Affiliation: | (1) College of Veterinary Medicine, University of Maryland, 20742 College Park, Maryland, USA;(2) The Maryland Agricultural Experiment Station, University of Maryland, 20742 College Park, Maryland, USA;(3) Agricultural Research Service, Helminthic Diseases Laboratory, US Department of Agriculture, 20705 Beltsville, Maryland, USA;(4) Present address: Department of Toxicology and Pathology, Hoffman-La Roche, 340 Kingsland Street, 07110 Nutley, New Jersey, USA |