Surveillance and epidemiology of Lyme borreliosis in the Czech Republic in 2018 and 2019

Lyme borreliosis (LB), the most prevalent vector-borne disease in Europe, is caused by Borrelia burgdorferi sensu lato complex species and transmitted by the tick Ixodes ricinus. The Czech Republic is an endemic country for LB. The disease affects the skin, neurological, musculoskeletal, cardiac or ocular tissue, and the most frequent clinical manifestations are erythema migrans and Lyme neuroborreliosis. In 2018, the EU case definition of Lyme neuroborreliosis was published, and neuroborreliosis has become reportable to the European Surveillance System. In this paper, we describe the LB surveillance system and reporting of human cases in the Czech Republic. Epidemiological characteristics of Lyme borreliosis are presented for 2018 and 2019. Gaps in and limitations of the existing national LB surveillance system were identified with regard to the reporting of neuroborreliosis in accordance with the EU case definition. In the Czech Republic, LB surveillance is nationwide, comprehensive, and mandatory. Case based data on all clinical manifestations of incident LB are reported to the electronic Information System of Infectious Diseases (ISIN). In 2018 and 2019, 4724 and 4102 LB cases, i.e., 44.5 and 38.4 cases per 100,000 population, were reported to ISIN, respectively. Overall, 46.3 % of cases were male and 53.7 % were female. The highest morbidity was observed in adults 50–75 and children 5–9 years old. The most affected regions were Vysočina and Olomoucký. Nine districts recorded more than 100 cases per 100,000 population. Erythema migrans appeared in 3173 (67.2 %) and 2756 (67.2 %) patients in 2018 and 2019, respectively. In 2018, 596 (12.6 %) Lyme neuroborreliosis cases were diagnosed only on the basis of clinical manifestations while in 2019, a total of 567 (13.8 %) cases of neuroborreliosis fully meeting the EU case definition were reported. The Czech Republic is an endemic country for LB with some hotspots, similar to some central, northern and north-eastern European countries. To implement the EU neuroborreliosis surveillance in the Czech Republic, ISIN technical update, addition of required variables to it, preparation of legislation update, and training of health professionals were needed.