Epidemiology

In the UK:

• around 1000-3000 cases are estimated to occur each year in the UK (1)
  • 959 laboratory confirmed cases were reported by the Health protection Agency (HPA) in 2011, which is a 3.6-fold increase since 2001
    • this equates to a rise in the incidence of serologically confirmed cases from 0.50/100 000 in 2002 to 1.64/100 000 in 2010
• the highest attack rates occur in people aged 45–64 years, followed by those aged 24–44 years
• affects males and females equally
• out of indigenously acquired infections, around two-thirds were resident in the southern counties of England
  • recognised foci include: New Forest, Thetford, Salisbury Plain, Exmoor, the Lake District, parts of the South Downs, West Sussex, Surrey, Wiltshire, West Berkshire, the Yorkshire moors, the Scottish Highlands and islands and parklands such as the Royal London parks of Richmond and Bushy.
• infection acquired abroad are usually from endemic regions of France, Germany, Austria, Scandinavia and eastern European areas, such as Slovakia and the Czech Republic and from the USA.
  • in recent years, migrants from central and eastern European countries (regions with high prevalence of Lyme borreliosis) have also contributed to higher incidence of infection identified (but not necessarily acquired) in the UK (1,2).

Rest of the word

• in the USA
  • around 20,000-30,000 cases/year are reported
  • actual number of annual cases may be as high as 300,000
• in the Europe
  • around 200 000 cases are reported annually in the whole of Europe.
  • highest prevalence of Borrelia infected ticks in Europe is seen in Austria, the Czech Republic, Germany, Switzerland, Slovenia and Slovakia,
    • in Germany, more than 60,000 cases are reported
• it is not seen in tropical regions or in Australia or New Zealand (1,2).

Other features are as follows:

• occupationally acquired Lyme borreliosis is seldom reported. Most cases occur in forestry workers, farmers, deer handlers and gamekeepers (3).
• birds help to distribute infected ticks during their migratory flights
• early clinical manifestations peak during the summer months (from June to October) which is consistent with greater tick activity
• late manifestations occur throughout the year which may be due to
  • delay of diagnosis due to non specific features of the disease
  • long incubation period of some of the late clinical manifestations

Reference:

• (1) Dubrey SW et al. Lyme disease in the United Kingdom. Postgrad Med J. 2014;90(1059):33-42
• (2) Shapiro ED. Lyme Disease. The New England journal of medicine. 2014;370(18):1724-1731.
• (3) Public Health England. Guidance. Lyme borreliosis epidemiology and surveillance 2013