The Centers for Disease Control and Prevention announced that a third person had tested positive for Middle East Respiratory Syndrome (MERS) virus. An Illinois man apparently contracted it from the MERS patient in Indiana, making it the first case transmitted in the U.S.. His test for MERS on May 5 came back negative, but the most recent results show that he has already been infected with the virus. However, he is reportedly feeling well and has shown no symptoms. Health officials suspect that the man developed antibodies that fought off the MERS virus. Despite this mild response to the lethal virus, the CDC is still warning people to be vigilante about MERS. “This latest development does not change CDC’s current recommendations to prevent the spread of MERS. It’s possible that as the investigation continues others may also test positive for MERS-CoV infection but not get sick,” said David Swerdlow, head of the CDC’s MERS response team.