Hepatitis C is caused by the hepatitis C virus (HCV), a spherical, enveloped, positive-strand RNA virus, approximately 50 nm in diameter.
Transmission of HCV is bloodborne and occurs mainly through sharing drug-injection equipment, from transfusion of unscreened blood, or from untreated clotting factors. In developing countries, unsterile medicinal and other injection practices account for many HCV infections. Although infrequent, HCV can be transmitted through other procedures that involve blood exposure (such as tattooing) and during sexual contact.
Approximately 2%–3% (130–170 million) of the world’s population has been infected with HCV. In many developed countries, including the United States, the prevalence of HCV infection is <2%. The prevalence is higher (>2%) in several countries in Latin America, Eastern Europe, and the former Soviet Union, and certain countries in Africa, the Middle East, and South Asia; the prevalence is reported to be highest (>10%) in Egypt (Map 3-05). The most frequent mode of transmission in the United States is through sharing drug-injection equipment. Travelers’ risk for contracting HCV infection is generally low, but travelers should exercise caution when traveling to countries where the prevalence of HCV infection is ≥2%, as the following activities can result in blood exposure:
Receiving blood transfusions that have not been screened for HCV
Having medical or dental procedures
Activities such as acupuncture, tattooing, public shaving, or injection drug use in which equipment has not been adequately sterilized or disinfected, or in which contaminated equipment is reused
Working in health care fields (medical, dental, or laboratory) that entail direct exposure to human blood
Map 3-05. Prevalence of chronic hepatitis C virus infection1
1 Negro F, Alberti A. The global health burden of hepatitis C virus infection. Liver Int. 2011 Jul;31(2 Suppl):1–3. Data used with permission from John Wiley and Sons.
Most people (80%) with acute HCV infection have no symptoms. If symptoms do occur, they may include loss of appetite, abdominal pain, fatigue, nausea, dark urine, and jaundice. Of those who develop chronic HCV infection, the most common symptom is fatigue; severe liver disease develops in about 10%–20% of infected people. HCV is a major cause of cirrhosis and hepatocellular cancer and is the leading reason for liver transplantation in the United States.
Two major types of tests are available: IgG assays for anti-HCV antibodies and nucleic acid amplification testing to detect HCV RNA in blood (viremia). Assays for IgM, to detect early or acute infection, are not available. Approximately 75%–85% of people who seroconvert to anti-HCV, indicative of acute infection, will progress to chronic infection and persistently detectable viremia. False-negative antibody test results, while rare, may occur early in acute infection, usually in the first 15 weeks after exposure and infection.
Treatment for hepatitis C is rapidly evolving. Currently, sustained virologic response (SVR), which is considered a cure, is achieved in 50% of patients taking the previous standard treatment of pegylated interferon and ribavirin for 24–48 weeks. In May 2011, 2 new protease inhibitors, telaprevir and boceprevir, were approved to treat hepatitis C in the United States. When these drugs were added to a regimen of pegylated interferon and ribavirin in clinical trials, SVR rates increased to 75% for those also receiving telaprevir and to 63% for those also receiving boceprevir among people with HCV genotype 1 (the most common genotype in the United States). Treatment is most effective for people diagnosed within the first year of infection. However, this is difficult as serologic markers of acute infection are lacking and most acute cases are only mildly symptomatic or asymptomatic.
No vaccine is available to prevent HCV infection, nor does immune globulin provide protection. Before traveling, people should check with their health care providers to understand the potential risk of infection and any precautions they should take. When seeking medical or dental care, travelers should be alert to the use of medical, surgical, and dental equipment that has not been adequately sterilized or disinfected, reuse of contaminated equipment, and unsafe injection practices (such as reuse of disposable needles and syringes). HCV and other bloodborne pathogens can be transmitted if instruments are not sterile or the clinician does not follow other proper infection-control procedures (washing hands, using latex gloves, and cleaning and disinfecting surfaces and instruments). There are still a few areas of the world, such as parts of sub-Saharan Africa, where blood donors may not be screened for HCV. Travelers should be advised to consider the health risks if they are thinking about getting a tattoo or body piercing or having a medical procedure in areas where adequate sterilization or disinfection procedures might not be practiced. Travelers should be advised to seek testing for HCV upon return if they received blood transfusions or sustained other blood exposures for which they could not assess the risks.