A new assessment by the pest control company Orkin has awarded Chicago, Illinois, the Windy City, a new title: Rat City USA.

Reviewing its client and jobs list for 2013, the national pest control company fond that Chicago topped its lists for rat removal work.

In a press release, Orkin noted that October is a prime month for rat activity as the pests begin to root for food for the coming cold weather and start looking for places indoors to wait out the winter.

“Each fall, rats and mice invade an estimated 21 million American homes,” Orkin said. So, “it is not uncommon for homeowners and businesses to begin spotting rodents beginning in October.”

“Each city on this list is a major urban area that provides ideal conditions for rats and mice to thrive,” entomologist and Orkin Technical Services Director Ron Harrison, Ph.D said in the press release. “Commensal rodents depend on humans and their resources to survive, so unless residents and city officials take proactive steps to prevent rodents, infestations can easily get out of hand. It’s important to remember that this list is based solely on the number of treatments Orkin performed last year. While your city may not be ranked high on the list, that does not mean you should be any less vigilant.”

Topping that list is President Barack Obama’s hometown, rat infested Chicago, Illinois.

Orkin reminds readers that rodents aren’t just a nuisance, “they also pose severe health threats.”

Through their bites, droppings and urine they spread all sorts of diseases. It should be remembered that the Bubonic Plague that killed millions of Europeans in the Dark Ages was carried on the backs of rats.

The rest of the top 20 “rattiest” cities were Seattle-Tacoma, Detroit, Cleveland-Akron-Canton, Baltimore, Miami-Fort Lauderdale, Dallas-Fort Worth, Denver, Houston, Atlanta, Boston-Manchester, Minneapolis-St. Paul, Sacramento-Stockton-Modesto, Syracuse, Indianapolis, and Charlotte.

Follow Warner Todd Huston on Twitter @warnerthuston or email the author at igcolonel@hotmail.com