Retrospective study of human cystic echinococcosis in Italy based on the analysis of hospital discharge records between 2001 and 2012.

Cystic echinococcosis (CE) is an important zoonotic parasitic infection. The European Centre for Disease Control highlights that Italy lacks a surveillance system for CE. Due to the lack of official data, we analysed the Hospital Discharge Records (HDRs) drawn from the National Ministry of Health. The aim of this study was to analyse data from the HDRs with CE-related diagnoses in Italy from 2001 to 2012 to assess the current status and trend of disease epidemiology. A total of 16,550 HDRs related to the admission of 10,682 Italian patients were examined. The HDRs were analysed according to the patient's region and province code to evaluate the demographic and clinical characteristics of each case, together with the annual incidence rates of hospital cases (AIh) in administrative divisions in rural and urban areas. Lesions occurred frequently in the liver (83.6%) and lungs (8.4%). Patients ranged in age from 1 to 100 years (mean 59.8), and 57% were over 60 years old. The highest average AIh was registered in the Islands with 4.6/10(5) inhabitants (6.9/10(5) in Sardinia and 4.3/10(5) in Sicily), followed by the South with an average AIh of 1.9/10(5) inhabitants (5.4/10(5) inhabitants) and the Centre with an average AIh of 1.07/10(5) inhabitants (there was an AIh of 1.65/10(5) in Latium). The analysis for trend showed a statistically significant decrease in the AIh throughout the study period (e.g., in the Islands r(2)=0.98, p<0.001). An AIh over 2/10(5) inhabitants was observed in 31/110 provinces. Rural areas with comprehensive development problems had a relative risk of CE of 5.7 (95% CI, 5.3 to 6.9) compared to urban areas. The relative risk increased between areas where sheep breeding is widespread compared to those where it is less prevalent. This study shows a detailed picture of the geographic distribution and the epidemiological situation of CE in Italy, indicating that CE continues to be a significant public health problem in Italy. The retrospective study of HDRs is useful for the evaluation of the status of disease epidemiology; however, a surveillance system is needed to report confirmed cases of human CE.