Bulletins Index

Caithness Field Club

Caithness Field Club Bulletin
2008

In view of the risk when in the northern countryside, I have obtained this formal advice from the NHS Direct website and thought it worth promulgating since there were a few points that I was not aware of � Ed.

Introduction
Lyme disease was first identified in 1975 after a number of cases occurred in a town called Old Lyme, in Connecticut, USA. However, it is not a new disease and it has been known in Europe under different names since the 19th century. Lyme disease is found in a wide range of places including parts of Europe, North America, the former USSR, China and Japan.

Lyme disease is caused by infection with spiral bacteria called 'Borrelia burgdorferi'. The bacteria are spread by infected ticks (small, blood sucking ectoparasites) when they attach to your skin and feed on your blood.

Ticks are usually found in places such as forests and heath land, so the infection is most likely to be caught in these areas. However, they can also be found in some parks. Ticks are very small (about the size of a poppy seed) and can easily be overlooked. Late spring, early summer and autumn are the most likely times for infection, as these are the peak times of the year for tick feeding. Most ticks are not infected with the bacteria that cause Lyme disease. Even if a tick is infected, it does not spread the bacteria in the first few hours of its feed, so there is a very low risk of infection if a tick is removed quickly.

A tick bite usually looks like a lump with a small scab on the skin surface at the site of the bite. Most people with Lyme disease then develop a reddish skin rash in a ring shape, and this may be the only sign of infection. The rash spreads out from the site of a bite after 3 to 30 days. Other common symptoms with early Lyme disease include tiredness, headache, joint pains, and flu-like symptoms.

Without treatment, these symptoms may last for weeks or even longer. Rarely, there are serious complications, and in some cases, these can occur several years later.

Early detection and treatment of the disease helps to relieve the symptoms and shorten the illness. For this reason, it is important to be aware of the symptoms, particularly the rash, so that treatment can be given early.

Symptoms
Some infected people have no symptoms at all. However, the first sign is usually a pink or red spot at the site of the tick bite. This appears between 3 and 30 days after biting, and expands steadily, often with an inflamed red border.

As the rash spreads, the previously affected skin may return to a more normal appearance forming an expanding 'target pattern' with a flat border, which may become quite large (10-70 cms) if left untreated. This rash is called 'erythema migrans'. Some erythema migrans rashes may not have a target-type appearance, but can be more evenly coloured. A rash that develops within a day of a bite is not erythema migrans, but could be due to a sensitivity reaction, or a more common type of skin infection.

The following symptoms may also develop in the first few weeks of an infection:

• tiredness/fatigue,
• generally feeling unwell,
• headache,
• fever,
• aches in muscles and joints,
• a stiff neck, and
• swollen glands (enlarged lymph nodes).

In rare cases there are more serious complications. These can affect the nervous system, joints, heart and other tissues.

Causes
Lyme disease is caused by spiral-shaped bacteria known as 'Borrelia burgdorferi'. They are spread from one animal to another by tick bites and can be transmitted to people when a tick feeds on an infected animal, then goes on to bite a human. The infection is not transmitted directly from person-to-person, or from other animals.

Woodland, heath land or occasionally parkland areas where deer live, are the most likely places to catch Lyme disease. The risks are higher if you are working, camping or involved in outdoor activities in these areas. The most likely time to be infected is in late spring, early summer or autumn.
Diagnosis

A doctor will usually make the diagnosis based on your symptoms, such as the erythema migrans rash. You might be asked if you have visited an area where catching the disease is possible.

Lyme disease can be difficult to diagnose, especially if you have been bitten by a tick, but do not realise. Therefore, it is important to be aware of the symptoms and the kind of places and activities that can put you at risk, and to be aware of ways to reduce risks.

It is difficult to identify the bacteria, so the internationally recognised criteria for diagnosis of Lyme disease are based on tests that look for specific antibodies (products of a person's immune response to the infection) in the blood. Antibodies may not be found in the first weeks after infection, but in the later stages it is easier to detect them.

Treatment
Oral (taken by mouth) antibiotics are usually recommended for the treatment of early Lyme disease.
Intravenous (given by a fine tube directly into a vein) antibiotics are sometimes necessary in complicated cases. These medicines are very effective for treating the infection, and can prevent serious complications developing. However, there is no evidence to show that continued courses of antibiotics are of benefit.

Complications
Complications of Lyme disease are rare, but they can be serious. They include:

• nervous system problems such as meningitis, facial palsy (causing weakness of the facial muscles, with drooping of one or both sides of the face), radiculopathy (causing a shingles-type of pain, or change of sensation, usually in the trunk of the body or a limb) and rarely encephalitis,
• damage to the joints leading to arthitis , and
• very rarely, heart problems such as heart block, inflammation of the heart muscle (myocarditis) and inflammation of the bag that surrounds the heart (pericarditis).

Early diagnosis and treatment can help to prevent these complications.

Prevention
The best way to prevent Lyme disease is to be aware of the risks when you visit areas where ticks are likely to be found, and by taking sensible precautions. Travellers to other European countries or to North America, where the infection occurs more often than in the UK, should also be aware of the risks.

No vaccine is currently available. You can reduce the risk of infection by:

• being aware of ticks, and which areas they normally live in,
• wearing appropriate clothing in tick infested areas (a long-sleeved shirt, with trousers tucked into your socks),
• using insect repellents,
• inspecting your skin for ticks, especially at the end of the day - include your head, neck and skin folds (armpits, groin, and waistband),
• making sure that your children's head and neck areas, including scalps, are properly checked,
• checking that ticks are not brought home on your clothes, and
• checking that pets do not bring ticks into the home on their fur.

If a tick is found on the skin, it should be removed by gently gripping it as close to the skin as possible, preferably using fine toothed tweezers, and pull steadily away from the skin. Do not use a lighted cigarette end, a match head or volatile oils to force the tick out. Some veterinary surgeries and pet supply shops sell inexpensive tick removal devices, which may be useful for people who are frequently exposed to ticks.