Infectious Disease

Stopping the Spread: Prevention and Transmission

At a Glance

Zika virus is spread through Aedes mosquito bites, sexual contact, and from a pregnant person to their fetus. Prevention requires using EPA-registered insect repellents, wearing protective clothing, and observing strict waiting periods (2-3 months) for unprotected sex after traveling.

Preventing the spread of Zika requires a “layering” approach to protection. Because the virus can be passed through physical contact as well as mosquito bites, you must manage several different types of risk simultaneously to keep yourself and your family safe.

The Three Routes of Spread

1. Mosquito-to-Human

The most common way the virus spreads is through the bite of an infected Aedes mosquito ^[1].

The Environment: These mosquitoes live near people and are most active during the daytime, particularly around sunrise and sunset ^[2].

2. Sexual Transmission

Unique among most mosquito-borne illnesses, Zika can be transmitted through sex ^[1].

Persistence in Semen: The virus can hide in the prostate and survive in semen for much longer than it stays in the blood ^[3].
Silent Spread: You can pass Zika to a partner even if you never had symptoms ^[4].

3. Vertical Transmission

This occurs when a pregnant person passes the virus to their fetus during pregnancy ^[5].

Prevention Checklist: Mosquito Bites

Choose the Right Repellent: Use EPA-registered insect repellents. Look for active ingredients like DEET, Picaridin, IR3535, or Oil of Lemon Eucalyptus ^[6]^[7]. DEET and Picaridin are generally considered safe for use during pregnancy ^[8].
Dress for Defense: Wear long-sleeved shirts and long pants. You can also treat your clothing with permethrin, an insecticide that kills mosquitoes on contact ^[9].

Prevention Checklist: Sexual Transmission & Family Planning

To protect partners—especially those who are pregnant or may become pregnant—strict timelines for “safer sex” (using condoms or abstaining) are required. These waiting periods apply regardless of whether the traveler ever developed symptoms.

Who Traveled?	Waiting Period (Condoms or Abstinence)
Men	At least 3 months after returning or after symptoms begin ^[10]^[11].
Women	At least 2 months after returning or after symptoms begin ^[10].
During Pregnancy	If a partner has traveled, couples should use condoms or abstain for the entire duration of the pregnancy ^[10].

A Note on Fertility Treatments: If you are undergoing fertility treatments like IVF, you and your partner must strictly observe these exact same travel avoidance and waiting period guidelines before transferring an embryo.

Travel Considerations for Pregnancy

Health organizations strongly advise that pregnant individuals should not travel to areas with active Zika outbreaks ^[12]. If travel is absolutely necessary, it is vital to talk with a healthcare provider first and follow the bite prevention checklist with 100% consistency.

Common questions in this guide

How is the Zika virus spread?

Zika is primarily spread through the bite of infected Aedes mosquitoes during the daytime. It can also be transmitted sexually and passed from a pregnant person to their fetus.

Can you pass Zika to a partner if you don't have symptoms?

Yes, you can transmit the Zika virus to a sexual partner even if you never develop any symptoms. The virus can hide in the prostate and remain in semen, making it contagious without causing the infected person to feel ill.

How long should we wait to have unprotected sex after traveling to a Zika area?

Men should wait at least 3 months after returning from a Zika area or after their symptoms begin. Women should wait at least 2 months. During this waiting period, couples must use condoms or abstain from sex to prevent transmission.

Are mosquito repellents safe to use if I am pregnant?

Yes, EPA-registered insect repellents containing active ingredients like DEET and Picaridin are generally considered safe for use during pregnancy. It is highly recommended that pregnant individuals use these repellents to prevent mosquito bites.

Curated prompts to bring to your next appointment.

1.Which specific brands of insect repellent do you recommend as safest for use during pregnancy?
2.If my partner traveled but I didn't, exactly how many weeks must we use condoms?
3.We are undergoing IVF; do these waiting periods apply to embryo transfer?

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References (12)

1
Male-to-Male Sexual Transmission of Zika Virus--Texas, January 2016.
Deckard DT, Chung WM, Brooks JT, et al.
MMWR. Morbidity and mortality weekly report 2016; (65(14)):372-4 doi:10.15585/mmwr.mm6514a3.
PMID: 27078057
2
Experimental transmission of Zika virus by mosquitoes from central Europe.
Heitmann A, Jansen S, Lühken R, et al.
Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin 2017; (22(2)).
PMID: 28106528
3
Replication of Zika Virus in Human Prostate Cells: A Potential Source of Sexually Transmitted Virus.
Spencer JL, Lahon A, Tran LL, et al.
The Journal of infectious diseases 2018; (217(4)):538-547 doi:10.1093/infdis/jix436.
PMID: 28968863
4
An autochthonous case of Zika due to possible sexual transmission, Florence, Italy, 2014.
Venturi G, Zammarchi L, Fortuna C, et al.
Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin 2016; (21(8)):30148.
PMID: 26939607
5
Dynamics and optimal control of a Zika model with sexual and vertical transmissions.
Huo HF, Fu T, Xiang H
Mathematical biosciences and engineering : MBE 2023; (20(5)):8279-8304 doi:10.3934/mbe.2023361.
PMID: 37161197
6
Repellents against Aedes aegypti bites: synthetic and natural origins.
Noguera-Gahona M, Peña-Moreno C, Quiñones-Sobarzo N, et al.
Frontiers in insect science 2024; (4()):1510857 doi:10.3389/finsc.2024.1510857.
PMID: 39911593
7
An updated review on the safety of N, N-diethyl-meta-toluamide insect repellent use in children and the efficacy of natural alternatives.
Ghali H, Albers SE
Pediatric dermatology 2024; (41(3)):403-409 doi:10.1111/pde.15531.
PMID: 38682561
8
The toxicity of picaridin containing insect repellent reported to the National Poison Data System.
Charlton NP, Murphy LT, Parker Cote JL, Vakkalanka JP
Clinical toxicology (Philadelphia, Pa.) 2016; (54(8)):655-8 doi:10.1080/15563650.2016.1186806.
PMID: 27213820
9
Technological Advancements in Mosquito Repellents: Challenges and Opportunities in Plant-Based Repellents.
Hazarika H, Krishnatreyya H
Acta parasitologica 2025; (70(3)):117 doi:10.1007/s11686-025-01054-7.
PMID: 40434490
10
Update: Interim Guidance for Prevention of Sexual Transmission of Zika Virus--United States, 2016.
Oster AM, Russell K, Stryker JE, et al.
MMWR. Morbidity and mortality weekly report 2016; (65(12)):323-5 doi:10.15585/mmwr.mm6512e3.
PMID: 27032078
11
Sexual Transmission of Zika Virus and Persistence in Semen, New Zealand, 2016.
Harrower J, Kiedrzynski T, Baker S, et al.
Emerging infectious diseases 2016; (22(10)):1855-7 doi:10.3201/eid2210.160951.
PMID: 27454745
12
Zika Virus -10 Public Health Achievements in 2016 and Future Priorities.
Oussayef NL, Pillai SK, Honein MA, et al.
MMWR. Morbidity and mortality weekly report 2017; (65(52)):1482-1488 doi:10.15585/mmwr.mm6552e1.
PMID: 28056005

This page provides information on Zika virus prevention for educational purposes only. Always consult a healthcare provider or travel medicine specialist before making travel or family planning decisions.

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