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:

• When working outdoors, wear clothing that covers the hands, arms, legs, and other exposed skin. Wear mosquito netting over your hardhat to protect the face and neck. 
• Use insect repellent with an EPA-registered active ingredient, and always follow label precautions and manufacturer instructions for use.
• Get rid of sources of standing water (tires, buckets, cans, bottles, barrels) whenever possible to reduce or eliminate mosquito breeding areas.

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/