Detection of "Candidatus Rickettsia andeanae" in Rhipicephalus sanguineus sensu stricto (Acari: Ixodidae) from Rapa Nui-Easter Island

Background: Rickettsioses are vector-borne emerging diseases caused by pathogenic bacteria of the genera Rickettsia and Orientia. Bacteria of these genera have been described in northern and southern Chile, respectively. Aim: To determine the presence of Rickettsia spp. in ticks collected from domestic dog in Rapa Nui-Easter Island, Valparaiso Region. Methods: 20 stray dogs were sampled during October 2018. Overall, eight adult ticks were collected from seven animals (prevalence: 35%); after morphological identification, were submitted to DNA extraction and amplification and sequencing of the tick mitochondrial 16S DNA gene. The screening for Rickettsia was performed targeting the OA (citrate svnthctasc) gene. Results: A phylogenetic analysis confirmed the identity of the ticks as Rhipi-cephahrs sanguineus sensu stricto. In two ticks (25%), we retrieved identical sequences of gltA compatible with "Candidanis Rickettsia andeanae", which formed a monophyletic group with conspecific isolates obtained in Brazil, Chile and Peru. Conclusions: This study proves the presence of "Ca. R. andeanae" in R. sanguineus s. s. at Rapa Nui-Easter Island, which also corresponds to the first report of this Rickettsia spp. in R. sanguineus complex for Chile.