McCANN: We are certainly, I'm sure, trying to discern that that was an actual voice transmission, and not a pre-recorded transmission designed to deceive the U.S. concerning his whereabouts.
The last recorded case of human to human transmission came in October 1977 when a cook called Ali Maow Maalin, living in a Somali village, contracted the illness.
To make sure the transmission would make it back to Earth, the images sent back by the astronauts were recorded at 10 frames per second (fps), and had to be converted to 60fps in order to be broadcast.