Heatwave-associated Vibrio infections in Germany, 2018 and 2019

Abstract

Background Vibrio spp. are aquatic bacteria that prefer warm seawater with moderate salinity. In humans, they can cause gastroenteritis, wound infections, and ear infections. During the summers of 2018 and 2019, unprecedented high sea surface temperatures were recorded in the German Baltic Sea. Aim We aimed to describe the clinical course and microbiological characteristics of Vibrio infections in Germany in 2018 and 2019. Methods We performed an observational retrospective multi-centre cohort study of patients diagnosed with domestically-acquired Vibrio infections in Germany in 2018 and 2019. Demographic, clinical, and microbiological data were assessed, and isolates were subjected to whole genome sequencing and antimicrobial susceptibility testing. Results Of the 63 patients with Vibrio infections, most contracted the virus between June and September, primarily in the Baltic Sea: 44 (70%) were male and the median age was 65 years (range: 2–93 years). Thirty-eight patients presented with wound infections, 16 with ear infections, six with gastroenteritis, two with pneumonia (after seawater aspiration) and one with primary septicaemia. The majority of infections were attributed to V. cholerae (non–O1/non-O139) (n = 30; 48%) or V. vulnificus (n = 22; 38%). Phylogenetic analyses of 12 available isolates showed clusters of three identical strains of V. vulnificus, which caused wound infections, suggesting that some clonal lines can spread across the Baltic Sea. Conclusions During the summers of 2018 and 2019, severe heatwaves facilitated increased numbers of Vibrio infections in Germany. Since climate change is likely to favour the proliferation of these bacteria, a further increase in Vibrio-associated diseases is expected.

Epidemiological and microbiological investigation of the large increase of vibriosis in northern Europe in 2018

“…The majority of vibriosis cases in the study countries were domestic and males were more frequently affected than females, consistent with other reports [12, 21]. Even though the majority of cases were present among adults, about a fifth of the detected cases were among children up to 14 years of age, who mostly had ear infections and mild vibriosis; severe infections on the other hand were found to be associated with increasing age.…”

“…It is well documented that vibriosis is more frequently reported in summer [2, 6, 11, 12, 18]. Our results from 2018 confirm this pattern with the majority of infections occurring in summer months.…”

“…Our study provides a detailed overview on the occurrence of vibriosis in the Nordic and Baltic Sea regions in 2018. In context of epidemiological and microbiological findings as well as conducted studies from 2014-2018 [11, 12], our results highlight the importance of vibriosis as a concern to public health in this geographic area. Even though the data have been collected using different systems, the study countries reported similar patterns in terms of population affected by sex and age-group distribution.…”

“…The Baltic Sea region is one of the areas where increasing numbers of cases related to Vibrio species causing vibriosis (VCV) have been reported in the last decades [6]. Several studies have shown how the occurrence of heatwaves, that lead to an increase of sea surface temperature, are linked with an increase of the number of reported vibriosis cases [4, 7-12]. For instance, 2006, 2010, and particularly 2014 (the warmest year in historical records to that date), were the years with a significantly warm summer in the Baltic Sea region, and were also the years with the largest number of vibriosis cases reported [6, 11].…”

Epidemiological and microbiological investigation of a large increase in vibriosis, northern Europe, 2018

“…Our study provides a detailed overview on the occurrence of vibriosis in the Nordic and Baltic Sea regions in 2018. In a context of epidemiological and microbiological findings as well as studies conducted from 2014 to 2018 [ 11 , 12 ], our results highlight the importance of vibriosis as a concern to public health in this geographical area. Even though the data had been collected using different systems, the study countries reported similar patterns of sex and age group distribution in the affected population.…”