Hepatitis C virus (HCV), a spherical, enveloped, positive-strand RNA virus.
Transmission of HCV is bloodborne and most often involves exposure to contaminated needles or syringes or receipt of blood or blood products that have not been screened for HCV. Although infrequent, HCV can be transmitted through other procedures that involve blood exposure, such as tattooing, during sexual contact, or perinatally from mother to child.
Globally, an estimated 170 million people are living with HCV infection (chronically infected), and almost 500,000 were estimated to have died from HCV-related liver disease in 2010. Although the quality of epidemiologic data varies widely across countries and regions, the most recent global estimates indicate that the prevalence of HCV infection is <2% in many developed countries, including the United States (Map 3-05). 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 (approximately 10%) in Egypt. The most frequent mode of transmission in the United States and most developed countries is through sharing drug-injection equipment. In countries where HCV is more common (≥2% prevalence), the predominant mode of transmission is from unsafe injections and other health care exposures where infection control practices are poor. Travelers’ risk for contracting HCV infection is generally low, but they should exercise caution, 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, being shaved, 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. Global epidemiology of hepatitis C virus infection1
1Disease data source: Mohd Hanafiah K, Groeger J, Flaxman AD, Wiersma ST. Global Epidemiology of Hepatitis C Virus Infection; New Estimates of Age-Specific Antibody to HCV and Seroprevalence. Hepatology. 2013; 57:1333–1342.
Most people (80%) with acute HCV infection have no symptoms. If symptoms 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 approximately 10%–20% of chronically infected people, but progression to end-stage liver disease is slow and typically does not occur until ≥20 years after infection. This progression is often clinically silent until late in the course of disease, and in the absence of HCV testing, most people are unaware of their infection. Nonetheless, 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 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. Because a positive HCV antibody test cannot discriminate between someone who was previously infected but resolved or cleared the infection and someone with current infection, it is essential that HCV RNA testing follow a positive HCV antibody test to assess current (chronic) HCV infection. 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 has evolved dramatically since the approval of 2 protease inhibitors (boceprevir and telaprevir) in 2011 in the United States. Since then, a number of new direct-acting antiviral agents have been approved or will be approved in the next few years that will obviate the need for injectable interferon. The new treatments offer all-oral regimens, short duration of therapy (from 6–12 weeks to 24–48 weeks), few side effects, and high cure rates (>90%). Travelers who think they may have been exposed should see their health care provider upon return and get tested for HCV, and if found to have evidence of infection, be referred for care. No therapies for HCV postexposure prophylaxis are available; however, this may change as new treatments are approved. The most up-to-date treatment information can be found at www.hcvguidelines.org.
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, or 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). In some parts of the world, such as parts of sub-Saharan Africa, 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.
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