First Known Outbreak of Legionnaires Disease

On this day in 1976, members of the American Legion arrive in Philadelphia to celebrate the bicentennial of U.S. independence.

Soon after, many began suffering from a mysterious form of pneumonia. Their ailment would come to be known as Legionnaires disease.

About 4,000 delegates from the Pennsylvania chapter of the American Legion met at the Bellevue-Stratford Hotel in Philadelphia for a four-day gathering. While at the hotel, built in 1900, the Legionnaires did not notice anything unusual. However, several days after the event ended, many attendees became sick. By August 2, 22 people were dead and hundreds connected to the gathering were experiencing pneumonia-like symptoms.

The first recognized outbreak occurred on July 27, 1976 at the Bellevue Stratford Hotel in Philadelphia, Pennsylvania, where members of the American Legion, a United States military veterans association, had gathered for the American Bicentennial. Within two days of the event’s start, veterans began falling ill with a then-unidentified pneumonia. They were tachypneic and complained of chest pain. As many as 221 people were given medical treatment, and 34 deaths occurred. At the time, the U.S. was debating the risk of a possible swine flu epidemic, and this incident prompted the passage of a national swine flu vaccination program. That cause was ruled out, and research continued for months, with various theories discussed in scientific and mass media that ranged from toxic chemicals to terrorism (domestic or foreign) aimed at the veterans.

The Bellevue Stratford Hotel was host to the 58th convention of the American Legion in July 1976 and within a day visitors began to feel unwell. The symptoms of coughing, fever and breathing difficulties were not considered unusual given that over 4000 Legionnaires and their friends and families were in attendance, but by July 27th the first death had been reported.

Events at the beginning of the year were to play a part in the unfolding story of Legionnaires Disease.