Sweat may be another way to pass on hepatitis B infection during contact sports, suggests research published ahead of print in the British Journal of Sports Medicine.
Hepatitis B virus attacks the liver and can cause lifelong infection, cirrhosis (scarring) of the liver, liver cancer, liver failure, and death.
The research team analysed blood and sweat samples from 70 male Olympic wrestlers for evidence of hepatitis B infection (HBV).
The wrestlers, who were all aged between 18 and 30, were all asked about injuries, as blood-borne infection is a common route of transmission.
Over a third said they had had bleeding or weeping wounds during training and competition.