Marathon County Health Department investigates reports of illnesses related to food and water born diseases. The public health nurses and sanitarians work to identify the source of the illness and contain the spread of the disease. Some commonly reported diseases are Salmonella, Cryptosporidium, Campylobacter, Norovirus, and Giardia. Salmonella Fact Sheet Cryptosporidum Fact Sheet Camylobacter Fact Sheet Norovirus Fact Sheet Giardia Fact Sheet