OSHA, the U.S. Department of Labor and Centers for Disease Control are all actively encouraging workers who are outside for the bulk of the day in the Southern USA to take steps to protect themselves from zika virus exposure. Mosquitos carrying the virus are more likely to bite during the day. Tips for preventing Zika and other mosquito-borne diseases include:
OSHA has set up a website to educate workers about prevention techniques: https://www.osha.gov/zika/ for comprehensive information. The site also provides a Spanish version of the interim guidance, and a QuickCard for outdoor workers in English and Spanish.
Learn more from the DOL: https://blog.dol.gov/2016/08/02/how-to-protect-workers-from-zika-exposure/
Learn more from the CDC: http://www.cdc.gov/zika/