Lyme disease

What is Lyme disease?

The infection was first described in 1975 after several cases occurred a town called Old Lyme, in Connecticut, USA. However, the link between tick bites and a condition affecting the nervous system has been recognised for much longer and was known as tick-borne meningoencephalitis

Ticks can be tiny, just one or two mm across and their saliva contains painkillers, anticoagulants and immune suppressants. Many bites, therefore, go unnoticed. If undetected, the tick will typically remain in place for several days, and will drop off when finished feeding.

The bacteria are carried in the tick's gut, and can take some time to move into its mouthparts and then into your body. The risk of infection increases the longer the tick is left in position. Normally, the risk is minimal if the tick is removed or falls off within 24 hours. However, it’s possible to be infected at any time after a bite. A partially fed tick, for example, can pass on the infection relatively quickly. In any given tick population, it’s thought that about 15 to 20 per cent carry Lyme disease. Only a small percentage of tick bites will lead to the condition.

Once the person is infected with Borrelia burgdorferi bacteria, there are several possible outcomes. The infection may be cleared without problems (some people have no symptoms but develop antibodies showing they have been exposed to the bacteria).

Alternatively the bacteria may spread through the body causing symptoms of infection, or in some cases it may trigger an immune response that leads to symptoms such as arthritis.

Lyme disease symptoms

The initial tick bite may be so small that more than half of those bitten don’t even notice or remember a bite. Between two days and four weeks later, an expanding, circular red rash appears in about 40 per cent of cases, usually at or near the site of the bite.

Sometimes several of these rashes appear, which usually don’t itch or burn. Tiredness, headache, joint pains and flu-like symptoms may also occur. If no treatment is given, the rash will typically persist for two to three weeks. After that about one in three people have no further problems.

If no treatment is received, more than 60 per cent of those with Lyme disease will go on to stage 2 of the condition within six months. A wide range of symptoms have been recorded including:

• Fatigue
• Symptoms similar to meningitis
• Peripheral nervous symptoms such as numbness or tingling sensations
• In some cases psychiatric symptoms

These episodes may go on for many years. There may also be problems with nerve palsies (for example, weakness of the nerves to the muscles of the face), inflammation or damage of the nerves, abnormal heart rhythms, and severe malaise.

For some people Lyme disease then persists in a chronic form or Stage 3, where arthritis, neurological damage and fibromyalgia (severe aching and weak muscles) continue to affect them long term.

The symptoms of Lyme disease are partly determined by the particular strain of B burgdorferi bacteria. The strain most often seen in Europe tends to lead to neurological or nerve disease.

Lyme disease causes and risk factors

It's not just visitors to rural North America who might be exposed to these tick-borne infections. Infected ticks can be found across the UK, and anyone who enjoys exploring our woodlands and uplands may also be at risk. People like gamekeepers, farmers and hunters are also at risk.

Cases have occurred in urban parks and gardens too. The common factor is the presence of deep vegetation and a supply of mammals and birds for ticks to feed on.

Avoid being bitten. Ticks in the nymph stage are tiny and spider-like (about the size of a poppy seed), so are difficult to see. The larger ticks you might see on your pets are the adult stage of the same species. They can attach to any part of the body, especially to moist or hairy areas in the groin, armpits, and scalp.

When camping or walking in places where the ticks may be, the following measures are helpful:

• Wear long sleeves and trousers
• Tuck trousers into socks
• Wear light-coloured clothing so ticks are easier to see
• Try not to sit on the ground in areas of vegetation
• Consider using insect repellents
• Keep to pathways and, where possible, avoid areas of overgrown vegetation
• Check for ticks regularly during the day and especially before going to bed
• Remove any ticks found attached to the skin straight away

Remove ticks using a purpose made tool, or fine forceps, which hold the tick close to the skin without squeezing its body. Apply antiseptic cream after removal. Don't use your fingers, or apply heat, petroleum jelly or any other creams or chemicals.

Lyme disease treatment and recovery

If you think you may have been bitten, tell your doctor, and mention where you've been walking, especially if you know that there are ticks in that area. When infection with Lyme disease is suspected, blood tests can be used to help support the diagnosis, but don’t identify all cases.

Once Lyme disease has been diagnosed, treatment is with antibiotics which need to be at high dose and may need to be given as a prolonged course , sometimes even intravenously for maximum effect. Some complications of Lyme disease need specific treatments – for example if a person develops a slow heart rhythm, they may need a pacemaker

In most cases symptoms settle (even if treatment isn’t given, symptoms may eventually get better) but Lyme disease can cause more serious long term problems. Given the small amount of research in this area, medical opinion is divided as to the cause and best treatment for long term symptoms.