Lyme borreliosis in Portugal caused by Borrelia lusitaniae? Clinical report on the first patient with a positive skin isolate.

Background: Borrelia lusitaniae was isolated from an Ixodes ricinus tick in Portugal in 1993 for the first time. Further, this borrelia genospecies has been found in ixodid ticks collected around the coasts of southern Portugal and North Africa. Its reservoir has not been defined yet. B. lusitaniae was isolated once until now from a patient with a long standing and expanding skin disorder.

Patient And Methods: A 46-year-old Portuguese woman presented with a skin lesion on the left thigh which had evolved slowly over ten years. The patient reported limb paraesthesias, cramps, chronic headaches, and cardiac rhythm disturbances. History of tick bites was negative nor had the patient ever noticed a skin lesion comparable with erythema chronicum migrans. Skin biopsies were taken for histological evaluation, culture and DNA detection. Antibodies to borrelia were searched by indirect immunofluorescence assay and Western-blot.

Results: A bilateral carpal tunnel syndrome and local synovitis was diagnosed. Dermato-histology was normal, serology was negative. Spirochaetal organisms were cultured from a skin biopsy and identified as B. lusitaniae. The patient improved after a 2-week course of intravenous ceftriaxone; the skin lesions did not expand further.

Conclusions: This culture confirmed skin infection by B. lusitaniae in a patient from Portugal suggests an additional human pathogen out of the B. burgdorferi sensu lato complex in Europe, particularly in Portugal.