Making a distinction between facial palsy due to Lyme neuroborreliosis (LNB) and idiopathic facial palsy (IFP) is of importance to ensure timely and adequate treatment. The study objective was to assess incidence and patient characteristics of facial palsy due to LNB. Hospital records were reviewed of adult patients with facial palsy visiting the departments of neurology and/or otorhinolaryngology of Gelre hospitals between June 2007 and December 2017. Gelre hospitals are located in an area endemic for Lyme borreliosis. Patients with LNB had pleocytosis and intrathecal antibody production or pleocytosis with positive IgG serology. Patients with IFP had negative serology. Clinical characteristics were compared between patients with LNB and patients with IFP. Five hundred and fifty-nine patients presented with facial palsy, 4.7% (26) had LNB and 39.4% (220) IFP. The incidence of facial palsy due to LNB was 0.9/100 000 inhabitants/year. Over 70% of patients with facial palsy due to LNB did not report a recent tick bite and/or erythema migrans (EM). Patients with facial palsy due to LNB presented more often in July to September (69.2% vs. 21.9%, P < 0.001), and had more often headache (42.3% vs. 15.5%, P < 0.01). To reduce the risk of underdiagnosing LNB in an endemic area, we recommend testing for LNB in patients with facial palsy in summer months especially when presenting with headache, irrespective of a recent tick bite and/or EM.

Bird-specific ticks do not infest humans and livestock, but these ticks often share their avian hosts with generalist ticks that do. Therefore, their feeding activity may have an impact on the transmission of pathogens outside bird–tick transmission cycles. Here we examined the seasonal feeding activity of the tree-hole tick (Ixodes arboricola) in relation to the activity of its hole-breeding hosts (Parus major and Cyanistes caeruleus). We analysed data on ticks derived from birds, on the abundance of engorged ticks inside nest boxes, and on bird nests that were experimentally exposed to ticks. We observed a non-random pattern of feeding associated with the tick instar and host age. The majority of adult ticks fed on nestlings, while nymphs and larvae fed on both free-flying birds and nestlings. Due to their fast development, some ticks were able to feed twice within the same breeding season. The highest infestation rates in free-flying birds were found during the pre-breeding period and during autumn and winter when birds roost inside cavities. Except during winter, feeding of I. arboricola overlapped in time with the generalist Ixodes ricinus, implying that tick-borne microorganisms that are maintained by I. arboricola and birds could be bridged by I. ricinus to other hosts.