Warm summer weather brings mosquitoes and, this summer, that may also trigger worries about the spread of the Zika virus. The virus, which has spread throughout South and Central America in recent months, has alarmed public health officials around the world because infection during pregnancy is linked to a serious birth defect called microcephaly. Microcephaly causes a newborn baby’s head to be abnormally small, affecting brain development. The Zika virus has also been linked to cases of Guillain-Barre syndrome, an autoimmune disease that causes loss of motor control.
The effort to protect Americans from the Zika virus is taking place on two fronts: educating people who are traveling to regions with Zika outbreaks and monitoring conditions in the United States for signs that mosquitoes may be carrying the virus. Doctors have diagnosed 29 locally acquired cases of Zika virus in Florida, but individuals throughout the U.S. have acquired the disease during overseas travel or sexual contact with an infected individual who had been overseas.
The good news is that the Zika virus appears relatively harmless in people who are not pregnant, says Ian Lipkin, director of the Center for Infection and Immunity, Mailman School of Public Health at Columbia University Medical Center in New York.
“Zika is a mosquito-borne virus that was originally identified in Africa over 60 years ago,” he says. “More recently it has spread to South America and the Caribbean. It’s not usually associated with severe disease—many people who are infected with this virus are going to have no symptoms of it all, or they’ll have symptoms that are mild and consistent with the flu or any wide range of other very common diseases.”
The most common symptoms of Zika are fever, rash, joint pain, and conjunctivitis (red eyes). The symptoms typically last several days. It’s rare for someone with Zika to die, and most people don’t have symptoms serious enough to go to the hospital. Many people might not realize they have been infected, according to the CDC. There is no treatment for the disease and no vaccine to prevent getting it.
However, in pregnant women, the virus appears to impact the baby’s brain development, causing microcephaly. That’s why women who are pregnant or may become pregnant should avoid travel to Zika impacted-areas, and if they must travel, should take special precautions, CDC experts say.
“People can reduce their risk by avoiding exposure to the mosquito that carries Zika,” Lipkin says. “One way is to wear insect repellent, which reduces the risk that a mosquito is going to find you attractive. We are also hoping to prevent the virus from spreading by using methods to decrease the mosquito population.”
The CDC also notes that men who live in or have traveled to an area where Zika is prevalent can pass the virus to their sexual partners. If these men have a pregnant partner, the CDC recommends abstinence or “consistently and correctly using condoms” during the pregnancy.
According to the CDC, Zika virus was first discovered in 1947. Since then, outbreaks have been reported in Africa, Southeast Asia, and the Pacific Islands. The Zika virus will continue to spread, experts say, but it’s difficult to determine where and when.
U.S. public health experts are familiar with the threat of mosquito-borne viruses. In recent years, parts of the country have experienced small outbreaks of Dengue fever carried by mosquitoes and have implemented detailed vector control and surveillance programs, says Jeffrey Shaman, PhD, an associate professor of environmental health sciences at the Mailman School of Public Health.
“The species that can carry the virus, Aedes Aegypti, is found only in the south of the Gulf States, basically in Florida,” he explains. “Another species, Aedes Albopictus, can be found as far north as Chicago, and it’s been argued that that one may also be capable of transmitting Zika. We do not expect the virus to gain a foothold in the U.S. because our infrastructure prevents widespread interaction between mosquitoes and people. We may have some isolated cases of Zika virus here, many of them imported.”
The CDC has suggested that pregnant women avoid traveling to areas where Zika has flourished. For people who are traveling, detailed travel guidelines exist to help you minimize your risk of contracting Zika. For information on the risk of Zika infection in a specific part of the world, see the CDC’s travel advisory web page .