Discovery of Rickettsia spp. in mosquitoes collected in Georgia by metagenomics analysis and molecular characterization

Adam R Pollio; Ju Jiang; Sam S Lee; Jaykumar S Gandhi; Brian D Knott; Tamar Chunashvili; Matthew A Conte; Shannon D Walls; Christine E Hulseberg; Christina M Farris; Drew D Reinbold-Wasson; Jun Hang

doi:10.3389/fmicb.2022.961090

Discovery of Rickettsia spp. in mosquitoes collected in Georgia by metagenomics analysis and molecular characterization

Front Microbiol. 2022 Sep 8:13:961090. doi: 10.3389/fmicb.2022.961090. eCollection 2022.

Authors

Affiliations

¹ Walter Reed Army Institute of Research, Silver Spring, MD, United States.
² Naval Medical Research Center, Silver Spring, MD, United States.
³ Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States.
⁴ U.S. Army Medical Research Directorate - Georgia (USAMRD-G), Walter Reed Army Institute of Research, Tbilisi, Georgia.

Abstract

Arthropods have a broad and expanding worldwide presence and can transmit a variety of viral, bacterial, and parasite pathogens. A number of Rickettsia and Orientia species associated with ticks, fleas, lice, and mites have been detected in, or isolated from, patients with febrile illness and/or animal reservoirs throughout the world. Mosquitoes are not currently considered vectors for Rickettsia spp. pathogens to humans or to animals. In this study, we conducted a random metagenome next-generation sequencing (NGS) of 475 pools of Aedes, Culex, and Culiseta species of mosquitoes collected in Georgia from 2018 to 2019, identifying rickettsial gene sequences in 33 pools of mosquitoes. We further confirmed the findings of the Rickettsia by genus-specific quantitative PCR (qPCR) and multi-locus sequence typing (MLST). The NGS and MLST results indicate that Rickettsia spp. are closely related to Rickettsia bellii, which is not known to be pathogenic in humans. The results, together with other reports of Rickettsia spp. in mosquitoes and the susceptibility and transmissibility experiments, suggest that mosquitoes may play a role in the transmission cycle of Rickettsia spp.

Keywords: NGS; One Health; Rickettsia; country of Georgia; metagenomic; mosquito; pathogen discovery; vector-borne disease surveillance.