A study on the basic epidemiological parameters of viral hepatitis a in the region of Plovdiv,Bulgaria

INTRODUCTION: Infection with hepatitis A virus is of great importance to public health. The disease has a worldwide occurrence due to inadequate sanitation and the variable seroprevalence rates in the community. OBJECTIVE: The present report investigates the epidemiological features of hepatitis A in the region of Plovdiv and outlines the most important epidemiological features of the disease. MATERIALS AND METHODS: In 1999 (a year with a lower hepatitis A prevalence) the basic epidemiological characteristics of the disease were studied: overall morbidity and mortality rates, age, sexual and seasonal distribution, and prevalence in rural and urban areas. The study was carried out in a cohort of 288 patients with hepatitis A admitted to the Clinic of Infectious Disease of the Medical University in Plovdiv. All patients were anti HAV IgM positive. Routine clinical, laboratory, epidemiological and statistical methods were used. Laboratory and serological tests were performed at the Center for Disease Control, Plovdiv and at the University Clinical Laboratory. RESULTS: Of 423 patients with acute viral hepatitis 288 (68.09%) had hepatitis A. In 1999 the morbidity rate for the region of Plovdiv was 49.55 per hundred thousand (intermediate). Disease prevalence was the highest in preschool and early school age as well as in the age groups 20-29 (84.67 per hundred thousand) and 30-39 (71.59 per hundred thousand). Urban residents accounted for 79.85% of the cases. The male/female ratio was 1:1. 82.25% of the preschool children did not attend day-care centers. History of contact with sources of infection was elicited from 17.01% of the patients. Disease rates peaked in October through December (maximum in October). CONCLUSIONS: Accumulated data could contribute to more effective disease control.