Global Alert and Response (GAR)

Hepatitis C

Hepatitis C - an introduction

- What?
- How?
- Who?
- Where?
- When?
- Why?

Hepatitis is a general term meaning inflammation of the liver and can be caused by several mechanisms, including infectious agents. Viral hepatitis can be caused by a variety of different viruses such as hepatitis A, B, C, D and E. Since the development of jaundice is a characteristic feature of liver disease and not just viral hepatitis, a correct diagnosis can only be made by testing patients’ sera for the presence of specific anti-viral antibodies.

The first demonstration that most cases of transfusion-associated hepatitis were caused by neither hepatitis A virus (HAV) nor hepatitis B virus (HBV), the only two known human hepatitis 39, 74 viruses at the time, came in 1975. This new form of disease was called non-A non-B hepatitis and the presumed etiologic agent, non-A non-B hepatitis virus.

In 1989 the virus responsible for most transfusion-associated non-A non-B hepatitis was identified and cloned, and named hepatitis C virus (HCV).19, 39, 74

Hepatitis C is also called type C hepatitis, Parenterally transmitted non-A non-B hepatitis (PT-NANB), Non-B transfusion-associated hepatitis, Posttransfusion non-A non-B hepatitis, HC.

What causes the disease?
Hepatitis C is caused by infection with the hepatitis C virus (HCV), an enveloped, single stranded, positive sense RNA virus.39, 52, 74

The virus infects liver cells and can cause severe inflammation of the liver with long-term complications.96

The onset of disease is usually insidious, with anorexia, vague abdominal discomfort, nausea and vomiting, fever and fatigue, progressing to jaundice in about 25% of patients, less frequently than hepatitis B.5, 41, 55, 94, 96

Of those exposed to HCV, about 40% recover fully, but the remainder, whether they have symptoms or not, become chronic carriers. Of these, 20% develop cirrhosis. Of those with cirrhosis, up to 20% develop liver cancer.5, 96

How is HCV spread?
Hepatitis C virus is usually spread by sharing infected needles with a carrier, from receiving infected blood, and from accidental exposure to infected blood. Some people acquire the infection through nonparenteral means that have not been fully defined, but include sexual transmission in persons with high risk behaviours, although transmission of HCV Is less common than that of HBV and HIV.11, 41, 96

HCV is not spread by breast feeding, sneezing, coughing, hugging, sharing eating utensils or drinking glasses, other normal social contact, food or water.56

Mother-to-baby transmission is now well documented, but uncommon.39 Needs a high viraemia (>1 log?) as found in HIV co-infection5

A person who has hepatitis C can still get other types of hepatitis, such as hepatitis A or hepatitis B.56

Who is susceptible to infection?
Susceptibility is general. Humans and chimpanzees are the only known species susceptible to infection, with both species developing similar disease.101

Where is HCV a problem globally?
HCV infections are common worldwide. It is estimated that about 3% of the world’s population have HCV. There are about 4 million carriers in Europe alone.96

When is hepatitis C contagious?
HCV positive persons are those who:
         - have anti-HCV antibodies in their blood,
         - have HCV RNA or HCV core antigen detected in their blood

All HCV positive persons are considered potentially infectious. Imprudent contact with their blood can lead to HCV infections.

HCV positive persons should :
• not donate blood, body organs, tissue, or semen
• not share toothbrushes or razors
• keep cuts and skin lesions covered

The presence of anti-HCV antibodies cannot be confirmed until 12-27 weeks after exposure creating a window period of seronegativity and potential infectivity.95

HCV RNA, as detected by polymerase chain reaction (PCR) or HCV core antigen detection, becomes positive within days of inoculation, PCR has become the method of choice for early diagnosis, core antigen detection is currently under evaluation.28, 51, 92

There are no available vaccines for HCV. Why?
Currently there is no vaccination against hepatitis C. One reason being that the virus comes in many forms and constantly mutates leading to “swarms” of closely related viral genomic sequences (referred to as quasi-species).7, 73, 96