Health Articles

Guide_lymedisease_v2.indd

measured on a thumb, the nymph is 2mm IntroductionLyme disease was fi rst described in the USA in 1974 available from the Health Protection Agency (HPA)2 and takes its name from Old Lyme in Connecticut, Lyme Borreliosis Unit based at Southampton General where the fi rst outbreaks were noted. The illness had been known by a variety of names in Europe since the The aim of this guide is to raise awareness of Lyme nineteenth century, and its relationship with tick bites disease and methods of prevention.
was recognised in both continents. Ticks are present in many parts of the UK1 and the number of reported cases of Lyme, though small, is rising each year. About Cause of Disease 20% are acquired abroad, in other European countries or north America. Specialist tests and advice are Lyme disease is caused by the spirochaete bacterium Borrelia burgdorferi and is spread to humans (and many other mammals and birds) by the bite of the common tick, Ixodes ricinus. The tick feeds on blood at each of the larval, nymph and adult stages of its life cycle and after feeding on blood the nymph drops off the host and matures adults fi nd their tertiary into an adult hosts: deer, humans, dogs etc eggs laid in spring, appear as larva during the spring/ summer at two years old the adult the dormant females lay after feeding an nymph wakes in adult is enlarged out spring and fi nds a of all proportion to secondary host in its original size deer, humans and other mammals larva use mice and birds as their fi rst host, fall off, become nymphs and go dormant for six months adults mate and eventually fall off the host Lyme Disease • 21.08.07 The Deer Initiative 2007 • www.thedeerinitiative.co.uk No responsibility for loss occasioned to any person acting or refraining from action in reliance on or as a result of the material included in or omitted from this publication can be or is accepted by the author(s)

when feeding can pick up or pass on the spirochaete. Apart from erythema migrans none of the symptoms Between stages ticks leave their host, mature to the is unique to Lyme disease, which may make diagnosis next stage then "quest" for a new host by clinging to the tips of long cover such as grass or bracken to be picked up as the host walks by.
It is thought that birds and small mammals such as mice are the main spirochaete reservoirs. These are the usual hosts for larvae and nymphs. Larger mammals such as deer and sheep are important fi nal hosts for adult ticks, but most ticks do not carry infection at any stage of their lifecycle. The risk of infection from an infected tick attached for 24 hours or less is very low, so early removal of ticks (within hours of attachment) is effective in reducing risk of infection.
The nymph is the most important vector to humans because its small size makes it diffi cult to detect and it may therefore stay embedded for longer. Adult ticks are more likely to have become carriers but fortunately they are easier to see and more likely to be removed before passing on the infecting agent. (above right): the back shows early symptoms of lyme Adult ticks which have fed and fallen from their host disease, while the arm (left present no danger since they will not feed again. Lyme above) shows the disease at spirochaetes cannot be transmitted by eating even well developed stage. raw meat from infected animals and are not spread to remove (below) hold tweezers fi rmly and use constant pressure to pull tick Signs & Symptoms free of skin Tick bites are not usually itchy or painful, and so may easily be missed. Occasionally people who have had many tick bites may become sensitised to them, and may experience mild itching. If spirochaetes have been transmitted the most common, and sometimes only symptom, is a spreading rash (erythema migrans) which may persist for weeks if untreated. Some patients may also suffer "fl u like" symptoms in the period after being bitten. Either symptom following a bite or exposure to a tick environment should indicate a trip to the doctor and will form an important part of Diagnosis is easiest where there has been a known tick the diagnosis.
bite followed by a rash. Unfortunately many people Occasionally more serious symptoms may appear after are not aware that they have been bitten, which, in weeks or months and can affect the nervous system, areas where the incidence of the disease is low, may joints (especially the knee) and rarely the heart and lead doctors to mistake the diagnosis. Blood tests are other tissues.
typically useful only after two to six weeks following Facial palsy, ‘viral type' meningitis, pain from nerve infection, as they test for antibodies (the body's infl ammation, disturbance of sensation and clumsiness immune system response to infection), which take a are some of the nervous system complications. Lyme little time to develop. Antibody tests are useful but disease occasionally triggers a post-infection syndrome not infallible, but it is very uncommon for people with similar to fi bromyalgia or chronic fatigue syndrome.
late stage infection to have negative antibody tests. Lyme Disease • 21.08.07 The Deer Initiative 2007 • www.thedeerinitiative.co.uk No responsibility for loss occasioned to any person acting or refraining from action in reliance on or as a result of the material included in or omitted from this publication can be or is accepted by the author(s) A positive test may only indicate past exposure to clothing to be worn for traveling home in. disease, not necessarily a current infection, especially ♦ Examine for ticks every three to four hours and in people who have had frequent tick exposure. at the end of each day spent in a tick habitat. It is important that those at risk recognise the Pay particular attention to skin folds, e.g. groins, possibility of infection and when appropriate make armpits and waistband area.
doctors aware that they have experienced a tick bite ♦ Children especially should be checked around or been exposed to ticks. Lyme appears to be far the scalp and face. more common in people who have had recreational (holidays etc) rather than occupational exposure.
Flea/tick collars or products such as Frontline will help to protect pets from ticks.
Lyme disease acquired at work is a reportable occupational disease under the Reporting of Injuries, ♦ Consult your doctor if a rash or other symptoms Diseases and Dangerous Occurrences Regulations develop within a few weeks of a tick bite. (RIDDOR) 1995.
Removing embedded ticks: ♦ Remove ticks as soon as possible♦ Antibiotics form the mainstay of treatment for the early Using a tick removal hook, forceps or tweezers manifestations of Lyme disease, and are effective at grip the head of the tick as close to your skin as preventing the later symptoms. Later stage infections also respond to antibiotics, but recovery may be ♦ Pull steadily upwards, taking care not to crush slower if there has been signifi cant tissue damage. For the body of the tick.
most patients the long term outcome is good. There is ♦ Do not be concerned if parts of the head currently no vaccine for Lyme disease.
of the tick remain in the skin but do apply a disinfectant and watch for other skin infections or irritation.
Preventing tick bites is the most effective way of ♦ Do not attempt to burn the tick off or use any avoiding Lyme disease. substance to remove it.
♦ Tick bites are most likely in spring, early summer and autumn when walking in areas of cover such as woodland, moorland, long grass or bracken. Avoid these areas where possible. ♦ Covering exposed skin with long trousers 1http://www.searchnbn.net/ tucked into socks and long sleeved shirts with cuffs fastened will help to prevent direct contact. Wear boots or shoes rather than sandals. ♦ Insect repellents can help, especially if applied to the naked skin. Alternatively trousers can be sprayed with insect repellent or insecticide (Permethrin) impregnated clothing is available.
♦ Ticks can live for a long time in clothing so brushing off clothes before going indoors is a sensible precaution ♦ Those whose workplace is outside and in tick infested areas could carry a spare change of Lyme Disease • 21.08.07 The Deer Initiative 2007 • www.thedeerinitiative.co.uk No responsibility for loss occasioned to any person acting or refraining from action in reliance on or as a result of the material included in or omitted from this publication can be or is accepted by the author(s)

Source: http://www.thedeerinitiative.co.uk/uploads/guides/118.pdf