Hepatitis C virus (HCV), the major causative agent of non-A and non-B hepatitis, poses a serious worldwide health problem. An estimated 100 million individuals worldwide are chronically infected with HCV. High prevalence rates have been found in Southeast Asian countries, such as Thailand, Malaysia and India.1-3 Hepatitis C is the most common chronic blood-borne infection in the U.S. 4 In Pakistan, the seroprevalence of HCV is 6.7% in women and 1.3% in children. Hepatitis C accounts for approximately 20% of cases of acute hepatitis, 70% of chronic hepatitis and 30% of end-stage liver disease in the U.S.
6The hepatitis C virus is a single-stranded RNA virus of the Flaviviridae family. Individual isolates consist of a closely related yet heterogeneous population of viral genomes (quasispecies). Probably as a consequence of this genetic diversity, HCV has the ability to escape the host's immune surveillance, leading to a high rate of chronic infection. The extensive genetic heterogeneity of HCV has important diagnostic and clinical implications, perhaps explaining the variation in clinical course, difficulties in vaccine development, and lack of response to therapy.
7HCV is generally transmitted by the parenteral route. It is also transmitted by needle-stick injuries, sexual contact, and vertically from mother to fetus.8 Hepatitis C exposure and antibody positivity rates among injection drug users have been reported to be higher than 50% compared to 10% in the same general population.9-12 Other known risk factors include ear piercing, acupuncture, tattoos, and cultural procedures involving blood contact.
13-15The use of inadequately sterilized undisposable medical materials, e.g., needles and scalpels, has also been shown to transmit HCV.
16There is some evidence of occupational and nosocomial transmission of HCV infection. Inadvertent needlestick injuries and lack of application of universal precautions may be contributing factors.15 About 80% of HCVpositive surgical operation room personnel in a hospital in Pakistan had more than four needle-stick injuries per year in five years. 17 In one Pakistani community, HCV seroprevalence was 6.5%, and individuals who received more therapeutic injections were found to be at a higher risk of infection.
18Data on the natural history of HCV is limited because the onset of infection is often unrecognized, and the early course of disease is indolent and protracted in most individuals.19 Approximately 60%-70% of HCV patients have no discernable symptoms, 20%-30% may have jaundice, and 10%-20% may have nonspecific symptoms (e.g., anorexia, malaise, or abdominal pain). About 75%-85% go on to develop chronic hepatitis. Research indicates that 10%-20% of chronically infected individuals are likely to develop cirrhosis over a period of 20-30 years, while 1%-5% may go on to develop hepatocellular carcinoma. Reports from Pakistan show that 22%-33% of biopsy-proven cases of hepatocellular carcinoma had HCV infection.
20,21The volume of epidemiological data concerning hepatitis C is smal...