Although they had no contact with pigs, seven people in two states have been struck with an unsual strain of swine flu.
This virus was found among five people in California and two in Texas. Health officials are concerned that the virus is being transmitted person-to-person since California individuals had contact with one another.
This unusual strain appears to be resistant to two common flu treatment drugs, however Relenza and Tamiflu appear effective.
Currently there are 800 suspected cases of swine flu in Mexico, reports The World Health Organization (WHO).
Mexican officials have closed schools and are urging people with flu-like symptoms to stay home when possible.