A rare tick-borne illness has been detected in California, sending one person to the hospital and prompting renewed warnings from state health officials about tick safety in Northern California.
The California Department of Public Health confirmed the case in April, telling SFGATE on June 12 that the bacterium Rickettsia lanei was identified in a patient who was likely infected while traveling in Northern California. The patient was hospitalized for an undisclosed period and later released.
Officials have not disclosed the person’s symptoms or the exact location of exposure.
What is Rickettsia lanei? Rare tick-borne bacteria explained
Rickettsia lanei is part of the spotted fever group of bacteria, the same family that includes the more widely known — and potentially deadly — Rocky Mountain spotted fever.
The bacterium was first identified in Sonoma County in 2018, when a patient was initially misdiagnosed with Rocky Mountain spotted fever due to similar symptoms, according to the California Department of Public Health.
Since that discovery, only four human cases have ever been documented:
Because of the extremely small number of infections, a CDPH spokesperson told USA TODAY that “it is difficult to make generalizations” about how the disease affects people or how best to raise awareness.
Where infected ticks have been found in California
Despite the rarity of human infections, researchers continue to track ticks carrying Rickettsia lanei in California.
The California Department of Public Health says infected ticks have been identified in:
These included:
Rabbit ticks are typically found near rabbits in brushy or grassy areas and rarely bite people. Pacific Coast ticks, however, are more relevant to public exposure and are commonly found in:
Symptoms of spotted fever infections: How illness can progress
Health officials say infections linked to spotted fever group bacteria often present with common but potentially severe symptoms, making them difficult to distinguish early.
According to CDPH, symptoms may include:
Many patients also develop a rash that often starts on the hands and feet before spreading.
In documented Rickettsia lanei cases, three of the four patients developed a rash. While no deaths have been reported, all known patients required hospitalization due to the severity of illness, including time in intensive care, CDPH said.
Symptoms typically appear two to 14 days after a tick bite and can worsen quickly if left untreated. Fever associated with infection can last two to three weeks.
Why diagnosis is difficult — and why early treatment matters
One of the biggest challenges with Rickettsia lanei is that it closely mimics other spotted fever illnesses, especially Rocky Mountain spotted fever.
Doctors often must rely on specialized lab testing using blood or skin samples to confirm the diagnosis. However, those tests may not immediately detect the infection.
Because of that delay, health officials stress that doctors should act quickly if a spotted fever infection is suspected.
“It is important that health care providers begin treatment with doxycycline as soon as a spotted fever group Rickettsia infection is suspected, and not to wait for the result of a blood test,” CDPH told USA TODAY.
Rocky Mountain spotted fever — a related illness — affects about 1,000 people annually in the U.S., primarily in the Southeast and south-central regions. California typically reports only a small number of cases.
Tick safety in California: How to protect yourself outdoors
Health officials say the risk to the public remains low, but simple precautions can significantly reduce the chance of exposure.
CDPH recommends:
Ongoing tick surveillance across Northern California and the Pacific Coast continues to monitor for rare pathogens like Rickettsia lanei.
Contributing: SFGATE reporting; California Department of Public Health; USA TODAY.
This article originally appeared on Palm Springs Desert Sun: Rare tick-borne bacteria case in California sends patient to hospital
Reporting by Noe Padilla, USA TODAY NETWORK / Palm Springs Desert Sun
USA TODAY Network via Reuters Connect
By Noe Padilla, USA TODAY NETWORK | USA TODAY Network
