Paul, The Sac-Yolo Mosquito Abatement District is following a rather robotic rule-of-thumb (developed for other diseases) that causes them to spray automatically when the disease prevalence in mosquitoes reaches 5 per thousand. This does not take into account the effects on stream invertebrates (which have now been shown to be severe) or on the long-term epidemiology of West Nile (which has not been modeled). No risk-benefit analysis is done. There is no thoughtful, researched evaluation. When 5 of 1000 mosquitoes have West Nile, they spray.
This is not a validation of spraying. It is an affirmation of bureaucratic inertia. Patrick Paul Cherubini wrote: > On July 21 Patrick Foley wrote: > > >> As for Sacramento-Yolo West Nile spraying [in August 2005]: >> The Sacramento-Yolo Mosquito Abatement District carefully avoided a >> public discussion of their spraying in Davis, the home of UCDavis, until >> after their very dubious spraying strategy was already decided. When >> they did attempt to conduct a no-public-discussion "informational" >> meeting to a room full of scientists, they were met with a good deal of >> scorn. Very little serious epidemiological work has gone into the >> spraying plans. >> > > Yet after listening to the arguments of the anti-spray segment of the > academic community at UC Davis for the past year, the Sacramento-Yolo > Mosquito Abatement District has still decided in favor of aerially spraying > the city of Davis, including the UC Davis campus, this summer. In fact, a > Davis newspaper announced today that the aerial spraying of Davis > will take place later this week: > > http://www.davisenterprise.com/articles/2006/07/31/news/153new1.txt > > "On Thursday and Friday nights, airplanes will spray pesticide > over Davis and Woodland in an effort to slow the spread of > West Nile virus." > > "The Sacramento-Yolo Mosquito and Vector Control District, working > with UC Davis, will trap for mosquitoes before and after spraying. Last > year in Sacramento County, spraying was successful in killing better than > 75 percent of the mosquito population." > > The chemical insecticide contains piperonyl butoxide. According to > http://www.stopwestnilesprayingnow.org/Risk.htm piperonyl butoxide > "has been shown to induce DNA damage in several different assays for > genotoxicity and also to function as an endocrine disruptor." > > Evidently the Sacramento-Yolo governement public health authorities > has not found the anti-spray arguments of the academic community very > compelling. > > Paul Cherubini > El Dorado, Calif. > >
