Abstract

 Background and Objectives

 Hepatitis A virus (HAV) is a hepatotropic virus and a member of the Hepatovirus genus within the Picorna-viridae family. Among HAV-infected individuals, children under 6 years old are typically asymptomatic, whereas older children and adults develop jaundice. Studies carried out in different regions of the world have demonstrated a reduction of HAV infection in children under five and a gradual increase among adolescents and adults. The frequency of acute hepatitis A infection was investigated among different age groups by molecular and serological procedures in this study.

 Materials and Methods

 This research was a cross sectional study. During the period of 12 months, from October 2005 to 2006, a total of 308 patients with a diagnosis of Hepatitis A were admitted and analyzed at Tehran Regional Educational Blood Transfusion Center in Tehran. The serum samples were tested for viral hepatitis (HAV, HBV , and HCV). Of these samples, 62 were positive for HBV or HCV and were excluded from this study. The 246 remaining serum samples were included. Serum specimens were tested for IgM anti-HAV antibody using a commercial enzyme immunoassay. Differences in the prevalence of IgM anti-HAV among different age groups were analyzed using the chi-square test. HAV RNA was detected by nested Reverse Transcription-Polymerase Chain Reaction (RT-PCR).

 Results

 IgM anti-HAV antibodies were detected in 29 (11.8%, CI 95%= 7.77-15.83) of 246 patients. The frequency rates of IgM anti-HAV antibodies in the studied population were 17.8% within the age range of 0-10 years, 23.1% within the range of 11-20 years, 14.7% within the range of 21-30 years, 3.2% within the range of 31-40 years, and 0% within the age range of above 40 years. Significant difference was observed between different age groups. The frequency of IgM anti-HAV was higher within the age range of 11-20 years (23.1%) as compared to other age groups. HAV RNA was detected in 25 of 29 (86.2%) serum samples.

 Conclusions

 With improvement in sanitary conditions, it is necessary to perform new studies on HAV infection prevalence and incidence in different age groups of the country. These data will be useful for future vaccination planning.

 Key words: Hepatitis A virus, Incidence, IgM, RT-PCR