A new billboard in Brazil aims to attract and kill mosquitos, as part of a campaign launched by two advertising agencies. The "Mosquito Killer" billboard, created by the agencies Posterscope and NBS, emits carbon dioxide and a lactic acid solution to mimic human breathing and sweat. Mosquitos that are lured to the billboard become trapped inside, and eventually die.

The idea, according to the agencies, is to help combat the Zika virus, which is carried by mosquitos and has spread rapidly across Brazil and Latin America. More than 1.5 million Zika cases have been recorded in Brazil since April 2015, according to the World Health Organization (WHO), and the US Centers for Disease Control and Prevention this month confirmed that the virus can lead to microcephaly — a condition that causes babies to be born with abnormally small heads.

Two billboards have been installed in Rio de Janeiro, and the creators have called on others to install more, using the technical specifications that they have published for free online. They say the billboard is designed to attract the Aedes aegypti mosquito, the species that has been found to transmit Zika, and that it can lure the insects within a radius of up to 2.5 kilometers (about 1.6 miles).

The WHO has acknowledged that mosquito traps may help curb the spread of Zika, though the organization says further research is needed to determine their efficacy. Chris Jackson, a pest control expert at the University of Southampton, tells the BBC that "anything that can be done to reduce the prevalence of the mosquito is a good thing," though he notes that the Mosquito Killer billboard could inadvertently cause more people to be bitten, depending on where it's placed.

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