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The critters that spread disease and creep us out


She lifted the toilet seat and screamed.It had half-crawled, half-swum up the pipe into the porcelain bowl, dragging its belly through the city's sewage, its hide glistening with waste. It came from an underground colony to Virginia-Highland in search of fresh meats, fruits, grains and vegetables. Back where it came from, it would kill and eat its brother if the food supply was low. But it would just as soon push through sewage to feed off you.

Rats are not like us. Their senses of hearing, smell and touch are keener than ours. They can hold their breath longer, fall farther, claw deeper. They will fight each other to the death to prove themselves to their peers.

Theirs is a world of structure. "They use their strength and viciousness to keep certain members of the society confined to certain areas," says Maxcy Nolan, a retired University of Georgia entomologist. "They respect that hierarchy because if they don't, they can get hurt or killed."

The are not like us. But they need us. We are their providers. They live in families of 10 or 20 in our pipes and sewers, our attics and trees. They are not at home at ground level, but they cannot resist the feast and warmth a human home offers. They nibble on our leftovers to fill their 10- to 17-ounce frames. Pound for pound, they are among the most dangerous and damaging creatures people have known.

About every city has rats. What sets Atlanta apart is its rat-friendly environment, and the local government's tepid response to rat control. The city phased out its Rat Attack team nearly 11 years ago, and Fulton County has slashed funding and staff positions for its own rat patrol. At the same time, there are more people in metro Atlanta, most of them living a more comfortable life, than ever before. So there are likely more rats, living off our fat. A headcount is not available, but scientists, exterminators and officials estimate that there is one rat for every person. Around 4 million people live in the Atlanta area.

Atlanta's growth and development has forced rats and residents to share closer quarters. To accommodate the influx of people and businesses, utility companies have tunneled underground to extend sewer and water lines. Contractors have gutted and renovated abandoned buildings to create luxury lofts. Bulldozers have leveled fields to make way for Super Wal-Marts. The construction has riled the rats that lived in these up-and-coming pockets.

"When you disrupt the normal rodent pattern," Nolan says, "you expose people to more rodents and the problems associated with rodents."

Ancient kind of germ warfare
The Norway rat arrived hundreds of years ago, not from Norway but on ships originating in Asia. It thrives in burrows, basements and sewers, and can grow to a pound in weight and a foot in length. People swear they've seen bigger. Residents and business owners in downtown Atlanta run into their share of Norway rats.

The smaller roof rat, which lives in trees and attics, weighs up to 10 ounces and grows up to 8 inches. It, too, arrived years ago by ship. It currently shacks up in wooded neighborhoods, like north Fulton and the suburbs.

Both species have short lifespans, but thousands of years of evolution endowed them with unrivaled survival skills. The roof rat is a skilled climber, the Norway a swift swimmer. Both have fangs that grow constantly, allowing them to gnaw through concrete or metal without shortening their teeth.

They multiply at a manic rate. Female Norway and roof rats live about 18 months and can give birth to more than 10 litters producing more than 180 total babies. Each of the offspring, like the generations before, can carry 100 different bacterial and viral diseases. They are conditioned to survive all but the worst of those diseases, and they carry them to us.

"In many cases, these disease organisms have co-evolved with these specific hosts for thousands of years, or millions of years," says Dr. James Mills with the Centers for Disease Control and Prevention. "In the natural cycle of these diseases, humans have not been present. They're dead-end hosts and they happen to get in the way of the transmission, like catching a stray bullet."

Mills studies the ecology of animals -- most often rats -- that carry viruses like hantavirus, or bacteria like Yersinia pestis (the plague) and leptospira. He is an expert in rat-borne diseases as they relate to places as distant as China and as far back as two millenia ago, and he has reached a disturbing conclusion about the relationship between man and rat.

"It may be," he says, "the most dangerous interaction between a human and any other animal."

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