Salmonella typhimurium DT104:: has it had its day?

IN the 1990s, there was an epidemic of salmonellosis in humans and domestic livestock in the UK. The predominant Salmonella in humans remained 5 enteritidis phage type (PT) 4. However, secondary to that there was a dramatic increase in 5 typhimurium definitive phage type (DT) 104 with chromosomally encoded multiple antibiotic resistance. Recent falls in reported cases of DT104 in humans and livestock suggest that the epidemic may gradually be drawing to a close, but, despite a great deal of research, it is still not known for certain where the outbreak started and why DT104 was able to cause such a large epidemic when most Salmonella strains remain localised, The widespread dissemination of DT104 in humans, livestock and the environment means that increased attention to Salmonella control should be maintained both in agricultural and food processing and preparation areas and in waste disposal to reduce the risk of such an epidemic occurring in the future. This article discusses aspects of the epidemiology, clinical manifestation and control of DT104 infection in humans and in various sectors of the livestock industry.