| repeated west nile virus epidemic transmission in kern county, california, 2004-2007. | west nile virus (wnv) has remained epidemic in kern county, ca, since its introduction in 2004 through 2007 when the human case annual incidence increased from 6-8 to 17 per 100,000, respectively. the 2007 increase in human infection was associated with contradicting surveillance indicators, including severe drought, warm spring but cool summer temperature anomalies, decreased rural and urban mosquito abundance but increased early season infection in urban culex quinquefasciatus say, moderate av ... | 2009 | 19198528 |