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Friday, August 10, 2007

Davis City Council Remains Silent as Sacramento Presses for Answers on WNV Spraying

According to an article that appeared in the Sacramento Bee on Thursday, Sacramento City Councilman Rob Fong is asking tough questions about the aerial spraying of urban areas as a means to control the local mosquito population. The Sacramenento City Council took up the issue last night.

I find it noteworthy that the Sacramento City Council would be asking a number of tough questions about the effectiveness of the spraying and also questioning whether we in fact know enough about the environmental and health effects of the use of these chemicals.

Councilmember Rob Fong told the Sacramento Bee:
"They're telling us it's OK to use these chemicals because we don't know yet whether anything bad can happen as a result. I'm just not comfortable with that."
One reason I find this so interesting has been the lack of interest on the part of the Davis City Council to ask similar tough questions. Last year when the Davis City Council took up this issue, only one councilmember, Lamar Heystek, sought to oppose aerial spraying in urban areas. His motions died for the lack of second. It now appears that the Sacramento City Council has shown action where the Davis City Coucnil accepted the official findings of the experts.

However, when pressed by Councilmember Fong, Sacramento County's Public Health Officer, Dr. Trochet and Dave Brown, manager of the Sacramento-Yolo Mosquito and Vector Control District, were forced to acknowledge the chemicals are possible carcinogens and that they have no idea of the long-term effects because they have not done long term studies.

As I wrote last year, I am not a doctor or a scientist, so I do not know whether spraying presents a health and/ or environmental hazard. However, as always, I am concerned about the process. Particularly the lack of local control and the lack of clear scientific evidence that would dispel or confirm some of the concerns raised by activists and environmentalists.

The first problem I have with the process is that the mosquito abatement district operates outside of direct local control. Sacramento City Attorney Eileen Teichert for example has determined that the city lacks the legal authority to opt out of aerial spraying. However, the city could appeal a spraying decision to the state or file a lawsuit. The lack of local control by elected officials who have had their power usurped by an unelected bureaucratic body remains a very disturbing feature of this issue.

Second, unlike the case with the Sacramento City Council, I do not believe that the City of Davis asked tough questions and drew up satisfactory answers to two crucial questions.

The first question is the long term health effects. We do not have good answers to this question because long term studies have not been performed.

The second key question is one that we should have at least some data on--how effective is the spraying at reducing the adult mosquito population and reducing the spread of the West Nile Virus.

However, there are two different answers to this question depending on who you ask.
"David Brown, who heads the Sacramento-Yolo district, said he's convinced aerial spraying has greatly reduced the number of infected adult mosquitoes. That in turn has reduced the public health risk, he said."
However, according to a number of activists and environmentalists, "No studies show conclusively that aerial spraying eliminates or decreases the incidence of West Nile virus infections"

Jack Milton, a UC Davis professor and local activist with Stop West Nile Spraying Now, suggests that the evidence is much weaker than they are letting on. In response to questions in August of 2005, the experts presented evidence. However, this evidence amounted to something considerably less than actual scientific study.
"It turns out that this paper is essentially an administrative report of how one district spent its money as WNv infections grew. It is not a study in any way, shape, or form about efficacy of adulticiding. They had ramped up all vector control activities, and there was no way in what they did to measure the efficacy of adulticiding at all. There was no comparative study, there was no model, there was nothing in there to allow anybody to draw any such conclusions."
Jack Milton concludes from this response:
"I suggest that if this is one of their two best pieces of evidence (the other one was a study, not in a peer-reviewed journal, which scholars at the University of Colorado have thoroughly criticized), they have essentially no evidence whatsoever."
It is not clear to me then that we have compelling evidence of the effectiveness of the spraying program. It is also not clear to me whether we know enough about the long term health effects of spraying urban areas.

That leaves us with one final question--how serious is the West Nile Virus threat that we are willing to take potential health risks with uncertain benefits.

As the two graphics show, the health risk currently compared to other public health problems seems fairly low with only 54 deaths from West Nile Virus from 2004-2006 in California. Compare that to other threats and you see a very small problem at this time. Obviously we should not scoff at the problem, and certain individuals are at more risk than others. But given the relatively low mortality rate of West Nile Virus it seems to me more reasonable to work at reducing risk for high risk individuals, rather than working on large environmentally questionable practices for something that in general is not a large threat to the average person.

According to Jack Milton,
"The disease is a rare and mild one for most people, and it is headed into chronic endemicity now, which will mean fewer and fewer cases in upcoming years, with some small fluctuations from year to year -- a dampened sine wave, if you will. Vector control and public health officials have sensationalized the issue and have engaged in fear tactics in order to peddle their snake oil. They have largely ignored the risks to people and the environment of the spray, and they have not even attempted to measure the effect of applying this poison in the way they are. At the same time they have exaggerated the risks of WNv, and their methods and statements have been very inconsistent."
It may be that these things are perfectly safe and we have nothing to worry about, but what concerns me most is that the Sacramento City Council is being much more aggressive with asking these questions at this time than the Davis City Council. Four of the five members of the Davis City Council seemed relatively unconcerned a year ago about any questions regarding spraying. A motion by Councilmember Heystek died for a lack of a second. Meanwhile the Sacramento City Council has taken the lead on this issue.

---Doug Paul Davis reporting