A mosquito-borne illness called the Zika virus is now spreading rapidly in South and Central America and the Caribbean, and it could arrive in the U.S. soon. It can make anyone sick for up to a week with symptoms like fever, rash, joint pain, and red eyes. But it's especially dangerous for women of childbearing age who are pregnant or considering pregnancy because it has been linked to microcephaly, a serious birth defect that causes an abnormally small head and incomplete brain development.

The outbreak has prompted the Centers for Disease Control and Prevention to issue a warning to take precautions for anyone traveling to 24 destinations in the Americas, but, most important, the CDC is recommending that all pregnant women should consider postponing their trip altogether. Here's what you should know to protect yourself and your family.

Why Zika Is So Concerning

The Zika virus normally does not cause illness that requires hospitalization or leads to death. Roughly one in five people infected with the virus develop symptoms, which are usually mild. The time from getting bitten to getting sick is likely to be a few days.

The Pan American Health Organization (PAHO) reports more than 16,000 Zika illnesses since the first cases were confirmed in Brazil in October 2015. Local transmission of the virus has been confirmed through lab testing in several countries in the Americas.

"The number of cases being reported is significantly lower than the actual number of cases." says Candice Burns Hoffmann, a CDC spokeswoman. "Many countries do not regularly test for Zika virus. Also, once the outbreak becomes common in an area, most people will not go to the doctor or get tested for the virus."  

Brazil has reported 4,180 cases of microcephaly, according to The New York Times, and Colombia has reported Zika infections in 1,090 pregnant women, a spokeswoman for PAHO told Consumer Reports. In addition, Guillain-Barré syndrome, which causes muscle weakness and sometimes paralysis, has been reported in patients with a probable Zika infection in French Polynesia and Brazil. The CDC says it is examining the link between Zika and the disorder.

Because there is neither a vaccine nor medication available to prevent a Zika virus infection, the American College of Obstetricians and Gynecologists recommends that women who are pregnant or considering pregnancy follow CDC guidelines and delay travel to those regions where Zika outbreaks are occurring.

"There is much that we do not yet know about the Zika virus," Mark S. DeFrancesco, M.D., president of the ACOG, said in a statement. "However, because of the associated risk of microcephaly, avoiding exposure to the virus is best." Women who have traveled to South and Central America and the Caribbean should be evaluated for Zika virus infection.  

How to Prevent Bites

For those who are planning to travel in spite of the warnings, the CDC asks that pregnant women, women who are trying to become pregnant, and everyone else should strictly follow steps to protect themselves. Because the mosquitoes that spread Zika are aggressive daytime biters and live indoors and outdoors, it's especially important to follow the CDC's precautions during daylight hours.

That includes using insect repellent containing deet, picaridin, lemon eucalyptus, or IR3535. All have been approved by the Environmental Protection Agency for use during pregnancy. Also wear long-sleeved shirts and pants, the CDC says. At night, CDC recommends sleeping in a screened-in or air conditioned room or under a mosquito bed net.

Consumer Reports' recent tests of insect repellents found that the most effective product, Sawyer Fishermen's Formula with 20 percent picaridin, was also one of the safest, helping to keep away Aedes mosquitoes—the same type that transmit Zika—for at least 8 hours. Off Deepwoods VIII with 25 percent deet also kept Aedes mosquitoes at bay for 8 hours. Our tests showed that repellents containing natural plant oils, such as citronella and lemongrass, did not work against mosquitoes.

CDC maps of mosquitoes capable of carrying Zika virus in the U.S
Two types of mosquitoes that are capable of transmitting the Zika virus live primarily in the southeastern U.S.
Photo: Courtesy of the Centers for Disease Control and Prevention

More Actions to Take

All cases of Zika virus in the U.S. so far have been found in returning travelers to the regions mentioned above. No one has gotten sick from being bitten in the U.S. But that may be changing as the two mosquito types known to carry the disease, Aedes aegypti and Aedes albopictus, can be found here (see maps above). If a homegrown mosquito bites an infected returning traveler it could pick up the virus and then pass it along to other people in the U.S.  

For this reason, it’s wise to use insect repellent, as noted above. You can also make it harder for mosquitoes to set up shop in your backyard. Female mosquitoes lay several hundred eggs on the walls of water-filled containers. The eggs stick like glue and remain attached until they are scrubbed off. If water covers the eggs, they hatch and become adults in about a week. To prevent them from hatching:
• Empty and scrub, turn over, cover, or throw out items that hold water, such as tires, buckets, planters, toys, pools, birdbaths, flowerpots, or trash containers. Do this once a week.
• Tightly cover water storage containers (buckets, cisterns, rain barrels) so that mosquitoes cannot get inside to lay eggs.
• Use wire mesh with holes smaller than an adult mosquito if you don't have lids.

If you have a septic tank, repair cracks or gaps, and cover open vents or plumbing pipes.

Guide to Mosquito and Tick Diseases

Serious Side Effects

Symptoms appear


Where Most Cases Occur

Common Symptoms