Abstract
1 Central Animal Laboratory, University of Nijmegen, 6500 HB Nijmegen
2 Department of Microbiology, Wageningen Agricultural University, 6703 CT Wageningen
3 The Netherlands; Tech Lab, Inc., Blacksburg, Virginia 24060
4 Centre for Molecular Medicine and Infectious Diseases, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
5 Protozoan Diseases Laboratory, U.S. Department of Agriculture Livestock and Poultry Sciences Institute, BARC-East, Beltsville, Maryland 20705
6 Department of Microbiology, Institute of Food Research, Reading Laboratory, Reading RG6 2EF, United Kingdom