Trends in incidence of tick bites and physician-reported early and late Lyme borreliosis in the Netherlands.

Lyme borreliosis (LB) is a prevalent vector-borne disease in Europe. Untreated, it can cause severe complications, with some patients experiencing persistent symptoms post-treatment. In the Netherlands, tick bite consultations and erythema migrans (EM) diagnoses tripled from 1994 to 2009, but tick bite consultations declined and EM diagnoses stabilized in 2014. This study examines trends in tick bite consultations, EM diagnoses, and other LB manifestations in the Netherlands from 2014 onward. In 2017 and 2021, questionnaires were sent to Dutch GPs to collect data on tick bite consultations and EM diagnoses. The 2021 survey additionally addressed disseminated LB and persistent symptoms attributed to LB. Data were analyzed using a negative binomial distribution, with bootstrapping applied to account for uncertainty. The population coverage was 51 % in 2017 and 32 % in 2021. The incidence of tick bite consultations per 100,000 was 534 (518-551) in 2017 and 447 (426-470) in 2021. The incidence of EM diagnoses per 100,000 was 150 (145-155) in 2017 and 147 (140-154) in 2021. In 2021, the incidence was 5.0 (4.2-5.9) per 100,000 for disseminated LB and 5.0 (4.4-5.5) per 100,000 for persisting symptoms attributed to LB. Compared to 2014, GP consultations for tick bites and EM diagnoses had increased in 2017. In 2021, tick bite consultations were lower than in 2017, likely due to COVID-19 restrictions. EM diagnoses were similar to 2017. Disseminated LB was lower in 2021 compared to 2010, whilst persisting symptoms attributed to LB remained stable.