In most cases, carriers with chronic hepatitis C infection have no symptoms. However, over time this blood borne virus can cause long term damage to the liver, including cirrhosis and hepatocellular carcinoma. Severe liver damage may not develop until 10-40 years after infection. Certain medical phenomena have been associated with the presence of hepatitis C, such as thyroiditis, cryoglobulinemia and some types of glomerulonephritis. Carrier of the virus may begin to develop symptoms after only a few years. Symptoms, when developed, are variable and dependent on individual carrier. They may include prolonged flu-like symptoms and any combination of the following: body aches, headaches, nightsweats, loss of appetite, diarrhea, fatigue, nausea, mild abdominal pain, upper right quadrant pain.

Most people are not aware that they carry the hepatitis virus until something causes them to require a physical exam, and then something routine is done, such as blood work. There are also cases where carriers have found out through blood donation or plasma donation that their blood carried a positive response to a HCV test.

There are several risk factors that qualify one for a higher risk of exposure to HCV virus. They include

Needle sharing.Those who inject drugs are at high-risk for getting hepatitis C because they may be sharing needles and other drug paraphernalia, which may be contaminated with HCV-infected blood. In fact, 60% to 80% of all IV drug users have hepatitis C infection.
Unprotected sex. Although HCV is not classed as a sexually transmitted disease, there is some transmission due to sexual activity. This is often as a result of infection with an actual STD. Many STDs cause sores or wounds around the genitals, and thus sexual activity will lead to the spread of HCV. It is important to note however, that the spread is due to blood-blood contact, rather than the presence of the virus in vaginal fluid or semen.
Multiple piercings or tattoos. Tattooing dye or needles used in tattooing or body piercing can carry HCV-infected blood from one customer to another if the tattoo/body piercing parlors do not use sterile techniques or supplies.
(Tattoos done non-professionally, as in a penal institution, are of great concern.)

Blood transfusions BEFORE 1992. Those who have had a blood transfusion before 1992 and hemophiliacs who have received clotting factor before that time are at risk because blood banks did not fully test the blood supply for hepatitis C before that year. Today, however, the risk of getting hepatitis C from a blood transfusion is almost zero.
Other risk factors include needlestick injuries, especially among health care workers, hemodialysis (equipment that filters blood may not be adequately sterilized between patients), and organ transplant before 1992.