Professor Fred Brown, who has died aged 79, was a molecular biologist specialising in virology, and a leading authority on foot-and-mouth disease (FMD).
During his 30 years at the Institute of Animal Health's Pirbright Laboratory in Surrey, Brown devoted much of his time to the study of FMD and other viruses, including rabies, and was an acknowledged international expert in the field.
His understanding of the structure and function of FMD led to the development of new vaccines and test kits. After his retirement, he continued his research at the US Department of Agriculture Plum Island Disease Center, where he was a visiting scientist from 1995.
In February 2001, when the most recent British outbreak of FMD was first diagnosed, Brown announced that it "would be crazy not to operate a programme of mass vaccination immediately".
Mass vaccination had been abandoned in western Europe in 1992, after defective vaccines had been thought to be the cause of outbreaks of the disease. But, Brown maintained, the new vaccines could not cause infections, and new testing could differentiate between vaccinated and infected animals.
Despite his attempts to persuade the authorities of the benefits of vaccination, to Brown's dismay the Government opted for a policy of mass slaughter, which he later described as the destruction of "innocent animals".
And although the culling of livestock on infected farms, and those located in a "contiguous cull" area, did eventually bring an end to the 2001 outbreak, Brown's supporters continue to maintain that vaccination and testing could have prevented the unnecessary slaughter of millions of animals.
After the 2001 outbreak, Brown was appointed to a Royal Society inquiry set up to learn lessons from it. But he remained disappointed that, when the disease had first been diagnosed, his advice had not been taken. The mass cull, he said in 2002, was "barbaric conduct" and "a disgrace to humanity".
Fred Brown was born on January 31 1925 at Burnley, Lancashire. He was educated at Burnley Grammar School, where he was captain of cricket and football. At Manchester University he took a First in Chemistry in 1944, followed by a PhD in 1948.
After a spell as a senior research assistant in the Christie Hospital, Manchester, in 1955 Brown joined the staff of the Foot-and-Mouth Disease Research Institute (today the Pirbright Laboratory).
There, working with several other scientists in the Department of Biochemisty, he pursued his interest in the structure and function of the constituent parts of micro-organisms, and in particular the genome and proteins of the foot-and-mouth disease virus particle.
During that time there were still frequent outbreaks of FMD across Britain, and evidence from epizootiological investigations indicated that many of them could be attributed to the import of meat and meat products from countries where the disease was constantly present, despite the use of foot-and-mouth disease vaccines.
The virus made contact with livestock - particularly pigs - in Britain through the swill feeding of waste food which had not been completely sterilised by heat treatment.
Also, in the 1950s and 1960s, during the course of vaccine campaigns to control the disease in several European countries, it became clear that in some outbreaks it was the vaccine which was responsible, due to the presence of small amounts of infective virus which had not been inactivated (killed) during the vaccine production process.
It became apparent, therefore, that if safer and more effective vaccines could be developed, and taken up in the countries from which meat products were imported, there would be fewer outbreaks of the disease.
At this point, Brown and his colleagues started to investigate the process of inactivation of the infectivity of virus particles by the action of formaldehyde during the production of vaccines. But they found that inactivation was not total, and the final product still contained a small
number of infective particles.
During a search for alternative chemical inactivants, Brown discovered that one of the aziridine compounds (AEI) gave the desired result: a safe and effective vaccine. This was a major breakthrough, and aziridines are now used universally in foot-and-mouth disease vaccine production units.
When applied to the European situation, vaccination in combination with modern sanitary measures resulted in dramatic reductions in the number of annual outbreaks; and the occasional outbreak, when it occurred, could in many cases be attributed to livestock imported from eastern Europe. Brown's studies of structure and the molecular profiles of different strains have also proved invaluable in the tracing of viruses.
After retiring as deputy director of the Pirbright Laboratory in 1983, he joined the staff of Wellcome Biotechnology as head of the virology and development department, working on the analysis of the structural basis for effective immunisation against several viruses affecting humans.
In 1990 he was appointed Adjunct Professor in the School of Epidemiology and Public Health, Yale University, and in 1995 became a consultant to the US Department of Agriculture at Plum Island, New York.
Brown was associated with almost 400 scientific papers on various aspects of animal virology, and served on many scientific committees, including the Spongiform Encephalopathy Advisory Committee.
He was appointed OBE in 1975, and elected a Fellow of the Royal Society in 1981.
A robust Lancastrian, Brown could be plain speaking, even blunt when necessary. He was a keen cricketer and an inspiring, energetic and helpful friend and colleague.
After undergoing triple bypass surgery in New York, he returned to Britain earlier this year. He died in Surrey on February 20.
Fred Brown married, in 1948, Audrey Alice Doherty, whom he met at Manchester University. She and their two sons survive him.