Vertical Transmission of Salmonella enterica ser. Gallinarum in Dermanyssus gallinae by the Mean of the Baudruche-Based Artificial Feeding Device

The poultry red mite (PRM) Dermanyssus gallinae is well known for its vectorial role for pathogens, such as Salmonella enterica ser. Gallinarum, the causative agent of fowl typhoid. Here, we ascertained the vertical transmission of S. Gallinarum across the PRM life stages, combining the Baudruche-based in vitro feeding system and a PRM-fitting DNA extraction and detection method by qPCR. Small-sized pools (4-5 specimens) of adult mites, eggs, larvae, and protonymphs, as well as single eggs, were tested for S. Gallinarum. The pathogen was detected in 89% of adult mites, 5% of single eggs, 17% of pooled eggs, 9% of larvae, and 43% of protonymphs. Additionally, the feeding rate for infected and uninfected mites was similar, while differences in ovipositing and fecundity rate were observed. The method allowed to confirm the infection of mites through the bloodmeal and to strongly suggest the transmission of S. Gallinarum across the PRM life stages. Furthermore, it allows to avoid in vivo studies and it could be useful for further investigating the vectorial role of D. gallinae or other hematophagous arthropods for infectious agents.