August 24, 2005
Transmission of Hepatitis C among Family Members
The prevalence of antibodies to Hepatitis C Virus (HCV) in Egypt is among the highest in the world. From the 1950s until 1982 hundreds of thousands were infected during mass campaigns to control schistosomiasis (a parasitic disease) using mass therapy with intravenous antimony compounds, but little is known about current risk factors and rates of transmission. Studies of high risk populations, such as intravenous drug users, shed little light on HCV transmission in Egypt where this high risk behavior is rare.
In a study led by G. Thomas Strickland, M.D. of the Department of Epidemiology and Preventive Medicine at the University of Maryland School of Medicine in Baltimore, MD and published in the September 2005 issue of Hepatology, Egyptian and American researchers surveyed rates of HCV infection in two rural communities having a prevalence of antibody to HCV of 24 and 9 percent.Hepatology, the official journal of the American Association for the Study of Liver Diseases (AASLD), is published by John Wiley & Sons, Inc., and is available online via Wiley InterScience at http://www.interscience.wiley.com/journal/hepatology.
A total of 10,112 HCV negative individuals were identified during an annual survey in 1997, with follow-up performed on an average of 1.6 years later in 6,738 subjects. Of these, 33 developed HCV antibodies, an incidence of 3.1/1000 person-years (PY), and 6.8/1000 PY in the 28 subjects in the village having the 24 percent prevalence of HCV. None of the 33 individuals was diagnosed with viral hepatitis or reported symptoms of acute hepatitis. An analysis of risk factors showed the strongest predictor of infection with HCV was having and anti-HCV positive family member. Among those that did, incidence was 5.8/1000 PY, compared to 1.0/1000 PY; 27/33 incident cases had an anti-HCV positive family member. Parenteral exposures increased the risk of HCV, but were not statistically significant; 67 percent of seroconverters were less than 20 years old, and the highest incidence rate (14.1/1000 PY) was in children under 10 living in households with an anti-HCV positive parent in the village with the high prevalence of HCV antibodies. The infection rate was also increased (13.1/1000 PY) in men married to an HCV positive woman.
"We believe HCV exposures in rural Egyptian communities are usually less intense than those in individuals infected by contaminated blood, either from transfusion of blood or a blood product, or from abuse of intravenous drugs," the authors state. Although not statistically proven to be a risk in this study, they cite frequent injections, usually given at home for health purposes with syringes and needles sometimes used for more than one person, as the most common parenteral exposure route. The strong relationship between the risk of infection in children and the presence of HCV antibodies in their parents suggests that transmission of HCV is occurring between family members, possibly by exposure to infectious blood or saliva, or by sharing needles. In the past, mass treatment campaigns for schistosomiasis involving multiple injections may have caused numerous HCV infections in families, but this would not account for current infection rates, other than placing younger members of families living with those who contracted HCV in this way at higher risk.
The authors conclude: "It is exceedingly important to learn the mechanisms by which HCV transmission is occurring between family members so that preventive measures can be initiated, particularly in children having HCV-infected parents."
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