Mary E. Wilson, MD reviewing Pritt BS et al. Lancet Infect Dis 2016 Feb 5. Wilhelmsson P and Lindgren PE. Lancet Infect Dis 2016 Feb 5.

Clinical features appear to differ from those of known U.S.-based Lyme disease.

Of the many genospecies of Borrelia burgdorferi that cause Lyme borreliosis, only B. burgdorferi sensu stricto had been known in the U.S. Mayo Clinic investigators now describe a new genospecies in the upper Midwest.

Among >100,000 routine clinical specimens submitted from 2003 to 2014, polymerase-chain-reaction targeting of the oppA1 gene of B. burgdorferi sensu lato identified 6 specimens (5 blood and 1 synovial fluid, collected after 2011) that had a melting temperature outside the expected range. The patients (aged 10–67 years) with atypical specimens had fever (5 patients), diffuse or focal rash (4), neurological findings such as confused speech or visual difficulties (3), and knee pain and swelling (1); two patients were hospitalized.

Motile spirochetes in the blood were cultured; high-titer spirochetemia was documented. Multigene sequence analysis (from blood isolates) identified the organism as a novel B. burgdorferi sensu lato genospecies — candidatus B. mayonii.

All six patients had exposure to tick habitats; two recalled tick bites <30 days before illness onset. All six were treated with antibiotics and recovered, although one reported persistent fatigue. Of 658 Ixodes scapularis ticks tested, 19 (3%) were positive for B. mayonii, 195 (30%) for B. burgdorferi sensu stricto, and 2 ticks for both.

Citation(s):

Pritt BS et al. Identification of a novel pathogenic Borrelia species causing Lyme borreliosis with unusually high spirochaetaemia: A descriptive study. Lancet Infect Dis 2016 Feb 5; [e-pub].

Wilhelmsson P and Lindgren PE.Detection of a novel Lyme borreliosis pathogen. Lancet Infect Dis 2016 Feb 5; [e-pub]. 

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