Epidemiology of Mycobacterium bovis Disease in Humans in England, Wales, and Northern Ireland, 2002-2014

Abstract

Despite control efforts, Mycobacterium bovis incidence among cattle remains high in parts of England, Wales, and Northern Ireland, attracting political and public health interest in potential spread from animals to humans. To determine incidence among humans and to identify associated factors, we conducted a retrospective cohort analysis of human M. bovis cases in England, Wales, and Northern Ireland during 2002-2014. We identified 357 cases and observed increased annual case numbers (from 17 to 35) and rates. Most patients were >65 years of age and born in the United Kingdom. The median age of UK-born patients decreased over time. For 74% of patients, exposure to risk factors accounting for M. bovis acquisition, most frequently consumption of unpasteurized milk, was known. Despite the small increase in case numbers and reduction in patient age, M. bovis infection of humans in England, Wales, and Northern Ireland remains rare.

Keywords: England; Mycobacterium bovis; Mycobacterium tuberculosis; Northern Ireland; Wales; bacteria; epidemiology; tuberculosis and other mycobacteria; zoonoses; zoonotic diseases.

Figure 1

Annual number and incidence rate (no. cases/100,000 population) of notified Mycobacterium bovis cases by patient place of birth, England, Wales, and Northern Ireland, 2002–2014. Unknown place of birth includes notifications with an unknown place of birth and cases that have not been notified.

Figure 2

Annual number of notified UK-born Mycobacterium bovis cases, by patient age group, England, Wales, and Northern Ireland, 2002–2014.

Figure 3

Cases of Mycobacterium bovis disease in England, Wales, and Northern Ireland, 2002–2014. A) Density of human cases. B) Density of cattle herds with TB outbreaks. This material is based on Crown Copyright and is reproduced with the permission of Land & Property Services under delegated authority from the Controller of Her Majesty’s Stationery Office.