Rats have long been considered deadly pests. Once considered a modern myth, the rat flood in India has now been verified. Indeed, every fifty years, armies of bamboo rats descend upon rural areas and devour everything in their path. Rats have long been held up as the chief villain in the spread of the Bubonic Plague, however recent studies show that they alone could not account for the rapid spread of the disease through Europe in the Middle Ages. Still, the Center for Disease Control does list nearly a dozen diseases directly linked to rats. Most urban areas battle rat infestations. Rats in New York City are famous for their size and prevalence. The urban legend that the rat population in Manhattan equals that of its human population (a myth definitively refuted by Robert Sullivan in his book “Rats”) speaks volumes about New Yorkers’ awareness of the presence, and on occasion boldness and cleverness, of the rodents. New York has specific regulations for getting rid of rats—multi-family residences and commercial businesses must use a specially trained and licensed exterminator. Rats have the ability to swim up sewer pipes into toilets. Rat infestations occur around pipes, behind walls and near garbage cans.
In the United States, cities tend to be breeding grounds for rat infestations and according to a 2015 study by the American Housing Survey (AHS) found that 18% of the homes in Philadelphia found evidence of rodents. This was followed by Boston, New York City, and then Washington DC as the cities with the largest rat and mice problems.