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Using metagenomic sequencing, we identified a patient infected with Rickettsia lanei who was initially diagnosed with Rocky Mountain spotted fever (RMSF), a clinically similar disease caused by infection with R. rickettsii .
Our investigation highlights the importance of clinical, epidemiologic, and laboratory partnerships to leverage the discovery of novel pathogens. Spotted fever group rickettsioses (SFGRs) comprise multiple febrile, rash-associated illnesses caused by various arthropodborne, intracellular Rickettsia bacteria.
Rocky Mountain spotted fever (RMSF), the most severe SFGR, was first described in the western United States around the turn of the 20th Century ( https://www.niaid.nih.gov/diseases-conditions/rocky-mountain-spotted-fever ). For the next ≈100 years, RMSF was considered the only tickborne SFGR in the United States; however, since 2004, investigators have identified additional pathogens causing SFGRs of varying severity that share clinical features with RMSF ( 1 – 3 ).
Cases of RMSF have been described in Oregon, USA, since 1903 ( 4 , 5 ).
CDC Emerging Infectious Diseases Journal published a clinical update in Infectious Disease on 03 Mar 2026.
The item focuses on Rickettsia lanei Rickettsiosis, Oregon, USA, 2025.
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