Estimates place the worldwide risk of cancers from infectious causes at 16.1%.[1] Viral infections are risk factors for cervical cancer, 80% of liver cancers, and 15–20% of the other cancers.[2] This proportion varies in different regions of the world from a high of 32.7% in Sub-Saharan Africa to 3.3% in Australia and New Zealand.[1] Viruses are the usual infectious agents that cause cancer but Mycobacterium, some other bacteria and parasites also have an effect.