NEW : Eighty-two cases of swine flu confirmed by health officials worldwide . The WHO says the virus is highly contagious and can be spread through close contact with infected pigs or other animals such as birds, dogs and cats. Mexico health official : As many as 149 deaths may be from swine flu . Mexico closes all schools until at least May 6 .
NEW : Eighty-two cases of swine flu confirmed by health officials worldwide . U.S. urges travelers to avoid nonessential travel to Mexico . Mexico health official : As many as 149 deaths may be from swine flu . Mexico closes all schools until at least May 6 .