A layman's overview of Borreliosis in the UK

Although Borreliosis/Lyme disease is often said to be rare in the UK, it is not as rare as most people think. It has existed here for centuries, though not under its modern names (Borreliosis, Lyme disease or Lyme borreliosis). There are three reasons why it is often ignored or dismissed:

  1. It is difficult to diagnose because it produces a bewildering variety of signs and symptoms, most of which resemble those of other diseases and can thus lead to misdiagnosis. Its only specific sign is an Erythema Migrans (EM) rash, which occurs in fewer than 50% of patients and often in an atypical form instead of the classic “bull’s eye”.
  2. There is no single 100% reliable test for Lyme disease. The NHS currently uses a two-tier testing procedure; firstly an ELISA (Enzyme-Linked Immunosorbent Assay), which is followed (but only if positive) by a Western blot or ‘immunoblot’. However, the ELISAs that are used to detect a Borrelia infection were designed for epidemiological purposes and not for diagnosis. They rely on the presence of antibodies in a sample and are known to sometimes produce false results. This is because serologies indicate exposure to Borrelia bacteria only and do not directly indicate whether the organism is currently present. In addition, Borrelia bacteria have the ability to suppress the immune system, thus inhibiting the production of antibodies. Therefore Borreliosis requires a clinical diagnosis, with tests used only as an adjunct as they cannot conclusively rule out an active infection. A significant number of patients with Borreliosis who have tested negative by ELISA then go on to have fully diagnostic western blots.
  3. In England and Wales Borreliosis is not a notifiable disease, though some doctors report cases through a voluntary scheme, and laboratories report positive tests. Therefore, statistics can be inaccurate. In Scotland, Lyme disease is a notifiable condition but many doctors appear not to be aware of this and so cases can go un-recorded. The Government estimates that approximately 2000 people per year in the UK become infected, but some doctors consider that figure a serious underestimate, owing to cases that are not reported, patients that are misdiagnosed with other conditions, and asymptomatic carriers of the disease.

Increasing numbers

Tick numbers, and cases of tick-borne disease, in the UK have increased for several probable reasons:

  1. Climate change; warmer winters allow more ticks to survive.
  2. Frequency of foreign travel, not only by UK residents but now also by their pets, which have the potential to import infected ticks. The Pet Travel Scheme (PETS) requires pets to be treated for ticks not less than 24 hours, and not more than 48 hours, before checking in with an approved transport company, but animals are still reported to be entering the UK carrying infected ticks.
  3. Pets travelling abroad can be exposed to diseases which may then be transmitted to British ticks once the animals have returned to the UK.
  4. The reduction in sheep-dipping, motivated by concerns over the carcinogenic effects of organophosphates on human health.

The spread of disease

The "sheep tick" or "wood tick", Ixodes ricinus, can infect livestock (and sometimes humans) with Louping- ill, but it can also carry Borreliosis, sometimes with co-infections such as Anaplasmosis / Ehrlichiosis, Babesiosis, and possibly Bartonellosis. These co-infections can make the treatment of Borreliosis patients more difficult. Unfortunately Ixodes ricinus has a varied taste for prey, including birds, reptiles, many small mammals such as rats hedgehogs and squirrels, and also human beings. Because many of its prey are freely mobile, they can drop infected ticks in other areas (sometimes across oceans) or act as reservoirs of infection, ready to pass on pathogens to local ticks, thus spreading the disease.

Scale of increase

The World Health Organisation is concerned about the rise of tick numbers in Europe and the UK. The scale of this development may be seen in the observations of the Game Conservancy Trust, which has been studying the incidence of Louping-ill in Scottish red grouse chicks. Between 1985 and 2003 the percentage of grouse chicks infested with ticks increased from 4% to 92%, and up to 80% of the infected chicks died.

European doctors alerted

European countries such as Austria, Germany, Holland and France have alerted GPs and specialists to the growing problem of Borreliosis. Germany has polled all doctors to determine the probable infection rate, and has found that the rate has doubled in the last 10 years. The Dutch have carried out similar surveys. In Austria, every GP surgery displays warning signs about Borreliosis.

Urban ticks

It is commonly supposed that one can only be bitten by ticks, within the UK, in such places as meadows and woodland, and then only in acknowledged "hot spots" such as the New Forest. However, tick sampling by scientists has shown that ticks infected with Borrelia bacteria can be found throughout the UK, including the London parks. Urban Borreliosis is an issue that is little considered but could have serious implications for many people, including the homeless, who frequently sleep in parks and cemeteries.

Birds, hedgehogs and squirrels, domestic dogs and cats, can all carry ticks and all visit urban gardens. DEFRA (Department for Environment, Food, and Rural Affairs) describes Borrelia and Bartonella bacteria to be endemic to UK dogs and cats. Rats too are possible reservoirs for these diseases, and they can infest buildings as well as parks and gardens. The National Pest Technicians Association has reported a 39% increase in call-outs to rat catchers in the last six years, as a result of fortnightly rubbish collections imposed by councils to permit more recycling collections; other causes mentioned are fly-tipping, litter (especially fast-food containers), easily accessible compost bins, and councils charging fees for pest control, which leads residents to ignore a rat problem until it has escalated.

Pigeon colonies on buildings (such as Kings College, Cambridge) have been demonstrated to be a haven for Argas reflexus, a soft tick which will readily attach to humans, and which is known to be a potential carrier of Borreliosis. The World Health Organisation has highlighted urban sprawl as an increasing contributor to the spread of zoonotic diseases, including Borreliosis.

Awareness is essential

It is important for UK residents to become more aware of these facts, to take sensible precautions against tick bites, to learn how to remove an attached tick without increasing their own risk of infection, to recognise infection in themselves and others and to access prompt diagnosis and treatment if infection is suspected.