In mid-August, a human case of flea-borne typhus — previously called murine typhus — was confirmed in Fountain Valley, California. It’s the fifth human case of the rare disease this year, with all but one case contracted this summer.

Fleas become infected with typhus when they bite animals like rats, possums, and stray cats. Once infected, fleas carry typhus for life and can spread the bacteria that causes typhus to other animals and humans. Typhus cannot spread from person to person.