In recent years, a global increase in the number of reports of human vibriosis involving V. cholerae non-O1/O139 (NOVC) and other Vibrio spp. has been observed. In this context, the Belgian National Reference Center for Vibrio conducted an assessment of the presence of Vibrio spp. in recreational waters. Water sampling was performed monthly in different lakes in Wallonia and Flanders, including the North Sea. The collected water was then filtrated and cultured, and Vibrio spp. was quantified according to the Most Probable Number (MPN). Presumptive colonies were confirmed via MALDI-TOF, and PCR for virulence genes was applied if justified. No Vibrio spp. was found in the analyzed water bodies in Wallonia. However, NOVC was isolated from three different lakes in Flanders and from coastal water. In addition, V. alginolyticus and V. parahaemolyticus were also detected in coastal water. No clear impact of the pH and temperature was observed on Vibrio spp. occurrence. Our study demonstrates the presence of Vibrio spp. in different bathing water bodies, mostly in the north of Belgium, and supports the recommendation to include Vibrio spp. as a water quality indicator for bathing water quality assessment to ensure the safety of water recreational users in Belgium.

Aedes albopictus has recently established self‐sustaining populations in Hungary, but its microbiota—which may influence vector competence—remains poorly understood. We used Oxford Nanopore long‐read sequencing for full‐length 16S rRNA gene profiling of adult Ae. albopictus from two urban sites, Pécs and Barcs. Each location contributed 10 specimens, with contamination controls rigorously applied. Diversity metrics and co‐occurrence network analyses were performed using QIIME2, SparCC, and NetCoMi, with robustness assessed via simulated node removal and addition. Sequencing depth was sufficient to saturate rarefaction curves. Although alpha and beta diversity did not differ significantly between sites, the Pécs population exhibited greater taxonomic richness (100 unique taxa vs. 61 in Barcs) and denser, more clustered networks. Only 15 genera were shared, with Wolbachia dominating both communities. Networks differed in central taxa and structural properties: Pécs retained higher connectivity and shorter paths under perturbation, suggesting greater resilience. Removal of conserved taxa revealed location‐specific impacts on network stability, with Pécs more vulnerable to the loss of key genera. Negative interactions and compensatory taxa emerged post‐removal, indicating distinct reconfiguration strategies. Our findings highlight marked local variation in microbiome structure and robustness, even across a 65‐km gradient. These results establish a high‐resolution baseline for assessing how microbiota shape Ae. albopictus vector potential, informing microbiome‐based control strategies tailored to regional contexts.

Ticks are important vectors of zoonotic pathogens, and the presence of these pathogens can be influenced by factors such as the tick microbiome, which, conversely, is shaped by environmental conditions and the presence of tick-borne pathogens, as demonstrated in several studies conducted under controlled conditions. However, the extent of these influences under natural ecological conditions remains underexplored. In this study, we investigated the diversity of the microbiome and the prevalence of pathogens in Ixodes ricinus nymphs across three distinct Belgian ecoregions: Sandy Loam, Condroz, and Ardennes. Using real-time quantitative PCR (qPCR) and Oxford Nanopore 16S rRNA sequencing, we assessed how geography and pathogen presence influence tick-associated microbial communities. Our results revealed significant regional differences in microbiome composition and pathogen prevalence. Borrelia burgdorferi sensu lato (s.l.) was most prevalent in the Ardennes, while Anaplasma phagocytophilum was more common in the Sandy Loam region. Endosymbionts such as Midichloria mitochondrii and Spiroplasma ixodetis also exhibited distinct geographic distributions. Network analysis identified potential pathogen-microbiota interactions, with certain bacterial taxa showing positive or negative associations with specific pathogens. Moreover, microbiome composition was influenced not only by ecoregion but also by pathogens such as Rickettsia helvetica, suggesting that its colonization may actively shape microbial community structure, potentially through competition or facilitation mechanisms. Additionally, microbiome network robustness varied across ecoregions, highlighting the role of ecological context in shaping microbial interactions within ticks. These findings underscore the complex interplay between geography, pathogen presence, and microbial diversity in ticks, emphasizing the need to consider ecological variability when studying tick-borne disease dynamics. Understanding these interactions could inform microbiome-based strategies for vector control and disease prevention.