The Growing Rat Problem and COVID-19 Risk in New York City.

The rat population in New York City has grown from an estimated 250,000 in 1950 to around 2 million in 2014, covering 90% of the city. The increase is due to changes in how the city deals with trash and the rapid breeding of rats. The Norwegian brown rat arrived in America on ships from Europe about 250 years ago, and their first stop was likely New York City. Despite efforts to eradicate them, rats continue to thrive in the city.