The Soho outbreak in London in 1854 ended after the physician John Snow identified a neighborhood Broad Street pump as contaminated and convinced officials to remove its handle. Snow believed that germ-contaminated water was the source of cholera, rather than particles in the air (referred to as "miasmata"). His study proved contaminated water was the main agent spreading cholera, although he did not identify the contaminant. Though Filippo Pacini had isolated "Vibrio cholerae" as the causative agent for cholera that year, it would be many years before miasma theory would fall out of favor.