Brucellosis underreporting in Greece: Assessment based on aggregated laboratory data of culture-confirmed cases from public hospitals

Background: Brucella spp. isolation is one of the mainstays of brucellosis diagnosis. Simultaneously, the true brucellosis disease rate may be underrepresented in notification systems. This study aims at assessing the nosocomial capacity for Brucella spp. isolation and the underreporting rate of brucellosis cases in Greece. Methods: Data for Brucella spp. culture capacity and the number of isolations were collected annually from public hospitals nationwide, during 2015-2018. The number of unreported cases was estimated after subtracting the National Mandatory Notification System cases from the survey-captured isolations, matched by hospital and year. Results: Feedback was provided by 112 public hospitals (response rate: 97.4 %). Brucella spp. isolation capacity was completely absent in 27.7 % of hospitals; during the four years of the study, 11.3 %, 13.9 %, 20.0 %, and 25.2 % of the hospitals had isolation competence for one, two, three, or four years, respectively. Underreporting assessment was possible in hospitals that declared at least one Brucella spp. isolation (n =35) and unreported cases were identified in 19 (54 %). Α mean underreporting of 28.9 % of total cases was estimated for the whole period of the study ranging annually from 24.1 % to 35.0 %. The number of unreported cases per hospital ranged from one to 12 per year (median: 2, IQR: 5). Conclusions: Interventions for improving diagnosis and reporting of the disease are recommended. Assessment of brucellosis underreporting by comparing raw numerical data of survey-captured isolations and officially notified cases lacks the case by case specificity, however, keeping required data to a minimum achieves high feedback rate from hospitals and provides a tentative estimation of the notification deficit. © 2019, Lithografia Antoniadis I - Psarras Th G.P.. All rights reserved