Typhus cases climb in Los Angeles County amid rat surge and homelessness

In 2025 Los Angeles County saw a record 220 cases of flea-borne typhus, surpassing the 187 cases reported the previous year, and nearly ten-in-ten patients required hospitalization, according to the county health department. Dean Winslow, a Stanford infectious-disease physician, said the outbreak reflects broader sanitation failures tied to dense homeless populations living near rats. Data from the local homeless authority show a rise in homelessness across the county and city, creating environments where rodent exposure is common.

The city was recently named the nation’s “rattiest” city by a pest-control firm, a label Winslow attributed to weather, infrastructure and human behavior. He urged officials to prioritize rat control, noting that California’s 2020 law restricting several rodenticides may have limited effective pest-management options. Health officials recommend flea-preventive treatments for pets, keeping yards clean, securing trash, and reporting rodents to animal control. The mayor’s office did not respond to requests for comment.