Although the risk of spreading infection is higher in sports with greater skin-to-skin contact (i.e. wrestling, basketball, etc), all athletes can be at some risk for the spread of infection.
What harm can they do?
Depending on the infection, one can suffer from reoccurring itching/blistering/sores to life-threatening emergencies.
What should I do if I see signs of infection?
Follow-up with a physician and take any prescribed treatment as instructed.
How can I prevent future infections?
Proper daily hygiene
Thorough cleaning of any common surfaces before/after activity
Not sharing towels, water bottles, etc. with teammates