About This Project

Rats create public health issues in cities around the world because they carry diseases shared with people such as leptospirosis and plague. Rodent control may reduce the risk of disease by removing rats, but some methods like rodenticides might make rats more susceptible to disease. We have been studying the abundance and health of rats in Chicago and now aim to test whether rats exposed to rodenticides are more likely to carry disease.

Ask the Scientists

What is the context of this research?

We are studying rats in neighborhoods across Chicago, the city with the most rat complaints in the United States. We have shown that public complaints about rats indicate where rodent control is most needed and that uncontained garbage promotes problems with rats. Our previous work supports common-sense approaches to rat management, but we do not know how rodent control impacts risk of disease from rats.

Rodenticides cause several health problems for predators and we found that rats with visible signs of rodenticide poisoning are more likely to be infected with Escherichia coli, a common cause of food poisoning. Now we need your help to measure rat exposure to rodenticides and test whether poisoned rats are more likely to carry disease.

What is the significance of this project?

Rat-associated diseases cause serious illness in cities around the world. For example, a leptospirosis outbreak caused mortality and hospitalization in New York City in 2017. Rodent control programs are crucial for reducing risks from urban rats, but it is important to understand their effects on rat ecology to make them as effective and efficient as possible.

Our results will help us understand any negative effects from rodenticide baiting to refine these methods. For example, if poisoned rats are more likely to carry infectious diseases shared with people, our results would support management plans that minimize the use of rodenticides during disease outbreaks or in areas with higher disease risk.

What are the goals of the project?

Our main goal is to reduce health risks from urban rats by testing whether rats with higher exposure to rodenticides are more likely to carry harmful bacteria. Based on our previous work, we will need to test at least 80 rats to evaluate variation in infection across neighborhoods.

We will collect biological samples from 80 rats trapped as part of pest management operations and test them for rodenticides, leptospirosis, and bacteria such as Salmonella and Escherichia coli.