Zika Virus Causes, Symptoms, and Treatments

The Zika virus is spread by mosquitos.

What is the Zika Virus?

The Zika virus is a Flavivirus related to dengue fever, West Nile virus, yellow fever, and Japanese encephalitis viruses. Zika fever, as it is also known, is transmitted to humans through bites from a mosquito infected with the Zika virus. Common Zika infection symptoms include rash, fever, and joint pain as well as inflammation of the conjunctiva of the eyes, leading to redness. Typically the illness is mild and lasts from a few days to a week. Serious illness is rare, but in February 2016 the World Health Organization declared Zika virus infections as a public-health emergency due to severe birth defects associated with Zika infections during pregnancy.

Current Zika virus active transmission zone according to the CDC.

Where Did The Zika Virus Come From?

The Origin of Zika Virus

Zika virus received its name from its place of origin, the Zika Forest of Uganda. In 1947 the Zika virus was isolated and identified in Uganda. Blood tests from patients in 1951-1981 concluded that the Zika virus had spread to other African countries and even Indonesia.

Zika Outside of Africa and Indonesia

In 2007, Zika virus was found on Yap Island in the Indo-Pacific, which was the first documented account of the virus outside of Africa or Indonesia. Zika virus has continued to spread to North and South America. The first confirmed Zika outbreak in Brazil was reported in May 2015. Zika virus has continued to travel spread globally with Zika virus outbreaks now in Puerto Rico, the Caribbean, Mexico, and the United States.

No Zika virus vaccine is available.

Is There a Zika Virus Vaccine?

As of now, there is no vaccine available to prevent Zika virus infection. The best method of prevention is avoiding mosquito bites. The mosquitoes that transmit Zika virus are most active during the daytime. These mosquitoes transmit other viruses that can cause illness, including dengue and chikungunya virus.

Different species of mosquitoes carry different viruses.

Zika Infection Spread by Mosquitoes

Two species of mosquito, Aedes aegypti and Aedes albopictus are the typical vectors (carriers) of Zika virus. These are the same species of mosquitoes that can carry and spread dengue and chikungunya viruses. Mosquitos lay eggs in or near sources of standing water, in locations such as animal dishes, ponds, tires, buckets, or plant and flower pots. Aedes mosquitos live both indoors and outdoors and bite people most often in the daytime. If the mosquito bites a person infected with Zika, the mosquito becomes infected with Zika virus and can spread the virus when it bites another person.

Preventing mosquito bites can help prevent the spread of Zika virus.

Zika Prevention: Adults and Mosquito Bites

If you are concerned about preventing Zika virus infection, avoid mosquito bites by the following measures:

  • Cover as much skin as possible by wearing long sleeves and long pants.
  • When indoors, stay in areas with air conditioning or window and door screens.
  • Use a mosquito bed net if your sleeping area is open to the outdoors.
  • Treat gear and clothing with permethrin and follow directions for proper use. You can also purchase permethrin-treated products. Do not use permethrin directly on skin.

What Type of Bug Spray Should I Use to Prevent Zika Virus Spread?

Use insect repellents that are U.S. Environmental Protection Agency (EPA)-registered, and use them as directed. It is important that your repellent includes one of the following active ingredients:

  • DEET
  • Picaridin
  • IR3535
  • Oil of lemon eucalyptus
  • Para-menthane-diol (PMD)

Is Bug Spray Safe During Pregnancy?

Yes. According to the U.S. Centers for Disease Control (CDC), if used correctly EPA-registered insect repellents are safe and effective for pregnant and breast-feeding women. A study in Thailand, consisting of 900 pregnant women, proved that there were no harmful effects to their babies after giving birth when DEET was used during pregnancy.

Protect children from Zika virus by preventing mosquito bites.

Zika Prevention: Children, Babies, and Mosquito Bites

Protecting your child from mosquito bites can be done by covering the crib, baby carrier, or stroller with mosquito netting. Dress your child in long sleeves and long pants, keeping skin covered when possible. Do not use insect repellent on a child's hands, eyes, mouth, or on injured or cut skin.

Is Bug Spray Safe For Babies?

Never use insect repellent on babies younger than 2 months. Alternatively, use bug netting and avoid locations where mosquitos are present. Insect repellent containing DEET may be used on children older than 8 weeks. Products containing picaridin are considered safe once your child is over 2 years old. After your child turns 3, insect repellent containing PMD and oil of lemon eucalyptus are considered safe to use.

Bug Spray Tips for Parents

  • Insect repellents should only be used on exposed skin and clothing.
  • Wash off repellent at the end of the day with soap and water. Sleeping with repellents on increases the absorption of the chemicals into the skin.
  • Apply insect repellent to a child's face by spraying it onto your hands and then wiping the child's face.

Zika virus can be spread from human to human in some cases.

Zika Virus Spread from Human to Human

Can I Get Zika Virus from Having Sex?

Zika virus can be transmitted by a man to his sex partners. The Zika virus is present in semen longer than in blood. For this reason, physicians recommend the use of condoms to protect uninfected sex partners from getting the virus.

Zika Infection from Mother to Child

A pregnant women can infect her fetus with Zika virus during pregnancy or around the time of birth. As of now, there are no instances of infants acquiring Zika through breastfeeding.

Can I Get Zika from a Blood Transfusions?

Zika virus can be transmitted through blood transfusion. There have been many reports of Zika being transmitted through blood infusions in Brazil. During the Zika outbreak in the French Polynesian, 2.8% of blood donors tested positive for Zika. Do not donate blood if you have been possibly been exposed to possible Zika virus infection.

If you have Zika virus, prevent the virus from spreading by preventing mosquito bites.

How Long Does Zika Virus Stay in The Blood Stream?

If infected with Zika it is important to prevent additional mosquito bites. For about a week after infection, the virus is found in the blood of an infected person. If a mosquito bites an infected person during this time, the mosquito becomes infected and can spread Zika virus to another person when it bites again.

On in five infected people show symptoms of Zika.

Zika Virus: Symptoms and Diagnosis

What are the Symptoms of Zika Infection (Zika Fever)?

Only 1 out of 5 patients people with Zika infection will show symptoms. Zika symptoms include fever, joint pain, rash, and conjunctivitis (reddened eyes). Headaches and muscle pain are other possible symptoms of a Zika virus infection. Symptoms may develop within a few days to a week after infection and last for several days to one week. Severe illness and death are rarely a result of a Zika virus infection.

How is Zika Virus Diagnosed?

Health-care professionals can diagnose patients by completing history and physical exams. It is important to reveal any recent travel to areas where Zika is active. A blood test or urine test can confirm a Zika infection. Blood tests can differentiate Zika from dengue fever or chikungunya virus infections.

Pregnant women should take care not to contract the Zika virus.

Zika Virus and Pregnancy

The Zika virus has an extreme effect on a developing fetus in pregnant women, creating dramatic and often life-threating birth defects. In rare cases, Zika infection may cause fetal death and loss of pregnancy.

Zika and Microcephaly

Zika virus infection during pregnancy can causeis associated with microcephaly, a birth defect in which the baby's head is unusually small and under-developed. Infants born with microcephaly may display the following symptoms as a result:

  • Balance and coordination problems
  • Developmental delays
  • Trouble swallowing and problems feeding
  • Hearing loss
  • Hyperactivity
  • Seizures
  • Speech and vision problems
  • Cranial abnormalities

Should Pregnant Women Avoid Travel?

Women who are pregnant or who want to become pregnant should avoid travel to areas with known local Zika virus transmission. If you must travel, discuss the situation with your doctor and take precautions to avoid mosquito bites.

CDC issues travel warning to pregnant women over Zika virus.

Future Pregnancies and the Zika Virus

Wanting to have a baby but are concerned about Zika virus exposure? Pregnancy planning and safe sex is an essential part of preventing the spread of the Zika virus and its associateds birth defects.

Women Who Live in or Travel to Zika Regions

Women who plan to become pregnant but live in a known Zika virus al region should consult a physician before trying to conceive. Waiting at least 8 weeks to conceive is a recommended precaution for women with Zika exposure.

Men Who Live in or Travel to Zika Regions

Men who have been diagnosed with Zika infections should wait at least 6 months before safely trying to conceive as Zika virus lives longer in sperm cells than it does in the blood stream. Men who have been traveling to a Zika region but with no known infection should wait a precautionary 8 weeks to attempt conception.

Treat the symptoms of Zika virus with rest and fluids.

Zika Virus Treatment

Treatment for Zika virus is directed at relieving the symptoms of infection. If diagnosed with Zika, get plenty of rest and drink fluids in order to prevent dehydration. Medications such as acetaminophen (Tylenol) can relieve fever and pain. Patients infected with Zika virus should avoid mosquito bites for the first week of the illness in order to prevent the spread of Zika to others.

Medications to Avoid with Zika Fever

Do not take aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and naproxen until a dengue fever diagnosis has been ruled out due to a heightened risk of bleeding.

Zika virus spreads to the U.S. and around the globe.

Zika Virus Travel Notices

The CDC is working with individual states to monitor the presence of Zika virus in the United States. Health-care providers are encouraged to report suspected cases of Zika infection to state or local health departments.

Zika virus outbreaks in United States Territories such as the Puerto Rico, the U.S. Virgin Islands, and American Samoa have been reported. Local spread of the Zika virus in some areas of the mainland U.S. where Aedes mosquitos are present is possible.

If traveling to regions with active Zika virus outbreaks, follow the appropriate measure to prevent mosquito bites. If pregnant, avoid traveling to regions with active Zika virus transmission or consult your physician.

For the latest travel notifications regarding Zika Virus visit the CDC: Zika Travel Information website.

The Aedes species of mosquito carries the Zika virus.

Testing for Zika Virus

Better methods for diagnostic testing to identify Zika virus infection are becoming available. Both urine and blood tests are available for patients within two weeks of symptom onset. Individuals who suspect they may have a Zika virus infection should seek immediate medical care and undergo testing.

Individuals looking to conceive should seek medical advice before trying to get pregnant if they or their partner has recently been traveling to known Zika transmission regions. Tests for Zika virus in semen are now available.

Improved Zika virus testing and laboratory studies are underway.

Zika Virus Research

Preparations for the first human trials of a Zika vaccine are under way. Researchers are testing the Zika DNA vaccine GLS-5700. Trials will include the assessment of the safety and effectiveness of the Zika vaccine. An effective Zika virus vaccine is needed to stop the Zika virus pandemic.



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  • U.S. Department of Health & Human Services: "Zika 101"
  • CDC: "Zika Virus"
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