29/06/2025
A great article from Save Arlington Wildlife
Ok guys, so you may have seen the Boston Globe article on rats "spreading a deadly disease" that is a big threat to health of humans. Once again, the media tilted toward fearmongering about rats. And of course, other outlets are picking it up.
As someone who has actually read the study in full and interviewed the lead researcher/author of it only a few weeks ago for my book, I am going to clarify a few things.
- Lepto is not new in Boston among rats and has been around for awhile. Its rates might be becoming a bit more prominent with climate change but it's not like some new development that it's here.
- The study primarily found that rats are spreading the disease....among each other. But even with increases in their populations, the proportion of Lept has stayed more or less steady.
- The study found rats usually stick to very small geographic locations within their family groups and rarely stray from it. So the disease strains (in this case Lepto) remains relatively contained.
- The problem is when we disrupt/destabilize those rat populations, they force migrations of rats and they mix with other populations, creating new strains of the disease.
- What are some types of disruptions that cause this? Construction (according to the researcher). But also: aggressive poisoning and culling campaigns destabilize their populations and force migrations.
- That's right, the very things used to try to control rats, can be exacerbating the chances of facilitating disease and making public health threats they posed much worse. (Again the researcher spoke to me at length).
- Just to quickly underscore the last point: one study out of Chicago found rats with anticoagulant rodenticides in their system were more likely to have and transmit Lepto than rats that didn't. Another study from Vancouver found aggressive trapping of rats led to increased rates of Lepto among rats.
- Despite the threat of the headlines, the researcher told me repeatedly that the vast majority of people are at no real risk for contagion. That rats don't pose real threat.
- Let's be clear: the study was only able to find ONE person with Lepto that could be linked to a rat population--but even that case could not definitely be confirmed to be from a rat. That person was unhoused and living in a homeless encampment.
- Since the unhoused are less likely to seek medical care and have the resources to do so, it is possible more people in encampments are affected than we know. But obviously there's not a pandemic of Lepto wiping out encampments or felling people in them.
- To return to what the researcher told me, and what I posted about very recently, the demographic that have more valid risks of contracting rat-related diseases are the homeless and low income people living in substandard housing conditions where rats are entering their homes.
- The researcher was adamant, as am I, that this means we should be doing more to address these social inequities and shore up older infrastructure and crack down on slumlords.
- I would say this also means we should care more about housing the homeless (really housing folks, not just shoving them in sh*tty motels), if we care about the people truly vulnerable to rat-related diseases.
Do we want less rats? Let's remove our bird feeders (esp this time of year), only take trash to outdoor barrels right before pick up and divert your food waste from that trash as much as possible. Remove other attractants.