A Turkish study, published in the British Journal of Sports Medicine, recently reported the presence of occult hepatitis B virus (HBV) infection in 13% of Turkish Olympic wrestlers. Occult HBV infection is the detectable presence of virus through PCR (polymerase chain reaction), despite the lack of a viral protein called HBsAg (hepatitis B surface antigen) in the blood. The current standard for evaluating hepatitis B infection or immunity relies on measuring hepatitis antibody and antigen markers. By definition, the standard tests used in hospitals did not reveal hepatitis B in these wrestlers even though they were infected. Interestingly, 11% of the wrestlers also secreted HBV in their sweat.

Several studies estimate the HBsAg positivity (indicator for acute or chronic hepatitis B) to be roughly 7% in Turkey. This figure is less than the prevalence of occult HBV found in the wrestlers. For comparison, low-risk regions, such as the United States and Western Europe, have an HBV prevalence of <2%.

Although more studies are needed, it is interesting to speculate the significance of the recent findings. For one, there may be a higher prevalence of hepatitis B infection than earlier believed. It is not standard of care to test individuals for HBV DNA. The occult HBV category may comprise a large yet underdiagnosed group. On the other hand, by nature of their profession, wrestlers sweat copiously and engage in prolonged bodily contact. Their increased risk for exposure could have contributed to the increased prevalence in this population.

Hepatitis B possesses several modes of transmission: maternal-fetal, mucous membranes, exposure to blood via needlestick injuries or contaminated transfusions, and transplantation. Excessive bodily contact has been suggested before as a form of transmission, particularly in children, but the data are unclear. With the finding of HBV DNA in the sweat, we wonder whether this supports transmission through bodily contact and fomites. Should we be concerned about it? Our knowledge in this area of study is still superficial. I am only aware of a few groups engaged in epidemiologic and laboratory-based research of occult HBV. It is nevertheless possible that wrestlers in endemic areas may someday need to get vaccinated prior to participation in sports.

  • Sources
  • Bereket-Yücel S. Risk of hepatitis B infections in Olympic wrestling. Br J Sports Med 2007.
  • Maynard JE. Hepatitis B: global importance and need for control. Vaccine 1990;8 Suppl:S18-20.
  • Mehmet D, Meliksah E, Serif Y, Gunay S, Tuncer O, Zeynep S. Prevalence of hepatitis B infection in the southeastern region of Turkey: comparison of risk factors for HBV infection in rural and urban areas. Jpn J Infect Dis 2005;58:15-9.

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