The Zika virus is a mosquito-borne disease that can also spread through sexual contact and from a pregnant person to a fetus. It gained worldwide attention after being linked to microcephaly (a birth defect where the head is much smaller than expected) and other serious defects, so pregnant people and travelers still need to pay attention to current guidance.
What is the Zika virus?
The Zika virus was first identified in Uganda in 1947. It later caused major outbreaks in the Pacific and the Americas, but global transmission declined after 2017 and continues at lower levels in some countries.
Zika has been associated with Guillain-Barré syndrome, a rare neurological condition that can cause progressive muscle weakness and may require hospitalization. However, most people infected with Zika do not develop symptoms.
In order for Zika to spread widely, it needs both infected people and mosquito vectors, especially Aedes mosquitoes. It can also spread through sex and from a pregnant person to a fetus, so mosquito control is only one part of prevention.
How does the Zika virus affect pregnant people?
Zika infection during pregnancy can be serious because the virus can cross the placenta and affect the fetus. It has been linked to microcephaly and other congenital brain and birth defects.
Does the United States have the mosquito that carries the Zika virus?
Yes. Aedes mosquitoes are present in the United States, including parts of Missouri, and they can transmit Zika if the virus is introduced. Missouri health officials note that the state has had travel-related Zika cases, but no reported cases from local mosquito bites.
Aedes mosquitoes are often active during the day and can bite at dawn and dusk as well. They breed in standing water, so removing water-holding containers around homes and work sites is an important prevention step. You can identify them by the black-and-white stripes on their legs and backs.
Are there people infected with Zika in the United States?
The Centers for Disease Control (CDC) says there is no current local transmission of the Zika virus in the continental United States. Current U.S. cases have been rare and primarily travel-associated rather than locally acquired.
After a person is bitten by an infected mosquito, the virus can incubate for a short period before infection develops. If another mosquito bites that person during the infectious period, the mosquito can pick up the virus and potentially spread it onward.
What are the symptoms of the Zika virus?
Some of the symptoms of the Zika virus include:
- Fever.
- Itchy rash.
- Red eyes.
- Joint pain.
- Muscle aches.
- Pain behind the eyes.
- Headache.
Most infections cause no symptoms. When symptoms do occur, they are usually mild and often do not require hospitalization.
How To Reduce Your Risk of the Zika Virus
The best way to lower your risk is to prevent mosquito bites, especially if you are pregnant, trying to conceive, or traveling to an area where Zika is active.
Tips to Avoid Mosquito Bites:
- Stay indoors when possible and use air conditioning or screened windows and doors.
- Wear long, light-colored clothing, and cover exposed skin.
- Remove standing water around your home, including flowerpot saucers, buckets, tires, gutters, and other containers.
- Use a fan outdoors when possible, since mosquitoes are weak fliers in moving air.
For Travelers
Before traveling, check whether your destination has a current Zika risk. The CDC now classifies destinations by geographic risk, and pregnant travelers should avoid areas with an active CDC Zika Travel Health Notice if possible. If travel is unavoidable, they should strictly follow precautions to prevent mosquito bites and sexual transmission during and after travel.
If you travel to an area with current or past Zika transmission, take steps to prevent mosquito bites after you return as well, since preventing mosquito exposure helps reduce the chance of local spread. Current CDC guidance says travelers returning from areas with current or past transmission should prevent mosquito bites for 3 weeks after return.
People who may have been exposed should also follow current guidance to reduce sexual transmission risk, especially if a partner is pregnant. CDC’s current recommendations vary by exposure category and destination risk level, so it is best to check the most recent CDC travel guidance before and after travel.
Is the Zika virus in Missouri?
There is no reported local mosquito-borne Zika transmission in Missouri. Missouri health officials note that the state has seen travel-related cases, but no cases from local mosquito bites.
If that changes, public health officials will update their advice about mosquito precautions and local risk. In the meantime, basic mosquito prevention is still a smart habit during warm months.
As always, the poison center is available 24/7 to answer any questions you may have at 1-800-222-1222.
Frequently Asked Questions
There is no specific antiviral treatment for the Zika virus. Care is usually supportive, which means resting, drinking plenty of fluids, and using over-the-counter medicine for fever or pain as directed by a healthcare provider. People who may have Zika should avoid aspirin and other nonsteroidal anti-inflammatory drugs until dengue fever has been ruled out, because those medicines can increase bleeding risk in some mosquito-borne illnesses.
Mosquito lifespans vary by species, temperature, humidity, and access to food and water. In general, many adult mosquitoes live for about a few weeks, though some can survive longer under favorable conditions. Reducing standing water helps break the breeding cycle, which is more effective than trying to target only adult mosquitoes.
Mosquitoes are not strongly attracted to light in the same way moths are. They are more drawn to body heat, carbon dioxide, sweat, skin odors, and dark clothing. Outdoor lights may make it easier for you to notice mosquitoes, but light itself is not the main thing drawing them in.
Wash the bite with soap and water, then apply a cold compress to help reduce swelling and itching. You can also use an over-the-counter anti-itch cream, calamine lotion, or an oral antihistamine if needed. Try not to scratch the bite, since that can irritate the skin and increase the chance of infection.
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Suggested APA citation:
Missouri Poison Center Trending Topics Blog. (2016, August 24). The Zika Virus & How To Avoid Mosquito Bites. Missouri Poison Center. https://missouripoisoncenter.org/zika-virus-and-mosquitos.