Fourth Global Case of Rare Tick-Borne Rickettsia Lanei Reported in California

A Northern California patient was hospitalized with a newly recognized and extremely rare tick-borne infection, Rickettsia lanei—the fourth documented human case worldwide (with prior California cases in 2004 and 2023, and a case in Oregon). The patient likely encountered an infected tick in a shaded area and was hospitalized for more than two weeks with fever, fatigue, headache, rash and loss of consciousness, but has since recovered. Rickettsia lanei is part of the spotted fever group, thought to circulate mainly in rabbits and can reach humans via the Pacific Coast tick; it was added to the list of newly recognized pathogens in 2024 and can resemble Rocky Mountain spotted fever. Public health officials emphasize tick prevention and ongoing surveillance.