"Major Walter Reed, an Army surgeon, proved that mosquitos transmitted the virus that caused yellow fever" If anyone else also asked himself how do you actuall

"Major Walter Reed, an Army surgeon, proved that mosquitos transmitted the virus that caused yellow fever" If anyone else also asked himself how do you actually prove that - not surprisingly, you infect volunteers with a mosquito that has bitten an infected person. Multiple tests were needed to establish the exact timeframe when the person is contagious.