Officials in Saudi Arabia said late Wednesday they have identified 18 new cases of Middle East Respiratory Syndrome (MERS) in the country, Reuters reports. The government also said four more people died of the disease Wednesday.

[Related: CDC Confirms First MERS Case Hits United States.]

The new cases raise Saudi Arabia’s official number of MERS cases to 449, making it the country hardest hit by the deadly virus, which kills about a third of the people it infects. 121 people have died from the virus in Saudi Arabia, where the number of infections has surged since April amid outbreaks in hospitals in Jeddah and Riyadh.