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August 22, 2006
(Special Edition) WEST NILE in South Chico
by Jack Lee
(Photo on left depicts the swampy area off Fair Street and south of the Skyway)
Larry Mitchell (ER Staff Reporter) and I interviewed Carl Pearson, Regional Supervisor for the Butte County Mosquito and Vector Control District this morning at the scene of the "hot spot" for West Nile infestation. (See sat. photo below). He was inspecting the spraying his office had just done in this unintentional "man-made" swamp, used by the City of Chico to control storm drain runoff.
We were pleasantly surprised to discovered the beaver dam that caused water to backup was now gone, removed hours early by a City crew. The small lake of brackish, black water had already dropped about a foot. But, without removing the beaver, any fix will only be termporary. Pearson said the dam could be rebuilt even in a matter of days, and the water would start to backup all over again. He said his office was doing all they could to
control the mosquito population, but for a longer term solution this would require a multi-agency effort. First, the beavers would have to relocated and that is a Fish and Game problem. Next, the City of Chico will likely be doing regular maintenance to keep the drainage point clear and open and his agency will continue to monitor for larva and spray as needed.
For about 3+ years, wild vegetation has been allowed to grow in this drainage area and it now qualifies as a "wildlife habitat" and a whole new set of rules govern it's management. Beavers are a protected species and whatever is done now to control them or any wildlife in this area, comes under the control of Fish and Game, as well as a number of environmental ordinances.
5 years ago this was just a big field with a ditch running through it, then the City created the catchments ponds to control neighborhood flooding in winter.
According to Pearson, the Culex pipiens mosquito, also known as the northern house mosquito, is the culprit here. Larva sampling has confirmed their presence, in abundance. It is a known carrier for encephalitis and is responsible for the transmission of the West Nile virus to humans, birds and other mammals. It is mostly brown in color with white markings on its legs and mouthparts. The female is a persistent biter, requiring blood meal to generate healthy eggs and prefers to attack at dusk and after dark. From eggs to biting mosquitos requires about 15 days, Pearson said.
Anyone in the Chico area with a mosquito problem should report it to Butte County Mosquito District, 533-6038 or 342-7350.
For additional information please read Larry Mitchell's articles on West Nile in today's paper and tomorrow's edition.
Posted by Post Scripts at August 22, 2006 12:27 PM
Comments
As a result of coverage of the West Nile risks in this blog and stories in the ER, it has occurred to me that I can use my forecasting skills and weather stations I've installed at schools around town and at www.bidwellranchcam.com to create a valuable public health service.
Mosquito activity (and thus biting probability)is quite predicable based on:
Temperature
Wind Speed
Humidity
Recent rainfall
Time of day
Since I have donated web enabled weather stations around some CUSD schools now, I think I shall create an automated system that will gather that data, interpret it, and forecast mosquito activity based on conditions measured at these stations. Hopefully, I can provide an automated forecast "widget" that will be inserted into web pages at schools to help adminstrators judge risk for outdoor activity and possibly even the ER's webpage as a central clearing house for the forecasts.
I believe that having a place where you can judge your risk based on realtime local weather data will be valuable for the public.
Comments on this idea are welcome.
Posted by: Anthony Watts at August 28, 2006 06:47 PM
I never pay any attention to the "epidemics" in the paper. They almost always turn out to be just the paper selling papers. And sure enough ...
I finally got around to reading up on the West Nile Virus. It's the flu ! Only you get it from a mosquito. Big deal.
The average infected school kid isn't even going to get sick. And while the bug does kill people, it only kills people who might die from any of the other flus we get every year.
You tell those mosquito abatement people to go easy on the poison.
Posted by: Libby at August 30, 2006 07:39 PM