In the wake of the first locally identified Zika infections in Florida, the Centers for Disease Control and Prevention (CDC) issued a travel advisory recommending that pregnant women avoid Miami's Wynwood neighborhood. Emily Toth Martin, an assistant professor of epidemiology at the University of Michigan School of Public Health, spoke with senior editor Sarah Feldberg about how Zika spreads and why the mosquitoes that carry it are so hard to combat.
Q: With Zika now transmitted by mosquitoes in the U.S., how might the spread here be different?
Emily Toth Martin
A: It's not necessarily about the Zika virus itself. I think the spread in the U.S. may have more to do with how we spend our days and whether we spend our days inside or outside, whether we have houses with screens on their windows and how close we live in proximity to each other. Those are all factors that change from country to country, and that is the reason why we're not entirely sure what Zika virus is going to look like in the U. S. compared to other countries.
Q: Why is this particular mosquito difficult to combat as a disease vector?
A: Aedes aegypti are day-biters, and so some of our classic techniques, like stay inside when dusk falls and use a bed net or use screens on your house, don't apply because these mosquitoes are active when we're out going about our day-to-day life. These mosquitos also really like urban areas. Being inside a sheltered area is not a barrier for this mosquito. They don't prefer the wide-open rural world.
Q: The Florida infections are in Miami's Wynwood neighborhood. Do you expect them to spread?
A: I have no idea. We've got a lot of summer left, and we've got this two-week time lag going on right now between when somebody could conceivably get infected and when we find out about it. That's about how long it takes for symptoms to become apparent. [The Florida Department of Health] has done a lot of testing and door-to-door testing, and they're pretty confident that they're not seeing anything yet outside of that box that they've drawn, but it is really hard to say.
Q: Is extra caution warranted for people thinking about traveling to places with Zika infections?
A: Carefully following mosquito prevention is smart: using mosquito repellent or wearing longer sleeves and longer pants when you're outdoors and trying to stay in screened-in areas when you're indoors. I think pregnant women should get their doctor involved and keep a close eye on the updates from the CDC and the updates from individual state health departments. Have your doctor go through those and decide what the risk/benefit is for each woman personally in traveling.
Q: From a public health perspective, how concerning are the first instances of locally transmitted Zika in the U.S.?
A: I think that what I hear most often with professionals in the field is frustration around the funding. Mosquito-borne illness is something the public health community has experience dealing with. They have strategies they can put into place. The CDC knows what they're doing, but we need the funding and the infrastructure to be able to do the work. A lot of this work is going to get done, but it's going to then hamper other public health efforts. We'll have to rob Peter to pay Paul. The government and Congress needs to invest in letting the public health professionals do their job.