In early 2015, news broke about a virus circulating through Brazil with devastating effects to newborns. The infection, known as Zika, spread mostly through the bite of a mosquito and began to cause global concern.
Seemingly sudden news to the public, Zika’s origins began decades ago in 1940s Africa. Since then, outbreaks have been reported in Asia and the Pacific. “Zika has been shifting around the globe,” says Karen Ann Ravin, M.D., Division Chief of Pediatric Infectious Diseases, Department of Pediatrics at Nemours/A.I. DuPont Hospital for Children in Wilmington, DE. Last spring Zika increased in Central and South America.
According to the U.S. Centers for Disease Control and Prevention (CDC), more than 5,000 Zika cases have been reported in the continental U.S. — including Delaware, New Jersey and Pennsylvania — with the majority being travel-related. Local transmission of Zika has been confirmed in Florida and Texas. Now documented in various parts of the U.S. and around the globe, many people wonder about the threat.
According to the CDC, one in ten Zika-infected U.S. moms had babies with birth defects in 2016.
Dangers to the unborn
“For most, Zika is a mild disease without serious complications,” says Henry S. Fraimow, M.D., epidemiologist at Cooper University Hospital in Camden, NJ. “Four out of five people never have symptoms,” he says. The common ones are fever, rash, headache, joint pain, conjunctivitis (red eyes) and muscle pain lasting for a few days to a week, but many aren’t ill enough to seek medical attention and rarely die of the disease.
But, “As millions have been affected, we’ve seen more of the uncommon complications of the virus,” says Dr. Fraimow. Zika, he says, is potentially catastrophic in pregnant women, because it poses a significant risk for a developing baby.
“The virus is unique among mosquito-borne viral infections in that it causes congenital infections,” says Dr. Ravin. During pregnancy Zika can cause a birth defect of the brain called microcephaly and other severe fetal brain defects. Microcephaly is a condition where an infant’s head is smaller than expected due to abnormal brain development. “Zika attacks the developing brain,” says Rebekah McCurdy, M.D., obstetrician-gynecologist at Thomas Jefferson University Hospital in Philadelphia.
Other defects of the virus may include feeding problems, hearing loss, seizures, vision problems, restricted joint movement, problems with brain development and too much muscle tone, which restricts body movement. This pattern of conditions is known as congenital Zika syndrome. Guillain-Barre´ syndrome, a condition in which the immune system attacks the nerves, is also linked to Zika.
Transmission of Zika
The transmission of the virus is primarily through an infected Aedes species of mosquito. Aggressive daytime biters, they also bite during the night. Aedes are found in the U.S. and worldwide. “The best way to prevent Zika infection is to prevent bites,” says Dr. Ravin.
Zika can also be transmitted sexually, though it’s a small risk. “We worry about pregnant women, what they can be exposed to directly and indirectly,” says Dr. Fraimow, and since “Half of pregnancies are unplanned; people should use adequate protection during sex,” says Dr. McCurdy.
In addition to Zika being spread from mother to child, it can also be passed through blood transfusion, though no confirmed U.S. cases exist.
“If you’re living in the Delaware Valley, we don’t think there’s a high risk of transmission locally. The real risk is to the places you travel,” says Dr. Ravin.
As it relates to the groups that may be of greatest risk of the virus, Dr. Fraimow sees the areas where the disease can potentially spread to be of biggest concern, and within that group, women of childbearing age. “The disease is hard to predict. We can’t say where it’s going to be tomorrow.”
There is no vaccine or medicine for the Zika virus.
How to protect against Zika
Prevent mosquito bites. Use an EPA-registered insect repellent. Wear long-sleeve shirts and long pants for yourself and your baby. Cover cribs and strollers with mosquito netting and control mosquitos in and around the home by installing screens and preventing long-standing water.
Be informed before travel. Visit wwwnc.cdc.gov/travel/notices for the latest CDC Zika-related travel recommendations. If you are pregnant or trying to get pregnant, it is advised not to travel to areas with a risk for Zika. Consider avoiding those areas or see your doctor for guidance.
Practice safe sex. Use male and female condoms or practice abstinence.
Nicole D. Crawford is a freelance writer.