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News
A flea-borne disease once nearly wiped out in the U.S. is making a troubling comeback. An outbreak in Los Angeles County has hospitalized six people, with 109 cases recorded so far this year — following a record 220 in 2025. Experts say warmer temperatures are fueling flea populations and accelerating the spread of the bacteria that causes typhus.
Flea-borne typhus, a disease that was nearly eradicated in the U.S. by the mid-20th century, is staging a serious comeback. Los Angeles County health officials issued a warning after six people were hospitalized in a cluster outbreak in a high-density neighborhood. The county has logged 109 cases so far this year, on the heels of a record-breaking 220 cases in 2025. Texas has also seen a dramatic surge, reporting over 8,600 cases between 2008 and 2025 — with 72% requiring hospitalization.
Experts point to climate change as a key driver. Warmer temperatures promote flea infestations, accelerate the flea lifecycle, and increase levels of Rickettsia typhi bacteria in flea feces — the primary transmission route to humans. Pets that roam outdoors, stray animals, and opossums are common vectors bringing infected fleas into homes.
By the Numbers:
Why it matters: Flea-borne typhus was removed from the national notifiable disease list in 1987 — it was that rare. Its resurgence, driven by climate change and urban wildlife, is a wake-up call for public health systems. Doxycycline is effective when started early, but delayed diagnosis remains a risk, especially among homeless populations with limited healthcare access.
