July 13, 2024

I, Science

The science magazine of Imperial College

Andrew Purcell

One of the IPCC’s key predictions for climate change in Europe is that we will experience, on average, milder winters. One of the problems warmer winters could cause is a significant rise in tick population numbers. Whilst this isn’t a problem we tend to hear too much about here in the UK, the prospect of rising tick numbers has got a lot of people in mainland Europe worried – and understandably so. Ticks are a major cause of several diseases and in many areas of Europe, vaccinations are recommended to help reduce the risk of contacting some of these rather nasty diseases. Three of the most common diseases carried by ticks include:


– Lyme disease or Lyme borreliosis is caused by bacteria called Borrelia. Early symptoms can develop within weeks. They may include tiredness, chills, fever, headache, muscle and/or joint pain, swollen lymph glands and blurred vision. A characteristic skin rash called erythema migrans may appear. It is generally a circular rash that may clear in the centre, resulting in a “Bull’s eye” appearance. It can expand and move around the body.

If early symptoms are not recognised, serious complications can develop weeks, months, or even years later. Later stage symptoms include arthritis in the large joints, which can recur over many years. Nervous system problems are common, e.g. numbness, meningitis (with fever, stiff neck and severe headache), Bell’s palsy (paralysis of the facial muscles) and memory problems. Some people experience irregularities of the heart rhythm.

Lyme disease should be diagnosed by a physical examination and medical history. This clinical diagnosis may in some cases be supported by laboratory testing. Diagnosis based on tests alone is not reliable – a negative result does not mean that the disease is not present. Symptoms can mimic those of other diseases. Diagnosis is easiest when there is a skin rash but this occurs in under 50% of patients.


– Babesiosis is caused by the Babesia parasite, an organism similar to that causing malaria. This attacks the red blood cells and its existence can only be shown by laboratory identification of the parasite. Symptoms, if any, begin with tiredness, loss of appetite and a general ill feeling. In severe cases, as the infection progresses, fever, drenching sweats, muscle aches and headache can follow, leading to complications such as very low blood pressure, liver problems, severe haemolytic anaemia (a breakdown of red blood cells) and kidney failure. Other cases usually have a milder illness and often get better on their own. The symptoms can take from 1 to 12 months after the tick bite to appear and can last from several days to several months.


– Ehrlichiosis is a bacterial attack upon the white blood cells. Symptoms usually appear 3 to 16 days after a tick bite. The most common symptoms are sudden high fever, tiredness, major muscle aches, severe headache, and, in some cases, a rash. Diagnosis is difficult, even in severe cases. Diagnostic tests are not widely available and the diagnosis of Ehrlichiosis is usually based on symptoms and a history of exposure to ticks. Severely ill patients can develop abnormally low numbers of white blood cells or platelets and kidney failure.

(Source: http://www.lymediseaseaction.org.uk/ticks)



In the UK, there is a major lack of knowledge concerning the dangers of tick bites. This knowledge gap also often extends to GPs and as such diseases contracted from tick bites can often remain undiagnosed. Thus, it is vitally important that people take the time to inform themselves about the dangers exposures to ticks can bring, particularly when travelling to high risk areas in continental Europe, such as those shown on the map below:




You may have missed it, but two weeks ago was National Tick Bite Prevention Week. You can visit the website for this here.

Also, for advice on the best methods of tick removal, please visit the BADA website here.