Director, Danish Centre for Experimental Parasitology. (2000-2003)
- Adjunct Professor, Royal Veterinary and Agricultural University, Denmark
- Senior Scientist, WHO/FAO Collaborating Centre for Emerging Parsitic Zoonoses, Danish Centre for Experimental Parasitology
- Consultant, Foodborne Parasitic Zoonoses Campaign, Rockville , Maryland
Prior to July 2000, Murrell was Deputy Administrator of the Agricultural Research Service (ARS), the U.S. Department of Agriculture's chief scientific research arm, in 1997. Murrell's appointment placed him in charge of directing ARS' National Program Staff (NPS) in Beltsville, Maryland.
Murrell first joined ARS in 1978 as chief of the Helminthic Diseases Laboratory. His research has been primarily on protecting animals and humans from infection by parasites that cause foodborne diseases. Murrell's studies sought to preempt infection and the onset of disease by understanding parasite epidemiology and host immunology. He has published over 270 papers, reviews, and book chapters. The majority of his publications deal with parasitic zoonoses, especially meat-borne helminths.
Currently, Murrell is leading grant-funded research projects in India on neurocysticercosis, and in Vietnam on fishborne parasitic zoonoses. He is also developing new guidelines for FAO and WHO on Taeniasis/Cysticercosis, and on Trichinellosis; publication expected in 2004.
Murrell is past-president of the American Society of Parasitologists, the American Association of Veterinary Parasitologists (AAVP), and the International Trichinellosis Commission. In 1984, Murrell was named ARS Outstanding Scientist of the Year, and, in 1988, he won the AAVP Distinguished Parasitologist Award. Murrell received a Fulbright Award in 1996. In 1997, he received the prestigious Presidential Distinguished Federal Executive Rank Award. He was inducted into the USDA-ARS Science Hall of Fame in 2002.