Outbreak of Legionnaires' disease at Stafford District General Hospital

Abstract

In April 1985 175 patients were admitted to the District or Kingsmead Stafford Hospitals with chest infection or pneumonia. 28 died. The medical diagnosis showed that this was Legionnaires' disease and the immediate epidemiological investigation traced the source of the infection to the air-conditioning cooling lower on the roof of the Stafford District Hospital. A Government Inquiry was set up to investigate how the infection occurred and why it became Britain's largest epidemic of Legionnaires' disease. This paper describes the case history of events. The infection was linked to one small zone in the hospital, the outpatients department. The initial investigation searched for engineering reasons to explain why this particular zone was the risk area. More detailed and wider epidemiological surveys subsequently showed that staff working in the whole area supplied with fresh air taken adjacent to the tower, had antibodies to the disease. The outpatients department was unique in having a very large transient population of susceptible individuals either receiving treatment or accompanying friends. The implications of this case are important to all practising engineers. The speed of such epidemics is frightening: The whole cycle of the outbreak started suddenly and was over before the investigations began.