International concern about the rapidly-spreading Zika virus escalated this week, as the World Health Organization suggested that it could be a global health emergency. While most of its symptoms are mild, there is evidence linking Zika to a birth defect known as microcephaly — infants born with abnormally small heads. More than 4,000 suspected cases of the birth defect have been identified in Brazil since October. On Tuesday, the Brazilian health minister warned the country is "losing badly" in its fight against the mosquito-borne illness, which has no treatment and no vaccine.

But a British company called Oxitec has a radical solution. They've created a genetically modified version of the aedes aegypti mosquito, the main carrier of both Zika and dengue. The technology has already been approved for pilot projects and commercial use in Brazil. But some, like Helen Wallace of GeneWatch UK, are concerned about its environmental impact. Brent speaks to Oxitec's CEO, Hadyn Parry, about how his genetically modified mosquitoes could help combat Zika — and whether they are safe.