[1] Statens Serum Inst, Parasitol Lab, Dept Bacteriol Mycol & Parasitol, DK-2300 Copenhagen S, Denmark
[2] Univ Copenhagen, Fac Life Sci, Dept Vet Dis Biol, Frederiksberg, Denmark
[3] Univ Copenhagen, Fac Life Sci, Dept Agr & Ecol, Frederiksberg, Denmark
[4] Aarhus Univ Hosp, Dept Infect Dis, DK-8000 Aarhus, Denmark