CHICAGO (CBS) — Experts have warned 2012 could be a bad year for West Nile — and it is.

CBS 2’s Brad Edwards reports the suburbs of Wilmette, Skokie, Evanston, Niles, Lincolnwood and Winnetka have all had batches of mosquitoes test positive for the virus.

NSMAD — the North Shore Mosquito Abatement District — is the font-line defense against West Nile. Its teams have fanned out the 80 square miles of Cook County it covers to spray mosquito killer, including spraying in the Skokie area Wednesday night.

“We’ve been going through a lot more tests and a lot more samples,” said NSMAD ecologist Chris Xamplas. “There’s a greater concern for public health right now.”

A CBS 2 crew watched one such test, which resulted in a positive result.

The recent weather isn’t helping.

“The prolonged heat speeds up the life cycle of the mosquito and the virus,” said Xamplas.

Mosquitoes that carry West Nile have shown up a month earlier than usual, and they won’t be going away until there’s a freeze to kill off the bugs.

Repellent with DEET is the top way to strike back – and be mindful at dusk to dawn, prime-time for mosquitoes. Other tips for avoiding mosquitoes include wearing long sleeves, long pants, made of light-colored fabric. You can also ward of mosquitoes with dryer sheets, like Bounce, because the bugs don’t like the scent.

Brad Edwards