Perspiration, saliva and tears contains an enzyme, lysozyme, that kills

Lysozyme is a naturally occurring enzyme that can be found in tears, saliva, sweat (perspiration), milk, and mucus. 

Animals manufacture this enzyme. It is crucial in the prevention of bacterial infections. The mucous membranes of the nasal cavity and tear ducts express human lysozyme. 

Because it is an antibacterial enzyme, it has a physiological activity that kills bacteria by attacking, hydrolyzing, and dissolving glycosidic bonds in their cell walls. 

Lysozyme does not destroy any of the virus and virus infected cells and protozoa as it functions to prevent the bacterial infection.