of the vector-borne disease program for the Ohio Department of Health.

In fact, the state health department has noted more than 150 different kinds of containers that can allow mosquitoes to breed. All it takes is a pool of water that lasts for four days to a week.

Tires are among the worst culprits.

"We've counted 10,000 larvae from a single tire," Restifo said.

Other common backyard breeding sites include birdbaths and clogged gutters. Often-overlooked sites include the water trays under outdoor flowerpots, equipment tarps, plastic trash as small as bottle caps in the weeds along creeks and ponds, and all sorts of plastic toys and decorations.

Decorative ponds are OK if they have fish or if they have fountains that aerate the water.

Tim Bonfield