West Nile Virus Activity 201120122013201420152016201720182019202020212022 Birds015189719112200720Mosquitoes000161620150000 Horses000000000000 Humans020100100000 2021 Alameda County WNV activity2020 Alameda County WNV activity2018 Alameda County WNV activity2017 Alameda County WNV activity2016 Alameda County WNV activity2015 Alameda County WNV activity2014 Alameda County WNV activityCalifornia West Nile virus activityNational West Nile virus activity