Brazil and Argentina have confirmed five swine flu cases within their borders as the virus affects more nations in South America.
Brazilian Health Minister Jose Gomes Temporao said four young adults contracted the flu outside the country, which is home to the continent's largest population.
He said three of them caught the virus in Mexico, and one in Florida. Only one remains hospitalized and is reported in good condition.
Argentine Health Minister Graciela Ocana said the first person sickened by the virus in her country is a man who returned from Mexico on April 25.
He has already been released from the hospital.
Before Thursday, Colombia was the only South American nation to confirm swine flu with its borders.