From 1952. I bet Truman could kick himself for all the funds and manpower he allocated to spreading epidemics, when it was all foiled because the Chinese people understood the importance of getting vaccinated. That's the way it goes. You might notice the US diplomat being foiled at the bottom has that ratlike nose (and whiskers!) so typical of Westerners.
(I don't know if the Chinese government really believed the United States was trying to decimate their population with diseases or if this was just a way to motivate their people to go get vaccinated... there's usually a gap between what any government says publicly and what is really going on.)