Thanks for Asking | Feb. 9, 2012

our local Jack-of-all-Facts tells you how it is

Frank Smoot |

I’ve heard that Eau Claire had the first outbreak of Legionnaires Disease. True?

Thanks for asking. It’s not actually true – but – the outbreak we had here was high profile and became vital in our understanding of Legionnaires Disease (LD), which is a severe pneumonia that develops from a nasty bacterium.

The first outbreak that fit our current idea of Legionnaires Disease dates from 1957 – Austin, Minn. – but the first that made a national splash occurred at an American Legion Convention in July 1976. About 220 Legionnaires took sick and 34 died. Veterans. In Philadelphia. During America’s Bicentennial. That kind of thing makes news.

Although the pattern of illness suggested something airborne, no source of the bacterium had yet been documented. But then, July 3, 1979, Luther and Sacred Heart Hospitals notified our state and joint city-county health departments that during the preceding two weeks, eight people had been admitted with “atypical” pneumonia. (By the end of the outbreak, 13 people had been hospitalized, four of whom died.

A group from the Center for Disease Control (CDC) came to Eau Claire. They joined the City-County Health Department and the state, and the team quickly discovered that every victim had been in the Holiday Inn – almost all for meetings, not as room-guests. (In 1979, the Holiday Inn was the round tower on Clairemont, currently The Plaza.)

The team set up an “air tracer study,” sending smoke and “oil of wintergreen” through the hotel’s ductwork. They discovered that an unsealed fireplace chimney allowed air to enter what the hotel called “Meeting Room 1.” Freakishly, a flow of vapor from a central-air cooling tower came DOWN the chimney and into Meeting Room 1 through the fireplace – even when the damper was closed. The cooling tower’s water tested positive for L pneumophila, the lil LD bug.

Besides commercial cooling towers (used in industrial cooling systems as well as in large central-air systems), potential sources of legionella-contaminated water include humidifiers, hot tubs, hot water systems, showers, nebulizers, architectural fountains with submerged lighting, ice-making machines, windshield washers, and darned near anything else that stores, then mists, warm water from a public water supply. (In warmer climates than ours, where a lot of people put tap water into their cars’ windshield-wiper tanks, those tanks are a surprisingly common avenue of infection, as demonstrated by the weird fact that professional drivers get LD at five times the rate other people do.)

Cooling towers are quite vulnerable to the bacterium, since they transfer heat out of the air into water – often warming the water to an “ideal” temperature of 100 degrees ... letting it stand ...  and then ... evaporating it into the air. If you want to make Legionnaires Disease, that’s the way to do it.

Ours was the first investigation to definitively determine how Legionnaires spreads – as well as one of the first health investigations in Wisconsin to use credit-card receipts to find potential victims, and one of the first state cases to use an “air tracer study” to discover what paths airborne particles follow in a commercial structure. CSI: Eau Claire.

The four dead were Chester Amundson of Barron, and Charles du Bois, Anton Anderson, and Rose Neibauer, all of Eau Claire. In 1981, widows of the three male victims sued the national Holiday Inn Corp. and a Janesville partnership that owned the Eau Claire hotel back then. I don’t know how that case came out.

Got a local question? Send it (17 S. Barstow St.) or email it ( and Frank will answer it!  Frank has lived in Eau Claire for most of the past 43 years. He is an editor and researcher at the Chippewa Valley Museum, which is open all year just beyond the Paul Bunyan Camp Museum in beautiful Carson Park. You should go there.