The three most important viruses transmitted through blood are HIV and Hepatitis B and Hepatitis C. You have probably heard about HIV. It is an, as of yet, incurable autoimmune disease, but it can be treated and controlled. HIV attacks the body’s own protection systems. When left uncontrolled, HIV leads to AIDS. AIDS slowly, but steadily, breaks down your body’s defences more and more, making you unable to recover from infections or cancers, eventually resulting in death.
The other blood-borne viruses Hepatitis B and C are also bad news. They both target your liver and can make you very sick. Worse, untreated Hepatitis C is one of the main causes of liver cancer. The tricky thing with Hepatitis B and C is that after infection, it can take weeks or sometimes years, even decades before you get any symptoms. But during that time the virus has already started its nasty work.