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More reports, fresh frissons: a New Jersey truck driver, Richard Wells of Turnersville, was hospitalized with severe fever and other symptoms of the unknown illness; so was Aldo Provenzano, 46, of Cherry Hill, N.J. Wells had delivered food to one of the hotels where Legionnaires stayed during the convention; Provenzano works in Philadelphia and had lunch in at least one restaurant patronized by Legionnaires. A New York State couple who attended the convention had to be hospitalized. A hot line set up by Philadelphia city officials to handle requests for information logged up to 400 calls an hour. A few people canceled vacation plans and the Legion called off an excursion that was supposed to bring 600 boys and girls to the city.
Then, as mysteriously as it began, the outbreak seemed to level off. There were no instances of victims passing on the illness to their families and friends, and so the first terrible fears of a rampaging epidemic began to dissipate. The disease seemed to spare completely the large 41st International Eucharistic Congress of Catholics in Philadelphia last week (see RELIGION). But the mystery of what caused the Legion deaths remained to be solved, and until it was, no one could be sure the killer might not just as suddenly revive, reappear and strike in force again.
In an effort to track down the Philadelphia killer, some 150 federal and state disease detectives—physicians, biologists, chemists—set to work in Pennsylvania in a massive microbe hunt that resembled a police dragnet. Working round the clock, state officials turned an office in Harrisburg into a sort of "war room." One wall of the makeshift headquarters was covered with a map pierced with colored pins tracing the outbreak of Legionnaires' disease—red pins for deaths, yellow ones for reported illness. At several desks, shirtsleeved workers transferred information onto large sheets of graph paper. At others, workers telephoned the state's more than 300 hospitals, trying to determine the exact number of victims and the exact circumstances surrounding each case.
As in most disease detection, much of the work is being done in the laboratory. Samples of tissues, fluids and waste have been obtained from the bodies of those who have died from the disease as well as those who appear to be surviving it. Some are being analyzed at state laboratories in Philadelphia; others have been sent to the U.S. Public Health Service's Center for Disease Control in Atlanta, where researchers are performing a series of sophisticated tests to try to isolate and identify the disease agent (see box page 68).
Like police work, most medical sleuthing is done in the field by the "shoe leather" epidemiologists, some from the state's public health service, others from the CDC. They crisscrossed the state to interrogate every one of the stricken Legionnaires and the families and friends of the deceased. Their quest: a common denominator, a set of experiences that would link all the victims, such as meals taken together, rooms in the same hotel, exposure to similar contamination. Their method: careful questioning and cross-referencing.