Title : Global analysis of botulism cases demonstrates underreporting in larger European nations
Background: Botulism is a rare illness caused by Clostridium botulinum toxin, causing death in 15% of hospitalised infected individuals. There is no coordinated collective worldwide reporting on cases with few reliable case frequency estimates. This study aimed to establish an international benchmark for case frequency.
Method: A comprehensive international multilingual literature search of Medline and Pubmed databases was performed for all historical research literature. An additional grey and government literature search was conducted in ten major languages. The databases of the ECDC, United States CDC, ProMED-mail and Gideon were also searched, all with a 19th January 2022 cut off.
Results: A total of 8997 documented cases since 1999 were uncovered, with 398 deaths (4.4% CFR) and hospitalisation a driver for case reporting (83.3%). Only 18 nations globally had published botulism case frequency estimates or a database series of cases capable of analysis. Excluding unsupported national estimates deemed as having wide deviations from calculated international mean (µ = 1.1 cpm), 15 nations were included in a linear regression analysis (y=0.41x; r=0.70); which revealed widespread underreporting compared to the regression estimate and calculated US CDC figures in all analysable European nations except Hungary, Italy, Poland and Romania (2004-2018 series; 0.47<x?<0.56, 95%CI). Case frequency series capable of variance from mean analysis (n=12) revealed large quartile spreads (x?<x?) and statistically significant deviation from global expected values in the global sample year (2017, P<0.05).
Conclusions: Analysis of national cases reported to the ECDC 2007-2020 compared to global estimates revealed underreporting of cases in four of the largest European nations (P<0.05). Better awareness of botulism poisoning among first point of healthcare contact and more robust reporting of presenting cases across Europe and EU nations would strengthen surveillance and may reduce morbidity and fatality long-term.