Table 1.

Summary of the 2004 analysis grid containing the possible actions according to the degree of virus activity.

Situation	Possible actions
No virus activity	- Verify the dead Corvidae reports - Maintain preventive activities (media)
Possible source of infection (infected Corvidae found)	- Target the geographical zone of activity and determine the population density - Assess clusters of dead Corvidae - Plan for mobile mosquito monitoring - Closely monitor equine cases - Maintain preventive activities (media)
Probable source of infection (infected mosquitoes or both infected Corvidae and infected mosquitoes found)	- Target the geographical zone of activity and determine the population density - Prioritise the analysis of dead Corvidae in the affected region - Assess clusters of dead Corvidae - Assess mosquito pool information (species and positivity) - Closely monitor equine cases - Integrate meteorological data into the analysis - Consider insecticide treatments - Increase preventive activities (media)
Confirmed source of infection (human cases detected)	- Associate probabilities with potential acquisition site - Target the geographical zone of activity and determine the population density - Prioritise the analysis of dead Corvidae in the affected region - Assess clusters of dead Corvidae - Assess mosquito pool information (species and positivity) - Closely monitor equine cases - Integrate meteorological data into the analysis - Consider insecticide treatments - Increase preventive activities (media)