Typhus outbreaks are spiking in Southern California, health department reports

Summer heat, check. Mosquitoes, check. Labor Day traffic, check.

Now add fleas carrying typhus fever to things Southern Californians have to worry about.

A report from the Los Angeles County Health Department released Thursday warns everyone — especially pet owners — to make sure they are keeping fleas at a distance, because they’ve found an increase in people getting sick this year when infected by the tiny pests carrying the flea-borne disease typhus, also known as typhus fever.

Cases of typhus have been on the rise in L.A. County since 2010, with 2024 experiencing a record-high number of cases numbering 187.

This year, there have been 106 cases reported, a rate that is higher than last year at this same time, the health department reported. And since the typhus season peaks now, in late summer and fall, health officials predict the number of cases and clusters of cases will rise in the next several weeks.

Localized disease clusters have been reported in central Los Angeles and the DPH is investigating a second outbreak in the city of Santa Monica with five cases so far.

The average number of cases in 2018 was about 60, but the numbers have been spiking. The 2020-2024 average is 143 cases, DPH reports show.

A look at the number of flea-borne typhus cases reported in Los Angeles County in the last decade. (image courtesy of LA County Department of Public Health)

In the past, outbreaks have occurred in Pomona (2015); Willowbrook (2017, 2018, 2022); Downtown L.A. (2018); Monrovia (2021); Glassell Park and Eagle Rock (2022); Boyle Heights (2022); Wilshire Center (2022) and L.A.’s Westlake area (2021, 2024-2025).

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Typhus is only spread by infected fleas. It is not transmitted person-to-person.

These infected fleas are found on rats, feral cats and opossums. A single opossum can carry as many as 700 fleas, according to vector control experts.

Pets such as dogs and cats can pick up the vector after going outdoors and bring them into the home. So flea control methods for pets are highly recommended.

The illness is caused by Rickettsia Typhi bacteria, which is spread by the infected fleas. People can become infected when flea feces get into the flea-bite site, or penetrate into cuts or scrapes on the skin or rubbed into the eyes.

“Flea-borne typhus is serious, but preventable,” said Dr. Muntu Davis, L.A. County’s health officer. “We urge people to take precautions by using flea control on their pets, avoiding contact with stray animals, and preventing wildlife from living in or next to their home or property.”

Detection can be difficult because the symptoms of typhus resemble other conditions. These include fever, headache, muscle pain/myalgia, nausea/vomiting and rash. Anyone with these symptoms should seek medical attention, Davis said.

Typhus can become serious but is rarely fatal, with a less than 1% fatality rate. Between June and October 2022, Los Angeles County reported three deaths, according to a report from the Centers for Disease Control and Prevention.

The DPH recommends several steps to take to prevent exposure:

• Reduce vegetation on a yard’s perimeter, where opossums or feral cats can hide

• Fill in holes in eaves, crawlspaces or sheds

• Don’t leave cat or dog food outside

• Pick up fruit from trees

• Keep garbage containers tightly covered

• Report stray animals or any signs of rodents or opossums near your property to local animal control officials.

• Use flea control medication on your pets

For more information regarding flea-borne typhus, visit: ph.lacounty.gov/Typhus.