[1] Univ Uppsala Hosp, Dept Med Sci, Infect Dis Sect, S-75185 Uppsala, Sweden
[2] Univ Kalmar, Kalmar Cty Hosp, Dept Clin Microbiol, Kalmar, Sweden
[3] Univ Kalmar, Dept Biol & Environm Sci, Kalmar, Sweden
[4] Lund Univ, Dept Anim Ecol, S-22362 Lund, Sweden
[5] Umea Univ, Swedish Def Res Agcy, FOI, Umea, Sweden
[6] Umea Univ, Dept Infect Dis, Umea, Sweden