Plots below: Top: Measureand and estimated mosquito infection rate (MIR) for 2017, measured MIR for 2012, and the 2005-2013 average MIR by Climate Division. In 2017, Week 15 ends on April 14, Week 30 ends on July 28, week 40 ends on October 6, and Week 45 ends on November 10. Lines can be turned off and on, scales can be expanded, and actual values can be viewed using a mouse. Bottom: Historical (2004-2013) plots of measured MIR and number of human cases per Week.
Years following warm and dry winters as well as hot dry summers are most conducive to high numbers of human WNV cases and high values of MIR. Few cases of WNV are found during wet summers that are either cool or hot. Cool, but dry conditions often result in a late start to the WNV season.