Walter Plowright is best known and will be remembered for the seminal work on rinderpest he conducted in Kenya during the 1950s and 1960s, work which led not only to an improved understanding of the epidemiology of wildlife-cattle rinderpest interactions but to development of an attenuated tissue culture-grown vaccine. This research was conducted at the East African Veterinary Research Organisation's (EAVRO) Muguga Laboratory where he worked with a team of veterinary scientists in various disciplines who became distinguished scientists in their own right for their work on a broad spectrum of African livestock diseases. This was an exciting time to be a veterinary virologist as it was right at the beginning of the discipline when techniques of in vitro virus cultivation were first becoming available. A good vaccine in the form of the goat-adapted vaccine had been widely available for decades and had made a significant impact on the circulation of rinderpest virus, despite its drawbacks, but it was adoption of the new culture techniques which enabled a novel vaccine to be developed.
Plowright conceived that the tissue culture rinderpest vaccine (TCRV, generally referred to as "the Plowright vaccine") would be cheaper, easier to manufacture, easier to scale up and above all else, easier to standardise to a high level of product safety. Through extensive laboratory and field trials, Plowright demonstrated that the attenuated vaccine was not only highly efficacious but was also completely safe in all classes of cattle and conferred a long lasting immunity, subsequently demonstrated to be life-long. Its availability ushered in a new era of rinderpest control which saw the disease progressively reduced in Africa and Asia as a result of its near universal adoption. Only with the perfecting of TCRV could internationally-coordinated campaigns be considered. As a result campaigns such as Joint Project 15 and the Pan-African Rinderpest Campaign were mounted from the 1960s. It is impossible to conceive how the current status of putative global disease freedom could have been reached without the "Plowright vaccine" and its derivatives of improved thermo-stability formulated in the 1980s. Many millions of doses were used within national and international campaigns until the 1990s when, with improved epidemiological understanding and reduced disease incidence and distribution, it became possible to replace mass vaccination with focussed vaccination, still using "Plowright's vaccine" but targeted at eliminating the residual reservoirs of infection. This tactic proved successful by 2001 when the last known case of rinderpest was confirmed in Kenya.
Plowright was born at Holbeach in the county of Lincolnshire in UK in 1923 and was educated at grammar schools in Moulton and Spalding. Having early in his life decided he wanted to be a veterinary surgeon he studied veterinary medicine and surgery at the Royal Veterinary College (RVC) in London during the war years, graduating as a Member of the Royal College of Veterinary Surgeons in 1944. On graduation, he was immediately commissioned into the Royal Army Veterinary Corps and posted to Kenya. After completing his military service in 1948, he returned temporarily to the UK to lecture at the RVC. However, his love of Africa soon lured him back there and in 1950 he returned to Kenya to work for the Colonial Veterinary Service at the Veterinary Research Laboratory at Kabete for three years before being transferred to the Nigerian Federal Veterinary Laboratory in Vom. His appointment in 1956 as head of the Pathology Department at the Muguga Laboratory took him back to Kenya at a time when Gordon Scott (1924-2004), himself destined to become an eminent virologist, was its very able Director. This was at a time when rinderpest was continuously ravaging African cattle herds and wild populations of buffaloes, antelopes and giraffe, not to mention the lives of livestock dependent farmers. Rinderpest was a major constraint to agricultural production and development at that time and was the major pre-occupation of colonial veterinary services in Africa. It was at Muguga over a period of 15 years that his work set the foundation for the eventual global eradication of rinderpest.
Kenyan independence saw the demise of the Colonial Veterinary Service and with this Plowright moved in 1964 to work for the Animal Virus Research Institute at Pirbright, Surrey in UK, but fortunately he was able to continue his links with EAVRO, to which he was seconded until 1971. Although rinderpest ranked highly in his professional portfolio he also made significant contributions to the understanding and control of other African livestock diseases, amongst which were malignant catarrhal fever and African swine fever.
Returning finally to UK, he resumed his academic career at the RVC as Professor of Microbiology and Parasitology and during that time he continued to conduct original research and supervised the doctoral studies of a number of veterinary virologists who went on to make significant contributions to veterinary science and are well-known names today. His final full-time post, from 1978 to 1981, was that of head of the Department of Microbiology at the Institute for Research on Animal Diseases in Compton, Berkshire, UK. After his formal retirement, Plowright's expertise continued to be in demand as a consultant and visiting lecturer and professor. In 1998 he gave the keynote address to the FAO Technical Consultation meeting on the Global Rinderpest Eradication Programme (GREP) in Rome and demonstrated clearly that, despite nearly 30 years having passed since he had last worked directly with rinderpest virus, he could still give a fascinating and up-to-date account of the science of rinderpest behaviour from a perspective covering virtually a century. In 2001 he made a valued contribution to the Royal Society's report on infectious diseases in cattle following that year's outbreak of foot-and-mouth disease in the UK. Sadly, increasing health problems limited his mobility in recent years and severely limited his acceptance of other invitations.
Plowright received numerous honours for his work including that of Commander of the Most Distinguished Order of Saint Michael and Saint George (CMG), fellowship of the Royal Society, fellowship of the Royal College of Veterinary Surgeons and the European Society of Veterinary Virology's Medal for contributions in the morbillivirus field; in 1984 he became the first recipient of the King Baudouin (of Belgium) International Development Prize and was given South Africa's Theiler Memorial Trust Award in 1994. Arguably the crowning accolade came in 1999 when, after nomination by FAO, he became a World Food Prize Laureate, an award given for contributions to advancing human development by increasing the quality, quantity or availability of food in the world.
Although his work can be looked at from a variety of perspectives, all of Plowright's considerable contributions to veterinary virology stemmed from his deep appreciation of the way in which cell culturing techniques could be developed to yield a more fundamental understanding of the nature of veterinary viruses. It is to the unique benefit of mankind that, in a period running from the late 1950s to the early 1970s, he chose to express his creativity by working on a variety of tropical animal diseases and was supported by the British Government to do so.
With his death the world has lost one of its most eminent veterinary virologists and authorities on rinderpest. The formal announcement by the United Nations Food and Agriculture Organization (FAO) and the World Organisation for Animal Health (OIE), due imminently, that rinderpest has been eradicated from the world will be a fitting and lasting memorial to this remarkable scientist. His pioneering work made an invaluable contribution to the achievement; it is only the second disease in history to have been eradicated through human efforts, the first being smallpox.
He is survived by his wife Dorothy who supported him loyally for much of his African and subsequent career.