Lyme disease in Northern Ireland – a look back on serological testing

Lyme disease is an illness caused by the spirochete Borrrelia burgdoferi. NICE guidance suggests an approach to diagnosis resting on clinical presentation, presence in an epidemiologically plausible area, and positive serology. It is however, well documented that serological diagnostics in European Lyme disease is problematic. There is a movement for Lyme advocacy, a voice that emphasises the poor diagnostics in this infection. With the spotlight on Lyme disease, we are increasingly seeing patients presenting in Northern Ireland across a broad range of specialities. Currently there is minimal data looking at the local epidemiology of Lyme disease. We present previously unpublished data looking at the demographics of those testing positive for Borrelia burgdoferi antibodies.

We collected data from all patients tested for Lyme disease in Northern Ireland from 2013–2018. We excluded negative results. A randomised selection of 300 cases were chosen. We recorded patient age, gender, origins of testing, home postcode, tick bite history, relevant travel history, duration of symptoms, timings of testing, antibody results including confirmatory testing and treatment.

Of the 300 selected patients 241 (80 %) were IgM positive and 83 (30 %) IgG positive using DiaSorin, Liason CLIA. The average age of presentation was 39 years old. There was a predominance of females tested (62%). 32 % of tests originated in primary care. Of the IgM positives only 41 (17 %) were confirmed by C6 peptide or lineblot in the reference laboratory (RIPL, Porton Down). The results highlight the likely low seroprevalence of Lyme disease in Northern Ireland.