A World Health Organization official is reminding millions of Muslims making a pilgrimage to Mecca, Saudi Arabia, to exercise basic hygiene as mass gatherings pose risks of spreading the Middle East respiratory syndrome.

The U.N. agency has recorded 827 cases of MERS and 287 deaths, mostly in Saudi Arabia. The virus is believed primarily acquired through contact with camels and is spread among humans through body fluids and droplets.

Mark Jacobs, WHO Western Pacific region director for communicable diseases, said Thursday that hand washing and keeping away from coughing people are simple ways to prevent the virus’ spread.

He says there’s a low chance of its spread in most settings, but health workers caring for MERS patients, people exposed to camels, and those in large gatherings are at some risk.