Figure 1. . . Comparison of risk estimates to human case occurrence for WNF and WWND, Los Angeles, California, USA. A) CMVRA estimates by using Culex pipiens quinquefasciatus mosquitoes collected by gravid traps. Dashed lines refer to the risk assessment thresholds of emergency planning at 2.6 and epidemic at 4.1. B) Vector index calculated with Cx. p. quinquefasciatus collected by gravid traps. Lines show risk levels discussed in text. C) Weekly counts of positive DYCAST grid cells compared with human case counts. WNF, West Nile fever; WWND, West Nile neuroinvasive disease; CMVRA, California Mosquito-Borne Virus Risk Assessment; DYCAST, Dynamic Continuous-Area Space-Time system.