The first case in this outbreak - "patient zero" - was a 68-year-old man who was diagnosed after returning from a trip to Saudi Arabia. He is still in hospital.Mers - which stands for Middle East Respiratory Syndrome - can cause fever, breathing problems, pneumonia and kidney failure.Experts believe it is not very contagious. Tan Wenjie, director of the virus department at the National Institute for Viral Disease Control and Prevention, said Mers could only spread "via close contact in a confined space".