The not-so-deadly West Nile Virus

[Michael Gochfeld]

As a public health professional who has had several opportunities to be 
responsible for controlling vector borne diseases (including by massive 
use of pesticides, including DDT) as well as studying them, I feel 
compelled to comment on the spraying issue vis-a-vis West Nile virus. 

Contrary to the 1999 news media in New York and the 2001 news media in 
Florida, West Nile is NOT a particularly deadly virus. And compared with 
many other public health problems it is a NEGLIGIBLE cause of mortality. 

The basis for this is given in the attached article which I completed 
last week. 

Whether or not there are risks to humans from the pesticides, there is 
little evidence that the pesticide use has been beneficial in reducing 
the risk of West Nile to humans (or to crows, if you're concerned about 
their health). 

Does anyone find it remarkable that there are no published accounts of 
the efficacy of spraying in controlling West Nile (or even the 
mosquitoes). 

Likewise, although there are abundant published accounts about the 
numbers of dead birds showing up from southern Canada to the Gulf Coast, 
denominator information is lacking.  Are 10 infected crows a lot or a 
little.  It's very difficult to tell because there are virtually no 
published accounts of the numbers of birds tested.  However, the few 
data points indicate that even for crows (a species especially sensitive 
to West Nile virus), fewer than half of the birds tested are positive 
for WNV.  Moreover, overall in NJ and NY, in the past two years more 
dead birds have succumbed from pesticide poisoning than from WNV 
according to state veterinarians. 

My argument is that it is not a case of human health vs ecological 
health, but that human health has benefitted little, if at all, from the 
spraying.  Moreover, in 1999 when the media was besotted with spraying, 
it failed to convey the messages from CDC and other agencies, regarding 
how people could reduce exposure to mosquitoes through control of 
breeding places. 

As the attached article based on CDC publications and web sites 
explains, only a minute proportion of people who become infected 
with WNV (generally less than a half or tenth of 1%) get seriously ill 
(of these about 10% die). The vast majority experience NO SYMPTOMS AT 
ALL.  They are only discovered when random serologic surveys are 
conducted in presumed endemic areas. 

Compared with the 2400 deaths in New Jersey from influenza and pneumonia 
in the year 2000, the one death from West Nile seems paltry (except to 
the family of the victim, of course).  

Moreover, West Nile isn't even a major cause of encephalitis/meningitis, 
causing only about 5% of the cases that occurred in the tri-state area 
in 2000. 

Call me when there is an epidemic of Eastern Equine, a disease that 
kills 25% or more of those infected, and shows a propensity for young 
people and children (who are apparently resistant to WNV). 

And while we're at it, compare the risks of slathering toddlers with the 
neurotoxic DEET to the negligible risk of West Nile infection in 
children. 

Balancing risks is important. MICHAEL GOCHFELD
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