Fig. 1
From: The burden of legionnaires’ disease in Belgium, 2013 to 2017
Surveillance pyramid for Legionnaire’s disease (LD) in Belgium in 2017. Illustration of how underreporting (UR; healthcare-level) and under-ascertainment (UA; community-level) affect the reported incidence of LD. The MFs account for cases lost to surveillance (reported incidence) at leach level. They were derived using this equation: MF = 1/x, where x is the probability of transitioning from one level to the next higher one we determined for the respective level based on available Belgian data and literature (see Additional file 1). MF: multiplication factor; CRS: capture-recapture study; UI: Uncertainty Interval