We found a diversity of Rickettsia spp. in seabird ticks from 6 tropical islands. The bacteria showed strong host specificity and sequence similarity with strains in other regions. Seabird ticks may be key reservoirs for pathogenic Rickettsia spp., and bird hosts may have a role in dispersing ticks and tick-associated infectious agents over large distances.
Keywords: Amblyomma loculosum ticks; Carios capensis ticks; Rickettsia africae; Rickettsia bellii; Rickettsia hoogstraalii; Rickettsia spp.; bacteria; genetic diversity; geographic range; host; host specificity; parasites; seabird ticks; terrestrial hosts; western Indian Ocean.