Cases of flea-borne typhus have hit an “all-time high” in a California county, according to public health officials.

A record 220 cases of the disease were identified in 2025 in Los Angeles County, the county public health agency reported April 2.

“Alarmingly, nearly 9 out of 10 people identified as infected with typhus required hospitalization, underscoring the seriousness of the disease and the urgent need for awareness and prevention,” the agency said.

Those infected ranged in age from 1 to 85 years old, health officials said.

Symptoms of flea-borne typhus typically include fever and a rash.

Three outbreaks in central Los Angeles, Santa Monica and the unincorporated neighborhood of Willowbrook in south Los Angeles County were reported in 2025.

There were 187 cases of flea-borne typhus in the county in 2024, the agency said.

Here’s what to know:

What is typhus?

There are several kinds of typhus, but flea-borne typhus, also called murine typhus or endemic typhus, is caused by a bacteria called Rickettsia typhi, the U.S. Centers for Disease Control and Prevention said.

It’s spread by fleas, which become infected when they bite infected animals, such as rats, cats or opossums, the agency said. Typhus causes fevers and other symptoms, but is rarely fatal.

Flea-borne typhus is an ancient disease but came to prominence in the United States 1910s and 1920s, with more than 40,000 cases in California and the South, the National Institutes of Health said.

Typhus has been around for centuries and is “as old as the plague,” Shannon Bennett, the chief of science and a microbiology curator at the California Academy of Sciences, told SFGate.

Another kind of typhus, carried by lice and caused by the bacteria Rickettsia prowazekii, produced historic plagues that devastated populations during times of war, famine and poverty, the National Institutes for Health said.

How common is typhus?

Flea-borne typhus is generally rare in developed countries but remains endemic in some parts of the world, mainly in tropical and coastal areas, the California Department of Public Health said.

An average of about 300 cases a year occur in the United States, mostly in Texas, California and Hawaii, the agency said.

How does typhus spread?

Not surprisingly, flea-borne typhus is spread by fleas. Fleas poop when they feed after a bite breaks the skin.

“This poop (also called flea dirt) contains the bacteria, which can be rubbed into the bite wound or other wounds and cause an infection,” the CDC said.

But most patients don’t notice a flea bite before catching typhus. People also can catch typhus by breathing in flea dirt or rubbing it into their eyes, the agency said.

What are the symptoms of typhus?

Symptoms of flea-borne typhus include chills, fever, headache, muscle aches like what you’d have with the flu, a rash, coughing, loss of appetite, nausea, stomach pain and vomiting, WebMD said.

Symptoms normally begin 10 days to two weeks after exposure and last two to three weeks if untreated.

What are the complications of typhus?

Typhus complications, if left untreated, can be deadly. They include brain and spinal cord inflammation, enlarged spleen, inflammation of the heart muscle or valves, internal bleeding, kidney damage, liver damage, low blood pressure, pneumonia and septic shock, WebMD said.

When should you see a doctor about typhus?

Notify your doctor if you think you have typhus or have been exposed, the Cleveland Clinic advised.

Call 911 or go to the emergency room if you experience a high fever or fever lasting more than a few days, confusion or other mental changes, seizures, difficulty breathing, chest pain or extreme tiredness or weakness.

How can you avoid typhus?

There is no vaccine for the flea-borne virus, the CDC said.

But you can reduce your risk of infection by keeping fleas off your pets, keeping rodents and wild animals away from your home and protecting yourself from flea bites.

How do you treat typhus?

Flea-borne typhus is medically treated with antibiotics, the California Department of Public Health said.

Most people recover from the illness in a few days with proper treatment.

How can you tell typhus from other illnesses?

Typhus can be distinguished from other fevers by a combination of high fever, severe headache, and a rash that begins on the trunk and spreads outward, typically sparing the face, palms, and soles, the Cleveland Clinic said.

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