Hepatitis is an inflammation of the liver. Hepatitis C is a specific type of hepatitis caused by the Hepatitis C virus, and is usually transmitted by blood products, but rarely from sexual activity (unlike Hepatitis B). Hepatitis C can cause an acute infection or a chronic (persistent) one.
Infection by a delta agent. This is a secondary agent on top of the infection with Hepatitis C. It can make the infection much more severe. Diagnosis is made by checking for anti-HDV in blood.
Hepatocellular (liver) cancer -- persons who have been infected with Hepatitis C, are at much higher risk of developing liver cancer