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Two big investigations cause confusing overlap
In Oklahoma City, folks take their bingo seriously. In one busy parlor, upward of 1,000 patrons come through on an average weekday and stay from one to eight hours. Serious players purchase a $20 pack of cards, fan them out, light a cigarette, take "daubers" — tubes of colored ink — and frantically mark the numbers on the cards, cigarette ashes dangling precariously over the tables.
When a case of TB turned up in just such a high-stakes bingo parlor, TB controllers had a fair idea of what they were up against. "We decided to go public," says H.R. Holman, media relations spokesman for the city’s TB control division. "We called the American Lung Association and borrowed their van, we got hold of a canopy tent from a local hospital, and we set up to do skin testing right there in front of the parlor."
More than 1,000 bingo patrons were skin-tested. Slightly more than a tenth were positive, but, according to city health department epidemiologist Jon Lowry, MPH, the positive reactors were scattered more or less at random throughout the parlor, without any particular concentration near the "hot zone" where the index case usually sat. Because the woman was a loner by nature and hadn’t been especially symptomatic before she was diagnosed, the incident might seem fairly straightforward.
It wasn’t. A couple of miles southwest of the bingo parlor, another big contact investigation was winding up, says Lowry. That investigation focused on an area with four bars that had been frequented by another person with TB, who was not diagnosed until his death. He had been sick for a long time and had spent months coughing, roaming the bars with his pals, sleeping on a bar pool table at night, and tending bar during the day. In that investigation, hundreds were screened, and Lowry found a big cluster of reactors.
Because the bingo parlor investigation followed closely on the heels of the bar investigation, and because the two places were only a couple of miles apart, Lowry decided to check zip codes of the bingo parlor patrons. To his surprise, most of the players came from a Northeastern zip code. The bars, meanwhile, were in a Southwestern zip code. He concluded that the bingo parlor, even though it’s centrally located, mostly serves patrons from the Northeast.
Two of the bingo patrons, however, did turn out to be bar patrons. In the bar investigation, the two had tested negative; now they were positive. To confuse the matter, they’d also been regulars in the bingo parlor’s "hot zone." In Lowry’s mind, that raised two questions: Were the two converters infected by the bingo player, who was perhaps more infectious than she appeared? Or, having been skin-tested twice in brief succession, were the converters good examples of older folks whose sleepy immune systems had roused themselves and, after a succession of skin tests, boosted?
In the end, Lowry weighed in with the second conclusion. He reasoned that the bar patrons, by the time the bar case had been identified, had plenty of time to mount a reaction. That meant the scattershot distribution of the positive tests in the bingo parlor probably reflected the background rate for that population, not the bingo player’s infectiousness.
Dale Gene Claflin, MD, the city’s TB control officer, says he plans to offer prophylaxis liberally, regardless of who infected whom. "We’ll probably prevent a few reactivation cases, if nothing else," he says. "After all, that’s what preventive medicine is all about."
As for Holman, he thinks about 1,000 people a day buying all those packs of cards at $20 a hit, and says he is sure of just one thing: "You and me, we’re in the wrong business."