The Study

a group of 7 persons who participated in a hare hunt in North Rhine-Westphalia, Germany, acquired tularemia. Two F. tularensis subsp. holarctica isolates were cultivated from human and hare biopsy material. Both iso-lates belonged to the FTN002–00 genetic subclade (derived for single nucleotide polymorphisms B.10 and B.18), thus indicating likely hare-to-human transmission. Tularemia is a zoonotic disease caused by the gram-neg-ative bacterium Francisella tularensis (1). Currently, there are 4 validly published subspecies. F. tularensis subsp. tularensis is the most virulent subspecies and occurs only in North America. F. tularensis subsp. holarctica is less virulent and occurs throughout the Northern hemisphere. F. tularensis subsp. mediasiatica was isolated in central Asia, and F. tularensis subsp. novicida, which has low virulence in humans, seems to be distributed globally (2). Various PCR-based assays have been established for the detection of F. tularensis or for the diagnosis of tulare-mia. An accurate population structure has been defined by using single nucleotide polymorphisms (SNPs) and inser-tion/deletion mutations (INDELs) with potential canonical properties. Currently, this population is divided into 4 major genetic clades: B.4, B.6, B.12, and B.16 (3–6). The taxo-nomic nomenclature of major clades in F. tularensis subsp. holarctica is based on clade-specific canonical SNP markers (3,4). In Europe, the strains of clades B.12 and B.6 dominate (6). The latter is found particularly in large areas in northern, western, and central Europe, including Germany (5–9)