Northern California resident infected with rare tick-borne illness

A California resident was hospitalized this spring following an infection with Rickettsia lanei, an extremely rare tick-borne bacterium. This case marks only the fourth known human infection worldwide, according to the California Department of Public Health. The patient, whose identity and location remain undisclosed, has been released from the hospital and is currently recovering.

What is Rickettsia lanei?

Rickettsia lanei is a newly recognized pathogen within the spotted fever group of Rickettsia. While researchers first identified the bacterium in rabbit ticks in Sonoma County in 2018, its potential for human transmission was initially unclear because rabbit ticks rarely bite humans. Recent research has since pointed to the Pacific Coast tick as a more likely route for human transmission.

Did You Know? The four known human infections of Rickettsia lanei include three cases identified in California, with the first two instances occurring in 2004 and 2023.

How does the illness present?

Symptoms of Rickettsia lanei infection often mirror those of other tick-borne illnesses, including fever, headache, muscle aches, and rash. Because these early symptoms are non-specific, they may not immediately signal a tick-borne disease to patients or medical providers. The Centers for Disease Control and Prevention (CDC) notes that related illnesses, such as Rocky Mountain spotted fever, can become life-threatening if not treated promptly with the antibiotic doxycycline.

Expert Insight: Samantha Carter notes that while the absolute number of reported Rickettsia lanei cases remains low, the severity of prior documented infections—which have included weeks-long hospitalizations and intensive care stays—highlights the importance of early clinical recognition and patient history in regions where Pacific Coast ticks are active.

What happens next?

Health officials may continue to monitor for additional cases as awareness of the pathogen grows among medical professionals. Since symptoms can resemble other infections, clinicians might increasingly consider Rickettsia lanei when evaluating patients who present with fever and rash following time spent in grassy, brushy, or wooded areas. Public health guidance remains focused on prevention and prompt intervention, as California typically reports only a small number of confirmed cases of Rocky Mountain spotted fever and Pacific Coast tick fever annually.

Frequently Asked Questions

What should I do if I find a tick on my body?
According to health officials, you should use fine-tipped tweezers to grasp the tick close to the skin and pull upward with steady pressure. You should then monitor yourself for symptoms and contact a healthcare provider if you become ill.

What are the symptoms of this infection?
Symptoms often include fever, headache, muscle aches, and rash. Early signs can resemble other common infections.

How is this illness treated?
The CDC recommends treatment with doxycycline for suspected tick-borne rickettsial diseases, noting that early intervention is critical to preventing life-threatening complications.

Have you taken extra precautions to check for ticks after spending time in wooded or brushy areas of Northern California?