Pest control manufacturer Orkin has released its list of the rattiest cities in the United States. The company bases the ranking on the number of treatments it performed in each metropolitan area in 2013.

With the advent of colder weather in the fall, rodents tend to infiltrate households to search for food and to build nests. Rats can squeeze through a hole the size of a quarter; mice need only a dime-sized opening.

While some rats might be considered cute, Orkin is quick to remind home and business owners that they can carry hundreds of pathogens that spread through their urine, droppings and bites.

“They are known carriers of deadly neurological and respiratory diseases like lymphocytic choriomeningitis virus and Hantavirus Pulmonary Syndrome,” the company notes. “Ticks, mites and fleas can feed on infected rodents, which can then transmit diseases like pox, plague and typhus indirectly to humans.”

On the other hand, conservation groups including the American Bird Conservancy and New York City Audubon say rat poison is killing wildlife, especially raptors, and pets in urban areas. The animals feed on dying rats, ingesting anticoagulant poisons that can cause fatal internal bleeding. Six conservation groups are filing a petition to ban several rat poisons from use in New York.