A New York City woman died from a rare disease last year that is typically spread through contact with rat urine. Rats are often perceived to be dirty, but how does disease spread from an infected rodent to an individual, and what can we do to prevent it?
The Wash spoke with Matt Frye, an entomologist from Cornell University’s New York State Integrated Pest Management Program who focuses on rodent prevention and education, to learn more.
The common perception of rats might still be the spread of diseases such as the bubonic plague in the 1300s, Frye said, but rats continue to pose a health risk today. Cornell University’s newest project, Scientific Coalition on Pest Exclusion, aims to change those common misconceptions and works to educate the pest control industry to prevent rodents from entering living and working spaces.
The Wash: What diseases are prevalent with rodents today?
Frye: One of the biggest ones right now is Leptospirosis. Last year, someone in New York actually died from Leptospirosis. The way people get Leptospirosis is that they are in direct contact with rodent feces or rodent urine. These people were living in an apartment complex in New York City where rats were in the building and rats were probably above their counters and in their kitchens, and they were probably exposed to pathogens that way.
In a lot of cases, researchers will capture the rats and look at what pathogens they carry, but there’s not often a direct link to how that’s affecting human health, so that’s why that one was so important.
Another one that’s current right now is typhus. In Los Angeles, there’s an outbreak of murine typhus, and that’s directly related to rat populations. Instead of humans coming into contact with rats directly, murine typhus is often transmitted through something like a flea. So the flea would feed on the rat, acquire a pathogen and then would feed on a person and transmit those pathogens.
This is a different route of exposure called indirect exposure.
The Wash: Does that have a different effect from the human health standpoint?
Frye: From the human health standpoint, you would just treat it as if you were treating any infection of a person. But when it comes to managing the populations, it’s fleas that are jumping off a rat, that are then biting people. We recommend taking approaches to rodent management because, if you just use snap traps for example, once the rat is dead, those fleas are going to leave the body. So, you want to treat the burrows where the rats are living so that they are contained within the burrow.
The Wash: How do you suggest people deal with rat issues in metropolitan areas?
Frye: That’s the toughest nut to crack of all! So, in New York, for example, they are trying so many different things to manage the rats, but they are missing the most important thing, which is sanitation. What happens is restaurants will put out their garbage at night, and it’s not picked up until the next day. So, rats kind of have this huge plate of food every single night. In places like parks, there are garbage cans that are designed to keep rats out if they contain any food that would be available to them, but they’re expensive and so cities don’t use them.
So, we have the wrong trash cans, and on the street there are just piles and piles of food waste that rats can eat. Eliminating that has to be the first step before there’s any large-scale management because, as long as they have food and a place to hang out, we’re going to continue to see rat problems.
But for individual buildings, lets say on campus, if there’s a rat problem, you could clean up the food spillage that’s around there. What we’re really advocating is pest exclusion where there’s an emphasis on making the outside of the building secure against rats and cockroaches so they can’t find their way in. It sounds so obvious, but the pest management industry really just relies on killing things once they get inside.
We’re trying to change the mindset of most professionals. We actually have a website dedicated to that called SCOPE, and it’s the Scientific Coalition on Pest Exclusion. And, we’re trying to get the industry to understand that they can still be making money doing that, and that they’d be protecting public health in a bigger way.