TY - JOUR T1 - <em>Borrelia</em> infection in rodent host has dramatic effects on the microbiome of ticks JF - bioRxiv DO - 10.1101/2021.03.15.435198 SP - 2021.03.15.435198 AU - Phineas T. Hamilton AU - Elodie Maluenda AU - Anouk Sarr AU - Alessandro Belli AU - Georgia Hurry AU - Olivier Duron AU - Olivier Plantard AU - Maarten J. Voordouw Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/03/15/2021.03.15.435198.abstract N2 - Background Vector-borne diseases remain major causes of human morbidity and mortality. It is increasingly recognized that the community of microbes inhabiting arthropods can strongly affect their vector competence, but the role of the tick microbiome in Borrelia transmission – the cause of Lyme disease – remains unclear.Results Here, we use a large-scale experiment to clarify the reciprocal interactions between Borrelia afzelii and the microbiome of Ixodes ricinus, its primary vector. In contrast to other reports, we find that depletion of the bacterial microbiome in larval ticks has no effect on their subsequent acquisition of B. afzelii during blood feeding on infected mice. Rather, exposure to B. afzelii-infected hosts drives pervasive changes to the tick microbiome, decreasing overall bacterial abundance, shifting bacterial community composition, and increasing bacterial diversity. These effects appear to be independent of the acquisition of B. afzelii by ticks, suggesting they are mediated by physiological or immunological aspects of B. afzelii infection in the rodent host.Conclusions Manipulation of the microbiome of I. ricinus larvae had no effect on their ability to acquire B. afzelii. In contrast, B. afzelii infection in the mouse had dramatic effects on the composition of the gut microbiome in I. ricinus nymphs. Our study demonstrates that vector-borne infections in the vertebrate host shape the microbiome of the arthropod vector.Competing Interest StatementThe authors have declared no competing interest. ER -