The danger of ticks

Close up of tick
Close up of tick

An unfortunate hazard of a walk in the countryside is the risk of contracting a tick born disease. Whilst the risk is small if the infection is not detected and treated in the early stages the long term consequences can be severe, sometimes fatal. Also many of the commonly used removal techniques actually increase the chances of infection! It is estimated there are 2,000 to 3,000 new cases of Lyme disease in England and Wales each year and numbers are on the increase. About 15% of cases occur while people are abroad. There are precautions you can take to avoid tick bites and these may be particularly useful abroad where in most countries there is a wider range of possible infections.

There are over 20 species of ticks in Britain but not all spread disease. Lyme disease is the main risk but ticks can spread other diseases with similar symptoms and effects. It is only the ‘hard backed’ Ixodes ricinus tick that carries Lymes disease and it is estimated that the disease is carried only by between 1% and 10% of these ticks with about a 25% chance of infection from a disease carrying tick.

Symptoms of an infection normally start with a rash, though not always. The rash often forms rings around the tick bite but can have many different appearences, including multiple, flat, raised, or blistering rashes. The rash may also vary in colour from light pink to dark purple. Rashes can also be missed if they are faint, if the skin is dark or the rash is beneath hair. Within 30 days of the rash forming mild to severe flu symptoms occur – coughs, sniffles, fever, headache, nausea and/or vomiting. Jaundice and blood in the urine can occur with certain infections. If left untreated the infection spreads into other tissues including the muscoskeletal system, the heart and the nervous system with potentially serious consequences. These late symptoms may not appear until several years after the infection. If caught early the infection can be treated with antibiotics.

Whilst ticks are commonly found in countryside areas frequented by deer and sheep, ticks can also be found in urban areas such as parks and gardens. They are brought in by visiting wildlife such as foxes, squirrels, hedgehogs and birds which are potential hosts of the Lyme disease bacterium. They are found in areas of dense vegetation, such as long grass, bracken, woodland, shrubs and ground-cover plants, from where they latch on to animals or people brushing past.

Ticks are small, ranging from 0.5mm at the larval stage to 11mm for a fully engorged adult. Ticks do not have heads but a Capitulum comprising the palps (sensory tactile limbs) and mouth parts. The palps locate the best feeding spot and help to position the mouth parts. The mouth parts consist of cutting limbs and the barbed hypostome, which has a groove along it to draw up the blood. Once the barbed hypostome is inserted the saliva glands secrete a cement like substance that tightly attaches the tick to the host.

The infectious bacteria reside in the gut and saliva glands. Infection can be caused by secretion of fluids into the blood or by defecation of infected material onto the hosts skin. To minimize the chance of infection the tick must be removed at the earliest opportunity.

How to remove ticks

Below are listed common methods of removal but most of these could make matters worse;

  • Smothering  with an airtight coating, e.g. nail varnish, olive oil, etc.
  • Killing the tick with alcohol or other solvent
  • Burning with a match or cigarette
  • Freezing with a chemical such as ethylene
  • Removing with tweezers, atick tool, fingers or fine thread.
  • Cutting of with a razor blade.

Smothering (which takes a long time as ticks breath very slowly), using solvents, burning and freezing all stress the tick which is then likely to regurgitate fluids into the blood stream increasing the chance of infection.
When using tweezers or fingers, unless you can only grip the head (Capitalum) there is a danger of squeezing the stomach contents into the blood-stream. Infection may also pass into the body through cracks in the skin of your fingers.
The ideal method is to use a tick removing tool that gently prizes the tick out of the skin. Ticks will bury them selves into the surface of the skin and the body may need to be lifted out of the skin using a fine point such as the tip of a knife so the removal tool can get a grip. Avoid trying to lift the tick with a blunt object such as a fingernail as this may squeeze infected fluids out of the stomach. Avoid twisting the tick during removal, which often causes the head to separate and remain embedded in the skin.

If no tick tool is available and the tick is large enough a piece of fine thread can be wound around the head and the tick gently extracted. Some researchers have suggested removing the tick with a disposable razor. The mouth parts will be left in the skin but these will work their way out or can be removed with a pin. The important thing is that the tick has been removed at the earliest opportunity, minimizing the chance of infection (Moehrle M. & Rassner G. Department of Dermatology, University of Tübingen, Germany).

After removing the tick, use an antiseptic solution to wash the bite location, the tool and your hands. Dispose of the tick without squashing between fingers as infection may enter through cracks in the skin.

How to avoid ticks

Keep skin covered when in “brushy” areas so wear trousers rather than shorts or a skirt. Button up collars and cuffs, wear a hat, tuck trousers into socks, choose clothes with elastic or drawstrings at the waist and wrist. Wear boots, not sandals. Clothing made from smooth or waxed material is hard for ticks to climb, and light-coloured fabrics make them easier to see. DEET based repellents are effective against ticks and some natural repellents (e.g. lemon eucalyptus oil) are also effective and safe to use on young children. To avoid ticks on overhanging vegetation, you can use a stick to tap the vegetation ahead of you, knocking off any waiting ticks.

Brush off clothing and check pets before returning home. Inspect yourself and children for ticks, as soon as possible, paying most attention to armpits, navel, groin and hairline (especially in children).

The insecticide Permethrin can be applied to clothing and equipment such as tents, sleeping bags or rucksacks. Do not apply this chemical directly to the skin and allow clothing to dry thoroughly before wearing (Permethrin is highly toxic to cats. Make sure they do not come into contact with treated clothing).

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