Epidemiology of HCV infection in the general population: a survey in a southern Italian town

OBJECTIVES

The objective of this study was to estimate the seroprevalence of hepatitis C virus (HCV) in the general population older than 18 years of age in a southern Italian town.

METHODS

The survey was conducted from July 2005 through January 2007 in Putignano, Bari, Apulia. A random 1:5 sampling from the list of records maintained by general practitioners was used. Serology for HCV, hepatitis B surface antigen (HBsAg), antibodies to hepatitis B core antigen (anti-HBc), and genotyping for HCV were performed.

RESULTS

Of a total of 2,195 serum samples tested, 58 (2.6%) were positive for anti-HCV antibodies. The prevalence increased from 1% in subjects aged <30 years to 7.7% in those aged 70 years and was similar in both males and females (3.1 vs. 2.4%, P=0.4). Approximately one-third of 58 positive subjects also showed alanine transaminase levels and 53.5% tested positive for HCV RNA by TaqMan PCR. Genotypes 2a and 1b were represented in 21 and 10 subjects, respectively. In a multivariate logistic regression analysis, age (adjusted odds ratio (OR) 1.05; 95% confidence interval (CI): 1.03-1.07), blood transfusion (adjusted OR 3.3; 95% CI: 1.7-6.3), and household contact with HCV-infected individuals (adjusted OR 4.8; 95% CI: 1.8-13.1) were the independent variables predictive of HCV infection. The overall HBsAg and anti-HBc prevalence rates were 0.5 and 12%, respectively.

CONCLUSIONS

This survey confirms that HCV infection is clearly also declining in southern Italy, especially among the elderly. HCV genotype 2a predominates, reflecting the current epidemiology of HCV in Italy. Age, blood transfusion, and household contact with HCV-infected individuals may have had a role in the spread of HCV infection.

Demonstration of HBsAg as the antigen component in circulating immune complexes detected by peg-solid phase test

The development of an enzyme-linked immunosorbent assay to identify HBsAg as the antigen component within circulating immune complexes using immobilized polyethylene glycol (PEG) is described. The method utilizes, on one hand, the ability of PEG to bind stably to plastic supports and, on the other, to precipitate circulating macromolecules. This method is easily performed, very cheap, quick and, above all, it helps define the biological nature of the immune complexes. HBsAg can be revealed as the antigen component of HBsAg/anti-HBs soluble immune complexes at concentrations of at least 20 ng/ml and either in antigen or antibody excess. Our results indicate that HBsAg circulates in a complexed form in 47% of HBsAg chronic carriers and in 10.7% of patients with liver disease who are positive for serum antibody to hepatitis B surface antigen (anti-HBs) and to core antigen (anti-HBc). None of the other groups of patients in the study had circulating HBsAg in the complexed form.