Temporal Diversity from Metabarcoding Survey and Zoonotic Pathogen Dynamics of Dermanyssus gallinae in Commercial Laying Hens

The poultry red mite Dermanyssus gallinae (PRM) is a hematophagous ectoparasite of major veterinary and public health concern, recognized as a potential vector of zoonotic pathogens. Despite recent advances in characterizing its microbiota, the temporal dynamics of the microbial community remain poorly understood. Here, we conducted a longitudinal metabarcoding survey of engorged PRM collected from a commercial cage-free laying hen farm over the laying hen’s productive cycle (30–105 weeks). High-throughput sequencing of the 16S rRNA V3–V4 region generated 412,078 sequences, identifying 186 bacterial species across all samples. Microbial richness peaked at 30 weeks (164 species), but sharply declined thereafter, with only 28, 55, and 43 species detected at 60, 90, and 105 weeks, respectively. Ordination (NMDS) and PERMANOVA analyses revealed significant temporal restructuring of microbial communities (R2 = 0.76, p < 0.01), with distinct clustering across sampling points. A small subset of taxa persisted throughout time, including the genera Bartonella and Rickettsiella, while many species exhibited transient or stage-specific occurrence. Notably, zoonotic pathogens such as Staphylococcus aureus, Kocuria massiliensis, and Bartonella vinsonii were detected, suggesting that PRM may harbor microorganisms of potential medical and veterinary relevance. Overall, our findings demonstrate that PRM harbors a highly diverse but temporally dynamic microbiota, which progressively contracts into a community dominated by stable symbionts. These results highlight critical windows for microbial succession and reinforce the relevance of microbiome-based surveillance and integrated control strategies within a One Health framework.