In 2012, years ahead of the 2016 Summer Olympics, the Brazilian metropolis of Rio de Janeiro embarked on an ambitious urban beautification project that involved dismantling a countless number of not-so-attractive beachfront billboards. Per city officials, the initiative aimed to “reduce the visual pollution and environmental degradation in a city renowned for its natural and architectural beauty.”

Now, with the Olympics just a few short months away, new billboards are actually going up around town as officials face a much more formidable threat than visual pollution in the form of a couple hundred ugly advertisements: the Zika virus.

To be clear, these aren’t your average Brazilian billboards hawking Fiats and fancy watches. In fact, the new billboards, which are more akin to modestly sized sidewalk-bound placards, aren’t advertising anything. Instead, they’ve been erected with a single mission: to curb the spread of Zika, a viral disease linked to serious birth defects in newborn babies, by trapping and killing Aedes aegypti mosquitoes.

A close and particularly scary relative of other mosquito-transmitted diseases like dengue, and yellow fever, Zika has been detected in several Latin American countries and beyond. Yet it remains largely concentrated in Brazil where an outbreak of the virus was first confirmed in May 2015. Roughly 1.5 million cases of Zika have been recorded in Brazil since the spring of 2015 by World Health Organization estimates.

Created by Brazilian advertising firm NBS and out-of-home media agency Potterscope, the aptly named the Mosquito Killer Billboard isn’t being heralded as a silver bullet — a surefire weapon against the virus that will magically eradicate the disease just in time for the Olympics. However, the Mosquito Killer Billboard’s creators are confident that the pseudo-advert, which has been installed in two highly trafficked areas around Rio with a third to come, will help to put a modest dent in the number of transmissions while also reminding the public to remain vigilant.

So how, you ask, does the billboard attract mosquitoes and subsequently trap and kill them?

It seduces them by mimicking the very things that send female mosquitoes buzzing, tout suite, toward exposed, bite-able human flesh: it sweats and breathes.

Capable of attracting mosquitoes up to 2.5 miles away, the billboard emits a heady mixture of lactic acid solution, which is found in human perspiration, and carbon dioxide — breath, essentially. Once drawn to the sweaty, breathy billboard, mosquitoes become trapped inside and die from dehydration. The board also harnesses fluorescent lights for added mosquito appeal.

NBS and Potterscope developed the idea under a Creative Commons License with the hope that other cities grappling with Zika and other mosquito-borne illness will also employ the unique and relatively inexpensive technology.

According to the BBC, the firms have no plans to sell ad space within the billboard. Instead, they’ll let Mosquito Killer Billboard’s mission — “This billboard kills hundreds of Zika mosquitoes every day” — speak for itself. The fact that legions of dead mosquitoes have visibly accumulated within the billboard drives the point home in an effective, albeit grisly, manner.

Speaking to the BBC, Dr. Chris Jackson, a pest control expert at the University of Southampton, acknowledges the benefits of the billboard: “I think anything that can be done to reduce the prevalence of the mosquito is a good thing. Particularly devices like this that attract and kill females that feed on blood, as it is only female mosquitoes that bite.”

Jackson, however, is wary of the billboard's high-density, high-visibility placement. That is, while it does make sense to place mosquito-killing billboards in the middle of the bustling city like Rio, it also puts the public at additional risk. Once mosquitoes pick up on that sweet, sweaty aroma of lactic acid and head toward the billboard, what’s stopping them from biting a person while en route?

“Maybe if it was not in a high-density place, where people are sitting perhaps with exposed legs ... otherwise, you're pulling in hungry mosquitoes and providing them with exposed human flesh,” notes Jackson.

Matt Hickman ( @mattyhick ) writes about design, architecture and the intersection between the natural world and the built environment.

Sweat-emitting Brazilian billboards lure Zika-carrying mosquitoes to their death
Sometimes you have to replicate humans to get the job done.