(NBC News) The second patient confirmed to have brought MERS to the United States from Saudi Arabia has been discharged from a Florida hospital.
The news comes on the heels of the announcement that a third person has shown evidence of the virus, and that he was infected in this country.
A man in Illinois, who had two business meetings with the first confirmed MERS patient in the U.S. has shown evidence that he too was infected with the virus.
A blood test shows his immune system made antibodies to fight a MERS infection, but samples from his respiratory tract never tested positive for the virus, so he couldn't spread it by coughing or sneezing.
"His immune system did kick in at some point in time to wall off the infection, so he has evidence of being infected but no evidence ever of being infectious," explains Dr. Lamar Hasbrouck, director of Illinois' Department of Public Health.
Experts say those most at risk for the virus are healthcare workers who treat patients or family members of the sick, but the Illinois case raises the question of whether casual contact can also spread MERS.
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