Here we’ve answered your most frequently asked questions about ticks, their bites and Lyme disease (Borreliosis).

Lyme disease is considered to be an ’emerging disease’. This does not mean it is a new disease, or that it has only recently become present in the UK and Ireland. It means that, for various reasons, it is becoming more prevalent. Until fairly recently, it was considered to be extremely rare in the UK and Ireland and it is for this reason that many of the references are from other European countries or the United States of America. If you cannot find the answer to your question here, you may find it in our sections on ‘Ticks’, ‘Diseases’, ‘Pet Diseases’, ‘Defence’ and ‘Tick Prevention’ If you still cannot find the answer to your question, please contact us and we’ll do our best to help.

 What does a tick look like?
Ticks are relatives of spiders, so they look a bit similar. Newly hatched ticks (larvae) only have six legs until they reach the second stage of their life cycle (the nymph). At this time they develop eight legs.

Ticks can vary in shape, colour and size, depending on the species, age and sex. Generally, when unfed they are oval, flat and small, like a sesame seed. Once they are completely engorged with blood they are coffee-bean-shaped.

The colour of ticks ranges from black or dark-brown, to a red-brown, when they haven’t fed. Ticks that are engorged with blood can range from a blue-grey colour to a purple-red or fleshy-pink. Some species of tick have slight patterns on their back, while others are plain.

Ticks can be hard-bodied or soft-bodied. Hard ticks have a hard shield on their backs while soft ticks have a leathery hood over their back and mouth parts Find out more in our Tick Appearance section.

How do I remove a tick from myself or my pet?
How you remove a tick is very important as it can help to prevent the transmission of disease-causing organisms or leaving bits of the tick behind, which can cause irritation, infection and scarring. Using methods of freezing, burning, or applying solutions to a tick may cause it to regurgitate (vomit) its saliva or stomach contents. These fluids may contain disease-causing organisms. See our section on Tick Removal for the safest ways to remove an attached tick and for our Myth Busting section.

Once I have removed a tick, what do I do with it?
As ticks can transmit certain infections, you may wish to keep any tick you have removed for a while. This is in case any symptoms of disease occur in the person or pet the tick was attached to. Showing the tick to the doctor or vet can aid their diagnosis by confirming that it was definitely a tick that caused the bite.

If you wish to keep the tick, place it in a freezer bag with a piece of paper containing the date of removal. Writing in pencil is best as it can’t be smudged off by moisture. Place the bag in your freezer until you no longer need it. Early symptoms may take several weeks to develop so keep an eye out. Check out our sections on Lyme disease for people and pets for information about signs and symptoms.

You may wish take part in Public Health England’s ‘Tick Recording Scheme‘ in which case follow the instructions by Public Health England on how to send the tick to them.

As ticks can carry infective organisms, it is important to dispose of the tick safely. This means that you must kill the tick and not allow it to wander off. Releasing the tick might allow it to continue with its life cycle and to bite another person or animal. Without allowing the tick (or any fluids from the tick) to come into contact with your skin, wrap the tick in tissue paper and squash it. Then dispose of it in your dustbin or flush it down the toilet. Wash your hands thoroughly or use a hand sanitising gel or wipe.

Does it hurt when a tick bites?
No, not usually, although some species of tick are reported to have painful bites. You are more likely to feel an adult tick on your skin because they are bigger and will come into greater contact with your skin and body hair. Larval and nymphal ticks (the first two stages in the tick’s life cycle) are much smaller and less likely to be felt.

Ticks have specialised saliva which numbs the bite area, prevents inflammation and keeps the blood flowing so that they can feed for prolonged periods of time. The saliva can cause slight localised irritation and sometimes an allergic reaction. However, a reddening around the bite area may also be early signs of disease. It is therefore important to learn to recognise the wide variety of presentations of rashes that are associated with tick-borne infection. If you have any concerns about a bite area, consult your GP. For more information about tick bites, please visit our tick Feeding section.

How does a tick transmit disease?
Ticks ingest disease-causing organisms from their wildlife hosts (the animals that tick’s feed on). These hosts act as a reservoir for the organisms and can pass them on to hundreds of ticks that feed on them. The infected ticks then seek another host and during their next feed they transmit the infective organisms into the new host. The cycle continues, potentially spreading the infection far and wide as infected hosts travel to new areas. Infected birds can cross oceans, and they can also transport the ticks themselves to new areas far from where they first attached. For more information, please see our Disease Transmission section.

What should I do if a tick bites me or my pet?
If you find an attached tick, use a safe method of tick removal. You may want to save the tick for later identification in case the person or animal the tick was attached to becomes ill in the following weeks. If you are bitten regularly, make sure your GP is aware of the fact that you are potentially exposed to tick-borne infections. If your pet gets bitten regularly, talk to your vet about a suitable repellent. A vaccine against Lyme disease is now available for dogs in the UK & Ireland. Talk to your vet for more information.

Although not every tick carries infective organisms, and not every bite will transmit disease, immediate removal of an attached tick is important as this can reduce the risk of disease transmission. The longer a tick is allowed to feed, the more organisms can pass into the bloodstream of the host (the person or animal that the tick feeds on). Regular checks for ticks on you or your pet will also help to find them before they have had a chance to attach and feed.

A tick bite can cause irritation and reddening at the bite site. This tick bite hypersensitivity reaction is caused by the body’s immune response against the tick’s saliva and is a common reaction in people and animals. The reaction will usually settle down within the first couple of days and doesn’t usually require medical / veterinary attention. A bite relief topical cream will usually make the area more comfortable. Scratching at a tick bite (or any insect bite) can introduce bacteria and cause a localised infection. You should seek medical / veterinary advice if there are continued signs of reddening, swelling and heat, or weeping / oozing at the bite site.

If you know that a tick bite occurred but the tick was squashed or brushed/scratched off, disinfect the bite site thoroughly. If possible, check that no mouth parts remain in the skin. If possible, attempt to remove any remaining mouth parts with a sterilised needle or fine-pointed tweezers. Do not attempt to remove remaining mouth parts from young children or anyone with health conditions where they are at risk of excessive bleeding or difficulty healing. Do not attempt to remove mouth parts from animals that are not of a steady, calm nature. In such cases, seek medical / veterinary advice.

If it is not possible to remove any remaining mouth parts yourself, keep a close eye on the bite site. Remaining mouth parts can often cause a localised reaction as the body tries to expel them. This may result in a reddening of the area where the bite occurred. Often this settles down over a few days and there may eventually be a lump or a circular scar at the bite site. Sometimes the area can remain irritated or become infected because of the remaining mouth parts. If there are signs of reddening, swelling and heat, or weeping / oozing, seek medical / veterinary advice.

Over the following weeks, keep a close watch for the development of any skin rashes. If any develop, photograph them and seek medical / veterinary attention. Photographs can be very useful during medical/ veterinary consultations after the rash has faded or resolved.

Rashes following tick bites in animals are rarely reported and can be difficult to spot under the animal’s coat. However, it is still advisable to inspect them as thoroughly and as often as possible.

If you suspect a tick bite has occurred but you didn’t see a tick, keep a watch on the bite site for any adverse skin reactions.

In all cases, if there is any change in the general health of the person or animal the tick was attached to, it is advisable to seek medical attention without delay.

See our Diseases and Petssections for comprehensive information on tick-borne diseases in the UK and Ireland.

See question 12 for further information about infected ticks and tick testing.

Where in the UK and Ireland are infected ticks present?
Some areas of the UK are often referred to as ‘hot spots’. These include the New Forest, Exmoor, the South Downs, Thetford Forest, the Lake District, the North Yorkshire Moors, and the Highlands and Islands of Scotland. However, there can be localised ‘hot spots’ in many areas.

Particular areas of land may provide a more suitable habitat for ticks than a neighbouring area, and therefore there can be a larger population of ticks there. It is also worth remembering that anywhere that has a diverse population of wildlife and good vegetation cover will harbour ticks, and a proportion of these ticks are likely to carry disease-causing organisms. These areas can include town parks and gardens. Public Health England (formerly The Health Protection Agency) advises that any area that supports a hard tick population poses a risk.

Public Health England has produced a fact sheet for GP’s and other healthcare professionals.

Lyme disease is endemic throughout most of Scotland. Health Protection Scotland has produced a fact sheet.

Public Health Wales has produced a ‘be tick aware‘ web page.

NI Direct (Northern Ireland’s Government Services) has produced a ‘Protect yourself against tick bites‘ web page.

In September 2011, Lyme borreliosis became listed as a notifable disease in the Republic of Ireland, where clinicians should notify cases to the Director of Public Health or the Medical Officer of Health for the local area of the patient’s residence. Prior to Lyme borreliosis becoming a notifiable illness, there was no voluntary surveillance scheme and therefore the annual number of cases has been unknown.

In 2007, 71 specimens, referred to what was the UK Health Protection Agency’s Lyme Borreliosis Unit from Irish hospital laboratories, were confirmed positive, suggesting a crude incidence rate of 1.67 per 100,000 in Ireland that year. However, the Health Protection Surveillance Centre (HPSC), Ireland, considers that the incidence is likely to be much higher. An analysis of the 2011 data for the Cork and Kerry region, then extrapolated to the 4.58 million population of the Republic of Ireland, suggests 250+ cases might have occurred that year.

The Health Protection Surveillance Centre have produced a fact sheet.

References and Further Reading
Notifiable Diseases and their respective causative pathogens. Health Protection Surveillance Centre, Ireland.

Health Protection Agency

Are there ticks around in winter?
Yes. Ticks can be active at temperatures as low as 3.5°C. They use plant debris (fallen leaves, branches and rotting vegetation) to shelter in during cold weather. The debris acts like a duvet keeping the tick warm. If snow falls on ground that has not been hardened by frost, the snow can also act like a duvet, insulating ticks against frost on the surface of the snow. On warmer winter days, the temperature can be sufficient for ticks to seek a host (a person or animal to feed on). Although there are considerably fewer ticks in cold weather, it is still possible to get bitten.

Age structure of a population of Ixodes ricinus (Acari: Ixodidae) in relation to its seasonal questing. A.R. Walker.

If my pet brings a tick into my home, will I get bitten?
It is almost guaranteed that pets will occasionally bring ticks into the home. Often the tick will already be attached and feeding on the pet. If it is dislodged during this process, it will often die, although it is possible for a detached tick to re-attach to a new host. If an unattached tick is brought into the home, it may have an opportunity to attach to a person. However, generally the level of humidity in our homes is too low for the survival of most tick species which pose a risk to people and pets, and they tend to get too dry and die as a result. The most effective way of preventing ticks entering the home is to keep pets treated against ticks and to check your own clothing before going inside.

References and Further Reading
Parasitology / Volume 37 / Issue 1-2 / January 1946, pp 1-20

The water balance in Ixodes ricinus L. and certain other species of ticks. A. D. Lees.

If a tick gets into my home, can it breed there?
Female ticks of the species that usually pose an infection risk to people and pets (Ixodes ricinus & Ixodes hexagonus) lay their eggs in soil and plant debris. This keeps the eggs moist enough to develop and hatch into tiny larvae. The larvae then need to feed on a host and moult, a process which also requires a relatively high level of humidity. Most homes are too dry for these ticks to survive in, and unsuitable for a female tick to lay her eggs and for egg development.

One species of tick called Ixodes canisuga (the British dog or fox tick) can survive in less humid environments and lay its eggs in cracks and crevices in ceilings and walls. Infestations can occur in kennels and catteries, and bites occur more commonly in working dogs.

Although not indigenous to the UK, Rhipicephalus sanguineus (the brown dog tick) has been identified in some buildings and on pets (usually after animals have travelled to central and northern Europe).

Infestation of buildings will require environmental treatment under veterinary guidance.

References and Further Reading
Parasitology / Volume 40 / Issue 1-2 / January 1950, pp 35-45

The ecology of the sheep tick, Ixodes ricinus L. spatial distribution. A. Milne.

How do I kill ticks in my home and garden?
Unfortunately, there are no licensed chemical products available to kill ticks in your garden. This is because chemical control is heavily restricted by laws and licensing, as it generally raises concerns regarding its effect on the environment and public health. However, you can help to deter ticks from your garden by using strategic landscaping and planting schemes. Check out our tick buffer method for more information.

Soft furnishings (such as carpets, curtains and pet bedding) in the home can be treated with Pyrethrum-based sprays, which are available from pet shops and veterinary surgeries. However, Pyrethrum-based products are highly toxic to cats and some other pet species. Overuse can also result in accidental poisoning in dogs and other pets. It is very important to follow the manufacturers’ instructions on the product packaging to avoid accidental poisoning to your pet, and it is advisable to discuss suitable products with your vet who will be able to take into account other pets in your home and advise you on an individual basis.

Keeping your pets treated against ticks will help to prevent them bringing ticks into the home. Talk to your vet about which products are most suitable for your particular pet.

If you live in a particularly heavily tick-populated area, it is advisable to use a repellent and suitable clothing when you are outside, and this will help to prevent ticks entering the house on your clothing.

Do all ticks carry disease?
No. Not every tick carries disease-causing organisms. It is difficult to quantify the proportion of infected ticks in the UK and Ireland as this can vary from area to area and from time to time. Not every type of organism carried by ticks will cause illness in people or their pets.

Testing individual ticks as a means to established whether a person or animal has become infected is not generally useful for the following reasons:

  • Even if the tick is carrying disease-causing organisms, it does not necessarily mean that transmission to the person or animal has occurred.
  • Tests have the potential for false-positive and false-negative reactions. If the test was falsely positive, inappropriate treatment could result. If the test was falsely negative, false assurance that the person or animal is not infected could result.
  • The person or animal may have been unknowingly bitten by a different tick to the one that was tested.

How many diseases can ticks carry?
Ticks in the UK and Ireland can transmit a number of infections. These include Lyme borreliosis, Anaplasmosis, Babesiosis, and Q fever. When a tick transmits another infection at the same time as Lyme borreliosis, this is termed co-infection. Cases of co-infections are rarely reported in the UK and Ireland, however, as with Lyme borreliosis there may be under-reporting.

Q fever is more frequently acquired through other transmission routes, such as contact with livestock birthing fluids. Lyme borreliosis may present differently if co-infection has occurred. Clinicians and veterinarians should be aware of the possibility of co-infections, which may also influence treatment choice.

If a tick carries several diseases, will I get them all?
No, not necessarily. Whether you contract a disease can depend on how long a tick has been able to feed on your blood. The longer it stays attached, the more organisms can transfer into your bloodstream. Therefore it is much safer to remove a tick as soon as you discover it, and to use a safe tick-removal technique. It can also depend on your body’s immune response as to whether you become ill. Some infections cause little or no effect to their host, while others can cause mild to severe symptoms. When several diseases are transmitted at the same time, the immune system has to work much harder and this can sometimes cause a patient to be more acutely ill. It can also make diagnosis difficult because some diseases have similar signs and symptoms. Reports of patients with co-infections (more than one infection transmitted at the same time) are rare in the UK and Ireland. However, it is possible that, as with Lyme borreliosis, an under-reporting occurs.

Can you die from a tick-borne disease?
It is possible, in very rare cases, for fatalities to occur from the type of tick-borne diseases that are present in the UK and Ireland. Such an event could arise from complications of the disease that affect the vital organs of the patient’s body, such as the brain, heart or kidneys. Patients without a spleen are at significantly greater risk from infection. Fatalities are mostly associated with diseases acquired abroad, such as Tick-borne encephalitis (TBE) or Crimean-Congo Viral Haemorrhagic Fever. These diseases are not present in the UK and Ireland.

Are there other ways to contract a tick-borne disease?
Some organisms that ticks can transmit have other ways in which they can be transmitted. Some can be inhaled from the contaminated dust of dried faeces, or through unpasteurized milk, or blood and birth fluids. Some can be transmitted through skin abrasions, or when splashes of infected material meet the mucous membranes of the eyes, nose or mouth of a host. Some can be transmitted through contaminated medical instruments or in blood products for transfusion. When transmitted in other ways, these diseases are no longer referred to as tick-borne.

Currently there is no evidence to suggest that Lyme borreliosis can be transmitted from person to person or directly from animals to people. There is also no robust evidence to suggest that Lyme borreliosis is transmitted by insects such as mosquitoes or fleas, despite reports of Borrelia burgdorferi being isolated from these insects.

References and Further Reading
Journal of Clinical Microbiology. J. Clin. Microbiol. August 1988 vol. 26 no. 8 1482-1486

Ticks and biting insects infected with the etiologic agent of Lyme disease, Borrelia burgdorferi. L. A. Magnarelli and J. F. Anderson.

What is the difference between Lyme disease and Borreliosis?
Lyme disease (not Lymes, Lyme’s or Lime) is a bacterial infection. The cause of Lyme disease is a spirochaete (a long, thin, spiral-shaped bacterium). When it was discovered, this bacterium was named ‘Borrelia burgdorferi’ after William Burgdorfer who discovered it. It is now termed Borrelia burgdorferi (Bb) sensu stricto (s.s.), which means Bb in the strict sense. Bb was the cause of a sudden cluster of cases in Old Lyme, Connecticut, in the United States of America in the 1970’s and Lyme disease is named after the town of Old Lyme.

Later on, other genospecies of Borrelia burgdorferi were discovered in Europe and other areas, and these were given different names. They all come under the umbrella term of ‘Borrelia burgdorferi sensu lato’ (Bb. s.l.), which means Bb in the broad sense.

In the UK and most of Europe, the most commonly found genospecies include Borrelia burgdorferi s.s, B. garinii, B. afzelii, and B. valaisiana. There is some evidence that the different pathogenic (disease-causing) genospecies can cause variations in signs and symptoms. B.b.s.s. is particularly associated with arthritic and neurological complications, B.garinii with neurological presentations and B. afzelii with Acrodermatitis Chronica Atrophicans (ACA), which is a skin manifestation of late disease where areas of tissue become severely inflamed and eventually die off. B. afzelii is also associated with peripheral neuropathy.

B.b.s.s. is the only pathogenic species identified in North America. It also occurs in Europe but is less prevalent than B. afzelii and B. garinii (the latter being the most prevalent in the UK). A significant proportion of infected ticks in the UK carry B. valaisiana, which only rarely causes Erythema Migrans (the rash associated with Lyme disease). Recent evidence suggests that B. afzelii can result in a more ring-like Erythema Migrans while B. garinii can result in more irregular lesions which tend to develop more rapidly.

Many physicians and veterinarians prefer to use the term ‘Borreliosis’ as an umbrella term for an infection of any strain. The term ‘Lyme borreliosis’ is also widely used. Antibiotics are the treatment of choice no matter which strain of infection is present.

Lyme borreliosis is a zoonotic disease (a disease that can be transmitted between animals and people), in this case, transmission is via a tick.

References and Further Reading
Journal of Clinical Microbiology. J. Clin. Microbiol. August 1988 vol. 26 no. 8 1482-1486

Ticks and biting insects infected with the etiologic agent of Lyme disease, Borrelia burgdorferi. L. A. Magnarelli and J. F. Anderson.

Wiener klinische Wochenschrift. September 2006, Volume 118, Issue 17-18, pp 531-537

Clinical appearance of erythema migrans caused by Borrelia afzelii and Borrelia garinii – effect of the patient’s sex. Bennet L et al.

What are the symptoms of Lyme disease?
Evidence suggests that symptoms of Lyme borreliosis can vary depending on which genospecies has caused the infection. Some people will not experience any symptoms at all. In 40-80% (reports vary) of laboratory-confirmed cases in the UK and Ireland, a rash occurs. This rash is termed ‘Erythema Migrans’ (EM), which gradually spreads from the site of the tick bite (primary lesion). The rash is usually over 5 cm in diameter and not painful or itchy, but there are exceptions.

The appearance of EM usually occurs between 2 and 30 days following the infected tick bite. The lesion gradually expands over several weeks and will resolve even without treatment. However, without treatment the patient is at risk of developing disseminated disease and the associated complications of infection with may be serious.

In most patients there is only one episode of Erythema Migrans but for some there may be multiple lesions simultaneously. Multiple lesions can be caused by multiple tick bites, however, in disseminated disease, multiple secondary lesions can occur which are usually smaller in diameter than the primary lesion.

Some people will experience no other symptoms than a rash. Some never present with a rash but will have ‘flu-like’ symptoms such as extreme fatigue, swollen lymph nodes, fever, and joint and muscle aches. They do not usually experience a runny nose or cough as with a head cold. Some will have a rash followed by ‘flu’-like symptoms.

Over the following weeks or months, untreated patients may go on to experience more serious manifestations. These can affect the nervous system (termed neuroborreliosis), joints and sometimes the heart. Facial paralysis, ‘viral-like’ meningitis, encephalitis and carditis can occur. Some patients experience nerve inflammation that can lead to pain, altered or loss of sensation or clumsiness of movement. Some patients experience cognitive dysfunction, such as poor short-term memory and an inability to concentrate. Inflammation of the optic nerve may also occur, causing pain and visual disturbance.

In late disease Lymphocytomas (bluish-red nodular lesions usually appearing on the earlobe or nipple) can occur, as can Acrodermatitis Chronica Atrophicans (ACA), which is a skin manifestation of late disease where areas of tissue become severely inflamed and eventually dies off. For further information, see our section on Lyme disease or our pets section for animal symptoms.

How is Lyme disease diagnosed?
A diagnosis should be made only after careful evaluation of the patient’s clinical history, physical findings and an evaluation of the patient’s tick-exposure risk. The latter is a more complex part of the evaluation as it is common for awareness or recollection of a tick bite to be lacking. Additionally, ticks can be present in more urbanised areas and there tends to be a reliance on the patient having visited a known endemic area for Lyme borreliosis to be considered. A lack of recollection of tick-attachment should not exclude Lyme borreliosis during evaluation.

Laboratory evidence of antibodies is not required for the diagnosis of Erythema Migrans. Laboratory evidence of infection is usually required with other clinical manifestations as many can be ambiguous. The analysis of cerebral spinal fluid for antibodies is generally used for the diagnosis of late neuroborreliosis.

A patient’s GP or specialist can send a blood sample for a screening test at a local hospital. If this test returns a positive or equivocal result, the blood sample is sent to a specialist laboratory for a confirmatory immunoblot (or western blot). The following laboratories perform confirmatory specialist tests for the NHS:

  • The Rare & Imported Pathogens Laboratory at Porton Down
  • The Communicable Disease Surveillance Centre (CDSC), Cardiff
  • The National Lyme Borreliosis Testing Laboratory, Scotland

From September 2013, Dr Matthew Dryden, consultant microbiologist at Winchester’s Royal Hampshire County Hospital (RHCH), England, will head a new National Lyme Disease Clinic. Dr. Dryden has over 20 years experience in treating hundreds of Lyme disease patients. A GP referral is required for appointments at this clinic.

How is Lyme disease treated?
Lyme borreliosis is treated with antibiotics, usually doxycycline or amoxicillin. Early treatment is the ideal as it will help to prevent complications of the disease and permanent tissue damage. If treatment is prescribed soon after the appearance of an Erythema Migrans, it will usually resolve within a few days.

If treatment commences later in the course of the disease, symptoms may be slower to resolve as it takes time for tissues to repair and inflammation to subside. Sometimes permanent tissue damage can occur, which includes damage to nerves. This can result in ongoing problems for some patients which may require ongoing supportive therapy (e.g. pain control).

Neuroborreliosis can require treatment with intravenous antibiotics. For more information, see our section on Lyme disease for treatment in people and Pets for animal treatment.

Is a rash always the first symptom of Lyme disease?
No. A rash associated with Lyme disease, which is called an Erythema Migrans (EM), may appear at any time during early or late disease. A primary lesion may occur at the bite site but secondary lesions (usually smaller than the primary lesion) can occur, often in multiples. A new study entitled ‘Differentiation of Reinfection from Relapse in Recurrent Lyme Disease’ suggests that recurrent EM is as a result of re-infection rather than relapse. However, this was a small study examining only 17 patients. Given the size of the study and the apparent variations in symptom presentation between different genospecies, wider study would be required to draw any firm conclusions.

Some studies have demonstrated that fewer than 50% of infected people develop an EM rash and some genospecies of Borrelia do not appear to present with any skin involvement. Flu-like symptoms and excessive fatigue are often the first noticeable indications of infection. Progression of the illness can lead on to symptoms including cranial-nerve facial palsy, meningitis, heart problems, arthritis and encephalitis (inflammation of the brain), to name but a few. The onset of symptoms and presentation can differ for each individual.

References and Further Reading
The New England Journal of Medicine. N Engl J Med 2012; 367:1883-1890November 15, 2012

Differentiation of Reinfection from Relapse in Recurrent Lyme Disease. Robert B. Nadelman, M.D., Klára Hanincová, Ph.D., Priyanka Mukherjee, B.S., Dionysios Liveris, Ph.D., John Nowakowski, M.D., Donna McKenna, A.N.P., Dustin Brisson, Ph.D., Denise Cooper, B.S., Susan Bittker, M.S., Gul Madison, M.D., Diane Holmgren, R.N., Ira Schwartz, Ph.D., and Gary P. Wormser, M.D.

Infectious Disease Clinics of North America. Volume 22, Issue 2, June 2008, Pages 235–260

Erythema Migrans.Patricia Dandache, MD, Robert B. Nadelman, MD

Does a Lyme disease rash always look like a bull’s-eye?
No. An Erythema Migrans (EM) can be atypical (not like a bull’s-eye).

The classic bull’s-eye rash is so called because it is circular in shape, with a clearing from the centre, like a target or the rings on a dart board. However, EM rashes can vary in shape, colour and size. Evidence suggests that this may be related to the particular genospecies causing the infection. An EM can appear on any location of the body, including the scalp where it may not be observed due to the location or because it is obscured by hair. Multiple rashes may appear in multiple locations in disseminated disease.

Can someone get Lyme disease again after treatment?
Yes. It is possible for someone who has had Lyme borreliosis and recovered to be bitten and infected again. However, a patient may also experience treatment failure if they were treated for an inadequate duration, or with an inadequate dose, or with an inappropriate antibiotic, in which case they will require another course of treatment.

It is possible for a subclinical infection (without apparent symptoms) to become clinical (with symptoms) if the immune system is compromised by another illness or an injury.

Is it only ticks that transmit Lyme disease?
Although Borreliae (the bacteria which cause Lyme disease) are reported to have been sporadically isolated from certain insects (such as mosquitoes and fleas), there is currently no robust scientific evidence to demonstrate that these insects could be effective vectors (creatures which carry and transmit disease) of Lyme borreliosis, and attempts to experimentally infect animals have not been successful. Our section on ‘Disease Transmission‘ explains the mechanism of disease transmission from a tick to its host.

There is also currently no robust scientific evidence to demonstrate that Lyme borreliosis could be transmitted through physical contact between people. Like Lyme borreliosis, Syphilis is a spirochaetal disease. Treponema pallidum, the spirochaete which causes Syphilis, is transmitted through direct contact as the disease causes infectious skin lesions, particularly in the genital area. The Syphilis spirochaetes contained in the moist skin lesions then invade the new host when they make contact with mucous membranes or minute abrasions in the host’s skin. There is currently no scientific evidence, however, to demonstrate that Borrelia burgdorferi can penetrate skin directly or survive on the surface of the skin or in genital mucous membranes.

There have been some studies using artificially inseminated animals with experimentally-infected semen containing a great number of spirochaetes. These studies do not demonstrate that Borrelia burgdorferi can naturally occur in human semen or that they can successfully transmit to another human.

A single study reported detection of the DNA of Borrelia burgdorferi in breast milk using a polymerase chain reaction (PCR) assay. PCR assays detect DNA from dead or living organisms but do not demonstrate the presence of living organisms.

It is recognised that PCR can be prone to false-positive reactions. The general consensus is that PCR is diagnostically useful for the detection of Borrelial DNA in tissue biopsies from Erythema Migrans and Acrodermatitis Chronica Atrophicans, and can be useful in examination of synovial fluid. Borrelial DNA is detectable in cerebral spinal fluid in only 10-30% of patients with proven acute neuroborreliosis. PCR is not recommended for examination of urine.

To date there is no scientific evidence to demonstrate that Lyme borreliosis can be transmitted through breast milk or other body fluids in humans.

It is recognised that untreated Lyme borreliosis during pregnancy may lead to infection of the placenta and possible complications including foetal death. No serious effects on the foetus have been found in cases where the mother receives prompt and appropriate antibiotic treatment (see question 34 for further information on Lyme borreliosis and pregnancy).

More study is needed to establish if there could be other potential modes of transmission.

 References and Further Reading
Journal of Clinical Microbiology. J. Clin. Microbiol. September 1998 vol. 36 no. 9 2658-2665  Diagnostic Value of PCR for Detection of Borrelia burgdorferi in Skin Biopsy and Urine Samples from Patients with Skin Borreliosis. S. Brettschneider, H. Bruckbauer, N. Klugbauer, and H. Hofmann.

Folia Parasitologica. 1998;45(1):67-72 Investigation of haematophagous arthropods for borreliae. Hubálek Z, Halouzka J, Juricová Z.

Journal of Clinical Microbiology. J. Clin. Microbiol. August 1988 vol. 26 no. 8 1482-1486 Ticks and biting insects infected with the etiologic agent of Lyme disease, Borrelia burgdorferi. L. A. Magnarelli and J. F. Anderson.

Journal of Medical Entomology. Volume 28, Number 5, September 1991 , pp. 750-753(4).  Apparent Incompetence of Dermacentor variabilis (Acari: Ixodidae) and Fleas (Insecta: Siphonaptera) as Vectors of Borrelia burgdorferi in an Ixodes dammini Endemic Area of Ontario, Canada. Lindsay, L. Robbin; Barker, Ian K.; Surgeoner, Gordon A.; McEwen, Scott A.; Elliott, Laurie A.; Kolar, Jan.

European Journal of Epidemiology 1996 Feb;12(1):9-11. Unusual Features in the Epidemiology of Lyme Borreliosis. L. Angelov

Zentralbl Bakteriol Mikrobiol Hyg [A]. 1986 Dec;263(1-2):40-4 The Prevalence and Significance of Borrelia Burgdorferi in the Urine of Feral Reservoir Hosts. Bosler and Schulze.

The British Veterinary Journal. 1995 Mar-Apr;151(2):221-4  Viability of Borrelia burgdorferi in Stored Semen. Kumi-Diaka and Harris.

The Journal of Parasitology © 1999 The American Society of Parasitologists Investigation of Venereal, Transplacental, and Contact Transmission of the Lyme Disease Spirochete, Borrelia burgdorferi, in Syrian Hamsters. J. E. Woodrum and J. H. Oliver, Jr.

Journal of Clinical Infectious Diseases. Clin Infect Dis. (1989) 11 (Supplement 6): S1460-S1469. doi: 10.1093/clinids/11.Supplement_6.S1460.  Epidemiology and Clinical Similarities of Human Spirochetal Diseases. George P. Schmid.

American Journal of Tropical Medicine and Hygiene. Am J Trop Med Hyg. 1991 Feb;44(2):135-9.  Relative infectivity of Borrelia burgdorferi in Lewis rats by various routes of inoculation. L. A. Moody KD, Barthold SW.

The Journal of Clinical Investigation. J Clin Invest. 2001 March 15; 107(6): 651–656. doi: 10.1172/JCI12484.   Borrelia burgdorferi and Treponema pallidum: a comparison of functional genomics, environmental adaptations, and pathogenic mechanisms. Stephen F. Porcella and Tom G. Schwan

Diagnostic Microbiology and Infectious Disease. Diagn Microbiol Infect Dis 21: 121-8.  Detection of Borrelia burgdorferi DNA by polymerase chain reaction in the urine and breast milk of patients with Lyme borreliosis. Bruno L. Schmidt, E. Aberer, C. Stockenhuber, H. Klade, F. Breier, A. Luger.

Are the symptoms the same in every Lyme disease patient?
No. Not everyone experiences an Erythema Migrans (the bull’s-eye rash associated with Lyme borreliosis) and there can be variations in the shape colour and size of Erythema Migrans. Other symptoms of Lyme borreliosis can be non-specific and can be confused with the symptoms of other conditions. Some patients may not experience early symptoms while other patient’s symptoms may wax and wane. See questions 18 and 22 for more information about symptoms and the variations in Erythema Migrans.

Some patients experience a worsening of symptoms when antibiotic treatment commences. This is termed a ‘Jarisch-Herxheimer reaction. Please see our section on ‘Lyme disease‘ for further information.

References and Further Reading  Jarisch-Herxheimer (J-H) and Lyme Disease

Does a negative test mean a person does not have Lyme disease?
No. All methods of testing have their limitations and can produce both false-positive and false-negative reactions. Antibodies may not be present for the first few weeks of infection, so a negative test does not exclude Lyme borreliosis. A second sample taken 2-4 weeks later may then go on to show seroconversion (the presence of antibodies where previously there were none). However, early treatment with antibiotics may prevent the development of a detectable antibody response. In late stage disease, patients may be seronegative, although this is considered a rare phenomenon.

False-positive reactions may occur in patients with certain conditions such as glandular fever, syphilis, rheumatoid arthritis, other autoimmune conditions and some neurological conditions. Some people who have previously been exposed to Borrelia burgdorferi may have antibodies which create a positive reaction in testing, even though they do not have a current infection.

Normally in the UK and Ireland a two-tier testing procedure is employed. This involves detecting antibodies to Borrelia burgdorferi in a patient’s blood. The first test (a screening test) is generally the C6 antigen-based enzyme linked immunosorbent assay (ELISA). Blood samples which then produce reactive or equivocal reactions go on to have an immunoblot or Western blot. This is a more sensitive test to detect the presence of antibodies which are specific to Borrelia burgdorferi. The significance of any result, negative or positive, should be interpreted carefully by clinicians in the light of the patient’s clinical presentation and tick exposure risk history. Erythema Migrans should always be treated on clinical suspicion without waiting for test results.

Polymerase chain reaction (PCR) tests are also available for the detection of B. burgdorferi DNA in fluid taken from infected joints and skin or tissue biopsies. Outside of such uses, it is recognised that PCR can be prone to false-positive reactions in the detection of Borrelial DNA.

References and Further Reading
Journal of Clinical Microbiology. J. Clin. Microbiol. September 1998 vol. 36 no. 9 2658-2665 Diagnostic Value of PCR for Detection of Borrelia burgdorferi in Skin Biopsy and Urine Samples from Patients with Skin Borreliosis.S. Brettschneider, H. Bruckbauer, N. Klugbauer, and H. Hofmann.

Is there a vaccine against Lyme disease?
Currently there is no vaccine for humans available in Europe or North America. Research into new vaccines is ongoing but it is unlikely that any vaccines will be available in the near future. The US vaccine LYMErix was launched in 1998 but it was subsequently withdrawn in 2002.In July 2013, a vaccine became available in the UK and Ireland for dogs. Ask your vet for more information.

Can people be infected with other infections at the same time as Lyme disease?
Yes. Multiple infections can be contracted from a single tick bite although recorded cases of multiple tick-borne infections are not common. When other tick-borne infections are contracted at the same time as Lyme borreliosis, this is termed ‘co-infection’. Ticks in the UK can carry a variety of disease-causing organisms concurrently. These include Anaplasma / Ehrlichia species, and Bartonella and Babesia species, as well as the different Borrelia genospecies. Other opportunistic infections may also result from the immune system being depressed by a Borrelial infection.

References and Further Reading
Journal of Clinical Infectious Diseases. 2001, vol33,5, 676-685(118ref.)
Coinfecting deer-associated zoonoses: Lyme disease, babesiosis, and ehrlichiosis.Thompson, Spielman and Krause.

What happens if treatment is delayed while waiting for confirmatory blood tests?
Although all stages of Lyme borreliosis are treatable with antibiotics, it is important that treatment begins as promptly as possible to avoid complications and permanent tissue damage.

In Mandell, Douglas and Bennett’s ‘Principles and Practice of Infectious Diseases’, Alan Steere MD wrote:

“It has been shown that virulent strains of Borrelia burgdorferi are able to resist elimination by phagocytic cells, thereby evading the first line in the host defence system against infection. This assists an infection to disseminate quickly”.

Dr. Steere also wrote:

“Borrelia burgdorferi seems to cross the cell monolayer at intracellular junctions, although it can penetrate through the cytoplasm of a cell. In a rat model, permeability changes in the blood-brain barrier began within 12 hours after inoculation with the spirochete, and the organism may be cultured from the cerebrospinal fluid within 24 hours”.

Although early treatment is the ideal, diagnosis can be difficult in certain cases, such as when the patient does not recall a tick bite, or a rash has not been observed, or the rash was not typical of Erythema Migrans. In such cases, a physician will usually seek laboratory evidence of a Borrelial infection before commencing with any treatment. As the symptoms of Lyme borreliosis can be ambiguous, other potential causes for the patient’s symptoms will need to be explored.

Diagnosis of clinical disease in animals can be equally difficult as erythema migrans are rarely reported and many animals can have antibodies to Lyme disease from previous exposure to ticks.

 References and Further Reading
The epidemiology, prevention, investigation and treatment of Lyme borreliosis in United Kingdom patients: A position statement by the British Infection Association

Is a full recovery certain?
No. The length of time a person has been infected before treatment, whether co-infections are present and whether the patient was treated promptly and correctly, can all have an impact on a patient’s recovery and whether permanent tissue damage occurs or not.

Some patients experience persistent subjective symptoms (such as fatigue, joint and muscle aches, pain and/or tingling, poor sleep, mood changes and memory or concentration loss) following treatment. In such cases, the patient should be carefully evaluated for clinical and laboratory evidence of ongoing Borrelial infection, and their treatment history reviewed as it may have been inappropriate or inadequate and re-treatment may be necessary.

Where there is no evidence of ongoing infection, and symptoms have continued for a short duration following treatment (under six months), it is generally considered that the patient is suffering from ‘Post-Lyme Symptoms’ and that, in time, these symptoms will subside as the body repairs itself. However, patients who (prior to appropriate treatment) had a long-standing infection, or severe presentations in acute illness, may have suffered permanent tissue damage. In such cases the patient may require rehabilitation and supportive treatment (e.g. pain control medication) for symptom relief.

In patients where symptoms have persisted for a longer duration following treatment (over six months), it is generally considered that the patient has Post-Lyme Disease Syndrome (PLDS). Again, this is more likely to occur in patients who (prior to appropriate treatment) had a long-standing infection or severe presentations in acute illness. In such cases the patient may require rehabilitation and ongoing supportive treatment (e.g. pain control medication) for symptom relief.

Some patients may be diagnosed with ‘Chronic Lyme disease’. However, this is a poorly-defined term and has been applied to a wide range of patients from those who are previously untreated with late manifestations of Lyme borreliosis (such as ACA or Neuroborreliosis), to those who have subjective symptoms without any evidence of active Borrelial infection, or those with neither evidence of active or past Borrelial infection.

Studies of prolonged antimicrobial treatments of patients with PLDS have not demonstrated sustained benefit from such treatments.

References and Further Reading

Clinical Microbiology & Infection. 2011 Jan;17(1):69-79.  Lyme borreliosis: Clinical case definitions for diagnosis and management in Europe. Stanek G, Fingerle V, Hunfeld KP, Jaulhac B, Kaiser R, Krause A, Kristoferitsch W, O’Connell S, Ornstein K, Strle F, Gray J.

European Federation of neurological societies guidelines on the diagnosis and management of European Lyme neuroborreliosis. Eur J Neurol 2010;17:8e16. Mygland A, Ljostad U, Fingerle V, Rupprecht T, Schmutzhard E, Steiner I.

The American Journal of Medicine. Am J Med 2010;123(1):79e86.  Subjective symptoms after treatment of early Lyme disease. Cerar D, Cerar T, Ruzic-Sabljic E, Wormser GP, Strle F.

The Pediatric Infectious Disease Journal. 2008 Dec;27(12):1089-94.  Lyme neuroborreliosis in children: a prospective study of clinical features, prognosis and outcome. Skogman BH, Croner S, Nordwall M, Eknefelt M, Ernerudh J, Forsberg P.

The New England Journal of Medicine. 2007;357:1422e30.  A critical appraisal of chronic Lyme disease. Henry M. Feder, Jr., M.D., Barbara J.B. Johnson, Ph.D., Susan O’Connell, M.D., Eugene D. Shapiro, M.D., Allen C. Steere, M.D., Gary P. Wormser, M.D.

Infectious Disease Clinics of North America. 2008;22(2):341e60.   Chronic Lyme disease: a review. Marques A.

International Journal of Epidemiology. 2005;34:1340–1345.  Post-Lyme borreliosis syndrome: a meta-analysis of reported symptoms. Victoria Cairns and Jon Godwin

Are cases of Lyme disease recorded?

How accurate is the recording of Lyme disease cases?

Should Lyme disease victims donate blood?

What if I am or become pregnant?