Global landscape and phylogenetic relationships of Rickettsia asembonensis: Insights from a multi-marker analysis of publicly available data

Ccamasacari C.; Ames C.; Loyola S. · Acta Tropica (2026) · DOI: 10.1016/j.actatropica.2026.108134

Resumen

Rickettsiosis is an emerging disease caused by bacteria of the genus Rickettsia transmitted by arthropods. Rickettsia asembonensis, first described in 2013, has been widely detected in vectors and, more recently, in animals and humans. Despite the growing number of reports, its epidemiology and the genetic relationships among reported strains remain poorly understood. This study provides an updated global overview of R. asembonensis by analyzing sequences, geographic distribution, host range, and temporal patterns using publicly available data for three conserved genes (17-kDa, gltA, and rrs) and three variable genes (ompA, ompB, and sca4). The study was conducted using genetic records available up to June 30, 2025, in the National Center for Biotechnology Information nucleotide database. A total of 477 genetic records of R. asembonensis and highly similar agents non-annotated as R. asembonensis were analyzed, including 368 conserved and 109 variable gene sequences. Among conserved genes, gltA and 17-kDa were most frequently reported, whereas ompB and ompA predominated among variable targets. Open reading frames coverage varied, with full-length sequences being uncommon. Phylogenetic analyses consistently grouped R. asembonensis entries with Rickettsia sp. and Rickettsia endosymbiont sequences, suggesting close genetic relationships but limited bootstrap support. Most records originated from the Americas (37.8%), with some also reported in Africa, Europe and Asia. Fleas were the principal hosts, and most sequences were reported between 2009 and 2020. Overall, these findings reveal the unequal availability and heterogeneity of genetic data and highlight the need for broader, standardized genomic surveillance to clarify its evolutionary relationships and distribution.

Instituciones: Universidad Peruana Cayetano Heredia