Testing done by a Chicago newspaper found trace amounts of the bug repellent DEET in the city's drinking water.

"In this age of West Nile virus, Lyme disease and other insect-borne health threats, millions of Americans have made slathering and spritzing themselves with the powerful repellent DEET part of their summer routine," according to the story published yesterday in the Chicago Sun-Times. "And now, testing done for the Chicago Sun-Times has found, it's in our drinking water."

Considering Kern's push to wear insect repellent in the wake of having the highest number of West Nile cases per county last year, one has to wonder how much DEET is in our drinking water.

(Read "West Nile: We were the epicenter last year — what lies ahead?", which ran in The Californian in March, for Kern's West Nile forecast.)

From the Sun-Times story:

The concentration detected in a sampling of Chicago tap water was low -- 8.3 parts per trillion. Health experts said the level found in the Sun-Times testing shouldn't pose a health hazard.

Still, said Mohamed Abou-Dania, a professor at Duke University who has done extensive research on the neurological effects of DEET, "This raises a red flag. [When] you have so many people using it, the risk is there."

And the chemical was detected in Chicago drinking water sampled in March, when one would expect the use of mosquito repellent to be low.

In other West Nile news, Kern has accumulated enough heat units to activate West Nile in mosquitoes, according to Richard Takahashi, entomologist with the Kern Mosquito and Vector Control District.

Heat units are often measured in degree days and represent the heat threshold at which the virus becomes active. The hotter it is the faster the disease replicates and mosquitoes breed.

From an e-mail Takahashi sent me:

This means we should begin to have positive mosquito pools and more positive dead birds and probably humans. The public really needs to protect themselves against mosquitoes from now until the end of the season (November). This year, as last, we are getting a lot of dead sparrows being picked up in the city. This probably means the birds are again congregating in the urban areas due to the drought. Not a good sign.

Takahashi said the district is also finding many abandoned swimming pools that already contain large populations of mosquito larvae and pupae, which also isn't encouraging.

There is some good news, though.

It took more than 3 weeks longer to build up the heat units this year (APR 16) than last year (MAR 23). This means there is less of a build-up of virus to date. Also at the end of 2007 there was not as large of an abundance as there was at the end of 2006.
 
During the last half of last week, we began trapping many more adult mosquitoes than previous weeks. This is a good indication that the mosquitoes are starting to disperse. The recent cool temperatures will slow things down again but as soon as the temperatures rise to their normal levels we are expecting to see more virus activity than we’ve seen to date.

No humans have been diagnosed with West Nile in California this year, the state Department of Public Health reports. Ten dead birds have tested positive for the virus so far, one of those coming from Kern.