Today is Global Handwashing Day. It's not rocket science. Dirty hands can spread infections and bring suffering, or even death, to others.
It's particularly important for health professionals to be scrupulous about hand hygiene. There is a long tradition of doctors harming their patients because of not washing their hands, e.g. many years ago many poor women died in childbirth because of doctors not washing their hands prior to examining patients and the women caught puerperal fever, which killed them. - See http://www.jameslindlibrary.org/trial_records/19th_Century/semmelweis/semmelweis_commentary.html
And as recently as 2006 the Telegraph reported that thousands of hospital staff fail to wash hands correctly. In my opinion, this is medical negligence. "Health staff carrying out wound care, such as changing bandages, failed to follow hand-washing guidelines on 86 per cent of occasions, while a quarter of staff did not wash their hands after contact with human waste.
The failure of staff to follow hand-washing guidelines is hampering the multi-million pound fight to combat MRSA, which is blamed for the deaths of as many as 5,000 patients each year."