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What You Need to Know About the Zika Virus

Zika transmission

What is Zika?

Zika is a disease caused by a virus primarily transmitted through the bite of infected Aedes mosquitoes. Most people who are infected with Zika do not develop symptoms. About one in five people infected with the virus develop the disease and symptoms are generally mild. Anyone who lives or travels in the impacted areas can be infected.

For printable facts and information on Zika and mosquito control, visit: (English); (Español); (kreyòl ayisyen)

To learn more to protect employees working outdoors, visit (English) and (Español).

The most common symptoms of Zika virus are fever, rash, joint pain, or conjunctivitis (red eyes). Symptoms typically begin two to seven days after being bitten by an infected mosquito. It can also be transmitted during sexual activity, or from a pregnant mother to her baby during pregnancy or around the time of birth. We do not know how often Zika is transmitted from mother to baby during pregnancy or around the time of birth.

In May 2015, the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika virus infection in Brazil. The outbreak in Brazil led to reports of Guillain-Barré syndrome and pregnant women giving birth to babies with birth defects and poor pregnancy outcomes.

Areas with Active Zika Virus Transmission

Those who recently traveled or plan to travel to areas where Zika transmission is ongoing could be at risk. For the latest Centers for Disease Control and Prevention (CDC) list of countries, visit:

Potential for Birth Defects

Zika is generally a mild illness, but there have been very few reports of potential links to Guillain-Barré syndrome (GBS); however, it is not yet known if Zika virus infection causes GBS.

The largest health impact of the Zika virus appears to be on infants whose mother was infected during pregnancy. There have been reports of a serious birth defect of the brain called microcephaly, a condition in which a baby's head is smaller than expected when compared to babies of the same sex and age, as well as other poor pregnancy outcomes in babies of mothers who were infected with Zika virus while pregnant.

Travel and Transmission Advisories

  • If you are pregnant, postpone travel to the locations where Zika virus transmission is ongoing. If your sexual partner has traveled to or lives in an area with active Zika virus transmission, barrier methods (condoms, dental dams) should be used for the duration of the pregnancy. Although no cases of woman-to-woman Zika transmission have been reported to date, these recommendations regarding the use of protection now extend to the female partners of pregnant women. Discuss your partner's potential exposures and history of Zika-like illness with your doctor.
  • If you are trying to become pregnant and have had possible exposure to Zika virus through travel or sexual contact, wait at least eight weeks before trying to conceive, regardless of whether or not you had symptoms. Men who have had possible exposure to Zika virus through travel or sexual contact are advised to wait at least six months before attempting conception with their partner.
  • If your male or female partner lives in an area with active Zika transmission, use barrier methods (condoms and/or dental dams) while there is active Zika virus transmission in the area. Sex includes vaginal, anal, and oral sex, and the sharing of sex toys.
  • If you are pregnant or may become pregnant and must travel to an area with Zika, talk to your doctor first and strictly follow steps to prevent mosquito bites and sexual transmission of Zika during your trip. If you traveled to an area with active Zika virus transmission up to eight weeks before your pregnancy was confirmed, discuss your travel history with your doctor.
  • Couples who are not pregnant and not planning to conceive in the near future, and who include at least one partner who had possible Zika virus exposure through travel or sexual contact should use condoms and/or dental dams correctly and consistently for at least six months for men and eight weeks for women to maximally reduce their risk for sexually transmitting the Zika virus.

Women who are pregnant or planning to become pregnant can find more information by visiting:

Mosquito Information and Prevention Strategies

The mosquito that most commonly transmits Zika (Aedes aegypti), as well as dengue and chikungunya, is very rare in Delaware. But we do have another Aedes species of concern for possible transmission of Zika, the Asian tiger mosquito, Aedes albopictus. Local Zika transmission via a mosquito is possible during mosquito season but it depends on a variety of factors. Regardless of the type of illness, the message is the same for every mosquito season and during travel: always protect yourself from bites. There are too many serious mosquito-borne illnesses to risk a bite.

To prevent mosquito bites:

  • Wear long-sleeved shirts and long pants.
  • Stay in places with air conditioning or that use window and door screens to keep mosquitoes outside.
  • Use Environmental Protection Agency (EPA)-registered insect repellents. All EPA-registered insect repellents are evaluated for effectiveness.
    • Always follow the product label instructions.
    • Reapply insect repellent as directed.
    • Do not spray repellent on the skin under clothing.
    • If you are also using sunscreen, apply sunscreen before applying insect repellent.
  • If you have a baby or child:
    • Do not use insect repellent on babies younger than 2 months of age.
    • Dress your child in clothing that covers arms and legs, or
    • Cover crib, stroller, and baby carrier with mosquito netting.
    • Do not apply insect repellent onto a child’s hands, eyes, mouth, and cut or irritated skin.
    • Adults: Spray insect repellent onto your hands and then apply to a child’s face.
  • Treat clothing and gear with permethrin or purchase permethrin-treated items.
    • Treated clothing remains protective after multiple washings. See product information to learn how long the protection will last.
    • If treating items yourself, follow the product instructions carefully.
    • Do NOT use permethrin products directly on skin. They are intended to treat clothing.
  • Sleep under a mosquito bed net if you are overseas or outside and not able to protect yourself from mosquitos.

Health care providers are required to report individuals with known or suspected Zika virus infection.

Zika, and many other mosquito-borne illnesses are considered "mandatory reports", meaning that health care providers are required to report individuals with known or suspected Zika virus infection to the Division of Public Health (DPH). This includes anyone with known or suspected Zika, but reporting is especially important in the cases of pregnant women, as well as newborns and infants born to women with known or suspected Zika infection.

Because of the similar geographic distribution and clinical presentation of Zika, dengue, and chikungunya virus infection, patients with symptoms consistent with Zika virus should also be evaluated for dengue and chikungunya virus infection, in accordance with existing guidelines.

To report a case of Zika virus or for further information, call the DPH Office of Infectious Disease Epidemiology at 302-744-4990 or fill out one of the forms below and fax or email to the Office of Infectious Disease Epidemiology at 302-223-1540 or

Providers are also encouraged to contact a DPH infectious disease epidemiologist prior to collecting specimens as all testing must be pre-authorized. At the time of this call, the epidemiologist will gather necessary travel and clinical history and assist with specimen coordination if testing is authorized.