Detection of Rickettsia-Infected Argas (Persicargas) giganteus on Osprey (Pandion haliaetus) from the Northeastern USA.

Ospreys (Pandion haliaetus), piscivorous raptors with extensive global distributions, can undergo extensive migrations. Migratory species can transport ectoparasites, including ticks, to new regions. Many soft ticks (Argasidae) are ornithophilic and occur in bird nests, occasionally causing nest abandonment and chick mortality through pathogen transmission, blood loss, or paralysis. Argas spp. soft ticks are distributed worldwide, with several species in the US, predominately in the western US. Argas (Persicargas) giganteus, has been documented on numerous passerine and raptor species in the western US and parts of Mexico. We detected A. giganteus on two Ospreys from Pennsylvania and Washington, DC, US, representing a significant recognized range expansion. Genetic analysis confirmed that ticks from both birds were A. giganteus: internal transcribed spacer 2, 12S rRNA, and 16S rRNA gene sequences were 100, 100, and 99.7% similar to A. giganteus, respectively. Most ticks tested (7/8, 88%) were Rickettsia spp. positive; six sequences were Rickettsia hoogstraalii, with one most similar (99.5%) to Rickettsia monacensis. Although A. giganteus is not known to infest people, R. monacensis is a cause of spotted fever rickettsiosis; the pathogenicity of R. hoogstraalii in humans is poorly understood. Furthermore, A. giganteus can probably cause tick paralysis in raptors, especially in young birds. Therefore, continued surveillance for A. giganteus and Rickettisa spp. is warranted, particularly because this tick and associated pathogens seem to be emerging in the eastern US.