It's possible, as sweat is a bodily fluid, but it is highly unlikely. The main factors for viral disease transmission, is Exposure, Viral load, and Immune Response. First off, most viruses survive and are transferred in the blood stream. If there was BLOOD in the sweat, it would increase the chance of disease transmission. Also, it would have to really be ALOT of sweat, in order to transmit enough of the pathogen into your system to cause problems.