Flea-borne typhus cases in Los Angeles county have reached an all-time high, according to an April report by LA County public health officials.

More than 200 cases of typhus – a bacterial infection caused by the Rickettsia Typhi bacteria – were reported in LA County in 2025, according to the report. Typhus symptoms can range from fever to sepsis, said Dr. Aiman Halai, the director of the Vector Borne Disease Unit at the Los Angeles County Department of Public Health’s Communicable Disease Control Program.

Although there has been an overall rise in typhus cases in LA County, there have not been any typhus outbreaks on UCLA’s campus, said Dr. Robert Kim-Farley, a professor in epidemiology and community health sciences at the Fielding School of Public Health.

“The risk (of typhus) is more community-wide,” he said. “I wouldn’t say to worry, but be mindful.”

Typhus is contracted when a flea-carrying the bacteria bites then defecates on a person, and the feces are rubbed into the bite, Halai said.

The bacterial infection cannot spread from person to person, and it requires transmission via fleas, said Dr. Timothy Brewer, a professor of medicine and epidemiology at the School of Public Health. Cases across LA County have likely risen because of an increase in the population of reservoir animals carrying typhus-infected fleas, Brewer added.

Hosts for fleas include rats, possums and cats, Kim-Farley said.

Students can minimize the spread of typhus by protecting their pets from fleas, keeping trash can lids tight, clearing their yards of debris to avoid attracting wild animals and not feeding or interacting with stray animals, Kim-Farley said.

“Avoid feeding or touching wildlife on campus – yes, even the squirrels,” Kim-Farley said. “If you have pets in your dorm or your apartment, keeping them on a year-round flea prevention is probably the single most effective way to prevent disease from getting into your own living space on campus.”

Because typhus symptoms are common to other illnesses, it is often harder to diagnose, Halai said.

Typhus, however, is often treated with antibiotics which are highly effective at eradicating the bacteria and alleviating symptoms, she added. Death rates for typhus are 1% to 4% for those who go untreated and less than one percent when treated, Kim-Farley added.

Increased homelessness rates in central LA county, Brewer said, are also associated with more rats breeding in the area, which could be correlated to the rise in typhus cases.

“Unique to our situation in Los Angeles is the large concentration of homeless population, and that probably is contributing to the rising numbers (of cases) as well,” Brewer said.

While Halai said the unhoused population has a higher risk of getting the typhus infection, she added that the disease can affect anyone.

“Typhus affects all populations, across all socio-economic groups in our county. And while homeless encampments can create the risk factors that can result in increased rodent populations or free roaming animal populations, so can many other factors,” Helai said. “It really is a disease that affects everyone and anyone.”