Abstract
Pathogens use diverse pathways to infect host populations by vertical and/or horizontal routes. Horizontal transmission of bacteria belonging to the B artonella genus via haematophagous vectors is well known. Vertical transmission of B artonella species was also suggested to occur but its routes remain to be unveiled. In a previous study, we showed the absence of transovarial transmission of B artonella species OE 1‐1 in X enopsylla ramesis fleas, and that fleas feeding on B artonella ‐positive jirds produced B artonella ‐positive gut voids. This current study aimed to investigate whether vertical nontransovarial transmission of B artonella occurs in fleas. For this aim, the X . ramesis– B artonella sp. OE 1‐1 model was used. Four groups of fleas including B artonella ‐positive and B artonella ‐negative female fleas and larval offspring had access to either B artonella ‐negative or B artonella ‐positive gut voids and faeces. Sixteen per cent of flea offspring that had access to B artonella ‐positive faeces and gut voids became B artonella positive. Our findings demonstrate that B artonella ‐positive flea faeces and gut voids are proper infection sources for flea larvae and indicate that vertical nontransovarial transmission of bartonellae occurs in fleas. This information broadens our understanding of B artonella transmission routes in flea vectors and enlightens pathways of bartonellae transmission and maintenance in flea populations in nature.