PATHOGEN DETECTION AND INTERVENTION METHODS FOR SHELLFISH
Location: Food Safety and Intervention Technologies
Title: In memoriam Dean Otis Cliver 1935-2011
Submitted to: Food and Environmental Virology
Publication Type: Other
Publication Acceptance Date: July 2, 2011
Publication Date: July 29, 2011
Citation: Richards, G.P. 2011. In memoriam Dean Otis Cliver 1935-2011. Food and Environmental Virology. 3(3):99-108. DOI: 10.1007/s12560-011-9064-7.
Dr. Dean O. Cliver, internationally recognized food and environmental virologist, died on May 16, 2011 at his home in Davis, California, after an intense but gallant battle with cancer. He is survived by his wife of 50 years, Carolyn Elaine Cliver, children and grandchildren. Dean was born March 2, 1935 and raised in Berwyn, Illinois, a suburb of Chicago. Summertime exposure to dairy farms in Wisconsin led him to obtain a BS in 1956 and a MS in 1957 in Dairy Husbandry from Purdue University. In 1958, Dean entered the doctoral program in Dairy Science at Ohio State University, where he began his research career with enteric viruses in the School of Veterinary Medicine. His pioneering efforts to propagate viruses led to the development of tissue and cell culture systems as well as early plaque assay procedures. He received his PhD in 1960 and remained at Ohio State to further pursue his research. In 1961, Dean joined the U.S. Army Biological Laboratories at Fort Detrick, Maryland, where he learned how to handle highly pathogenic agents. His research focused on Semliki Forest virus grown in chicken embryo fibroblasts. In 1962 he became a Research Associate and instructor at the Food Research Institute (FRI) at the University of Chicago, where he continued his research on the development of primary and secondary cell cultures and the propagation of viruses including poliovirus and reovirus type 3. He also studied irradiation as a potential intervention against viruses in food and water.
In 1966, Dean was offered a position at the University of Wisconsin at Madison, where he remained until 1995, moving up the ranks from Research Associate, to Assistant and Associate Professor, to Professor in 1976, and Professor Emeritus in 1995. During Dean’s tenure at the University, he continued working on the development of cell culture systems. He developed fluorescent microscopic techniques to identify reovirus type 3 in infected cells and built a solid foundation for the extraction and concentration of many types of viruses. His work covered a gamut of novel projects including the use of ultracentrifugation and dialysis with polyethylene glycol to concentrate viruses. He developed methods to filter out and elute viruses from filters of various compositions, which led to the virus adsorption-elution method, later popularized as the viradel method. He conducted research to look at irradiation as a method to inactivate viruses in shellfish and discovered the use of Cat-Floc, a polyelectrolyte sewage flocculent, as a useful reagent to extract viruses from wastewater and shellfish tissues. He also identified Freon TF as an excellent reagent to eliminate lipids from virus-containing food extracts. Some of Dean’s research on virus extraction from foods was funded by the U.S. Air Force School of Aerospace Medicine and later by NASA for application in the U.S. space program. Studies were designed to determine the possible presence of a host of viruses in potential foods for astronauts and in their drinking water. He evaluated NASA’s electrolytic silver-ion generator for water decontamination and determined that influenza type A and several enteroviruses were more resistant to the silver ions than other viruses. Environmental studies evolved to include research on wastewater treatment and the transport of contaminants through the soil, the accumulation and persistence of viruses in sewage sludge, the ability of ultraviolet light to inactivate viruses in treated effluent, mechanisms of degradation of viruses through enzymatic or biological processes, and the effectiveness of chlorine dioxide as a disinfectant. Dean acquired basic information on the effects of pH, temperature, and salts on the stability of enteroviruses.
In 1995, Dean retired from the University of Wisconsin, Madison, but maintained Professor Emeritus status. He became the Professor of Food Safety at the University of California at Davis. His research there led to the development of an immunomagnetic capture method for detecting hepatitis A virus in oysters. He also conducted studies showing that pasteurization did not inactivate all of the hepatitis A virus in milk, that bacteriophages are sensitive to chlorine dioxide, and that proteinase K and RNAse treatment of viruses may potentially differentiate infectious from inactivated viruses, as determined by reverse transcription-PCR. During this period, Dean served on several committees to recommend safeguards for working with prion diseases and to set the direction for future research.
An important job that Dean mastered was serving as the Head of the World Health Organization Collaborating Centre on Food Virology from 1975-1995 at Madison and from 1997-2007 at Davis. The purpose of the Collaborating Centre was to provide an international system of information sharing among virologists around the world. Dean maintained a list of bibliographic information on pertinent publications and distributed this information to interested laboratories worldwide. He maintained a list of food virologists with biographical highlights of each participant for distribution. For more history on Dean’s career in food and environmental virology, please refer to his excellent summary (Cliver, D.O. . Early days of food and environmental virology. Food and Environmental Virology, 2, 1-23).
Over the years, Dean taught courses including: Foodborne Disease Hazards, Advanced Microbiology of Foodborne Pathogens, Environmental Toxicology, Veterinary Food Safety, Foodborne Infections and Intoxications, Hazard Analysis Critical Control Point (HACCP) & Risk Assessment in Pre- and Post-Harvest Food Safety, and my personal favorite, Environmental Coprology, which is the study of feces. What better topic for someone who devoted their lifetime to the study of fecally-transmitted viruses. Dean mentored a large group of students who have become noted virologists in their own right. His research included studies on enteroviruses, with particular emphasis on poliovirus and coxsackieviruses, and later on caliciviruses, hepatitis A virus, and bacteriophages. He also diversified and studied bacterial pathogens, particularly Salmonella typhimurium, Escherichia coli, and Listeria monocytogenes. He also conducted research on the protozoan parasites Giardia lamblia and Cryptosporidium parvum. His professional works include over 250 book chapters, journal articles, and proceedings.
Dean retired from the University of California, Davis in 2007, but retained emeritus status until his death. He remained active in writing, editing, and speaking engagements, and in providing assistance to government and international organizations. Dean was commonly invited to give presentations, including keynote addresses, and enjoyed traveling throughout the world. He served on numerous editorial boards and performed countless reviews over his career. After Dean’s retirement, he continued to remain active. In 2008, Dean wrote that he had reviewed 45 manuscripts for 10 journals that year. That is dedication far beyond the call of duty, but pales to the over 500 manuscripts he reviewed since the year 2000. His reviews were always well balanced, honest, and constructive. Nearly everyone in the field has had multiple manuscripts reviewed by Dean. He always signed his reviews and asked editors to include his name in the response to the reviewers. As he frequently stated, “authors should have the right to confront their reviewers”.
On a more personal note, I worked with Dean during his final months on a book chapter and a presentation. Just two weeks before his death, he called me to discuss the progress of one of my lab’s research initiatives, which he found interesting. He was genuinely intrigued with science and the scientific method, and remained curious about its intricacies, twists and turns. By that time, he reported that his “healt