摘要：Background: Hepatitis A is a social disease and has great importance for public health in countries with high level of incidence rate. The problem is particularly serious for Bulgaria because the morbidity rate in the country is several times higher in comparison with the other countries of the European Union. The aim of the study is to establish the contemporary epidemiological characteristics of viral hepatitis A in Bulgaria. Methods: Analysis of the incidence rate and the age distribution has been done among two groups of the population differentiated depending on their hygienic living conditions: 1st group—living in bad hygienic conditions; 2nd group—living in good hygienic conditions. A large epidemic outbreak of hepatitis A with 1004 persons of Roma origin has been described. The comprehensive method for epidemiological research and serological methods for determining the diagnosis have been used. To study the risk factors the methods of case-control and multi-factor logistic regression are used. Results: Nine times higher incidence rate has been established in the 1st group 450/100,000 in comparison with the 2nd 50/100,000. The patients from the 1st group are predominantly children aged 5 - 9 years and from the 2nd adults aged 30 - 39 years. The level of significance of the risk factors for the biggest epidemic outbreak has been established—bad personal hygiene is of the greatest importance. The risk for travellers to countries and regions with high endemicity and during epidemic outbreaks has been shown. Conclusions: There are essential differences in the epidemiology of HAV between the groups with different hygienic living conditions. That is why the analyses of the incidence rate and age distribution of hepatitis A have to be done separately for different population groups. Recommendations for providing differentiated measures for prevention and control of hepatitis A among the two groups are given.
