You have dung beetles because they feed off dung! Which are the major components of building a mudhut. That’s not cleanliness, it’s FILTH.
Rats are very clean, intelligent animals. They get a bad rep for spreading diseases. Well, let it be said, there wouldn’t be disease if people didn’t build their huts out of sh!t! Clean sewerage systems means no poop on the streets and therefore very little to no disease!