Affiliation: | a Danish Centre for Experimental Parasitology, Department of Veterinary Microbiology, Royal Veterinary and Agricultural University, 13 Bülowsvej, DK-1870, Frederiksberg C, Denmark b Microbiology Section, Department of Ecology and Molecular Biology, Royal Veterinary and Agricultural University, 21 Rolighedsvej, DK-1958, Frederiksberg C, Denmark c Section of Zoology, Department of Ecology and Molecular Biology, Royal Veterinary and Agricultural University, 13 Bülowsvej, DK-1870, Frederiksberg C, Denmark d National Veterinary Laboratory, 27 Bülowsvej, DK-1790, Copenhagen V, Denmark |