Diseases
and Symptoms in People:
Lyme
disease
Probably the most recognised tick-borne disease in the UK is 'Lyme disease'. It
is just one of several diseases present in the UK. Lyme disease gets its name
after a cluster of cases that were discovered in Old Lyme, Connecticut, in the
US. It is caused by a spirochaetal bacterium called 'Borrelia burgdorferi' but
there are hundreds of differing strains and sub-types which result in varying
symptoms. These can range from more dermatological and rheumatological symptoms,
to more serious neurological manifestations.
Borreliosis (as the disease is more correctly termed to cover the differing
strains) can be extremely debilitating. European strains generally have more
neurological complications, presenting as 'viral-like' meningitis,
encephalopathy, facial palsy, peripheral neuropathy and other nerve
inflammation. This can lead to pain, altered or loss of sensation, and loss of
co-ordination. In severe cases paralysis may occur.
Often a target-shaped expanding rash (called an 'Erythema Migrans' or' EM rash')
is associated with Lyme disease. However, different strains can produce rash
variations, and some patients never present with one. Rashes can also be hidden
under hair, or in inaccessible places. This can make diagnosis difficult because
the only indication of infection may be flu-like malaise. An EM rash can also
resemble other dermatological conditions, such as ringworm, cellulites or an
allergic reaction, and misdiagnosis can occur as a result.
Borrelia bacteria are related to the syphilis spirochaete but are more complex.
They are pleomorphic (meaning they can change their physical form). This aids
them to evade the body's immune system and can make indirect methods of
detection (such as serologic testing) difficult.
A cocktail of infection
In addition to Borreliosis, ticks can carry a cocktail of bacterial, viral,
rickettsial and protozoal diseases concurrently. Anaplasmosis (a rickettsial
disease) is the most common co-infection. Multiple infections can complicate
both diagnosis and treatment.
A threat to travellers abroad
Tick-borne diseases occur worldwide but, for the European traveller, Tick-borne
encephalitis (TBE) is probably the greatest concern. This Flavivirus has spread
from central to north-west Europe. It is closely related to Russian
spring-summer encephalitis (RSSE) and Louping-ill (which is generally recognised
as a disease of sheep in the UK but can affect other animals and people). TBE
can cause serious inflammation of the brain and spinal cord which, in some
cases, can be fatal.
As of mid 2006, no TBE cases have been reported to the UK's Health Protection
Agency (HPA), although it is possible that some cases have occurred but not been
reported or recognised.
The TBE group of viruses are the only tick-borne diseases for which there are
vaccines. The vaccines are available from GP surgeries, health centres and MASTA
clinics. As there are currently no vaccines against other types of tick-borne
disease, the only defence against infection is knowledge about ticks and how to
remove them.
Diagnosis
Early diagnosis and
treatment of a tick-borne infection can help to prevent potentially serious
complications, such as cardiac damage, meningitis-type syndromes and even
paralysis.
Rashes
Be particularly aware of patients presenting with an expanding red rash (which
may be surrounding a possible bite wound), as this could be an Erythema Migrans
(EM) or 'bull's-eye rash', which is one of the early signs of Borreliosis (Lyme
disease). However, an EM may be atypical, or it may be hidden or absent.
Early onset
Be aware of patients presenting with flu-like symptoms (fever, swollen lymph
nodes, headache, stiff neck, general aches and pains) during late spring through
to autumn. These symptoms combined with an obvious bite wound, or known tick
bite, or rash, warrant immediate medical assessment.
Correct tick removal
Correct tick removal is essential in helping to avoid disease transmission.
Removal should take place at the earliest opportunity as the longer the tick
remains attached the greater the chance of transmission. Recent studies indicate
that transmission can occur in less than 12 hours of the tick attaching.
Tick removal should be performed with a bespoke tool (O'Tom hooks were favoured
in a comparison study1), or with fine-tipped tweezers used in an upward,
levering motion (do not twist when using tweezers).
Applying solutions to an attached tick, or burning, freezing, crushing or
scratching it off, can result in it regurgitating or spilling its stomach
contents, which may contain infective organisms.
Never handle a tick with bare hands as some infective agents can enter breaks in
the skin or the mucous membranes (touching eyes, nostrils or mouth).
For further information, please visit www.bada-uk.org
Produced by Borreliosis & Associated Diseases Awareness-UK (BADA-UK).
Registered Charity No. 1113329
1. Reference: Zenner L, Drevon-Gaillot E, Callait-Cardinal MP. Evaluation of
four manual tick-removal devices for dogs and cats. Vet Rec 2006; 159:
526–529.
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