A MAD'S WNV RISK CONSIDERATIONS

How would you assess the WNV risk in this hypothetical situation?

Gravid traps are set nightly to collect mosquitoes.

The VecTest was used to test for WNV using 50 mosquitoes/pool.

WNV positive birds were reported in May and steadily increased throughout the
state there after.

WNV positive mosquito pools are reported over a multi-county area and then
the state. A multitude of gravid trap samples test positive with the VecTest
at varying intensity (although the VecTest is only a qualitative test the
color intensity of the positive band does indicate relative viral titers)
indicating either one WNV positive mosquito per pool with varying viral
titers (super infective?) or perhaps multiple infected mosquitoes from the
same test pool.

A multitude of infected horses and other mammals are reported throughout the
state.

Sporadic human cases appear.

You get consecutive nightly WNV positive mosquito pools in ONE gravid trap
(most traps do not show consecutive positive pools). During one of those
consecutive evening collections you collect enough Culex to VecTest 3
mosquito pools from the same gravid trap and two of them are WNV positive.

The human cases continue to increase quickly in a major metropolitan area and
sporadically throughout the state.

MY QUESTION IS: How do you appropriately and simultaneously describe this
risk to:

The state?
At the county level?
At the city level?
The neighborhood around your consecutively WNV positive gravid trap?
The resident providing space for your consecutively WNV positive gravid trap
in their backyard?

Michael Szyska, Director

Northwest Mosquito Abatement District
147 W. Hintz Rd.
Wheeling, IL. 60090

847-537-2306 ext 22
847-537-2583 (fax)
Received on Tue Oct 29 10:25:51 2002