Prevalence and burden of dengue infection in Europe: A systematic review and meta-analysis

Imported dengue cases are thought to be important source for transmission of autochthonous dengue in Europe. We aimed to investigate the prevalence of dengue in Europe, its severity, and factors associated with it. Out of 5287 reports resulting from the search of nine electronic search engines, we included 174 reports. Meta-analysis was performed by pooling the event rate and 95% confidence interval (CI). Subgroup meta-analyses were performed to test the effect of the covariates. Among 20 284 reported cases, 130 autochthonous dengue cases were reported in eight countries with the highest number of cases reported in Israel (n = 41). The highest number of imported dengue cases was in Germany (n = 6638) then France (n = 6610). Most cases were imported from Southeast Asia (n = 2533) especially Thailand. Dengue infection cases increased with time, with 4157 cases reported in 2010. Second dengue infection and dengue serotype 2 were positively associated with dengue severity. The proportion of autochthonous dengue infection increased with time to reach 14.8% (95% CI, 7.6-26.9) in 2015. The pooled proportion of severe dengue was 6.18% (95% CI, 2.7-13.3). The United Kingdom and France had the highest rate of severe dengue (25%; 95% CI, 6.3-62.3, and 21.4%; 95% CI, 24.5-18.7, respectively). This change may be due to the surveillance efforts instead of true biological phenomenon; thus, the lack of surveillance is an obvious limitation. In conclusion, imported and autochthonous dengue has been increasing in Europe. Severe dengue began to increase recently in Europe. European health authorities should pay more attention for the diagnosis and control of dengue infection among returning travelers, especially the travelers with fever of unknown origin.