1. Department of Animal Supply, National Institute of Public Health and Environmental Hygiene, PO Box 1, 3720 BA Bilthoven, The Netherlands; Laboratory for Parasitology and Mycology, National Institute of Public Health and Environmental Hygiene, PO
Box 1, 3720 BA Bilthoven, The Netherlands
2. Laboratory for Parasitology and Mycology, National Institute of Public Health and Environmental Hygiene, PO Box 1,3720 BA Bilthoven, The Netherlands
3. Department of Animal Supply, National Institute of Public Health and Environmental Hygiene, PO Box 1, 3720 BA Bilthoven, The Netherlands
4. Laboratory for Pathology, National Institute of Public Health and Environmental Hygiene, PO Box 1, 3720 BA Bilthoven, The Netherlands