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Caithness Field Club Bulletin
|Beware of Lyme Disease (by NHS
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.
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.
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:
In rare cases there are more serious complications. These can affect the nervous system, joints, heart and other tissues.
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.
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.
Early diagnosis and treatment can help to prevent these complications.
No vaccine is currently available. You can reduce the risk of infection by:
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.