Scientists have a clearer idea of how a virus that likely originated with camels can cause deadly infections in people.

There is currently no cure for MERS, a respiratory illness that can lead to renal failure and kills 35 percent of the people it infects.

Researchers discovered that a common protease enzyme known as furin activates the MERS-CoV (Middle East respiratory syndrome corconavirus) to fuse with cell membranes and enter host cells.

Blocking furin at a specific point in the host cell entry process could lead to a treatment by preventing the virus from getting into cells, where it uses the cell’s reproduction mechanism to make new viruses.

Since it was first detected in humans in 2012 in Saudi Arabia, more than 830 people have fallen ill worldwide, mostly in the Middle East, Europe, and Asia, with a few cases in the United States. It may have originated in camels, though bats also carry a form of the virus.