With spreading Zika virus, much remains unknown
Mosquitoes are just as synonymous with summer as flip-flops, beach days, and cold drinks. This year, the pesky critters—although tiny in nature—are making an even bigger splash than usual.
It’s all because of Zika, a virus that has for the past year taken the tropics by storm. Present in the Aedes species of mosquito in a reported 40-plus countries, researchers say Zika-infected mosquitos are likely to spread in the United States within the next few months, hence an ongoing debate in Congress over Zika-related funding.
The primary way humans get the virus is through the bite of an infected mosquito, and a majority of cases in America to date—about 615—were in travelers, reports show.
In most cases, it’s not a particularly threatening disease. Eighty percent of people, when infected, don’t even know they have it. According to the Centers for Disease Control and Prevention (CDC), the most common symptoms, if they occur, are flu-like—fever, rash, joint pain, or conjunctivitis, and they last a few days. Once a person is infected, it’s believed he or she will be immune to Zika in the future.
Zika can pose a significant problem, though, when a woman who is pregnant or soon-to-be contracts the disease. Studies have proven a link between Zika and microcephaly (a smaller than normal head) and other severe fetal brain defects.
“The reason it’s become elevated, the reason it’s a crisis, is because of the babies,” says Sara Cherry, an associate professor of microbiology in the Perelman School of Medicine.
With no current treatment or cure for Zika, research in Cherry’s lab is trying to understand how flaviviruses such as West Nile, Dengue, and Zika affect hosts, with the goal of developing therapeutics.
“The more that we understand this type of pathogen the better,” says Cherry. “More of these pathogens are emerging and re-emerging globally, in part due to global warming, globalization, and urbanization. If our studies don’t help in this outbreak, it will help in the next one.”
The unknowns
Stephen Gluckman, medical director of Penn Global Medicine, says the risk of Zika affecting the fetus is still unknown.
“Is the risk one in 10 pregnancies? Is it one in 100 pregnancies? Is it one in 1,000? Or one in 10,000?” asks Gluckman, who in May spoke about Zika at the annual meeting of the American College of Physicians in Washington, D.C. “If we knew that, it would clearly modify our advice.”
Still, the CDC is recommending women who are pregnant avoid traveling to areas where the Zika virus is spreading. For pregnant women living in areas with Zika, or who have to travel to these areas, they should take steps to prevent mosquito bites—wear long-sleeved shirts and long pants, stay in places with window and door screens, avoid standing water, and use insect repellents.
It’s believed that when the fetus is infected early in pregnancy, the consequences might be more devastating.
“If they get infected later in pregnancy, the outcomes tend to be more subtle and they might not even be apparent until the child starts to attend school,” says Gluckman. “I’m not saying that to panic people, I’m saying that because like many other things about Zika, we just don’t know.”
Zika has also shown to be sexually transmitted: A man with Zika can pass it to his sex partners. Therefore, pregnant women should take steps to avoid getting Zika through sex.
Gluckman clarifies, “We don’t know how long that risk lasts for. Is it the first few days of the male’s illness or does it persist for weeks or months?”
The same unknown goes for how long the virus lasts in a woman’s blood, although it’s believed to be about a week, Gluckman says.
Some studies have also connected Guillain-Barré syndrome, which can cause temporary paralysis, with Zika, “although that association is less well-established, even more than microcephaly,” says Gluckman.
“Pretty much every known about Zika has an unknown component,” he adds.
In the field
Jack Ludmir, chair of the Department of Obstetrics and Gynecology at Pennsylvania Hospital, is on sabbatical working in Colombia, the country with the second-largest number of cases of Zika after Brazil.
While in two hospitals, Ludmir has seen between 25 to 30 pregnant women who had Zika symptoms. None of these babies has been affected so far.
“Most of the population I see are underserved and vulnerable,” Ludmir says. Their understanding of Zika is limited because they confront bigger challenges, such as poverty. Also, panic is minimal because microcephaly cases caused by Zika have been so rare.
“From the Colombian perspective, they’ve had over 70,000 cases of Zika in the general population,” says Ludmir, citing statistics from the National Institute of Health’s (NIH) bulletin. “They’ve had over 11,000 suspicious cases of Zika in pregnant women, and 4,100 of these cases have been confirmed by lab testing. So far, only five cases of microcephaly related to Zika have been confirmed. This is a very small number compared to the number of pregnant women exposed.”
Ludmir doesn’t deny that Zika can cause a problem, or think that people shouldn’t have concerns. Unfortunately, he says, there’s “no question” that there will be more cases of babies with microcephaly because of Zika in Colombia.
“The reason everyone is [talking about it now] is because for the first time in 50 years, we are describing another infection related to a virus that could cause fetal brain disruption,” he says. “We have to be cautious, it’s clearly important. But at the same time, there are other viruses [similar] to Zika, more common in nature and in Colombia and the tropics, such as Dengue and Chikungunya, that cause more problems including death, and we’re not talking much about it.”
Public perception
With warmer weather in reach, it’s rare to go more than a day without hearing or reading about Zika in the news. But a concern for Kathleen Hall Jamieson, director of the Annenberg Public Policy Center (APPC), is whether the media is conveying accurate and clear messages to the public about transmission and prevention of the virus.
Every week since February, working with research firm SSRS, the APPC has fielded ongoing “Annenberg Science Knowledge” surveys, testing the public’s awareness about Zika, changes in behavior because of the virus, and support for related public policies.
“We’re worried because much of the country is about to head into mosquito season and we don’t have the levels of knowledge we want,” Jamieson says.
One phone survey, which garnered responses from more than 1,000 adults, found that only about one in four Americans think “protecting against mosquito bites” is a step that people can take to avoid the negative health effects of Zika. Only about one in five said not traveling to an area with Zika, and 4 percent suggested the use of condoms or not having sex with a man who may have been exposed to Zika.
This means a relatively high number of people potentially won’t do what’s needed to protect themselves from Zika, Jamieson says.
“And who’s least likely to know?” asks Jamieson. “It’s the less educated, those with lower income, the most vulnerable. That means you have to push information even more aggressively through all of the available media channels.”
The shame, Jamieson continues, is that with the internet capacity of the media, “we don’t have every media company in the country posting on their webpages: ‘Things you need to know about Zika preparedness.’”
The APPC has also asked the public about views on fighting Zika with genetically modified mosquitoes, and is planning on asking if the Olympics in Brazil should be moved or postponed. Survey results are distributed mostly to reporters, as well as the CDC and NIH.
“We want the consequential science to be accurately and clearly communicated through the media,” says Jamieson. In addition, through the FactCheck.org’s SciCheck feature, the APPC is working to debunk false claims about Zika, to decrease the likelihood that incorrect information circulates.
Jamieson predicts the United States will see its first case of locally born transmission sometime in the next couple months, and perhaps the first case of microcephaly as a result of local transmission sometime in the next year.
“We hope that if those things happen, everybody involved in the communication process has increased the likelihood that the preparedness level is as high as we can make it,” Jamieson says. “If we can minimize the amount of risk, this will be a nonstory. That would be the nonnews you’d want to hear.”
