PMC

Map of Indian River County. Asterisks indicate the locations of sentinel chicken flocks. “M” is the site of the Vero Beach 4W meteorologic station.

The 1989 and 1990 distributions of daily collected female Culex nigripalpus plotted as a function of water table depth (WTD), same day. a) The 1989 distribution; b) the 1990 distribution.

Real-time forecast of the probability of epidemic St. Louis encephalitis virus transmission in Indian River County, Florida, July–October 2002, with 95% confidence intervals. Also shown are the weekly climatologic probabilities of epidemic St. Louis encephalitis virus transmission.

Time series of weekly, retrospective epidemic St. Louis encephalitis virus transmission forecast probabilities, January 1998–June 2002, with 95% confidence intervals. Also shown are the weekly, epidemic SLEV transmission probabilities as would be predicted from climatology (1978–1997).

Time series of study data 1978–1997. The blue line is weekly modeled water table depth (WTD); the black bars are the weekly percentages of posted sentinel chickens in Indian River County testing positive for hemagglutination inhibition antibodies to St. Louis encephalitis virus.

a) Best-fit bivariate logistic regression model of epidemic St. Louis encephalitis virus (SLEV) transmission based on the 1986–1991 record. Plotted for a continuous range of modeled water table depths (WTD) 11 weeks before transmission and fixed values of current modeled water table depths. b) Best-fit logistic regression model of epidemic SLEV transmission based on the 1978–1997 sentinel chicken record. Only antecedent drought conditions are statistically significant. Plotted for a continuous range of modeled water table depths 16 weeks before transmission.