Control of infection on the two sides of the Atlantic

Abstract

One of the most crucial tests of the hospital epidemiologist is the speed and skill with which he controls an outbreak. By definition an epidemic is an unusually large cluster vvhich is measured statistically as a significantly increased rate (PGO.05) above that of the background of endemic occurrence. Epidemics occur at a rate of approximately one per 10,000 admissions and account for less than 5% of all nosocomial infections (Wenzel et al., 1983; IIaley et al., 1985). However, they are emotionally charged events vvhich can lead to serious medical, legal and administrative liability. It, therefore, seems reasonable to review the control of epidemics in the USA and Europe. There are well recognized differences in approach to inv’estigating epidemics on the two sides of the Atlantic. ‘I’he Europeans favour a laboratory-based initiative where the medically qualified microbiologist starts epidemiological investigations following recognition of a problem from laboratory-based surveillance. The Americans, in contrast, often prefer to have a ward-based epidemiological approach from the outset. There is no evidence that either course is more efficient or efficacious, and both groups appear to be listening to the advantages of the complementary disciplines. If tradition counts, however, it seems that the English have all the advantages: not only microbiology but also statistics and epidemiology developed early in the UK. To begin with vital statistics was born in 1662 with the publication of the Bills of Mortality by John Graunt, a brilliant London merchant with no formal background in mathematics. In 1837 William Farr, who was the first director of the general registrar’s oflice, lifted vital statistics to a new era with his refined definitions and classifications of death rates by age, sex, region and disease. In the 19th century, Karl Pearson founded the field of biometry. In the face of such strength the bias toward the microbiological probably reflects the strong position of bacteriology in the teaching hospitals and the supply of medically qualified microbiologists to general service hospitals. Perhaps it is fair to suggest that the traditions of bacteriology and of statistics-epidemiology in the UK developed like two species in separate environments, not yet merging for sufficient time to develop a successful symbiosis. There are indications that the timing is right to test the union of microbiology and epidemiology in infection control. The Hospital Infection