Balancing the risks: vector control and pesticide use in response to emerging illness.

The competing public health concerns of vector-borne disease and vector control strategies, particularly pesticide use, are inherently subjective and difficult to balance. Disease response decisions must frequently be made in the absence of data or clear criteria. The factors to be weighed include the vector control measures versus those posed by the disease itself; short-term versus long-term disease management goals, specifically with regard to the issue of pesticide resistance; the need to distinguish among diseases of differing severity in making response choices; and the issue of pesticide efficacy. New York City's experience with West Nile virus has illustrated each of these issues. A framework for assessing the appropriate response to West Nile virus can serve to guide our response to likely new pathogens.