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You are here: Prevention & screening / Be aware / Viruses and bacteria

Viruses and bacteria

Virus as seen through a microscope

The connection between infections and cancer is an important one. In developed countries, 7% of all cancer deaths are thought to be the result of viral and other infections.

Cancers associated with viruses or bacteria

  • cervical cancer – human papillomavirus (HPV)
  • liver cancer – hepatitis B (HBV) and hepatitis C virus (HCV)
  • lymphomas – human T-lymphotropic virus 1 (HTLV-1)
  • nasopharangeal cancer – Epstein-Barr (EBV)
  • stomach cancer – helicobacter pylori (H. pylori)

Many of the viral infections associated with cancers cause clearly identifiable non-cancerous conditions (or precancers) before developing into cancer. Screening tests can help identify these signs – and if they are treated successfully – cancer may be prevented. Screening using the Pap test has reduced the incidence of cervical cancer because precancerous changes were detected and treated early.

The incidence of infection-related cancers in the US, Canada and in developing countries is increasing because of the AIDS virus.

Currently, there are vaccines for only HBV (hepatitis B virus) and HPV (human papillomavirus). Reducing the risk of infection remains the best way to help prevent some infection-related cancers. For example, using condoms may help prevent HBV and HPV infection.