At Home - Bill Bryson [130]
Mice are notable vectors of disease. Hantavirus diseases, a family of respiratory and renal disorders that are always disagreeable and often lethal, are particularly associated with mice and their droppings. (The name hanta comes from a river in Korea where the disease was first noted by Westerners during the Korean War.) Fortunately, hanta viruses are fairly rare, since few of us breathe in the frail vapors of mouse droppings, but if you get down on your hands and knees in the vicinity of infected waste—to crawl around in an attic, say, or set a trap in a cupboard—you run the risk in many countries of infection. Globally, over two hundred thousand people a year are infected with hanta viruses, which kill between 30 and 80 percent of their victims, depending on how quickly and well they are treated. In the United States, between thirty and forty people a year contract a hantavirus, and about a third of those people die. In Great Britain, happily, these diseases remain unrecorded. Mice have also been implicated in occurrences of salmonellosis, leptospirosis, tularemia, plague, hepatitis, Q fever, and murine typhus, among many others. In short, there are very good reasons for not wanting mice in your house.
Almost everything that could be said of mice applies equally, but with multiples, to their cousins the rats. Rats are more common in and around our houses than we care to think. Even the best homes sometimes have them. They come in two principal varieties in the temperate world: the emphatically named Rattus rattus, which is alternatively (and tellingly) known as the roof rat, and Rattus norvegicus, or the Norway rat. The roof rat likes to be up high—in trees and attics principally—so the scurryings you hear across your bedroom ceiling late at night may not be, I’m sorry to say, mice. Fortunately, roof rats are rather more retiring than Norway rats, which live in burrows and are the ones you see scuttling through sewers in movies or prowling around garbage cans in back alleys.*
We associate rats with conditions of poverty, but rats are no fools: they sensibly prefer a well-heeled home to a poor one. What’s more, modern homes make a delectable environment for rats. “The high protein content that characterizes the more affluent neighborhoods is particularly enticing,” James M. Clinton, a U.S. health official, wrote some years ago in a public health report that remains one of the most compelling, if unnerving, surveys ever taken of the behavior of domestic rats. It isn’t merely that modern houses are full of food, but also that many of them dispose of it in ways that make it practically irresistible. As Clinton put it: “Today’s garbage disposals in homes pour out a bountiful, uniform, and well-balanced food supply for rats.” According to Clinton, one of the oldest of all urban legends, that rats come into homes by way of toilets, is in fact true. In one outbreak, rats in Atlanta invaded several homes in wealthy neighborhoods, and bit more than a few people. “On several occasions,” Clinton reported, “rats were found alive in covered toilet bowls.” If ever there was a reason to put the lid down, this could be it.
Once in a domestic environment, most rats show little fear “and will even deliberately approach and make contact with motionless persons.” They are particularly emboldened in the presence of infants and the elderly. “I have verified the case of a helpless woman attacked by rats while she slept,” Clinton reported. He went on: “The victim, an elderly hemiplegic, hemorrhaged extensively from multiple rat-bite wounds and died despite emergency hospital treatment. Her 17-year-old granddaughter asleep in the same