Dr Linda Quick was a trainer of Chinese field epidemiologists who helped track, investigate and contain outbreaks.
"It was heartbreaking to watch," said Bao-Ping Zhu, a Chinese-American who served in that role, which was funded by the US Centers for Disease Control and Prevention (CDC), between 2007 and 2011. "If someone had been there, public health officials and governments across the world could have moved much faster."