Three weeks of repellent after you get home, for everyone else's sake

Zika virus disease is prevented in two ways: **protecting yourself from
mosquito bites**, and using condoms or not having sex.

Mosquito bites

Mosquitoes bite during the day and night — which rules out the common
assumption that dusk is the risky hour.

• Use an EPA-registered insect repellent
• Wear long, loose-fitting shirts and trousers
• Control mosquitoes indoors and outdoors, including window screens

The instruction that is not about you

**Even if someone does not feel sick, people returning to the United States
from an area with a risk of Zika should take steps to prevent mosquito bites
for 3 weeks, so they do not spread Zika virus to uninfected mosquitoes at
home.**

Three weeks of repellent after a holiday, while feeling entirely well, to
protect people you will never meet.

This is how a virus establishes itself somewhere it was not: an infected
traveller is bitten at home, the local mosquito becomes infected, and
transmission begins in a place with no travel history at all. Most people with
Zika have no symptoms, so "I feel fine" carries no information here.

Sex

The timeframes for males and females differ, because **the virus can stay
in semen longer than in other body fluids.**

Which means the precaution period after travel is not the same for both
partners, and the longer one governs.

Source: Centers for Disease Control and Prevention.