MERS is a viral respiratory illness caused by a beta coronavirus called MERS-CoV. It was first reported in Saudi Arabia in 2012 and has since spread to several other countries. Research has found that the virus transmits between humans and dromedary camels. Camels are believed to be the main animal reservoir for MERS-CoV. With millions of pilgrims expected to visit Mecca and Medina for Hajj, there are concerns about the potential spread of MERS during this pilgrimage and measures are being taken to help prevent transmission. Currently there is no vaccine for MERS.