Molecular Detection of Candidatus Rickettsia andeanae and Ehrlichia sp. in Amblyomma pseudoconcolor Aragão, 1908 (Acari: Ixodidae) from the Argentinian Patagonia

Abstract

This study presents the molecular detection of Candidatus Rickettsia andeanae and Ehrlichia sp. in Amblyomma pseudoconcolor Aragão, 1908 (Acari: Ixodidae) collected on a large hairy armadillo (Chaetophractus villosus (Desmarest, 1804)). On 12 October 2020, a specimen of C. villosus was found dead on the road in Río Negro province, Argentina. Molecular detection of Rickettsia and Ehrlichia agents was performed amplifying the gltA and 16S rRNA gene, respectively. One tick, determined morphologically and genetically as A. pseudoconcolor, was collected on C. villosus. The rickettsial agent detected in A. pseudoconcolor was identified as Candidatus Rickettsia andeanae. The Ehrlichia sp. strain showed high sequence similarity to different uncultured Ehrlichia sp. detected in horses, capybaras and Ixodes ornithorhynchi from Nicaragua, Brazil and Australia, respectively. The results of this study and previous findings suggest that A. pseudoconcolor may be a potential vector of some Rickettsia and Ehrlichia bacteria of unknown pathogenicity.

Diversity of rickettsiae in ticks (Acari: Ixodidae) collected from wild vertebrates in part of the Amazon, Cerrado, and Pantanal biomes in Brazil

“…Several studies have described infection by 'Ca. R. andeanae' in Amblyomma ticks, including A. parvum (Pacheco et al, 2007;Ogrzewalska et al, 2014;Nieri-Bastos et al, 2014;Lugarini et al, 2015;Maia et al, 2018), A. auricularium (Lugarini et al, 2015), A. sculptum (Witter et al, 2016), A. maculatum (Blair et al, 2004;Paddock et al, 2010;Flores-Mendoza et al, 2013), A. pseudoconcolor (Sebastian et al, 2022), A. tigrinum (Arrais et al, 2021), and A. triste (Abarca et al, 2012). The role of this bacterium as a human pathogen is still unknown (Ferrari et al, 2013); however, Krawczak et al (2023) have proposed that high infection rates by 'Ca.…”