{"id":7638,"date":"2026-06-21T05:01:31","date_gmt":"2026-06-21T05:01:31","guid":{"rendered":"https:\/\/sandiegorelocationnews.com\/index.php\/2026\/06\/21\/extremely-rare-tick-borne-disease-infects-northern-california-patient-what-to-know\/"},"modified":"2026-06-21T05:01:31","modified_gmt":"2026-06-21T05:01:31","slug":"extremely-rare-tick-borne-disease-infects-northern-california-patient-what-to-know","status":"publish","type":"post","link":"https:\/\/sandiegorelocationnews.com\/index.php\/2026\/06\/21\/extremely-rare-tick-borne-disease-infects-northern-california-patient-what-to-know\/","title":{"rendered":"Extremely rare tick-borne disease infects Northern California patient; what to know"},"content":{"rendered":"
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An individual from Northern California was hospitalized this year with a newly recognized and extremely rare tick-borne illness, becoming only the fourth documented case of the infection in the world, the California Department of Public Health confirmed.<\/p>\n

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The patient became seriously ill in late April with an infection involving Rickettsia lanei \u2014 a bacterium of the spotted fever group Rickettsia that is transmitted to humans by ticks, mites and fleas.<\/p>\n

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Two other cases of Rickettsia lanei have been documented in California: the first in 2004, followed by a second in 2023, a California Department of Public Health spokesperson confirmed in an email Friday. The fourth case was reported in Oregon.<\/p>\n

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According to health department officials, a patient, whose county of residence was not disclosed for privacy\u2019s sake, likely encountered an infected tick while traveling through a shaded area of Northern California. . Experiencing symptoms of a fever, fatigue, headache, rash and loss of consciousness, the person was hospitalized for over two weeks, when officials determined the patient was suffering from an infection borne by the Rickettsia lanei pathogen.<\/p>\n

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The patient has since been discharged and is recovering, the CDPH spokesperson added.<\/p>\n

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SFGate reported this latest human case of Rickettsia lanei on Jun. 12. Researchers first became aware of the pathogen in 2018, after it was detected in rabbit ticks in Sonoma County. It was only after a man presenting fever-like symptoms was tested in July 2023 that officials discovered the bacterium could infect humans.<\/p>\n

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\u201cRickettsia lanei likely circulates primarily in rabbits where it is maintained by the rabbit tick, which rarely bites people. Infections in rabbits and rabbit ticks appear to be uncommon,\u201d a CDPH spokesperson wrote in the email to The Bee. \u201cThe Pacific Coast tick, which bites humans more frequently, may occasionally acquire the organism from an infected rabbit, which is the most likely route for the rare human infections that have been identified.\u201d<\/p>\n

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Public health officials added the Ricketssia lanei bacterium to the list of newly recognized pathogens in 2024, after investigating the July 2023 case and a separate 2004 infection that were determined to have been caused by Rickettsia lanei. Both patients presented with symptoms similar to Rocky Mountain Spotted Fever, a life-threatening disease not normally contracted in California.<\/p>\n

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According to the study, the first patient was likely exposed to an infected tick when camping in San Mateo and Marin counties in June 2004. They were discharged after a 13-day hospital stay, during which they became comatose.<\/p>\n

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The second patient, reported in July 2023, likely came into contact with an infected tick while playing golf in Alameda and Contra Costa counties, officials concluded. After 22 days in the hospital, during which time they suffered septic shock with acute kidney injury, respiratory failure, cutaneous necrosis, gangrene and encephalitis, they were discharged.<\/p>\n

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Janet Foley, a professor of medicine and epidemiology at the UC Davis School of Veterinary Medicine, who spoke to SFGate when the case was first reported, warned that the tick-borne disease is highly serious given how similar symptoms are to Rocky Mountain Spotted Fever.<\/p>\n

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Ongoing tick surveillance efforts have identified a Pacific Coast tick infected with the bacterium and two infected rabbit ticks in Contra Costa and San Mateo counties, according to the CDPH.<\/p>\n

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What should I know about ticks?<\/h3>\n

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\u201cTicks are small, wingless bugs<\/u> that usually live in the woods or tall grass,\u201d the Cleveland Clinic said. \u201cThey bite people and animals to feed off of their blood.\u201d<\/p>\n

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Ticks can carry a variety of diseases<\/u>, with Lyme disease, Rocky Mountain spotted fever and alpha-gal syndrome among the most common, the Centers for Disease Control and Prevention said.<\/p>\n

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The U.S. Forest Service cautions hikers to stay away from areas with high grass and leaf litter<\/u>, and to hike in the middle of trails, to avoid ticks.<\/p>\n

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Here are some other tips from the Forest Service:<\/p>\n

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