Seroepidemiological research on hepatitis A (HA) in the city of Siena.

The circulation of Hepatitis A Virus in the city of Siena and the tight neighbouring area appears to be fairly rare. In fact, the number of cases suffering from Hepatitis A, admitted into the Clinic of Infectious Diseases of the University of Siena, has been 33 out of 4,905 patients (yrs 1975-1985). Of these, only 6 were patients resident in Siena. Seroepidemiological research, carried out with the ELISA method on 275 people of an age between 1 and 20 years, has confirmed a specifically low immunization as regards to Hepatitis Virus A (in fact the total antibodies were present only in 1.54% of the cases tested). This report is a long way off the one indicated in other Italian cities in the south as well as the central north of Italy; it can be put in relation to the peculiar demographical situation of the city or to the general fall of Hepatitis A Virus infection also indicated in other areas of the world.