You can get hepatitis B from sweat during contact sports, suggests an alarming new study.

Hepatitis B virus attacks the liver and can cause cirrhosis of the liver, liver cancer, liver failure — even death. It is usually thought to be passed on only through touching infected blood or mucous membranes.

A British research team analyzed blood and sweat samples from 70 male Olympic wrestlers, looking for hepatitis B infection (HBV).

Asked about injuries, more than a third of the wrestlers said they had had trained or competed while they had bleeding wounds.

None of the wrestlers tested positive for HBV antibodies, the sign of an active HBV infection. Nevertheless, small amounts of the virus were found in the blood of nine of the wrestlers, says the author of the study, which appears online in the March 2007 British Journal of Sports Medicine. This is not unusual because intense training temporarily lowers immune response, leaving the body more open to mild infections.

Eight also had particles of the virus present in their sweat.

The findings suggest that sweat, like open wounds, may be another way of passing on the infection. Some athletic organizations have made HIV testing mandatory for all contact sports but no such recommendations have been made for HBV. HBV, however, is far easier to pass on, because higher levels of the virus are found in the blood and sweat and because HBV can live longer outside the body than HIV.