Dr. Paul McKeown:

I am from the Health Protection Surveillance Centre. I am a consultant in public health medicine. In addition to concurring with Professor Butler, I would like to add some background information that might be useful. In the United Kingdom and Ireland, serosurveys have been undertaken over the years. In other words, blood has been taken from large groups of people and tested for the presence of past exposure to the borrelia bug, which we will call Lyme borreliosis. The testers have generally done this by using blood donor blood. There is a pool of blood taken from thousands of people that is tested for the presence or absence of Lyme disease. The first of the tests was undertaken in the New Forest in Hampshire. The New Forest is a well-known area that generates a lot of Lyme cases each year. It was found that the background positivity rate - in other words, the proportion of people in the New Forest area - was approximately 22%. The blood of approximately 600 subjects was tested. Therefore, something shy of one person in four had a positive blood test. I actually worked in the hospital that undertook the study. The consultant there was very used to harking back to us. We, a group of doctors, came in together and we were immediately enrolled in a study. I had a blood sample taken and I was positive for Lyme disease. The consultant said I had got it from the New Forest but since I had started work in the hospital only on the previous Monday, I believe I did not get it there. I was almost certainly bitten by a tick on one of many happy holidays as a child in Achill.

During Professor Butler's introduction, she made the very important point that the diagnosis will be based upon clinical features and the presence of a positive blood test. Irish figures suggest that, around Portumna, 8% to 10% of the background population have a positive Lyme test. In other parts of the west, the proportion is much lower. This shows it is a very localised phenomenon. We know the area where one is most likely to come into contact with and be infected by ticks is publicly accessible parkland. Around the west and south of Ireland, there are a number of areas that have concentrations of ticks that are infected. When somebody goes for a Lyme blood test or any other type of test, it is important to ensure the results are taken in conjunction with the clinical picture of what he or she is exhibiting. A positive test on its own can be misleading.