National Rat Summit Brings Together Experts to Tackle NYC's Rodent Issues

NEW YORK - Experts from the research community, academia, public service sectors, regulatory and more gathered in New York City Sept. 18-19 for the National Urban Rat Summit.

Organized by the City of New York, Office of the Mayor and Department of Health and Mental Hygiene, along with the New York State IPM Program at Cornell University, the two-day event was an opportunity for those involved in municipal rodent management to connect and share ideas on the complex and interagency-related challenges of achieving sustainable control of urban rats.

Kathleen Corradi, NYC's director of rodent mitigation (a.k.a., the city’s “Rat Czar”), said the goal was to bring together these rodent control experts in hopes of taking “a bold step forward in advancing the understanding of municipal rat management with a collective commitment to lead with science and put research into action."

© Brad Harbison

New York City Mayor Eric Adams spoke on day one and he noted that one of the reasons his administration has stepped up NYC’s “war on rats” is because he’s observed rats take a mental toll on residents. Adams said he’s heard stories about families being traumatized by lifting up toilet seats and finding rodents, or having them scurry on their feet when taking out garbage. “You think about that the whole day,” he said.

Adams said he has been encouraged with the city's efforts to transition from plastic garbage bags to trash bins. "We are seeing a decrease in [rodent] sightings because of the containerization of garbage," he said. 

Following Adams’ comments, speakers reviewed past efforts and current challenges of urban rat management. Highlights included:

Dr. Kaylee Byers, Simon Fraser University, British Columbia, Canada, discussed rodent-borne diseases and built on Adams’ comments about diseases and mental health issues rodents pose on residents. Byers shared some of the results of the Vancouver Rat Project, a collaborative research project to examine rat-associated zoonotic diseases in urban rat populations. Byers and her team collected rats from Vancouvers’ Downtown Eastside, an area that has a large homeless population. In one neighborhood, Byers and her team found Bartonella, Leptospira, streptobacillus and hepatitis E, which are diseases of zoonotic rat origin pathogens. In terms of mental health, Byers cited a study in Chicago in which residents reported struggling to sleep for fear of rodents.

Following Byers was fellow Canadian Dr. Chelsea Himsworth, University of British Columbia, who provided a historical perspective on municipal rodent management and its implications for the future. Himsworth and her team conducted interviews with individuals who held diverse roles and responsibilities for various inner-city rat management programs. One trend they identified was that stakeholders felt that total rat eradication should not be the goal. Instead, they suggested it is more efficient and effective to prioritize reducing infestations in certain high-risk groups.

Dr. Maura Murray, who works at the Lincoln Park Zoo in Chicago and the Urban Wildlife Institute, presented on the unintended consequences of rat mitigation involving anticoagulants. Murray shared concerns regarding secondary poisoning and encouraged the use of alternative rodent control strategies, including trapping, patching-up holes in walls and the use of exclusion products.

Dr. Jonathan Richardson and his team at the University of Richmond have dug deeper into the question: Are U.S. cities seeing increases in rat numbers? They examined data from 16 major U.S. cities and found that 11 out of the 16 cities did, indeed, have significantly increased trends of rat numbers. Only three cities reported significantly decreasing trends in rat numbers. Seventy percent of cities do have a statistically distinguishable increasing number of rats as measured by 311 proxy data. (311 is a special telephone number supported in many communities in Canada and the United States. The number provides access to non-emergency municipal services.) One variable the team looked at was climate change over a period of time. Cities that have warmed faster during the measured 50-year time period experienced faster increases in rat numbers.

Dr. Claudia Riegel, director of the New Orleans Mosquito, Termite and Rodent Control Board (NOMTRB), said municipal rodent control programs work best when departments communicate with one another. "Break down those silos. You learn something new every day when you make those connections. And those connections are what you are going to need to get the job done." Riegel shared a number of examples of how communication is helping NOMTRB with rodent issues. She mentioned that her team has been called to rodent control jobs and after taking care of the problem, they have provided instructions on simple sanitation practices like using secured garbage cans/dumpsters, securing candy on office desks, etc., and Riegel has been encouraged that some of these recommendations are being followed.

Dr. Caroline Bragdon, New York Department of Health and Mental Hygiene, shared how her department has been collecting and analyzing rat data to predict hot spots and target resources.

Renowned rodentologist Dr. Bobby Corrigan, president RMC Pest Management Consulting, said remote rodent sensor technology is among the most exciting tools he’s encountered in his 40-year career. “It's in its infancy, but it is very powerful, especially with AI coming on board.” Corrigan said that it will be a “no brainer” that all airports will be using remote sensoring and that this technology will be used in every airplane in the future. “To rodents, wires look like plant stems. I'm always nervous. I fly a lot. I want sensors in my airplane up in the ceiling.”

Day two of the summit involved collaborative group work to discuss municipal rat management, including best practices as well as brainstorming of possible innovations and technologies for the future.