Migratory birds are known to play a role in the long-distance transportation
of microorganisms. To investigate whether this is true for rickettsial agents, we
undertook a study to characterize tick infestation in populations of the migratory
passerine bird Riparia riparia (Passeriformes: Hirundinidae), the sand martin. A total
of 194 birds were sampled and ticks removed from infested birds. The ticks were
identified as female Ixodes lividus (Acari: Ixodidae) using standard morphological
and molecular techniques. Tick DNA was assayed to detect Rickettsia spp. using
polymerase chain reaction and DNA was sequenced for species identification.
A single Rickettsia spp. was detected in 100% of the ticks and was designated
Rickettsia sp. IXLI1. Partial sequences of 17-kDa and ompA genes showed greatest
similarity to Rickettsia sp. TCM1, an aetiological agent of Japanese spotted fever-like
illness, previously described in Thailand. Phylogenetic analysis showed that Rickettsia
sp. IXLI1 fitted neatly into a group containing strains Rickettsia japonica, Rickettsia
sp. strain Davousti and Rickettsia heilongjiangensis. In conclusion, this research
shows that U.K. migratory passerine birds host ticks infected with Rickettsia species
and contribute to the geographic distribution of spotted fever rickettsial agents.