ASHUNDREDSOF SHOPPER AND tourists stroll through an outdoor mall south of Miami Beach’s Lincoln Road, a white, unmarked van with tinted windows creeps through a nearby neighborhood. Then a second van appears, and a third and fourth. One eases to the curb and stops under the palms on a block of mostly two-story apartment buildings. As the other three vans silently roll on, three people step out, walk up the stairs into an apartment complex and knock on the first door they come to. One of them holds a clipboard and another an ice cooler—the clipboard for questionnaires; the cooler for samples.
It’s close to 90 degrees outside and nearly 7 p.m., so the folks who just got out of that white van hope the people who live here will be home, preparing dinner. They also hope they might be willing to provide a quick urine sample, because this neighborhood is one of the first spots in the continental United States where active transmission of the Zika virus has been confirmed. Between the end of July and late September, state health officials in Florida confirmed at least 120 cases of locally transmitted Zika, and new cases are reported nearly every day. Authorities have also trapped mosquitoes in Miami-Dade County that test positive for the virus. The unmarked vans and their teams are part of an emergency public health campaign to track the virus, learn how it spreads and do whatever they can to stamp it out.