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Date: Dec 10, 2002
Posted by: Norman Robbins (nxr@po.cwru.edu)

Dear West Nile List-Servers,

The following request will be sent to the head of CDC, Julie Gerberding, and also to CDC's Board of Scientific Counselors which meets on Dec. 12. I have incorporated many of the excellent comments and suggestions of members of this List-Serve, and ask you now to send me by direct e-mail (i.e. not to the List- Serve) a message indicating if you wish to be a co-signer. Please include your organizational position. There is no time to revise this request further, and I will need your replies no later than Tuesday Dec. 10 at 10 a.m. EST.

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It appears that much of CDC's West Nile Virus Response Program is based on expert opinion rather than scientific validation. This is a request for evidence-based recommendations (with supporting citations), an analysis of West Nile data to date, and a straightforward statement of uncertainty where the important questions listed below remain unanswered.

Specifically, we request that CDC provide resources and expertise to:

1. cull the literature and health department reports to document or qualify recommendations made by the CDC; and

2. perform CDC retrospective analysis of activities and outcomes in 1999-2002 to shed light on questions we will once again be debating in our communities in the next few months. We realize that there are many confounding variables in such studies, and that most operational programs have not had resources to carry out formal studies. Still, CDC has the expertise to select for analysis those cases nationwide where such variables happen to be minimal, and where adequate baseline data was obtained.

QUESTIONS FOR CDC:

What is the STATISTICAL EVIDENCE AND PROBABILITY RANGE (not opinion) that:

1. there is an optimal intensity, frequency, material and seasonal start-up time for larviciding?

2. URBAN adulticiding (at what intensity, frequency, area and method) reduces actual (not caged) mosquito populations, by species and for how long?

3. there are (or are not) acute or chronic human health effects of urban adulticiding in typical ULV amounts and frequency?

4. certain types of public messages or policies are more or less effective than others in reducing urban standing water (residential, public spaces, etc.), (including percentage of the public that follows the advice)

5. one or another type of surveillance (e.g. dead birds, gravid or C0-2/light traps, virus-positive mosquitoes, etc.) predicts human disease with what kind of probability range (and conversely that a certain number of negative birds predicts absence of WNV activity).

6. both gravid and C02/light traps are desirable for human disease prediction.

7. there is some level of mosquito density which predicts risk of animal or human disease and calls for more aggressive mosquito management

8. repellents prevent bites from Culex species in particular.

9. there is likely to be a higher proportion of seropositive humans within say 1 km of an index case.

None of the above questions about prediction, surveillance, etc. should be construed to imply that an integrated preventive mosquito management program is under question.

Norman Robbins Shaker Heights (OH) West Nile Task Force

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