He later explained, “I could make the case for focused spraying in areas where there were large populations of mosquitoes. But I had the sense that the community wanted to see the trucks. Everyone knew someone who got sick, and they wanted to do something.”
“This was ground zero,” Tracey McNamara said, gesturing toward the flamingo pool at the Bronx Zoo. In an aviary just beyond the pond, terns and gulls whirled and banked. Cages holding the zoo’s raptors—a regal bald eagle, hulking vultures, a snowy owl—were right behind us. You could see the apartment buildings that crowd the streets just outside the zoo boundaries. You could hear the occasional cawing of a crow.
It was in the summer of 1999 that the zoo began receiving calls from alarmed residents who had been finding dead birds, especially crows, in the city. By August, dead crows were turning up on the zoo grounds. McNamara, who until recently served as the head of the zoo’s pathology department, sent dead crows to the laboratory of the New York State Department of Environmental Conservation, in Albany, for analysis; meanwhile, hundreds of dead crows were piling up in the state lab’s refrigerators. McNamara, worried that some unidentified pathogen was threatening the zoo’s animals, performed her own autopsies. The damage shocked her. She saw hearts ravaged by inflammation. In the brains of the birds, she saw pronounced “cuffs” of inflammation around blood vessels—the most severe brain damage she had seen in 18 years of animal postmortems.
Meanwhile, Deborah Asnis, director of the infectious disease division at Flushing Medical Center in Flushing, New York, had become alarmed by several strange cases of neurological illness at the community hospital, people with unexplained fever and headache, gastrointestinal distress, then confusion followed by muscle weakness. Most of the victims lived in a Queens neighborhood known as Whitestone, a few miles south of the Bronx Zoo across a finger of the East River. After a flurry of behind-the-scenes activity, New York City health officials and the CDC announced on September 3 that the cases represented an outbreak of St. Louis encephalitis. Officials were ecstatic to have identified the culprit. The city immediately began spraying.
But there was a problem. All the textbooks that McNamara skimmed that Labor Day weekend agreed that St. Louis encephalitis virus doesn’t kill birds. And birds were dying all over the place, including now at the zoo. The flamingos grew visibly ill, unable to hold up their heads, their elegant pink necks buckled in a desperate battle against gravity. A beloved bald eagle developed a head tremor. Acormorant swam in endless circles in the aviary pond. One by one, all those birds, and more, died.