Response to “West Nile is Far More Risky than Aerial Assault.”

Jack Milton
Jim Northup

    Our response to the Roush, Washino, Parrella op ed of August 13, 2006, in the Davis Enterprise consists of four main points.  First, however, please note that the authors have correctly characterized the forced pesticide exposure of many people as an “assault.”

    1)  The infectivity and virulence of the WNV has been exaggerated in the media to the point of hysteria and irrational panic.  The actual risk of infection is minuscule.  For example, we wouldn't call 12 cases of flu over the course of six months "an epidemic".  Influenza is greatly more infectious than WNV and more virulent.  400 times as many Californians died from the flu last year as from WNV.  The chance of contracting a symptomatic infection of WNV averaged less than one in 10,000 last year.  And that was probably its "peak," as it now subsides to what is known as chronic endemicity, which will be so slight we should never hear of it again.  Indeed, it is not uncommon for a district to treat it as only a “common summer occurrence,” since “so few people get the disease.” 

     2)  In all the "evidence" of safety presented by vector control not a single study measured the aerial release of pyrethrum or pyrethroids.  They all pertain to focused ground spray.  There is a great distinction in the dynamics and duration of inhalation exposure as well as the broad exposure of "non targets" like people, birds and the little beneficial insects and larval spiders, etc.  A good scientist couldn't even begin to justify the claim to safety for an aerial spray based on the evidence of ground spray.  For instance, the most exposed creatures to this aerial bombardment will be the birds living in the tree canopy.  

    The UCD "experts" haven't even begun to show a consideration for the fact that these compounds, pyrethrum and piperonyl butoxide (PBO) and the hydrocarbon decay products of PBO are known to depress the immune system of vertebrates, including people and birds. This exposure to the infected bird population actually may end up protracting their disease, creating "Typhoid Marys" (the notorious one-woman carrier of an epidemic) out of birds that would otherwise recover in a few days. When asked why at least one study correlating the data to aerial spray couldn't have been performed the reply was "it would be unethical."  How does it become ethical to proceed without the scientific test and blanket the entire City with pesticides?

    3)  The aerial spray does not work.  The two studies put forward that claim to show this in fact don't prove any such thing. The DHS "study" is flawed beyond any scientific legitimacy.  There are 44 of the 154 cases of symptomatic disease, nearly 1/3 of the sample, that are completely unaccounted for, though they pad the claim of total infections.  That the DHS didn't even attempt to localize the situations where patients may have had their unfortunate encounters with mosquitoes is poor enough science as it is, but misplacing 44 patients seems stunning to us.  These persons may all have been homeless and "squatting" in certain well-known areas that were in fact under the spray.  If so, including them correctly might spoil the appearance of the DHS "proof".  

    With all that aside, the report lacks the necessary correlate to the mosquito population to be demonstrative of anything like proving a causality between the spray and the WNV "epidemic."  This kind of proof must come from sampling both the mosquito population and the human disease incidence and showing a decline in both consequent to spray.

    4) There are chemically sensitive individuals who are being dismissed by "the experts," but they are human beings with human rights. None of them is producing a mosquito nuisance, and vector control has no right or authority to spray their persons or properties.  This fits right in with the inappropriate application of the insecticidal agents that both we and "the experts" agree should be discontinued.