http://www.cdc.gov/niosh/topics/westnile/recout.html
National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention
Workers at risk of West Nile Virus (WNV) exposure include those working outdoors when mosquitoes are actively biting—farmers, foresters, landscapers, groundskeepers and gardeners, painters, roofers, pavers, construction workers, laborers, mechanics, and other outdoor workers. Workers can take steps to reduce their risk of WNV infection.