I have heard that bandied about for years, I’m 67. But cats have fleas too sometimes and they are all over everything you own if you let them in your house. So fewer cats may mean more rats, but I don’t see lack of cats adding to the epidemic. The cleanliness and hygiene sucked back then. I keep my 3 for mouse control and fortunately where I live now there aren’t many four legged rats. I have seen rats the size of some cats. A good bullet works on them and on the two legged kind too.
the cats here in the Philippines kill birds and mice, but yes, the rats are huge, the size of a small cat. But our Labrador kills them...
but mainly we have to rely on periodic rat poison, which is dangerous and we have to watch out that the dogs don’t eat it.
guns will work, but the problem is you don’t see them: We will only see one or two rats, but after the rat poison works, we sometimes collect eight or ten huge dead rats.