Pi Lambda Phi's problems with the city began Wednesday morning, when a fire inspector on a routine safety check was, he said, so overcome by the stench of rotting food and urine from the basement of the fraternity house that he had to cover his mouth and nose with his shirt.

The inspector contacted health officials, who followed the smell to the building's basement kitchen. The "before" photos by a city health officer, Frank Sasso, tell the story: a meat saw resting on a kitchen counter liberally sprinkled with mouse droppings. A catering dish on another counter containing a light bulb and a collection of cooked chicken thighs that Mr. Sasso said were weeks, perhaps months old. A toilet area in the bathroom adjoining the kitchen that was apparently in dire need of cleaning.

Most troubling to Mr. Sasso was the abundance of mouse excrement.

"This house was entirely compromised by rodent droppings," he said. One of the fraternity members kept a ferret, and its waste, too, Mr. Sasso said, was scattered across a bedroom floor.

The fraternity members' sloppiness, Mr. Sasso said, risked exposing them and their neighbors, which include a day-care center, to lymphocytic choriomeningitis, a virus spread by rodents that can cause swelling of the brain.

He declared the building uninhabitable and gave the residents a week to clean it up. By 10 A.M. Thursday, Mr. Sasso said, they had done so, and he rescinded the order.