Lyme disease bacteria detected in ticks across Luxembourg

• Clinical and Applied Virology
• Department of Infection and Immunity
• OH4Surveillance

Ticks are vectors of pathogens that cause diseases in humans and animals across Europe. However, the prevalence and diversity of these pathogens in Luxembourg remain understudied. In 2025, the Clinical and Applied Virology team at LIH collected approximately 4,500 ticks across Luxembourg and characterized their seasonal activity and geographic distribution.
Molecular analyses showed that approximately 17% of these ticks were infected with Borrelia burgdorferi sensu lato, a complex of bacterial species that includes the causative agents of Lyme disease. Molecular characterization identified five genospecies: B. afzelii, B. garinii, B. valaisiana, B. burgdorferi sensu stricto, and B. spielmanii. These genospecies are maintained in nature by different groups of vertebrate hosts, including rodents, birds, and hedgehogs, and vary in their ability to cause disease in humans. All except B. valaisiana have been confirmed to cause Lyme disease in humans, although symptoms may vary. For example, B. afzelii and B. garinii, the two most prevalent genospecies, are associated with different clinical manifestations of Lyme disease. Borrelia afzelii is more commonly linked to cutaneous manifestations, whereas B. garinii is frequently associated with neurological disease (https://doi.org/10.1128/JCM.39.4.1294-1298.2001).
Lyme disease typically develops within 30 days of infection and presents with flu-like symptoms and, in many cases, erythema migrans, a characteristic expanding red rash that often forms a bull’s-eye pattern around the tick bite. If left untreated, the infection can progress to disseminated disease, affecting the musculoskeletal, nervous, and cardiovascular systems (https://doi.org/10.3390/pathogens15030327).
Our findings highlight the diversity of Lyme disease-causing bacteria present in Luxembourg. The collected ticks were screened for additional bacterial, parasitic, and viral pathogens to provide a more comprehensive assessment of tick-borne disease risks in the country (News “No tick borne encephalitis virus detected in about 4500 ticks from all over luxembourg).

Disclaimer
This activity was supported by co-funding from the European Union’s EU4Health programme under Grant Agreement Nr 101132473 OH4Surveillance.
Views and opinions expressed do not necessarily reflect those of the European Union or HaDEA. Neither the European Union nor the granting authority can be held responsible for them.