San Francisco plague outbreak

The San Francisco plague outbreak occurred between 1900 and 1904, primarily caused by Yersinia pestis bacteria carried by fleas on rats. It spread through dense immigrant neighborhoods, where poor sanitation facilitated rat and flea infestations. The outbreak resulted in over 100 deaths and prompted strict public health measures, including rat control and quarantine efforts. This event highlighted the importance of sanitation and disease control in urban areas and was part of the larger history of plague pandemics that affected humanity for centuries.