The World Health Organization estimates 3 to 4 million people will be infected with the Zika virus within the next year. Symptoms include fever, rash and pink eye.
“It’s not a reason for panic or alarm in the U.S.,” says Dr. Robert Amler, vice president for government affairs and dean and professor of public health at New York Medical College in Valhalla, New York. “But it’s something that has to be watched closely so it doesn’t become more serious.”
Here’s what is certain about Zika and what you need to know:
How it Spreads
The vast majority of Zika cases spread via two types of aggressive mosquitoes: Aedes aegypti and Aedes albopictus. They’re ubiquitous in Latin America and the Southeastern United States, and they’re the same type of mosquitoes that spread West Nile, dengue and chikungunya virus. ”They bite all day long, not just at dawn and dusk,” Amler says. “They’re very resilient, and their eggs can literally survive in a bottle cap of water.”
There’s no evidence the virus spreads through urine or saliva, says Dr. Lyle Petersen, director of the division of vector-borne diseases and commander of the CDC’s Zika virus response program. “Everything we know about this virus so far is the primary way it is transmitted is via mosquitoes,” he says.
Zika can also spread through blood transfusion and sexual contact. While it stays in the blood for less than 28 days, how long it remains in the semen is uncertain, according to the CDC. In early February, the agency reported the first case of locally acquired Zika virus in the U.S., involving a patient who had sex with someone who recently returned from Venezuela. U.S. health officials are currently investigating more than a dozen possible Zika infections that may have been spread through sex, and scientists expect those numbers to rise.
“Certainly we’re concerned about this because if you have a man who is infected and infects his partner who may be pregnant, she could potentially become infected, and her infection will affect the fetus,” Petersen says. “We are very concerned about the sexual transmission part in the context of pregnant women.”
The 20 percent of those infected with Zika who show symptoms are likely to report a fever, rash, joint pain and pink eye, or perhaps muscle pain and headache. If symptoms do appear after infection, the CDC estimates it happens within a few days to a week. People who show symptoms of the virus and have traveled to a place where Zika has been reported are urged to see a health care provider, especially if pregnant.
If you’re particularly alarmed about Zika, this is probably why. There’s increasing evidence that pregnant women with Zika can give birth to babies with microcephaly, a rare birth defect defined by brain damage and an abnormally small head. Research published in the New England Journal of Medicine in February confirms that link. The findings strengthen the evidence that the virus is involved in the increase in microcephaly cases seen in Brazil. And according to the WHO, 41 of 462 cases of microcephaly in Brazil between November 2015 and February 2016 were confirmed to also have Zika. Still, much remains unclear, including whether women with no or minimal symptoms can pass along birth defects to the fetus.
There’s no cure or standard treatment for microcephaly, and the lifelong condition can lead to seizures, delayed standing or walking, learning disabilities, problems with moving and balance, difficulty swallowing, hearing loss and vision problems. It’s rare in the U.S., affecting about 10,000 newborns each year, according to the CDC.
The Brazil Ministry of Health reports that an increased number of people who have been infected with Zika also have Guillain-Barré syndrome, but it’s unclear whether there’s a link. GBS is a rare disorder that turns a person’s immune system against him or her by damaging nerve cells and causing muscle weakness or even total paralysis. It’s usually caused by strokes or injuries such as a spinal cord injury or broken neck, and most of the 3,000 to 6,000 people who develop it in the U.S. each year do recover.
At Ann & Robert H. Lurie Children’s Hospital of Chicago, Dr. Larry Kociolek says parents have expressed concern about travel. “Our advice remains consistent and largely based upon the recommendations of the CDC and our local public health officials,” says Kociolek, an attending physician of pediatric infectious disease. “For those [who] aren’t pregnant, the things they should do to protect themselves aren’t any different than what they should’ve done prior to the Zika virus circulating.” People who are concerned about exposure to Zika or any virus while abroad should check with a primary care physician or specialist to determine their risk for various infections in the regions they’re traveling to, he adds.
The CDC recommends men who live in or have traveled to active outbreak areas either abstain from sexual activity or use condoms during sexual contact. And health officials suggest travelers take steps to prevent mosquito bites by wearing long-sleeved shirts and long pants. Consider staying in places with air conditioning, and make sure there are screens over doors and windows and bed nets to keep mosquitoes outside.
The CDC recommends using EPA-registered insect repellents, even for women who are pregnant or breast-feeding. Make sure the one you select is marked with “EPA Reg,” which means it’s usually safe for women and children. And consider treating clothing or gear with permethrin, an over-the-counter insecticide that works by killing parasites like lice, or purchase permethrin-treated items that will continue to protect against pests like mosquitoes even after the clothing is washed multiple times.
There’s no cure or treatment for Zika, and a vaccine for the disease may not be developed for years, Petersen says. “We can definitely develop a vaccine for this. There’s no question,” he says. “We have quite good vaccines for other related viruses, so we’re not starting at ground zero. Nevertheless, it takes a long time to get a vaccine developed, manufactured, have all the safety tests and prove it is effective.”
In the meantime, if you have Zika, the CDC recommends treating it like you would a cold. Make sure you get plenty of rest, drink fluids to prevent dehydration and take Tylenol – or acetaminophen – for pain or fever. Don’t take aspirin or other nonsteroidal anti-inflammatory drugs, also known as NSAIDs, until dengue virus is ruled out, since aspirin and NSAIDs can worsen bleeding symptoms of dengue and lead to serious complications, especially in children.