The Zika virus, already common in parts of Africa and Asia and linked with hundreds of severe birth defects, is now spreading with alarming speed in the Americas. The World Health Organisation (WHO) has now declared this an international public health emergency ‘of alarming proportions’, requiring a coordinated international response. Brazil’s president Dilma Rousseff has issued a decree allowing public officials to enter abandoned or empty homes, by force if necessary, to eradicate the breeding grounds of the Aedes mosquito (which carries the virus). The officials will carry out educational campaigns and create public guidelines. They will target the mosquito breeding grounds in the north-eastern states, whose governors attended a teleconference with the president on Friday, along with the governors of Rio de Janeiro and São Paulo states. After the teleconference Rousseff admitted that Brazil is ‘losing the fight against Aedes’ but vowed that it will not lose the war.