Health officials have confirmed a new human infection of Rickettsia lanei in California, marking only the fourth known case of the bacteria worldwide. According to the California Department of Public Health (CDPH), the individual was diagnosed this year, joining a small group of cases since the pathogen was first identified in Sonoma County rabbit ticks in 2018. The bacteria causes symptoms similar to Rocky Mountain spotted fever, a condition that can result in coma, gangrene, and brain inflammation.
What is Rickettsia lanei and why is it dangerous?
Rickettsia lanei is a recently identified bacteria within the spotted fever rickettsioses group. Anne Kjemtrup, a research scientist and veterinarian with the CDPH, states the infection is rare but can be “fairly severe.” The illness mimics Rocky Mountain spotted fever, which is widely considered the most lethal vector-borne disease in the Americas. According to Janet Foley, a professor of medicine and epidemiology at the UC Davis School of Veterinary Medicine, the disease carries a higher lethality rate than hantavirus.
The bacteria is named after Robert Lane, a retired UC Berkeley professor who spent decades studying tick-borne diseases. It wasn’t until 2023 that scientists confirmed this specific organism could infect humans.
How did researchers identify the first human case?
The first recognized human infection occurred in July 2023, when a man arrived at a Bay Area emergency department with severe, fever-like symptoms. According to a 2024 report in Emerging Infectious Diseases, the patient’s condition deteriorated rapidly in the intensive care unit, leading to oxygen deprivation, seizures, and rising blood acid levels. Physicians only administered the antibiotic doxycycline after considering a rickettsial disease diagnosis. The patient survived after a 22-day hospital stay but suffered from kidney injury and gangrene in both hands.
How can you protect yourself from tick-borne illnesses?
While cases remain infrequent, experts advise proactive measures to minimize exposure to Pacific Coast ticks. Janet Foley recommends that outdoor enthusiasts stay on designated trails and avoid tall grasses where ticks often wait for hosts. Checking your body for ticks immediately after returning from the outdoors is a vital step in prevention. If you develop flu-like symptoms or a spotted rash on your limbs after time spent in nature, experts urge you to inform your physician about potential tick exposure immediately.
Physicians are encouraged by the CDPH to prioritize treatment with doxycycline if a patient presents with symptoms and a history of potential tick bites, rather than waiting for formal test results. Delays in treatment for spotted fever rickettsioses can significantly increase the risk of fatality.
Frequently Asked Questions
- What are the primary symptoms of Rickettsia lanei? Symptoms include high fever, muscle aches, headaches, and a distinctive “spotted” rash on the limbs.
- Is there a treatment for this infection? Yes, the antibiotic doxycycline is the standard treatment for spotted fever rickettsioses.
- How common are tick-borne diseases in California? While Rickettsia lanei is extremely rare, thousands of people across the U.S. are infected with various spotted fevers every year.
- Where are these ticks found? CDPH experts have identified the bacteria in Pacific Coast ticks along the California coast, including in Contra Costa County.
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