A “perfect storm” of conflict and the breakdown of state healthcare have left swathes of Isis-occupied Syria and Iraq vulnerable to outbreaks of infectious disease, America’s new science envoy to the Middle East has warned.

Dr Peter Hotez, a leading global health expert, said an outbreak of leishmaniasis, a disfiguring disease spread by sand flies, was already “out of control” in Syria, and he  also warned about the rising risk posed by Middle East respiratory syndrome (MERS) in a region where many hospitals have closed and disease surveillance control measures are hampered by fighting.