Brazil has declared an animal health emergency for six months after authorities detected its first-ever case of avian influenza virus in wild birds, according to a document signed by the government’s agriculture minister.

The South American nation, the world’s biggest chicken meat exporter with $9.7bn in sales last year, has confirmed at least eight cases of the H5N1 virus in wild birds, including one in Rio de Janeiro state and seven in the neighbouring state of Espirito Santo.