In England, rats presented a threat to public health and well-being. Rats were associated with bubonic plague and other diseases, such as cholera, typhoid, and typhus. It was discovered that many of those diseases were spread through contaminated water in the sewer system and with the aid of advanced sanitation, the risks reduced significantly, especially in wealthier boroughs. Because of the threat they presented, rats were consistently mentioned in the Medical Officer of Health reports from various London boroughs. To control the problems associated with rats, many boroughs had rat officers and rat weeks in order to decrease the number of infestations.