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Home Topics Infectious Diseases Infections A-Z Lyme borreliosis / Lyme disease Epidemiological Data ›  Lyme borreliosis in England and Wales 2010

Lyme borreliosis in England and Wales 2010

In 2010, 905 cases of Lyme borreliosis were identified in England and Wales residents, an incidence rate of 1.64/100,000 total population. This compares with 863 cases and an incidence rate of 1.59/100,000 in 2009. Excluding the 164 (18%) people known to have acquired their infection abroad during 2010, the total population incidence throughout all regions of England and Wales is 1.34/100,000. This however masks local incidence rates which may be higher in some regions.

Age and sex distribution

The age and sex distribution of serologically confirmed cases shows a trend broadly similar to previous years. In 2010 there were more males than females in age groups under 50 years but slightly more females than males in those aged 50 and over. In travel–associated cases there was however an overall female: male sex distribution of 1.14:1 (F:M).

People of all ages are susceptible to Lyme borreliosis with the majority of cases (65%) occurring in people between the ages of 30 to 64 years. The highest age-specific rates occurred in the 50-59 (2.28/100,000) and 60-64 (2.4/100,000) age groups. Overall, similar numbers of infections were reported in both males and females throughout all the age groups (443 females: 449 males and 13 for whom the sex was unknown).

Seasonality

The seasonal pattern of infections in 2010 was similar to that seen in 2009 and in preceding years.  Approximately 65% of patients had their sera tested for the first time between July and September; this represents a likely peak onset of symptoms several weeks earlier and is consistent with the major tick feeding period in the early summer months. Nine percent of blood samples were received and tested during the last two months of 2010, consistent with exposure to ticks or ‘ticky environments’ in late summer and early autumn.

Occupational infections

Lyme borreliosis is seldom reported as an occupational infection, but as such, it occurs more frequently in those whose occupations routinely take them into potential tick habitats, such as forestry workers, deer managers and stalkers, gamekeepers, farmers and military personnel on exercise.

Non-travel associated cases.

Seventy eight percent (n=575) of the 741 indigenously-acquired infections were identified in residents of the southern counties of England (the South-west and South-east Health Regions. Population-specific rates were 3.95/100,000 (337 cases) and 4.51/100,000 (238 cases) respectively. These include well-known regional foci of Lyme borreliosis around the New Forest, Salisbury Plain, Exmoor, the South Downs, parts of Wiltshire and Berkshire. All other regions had rates less than 1.0/100,000 population. Where information was available, a number of autochthonous cases were considered to have acquired their infection close to home or in nearby UK foci. In a number of cases, Lyme borreliosis was diagnosed following visits to the Highlands and Islands of Scotland where there is a potentially greater proportion of the landscape capable of providing suitable habitats for ticks.  A small number of cases have also occurred following visits to the Irish Republic.

Travel-associated cases

One hundred and sixty four (18%) patients reported overseas travel; most were in holidaymakers who presented with symptoms after visiting North America (15% of those who had travelled, usually to the eastern seaboard) and countries in continental Europe (85%), many of which have considerably higher local incidence rates1 than are found in England and Wales. Thirty two (20%) travel reports were from visitors to Poland, twenty one (13%) travel reports were from people who had been to France, 14 (9%) in visitors to Sweden and 8 (5%) from those who had been to Slovakia and 8 (5%) to the Czech Republic. Sixty percent (n=97) of those who travelled overseas had their sera tested for the first time between August and October (Figure 2.). Thirty three percent of those who travelled overseas in 2010 were from the South East Health region, followed by 23% from London and 16% and 9% respectively from the South West and North West health regions.

Clinical presentations

Diagnosis is primarily clinical and takes into account the risk of a tick bite or risk of exposure to ticks. The clinical presentations of Lyme borreliosis vary widely, attributable in part to differences in the borrelial genospecies implicated. The most commonly reported clinical presentation which was reported in 56% (n=509) of patients, was erythema migrans although only 81% of these (n=413) reported a preceding tick bite. The more severe late stage presentation of neuroborreliosis was reported in 12.3% (n=111) patients of whom 54% (n=60) had a facial palsy (6.6% of all Lyme borreliosis cases); 53% of facial palsies, many of which were bilateral, occurred in those aged under 15 years and most of these (60%) were in the 5-9 year age group. Influenza-like illness was reported by 15% of patients. Thirty eight percent (n=432) were identified with early stage Lyme borreliosis.

Commentary

The focal distribution patterns of Lyme borreliosis observed in England and Wales are similar to those seen in regionally in other European countries2 and can vary from year to year; they are in part, determined by the heterogenous spatial distribution of vector ticks. The incidence in humans often depends on a number of climatic and biotic factors which affect local tick populations and densities, tick survival and feeding behaviour. Exposure to ticks is also influenced by human factors such as residence in “ticky” areas and recreational and occupational activities, in the UK or overseas. These exposures may in turn be influenced by local, short-term weather conditions which can affect tick activity, and also impact on human outdoor activity (and therefore exposure to ticks).

A number of infections were reported in non-UK nationals many of whom returned to their home countries, often during peak holiday periods. Polish nationals were strongly represented in this category. The peak months for receipt of specimens from overseas travellers were August to October whereas the peak for receipt of specimens from those with indigenously acquired infections was June to September.

The overall incidence of Lyme borreliosis in England and Wales is low compared with many other European countries with higher incidence rates, some of which can also be highly localised. Areas with localised incidence rates can be difficult to identify and can often only be inferred. The precise location of infection is not always identified, nor details of the place of residence of the patient (which in some cases may also be the place of infection). The diagnostic peak between June and October correlates well with patterns of tick abundance and exposure through activities such as walking or camping in high risk environments. This peak is associated with infections acquired in the UK and overseas.

Lyme borreliosis in England and Wales has remained relatively stable for several years with only small annual increases. There have however been substantial annual increases in reference laboratory test referrals and an increase in the number of early infections identified.  These can be attributed in part to greater professional and public awareness. The absence of a dramatic increase in the number in the overall number of cases reported in England and Wales reflects diagnostic consistency and suggests that tick awareness messages from the Department of Health, the Health Protection Agency, Public Health Wales and other responsible organisations are well targeted and effective.

In comparison with many other European countries, the incidence of Lyme borreliosis is low; for example in Germany in 2002, it was estimated that there were at least 60,000 cases, giving an approximate incidence rate of 75/100,0002 with other reports of incidence rates up to 111/100,000 in some parts of Germany and over 100,000 cases annually in parts of Slovenia, Austria and some of the Baltic States3 in recent years. Further comparisons of European incidence rates can be found in references 1 and 4.

References

1. Hubalek Z. 2009 Epidemiology of Lyme borreliosis In: Lipsker D, Jaulhac B (eds): Lyme borreliosis. Curr Probl Dermatol. Basel, Karger, 2009, 37:31-50.

2. Mehnert WH, Krause G. 2005 Surveillance of Lyme borreliosis in Germany, 2002 and 2003. Eurosurveillance 10:83-5. Available online http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=531

3. Rizzoli A, Hauffe HC, Carpi G, Vourc’h GI, Neteler M, Rosa R. Lyme borreliosis in Europe. Euro Surveill. 2011; 16(27):pii=19906. Available online: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19906

4. Smith R, Takkinen J. 2006 Lyme borreliosis: Europe-wide coordinated surveillance and action needed? Eurosurveillance 11:E060622 1. Available online http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=2977


Last reviewed: 5 March 2012