SCIENTISTS must take part of the blame for delays and mistakes in tackling
the largest food scare in modern British history, says the report of the BSE
Inquiry, chaired by the senior judge Lord Phillips. Their generally uncritical
acceptance that BSE could not spread to humans meant early reassurances were
taken as gospel, the report states.
This helped lull the public into accepting that beef was safe to eat, and
blinded scientists to crucial warning signs as new data on BSE emerged.
It also bred complacency in British slaughterhouses, which for years
undermined measures to prevent BSE-contaminated meat entering the food
chain.
Advertisement
Contained in the 4000 pages are myriad lessons for governments and scientists
the world over who are charged with protecting their citizens from unsafe food.
The report provides a harrowing look at how science was mismanaged, misused,
misinterpreted and miscommunicated to the general public.
The terrible truth that BSE could spread to people emerged on 20 March 1996,
10 years after the first official case of BSE. During that time, “the government
did not lie to the public about BSE”, says the report, because it believed that
the risks posed by BSE to humans were remote. But it issued misleading
assurances that later destroyed public confidence, Phillips said at a press
conference last week to launch the report.
Several damaging myths emerged early on that played a large part in allowing
the disease to spread. The first sprang from the findings of John Wilesmith,
head of the Central Veterinary Laboratory’s epidemiology department in
Weybridge. Phillips praises Wilesmith for realising in 1987 that BSE was
spreading in meat and bone meal (MBM), the cattle feed made from the rendered
remains of dead animals.
But Wilesmith’s accompanying conclusions led to important assumptions, now
thought to be false, that put scientists on the wrong track for years. Wilesmith
concluded that BSE was the bovine form of scrapie, the spongiform encephalopathy
that had been known in sheep for 200 years. He also concluded, wrongly according
to Phillips, that it was changes in the processes for rendering cattle feed that
allowed the scrapie agent to infect cattle.
The report asserts that Wilesmith’s theories were based on the best evidence
available at the time. But instead of being critically tested, they were
blithely accepted by many other scientists. Because scrapie hadn’t posed
problems in humans, it was wrongly assumed that BSE wouldn’t either. “The fact
that scrapie does not infect humans was the rock on which we based all
reassurance,” says Paul Brown of the National Institutes of Health near
Washington DC.
Phillips concludes that the real source of the BSE outbreak was the chance
appearance of a new spongiform encephalopathy in a single animal during the
1970s (but see
“A killer is born”).
The practice of feeding bovine protein to cows then sparked an unstoppable
chain of cannibalistic infection later identified as BSE in cattle and variant
Creutzfeldt-Jakob disease (vCJD) in humans. “In this way, BSE spread rather like
a chain letter, and thousands of cows had been infected before the first
diagnosis,” said Phillips last week.
Critically, Wilesmith’s conclusions—that scrapie and rendering were to
blame— and the assumption that scrapie was “safe” were endorsed in 1989 by
the advisory committee set up to examine BSE, chaired by zoologist Richard
Southwood of the University of Oxford. This now seems surprising, because
scientists had known for 10 years that once a spongiform encephalopathy, such as
scrapie, jumped the species barrier it could become more pathogenic to other
animals.
“That was known among researchers at the time,” says Moira Bruce of the
Neuropathogenesis Unit in Edinburgh. Indeed, in a confidential memo given to the
inquiry, Raymond Bradley, head of pathology at the Central Veterinary
Laboratory, wrote in 1986 that while scrapie in sheep didn’t infect humans,
scrapie in cattle “might have posed a different risk”.
But the Southwood working party’s conclusion that BSE was unlikely to have
any implications for human health was repeated by government ministers whenever
they were asked about the safety of beef. The working party’s warning that “if
the assessment was incorrect, the implications would be extremely serious” was
quietly buried, says the Phillips report.
The damage caused by these fallacies was far-reaching. “The vast majority of
those involved in the response to BSE believed, subjectively, that it was not a
threat to human health,” says the report. “This belief was shared by many who
could see, objectively, that the potential risk was there.”
As a result, reassurances were issued until 20 March 1996, often by chief
medical officers who failed to realise that infective material was still
entering the food chain.
Worse still, the first warning signs that BSE could spread to other species
were ignored. In 1990, a cat was diagnosed with a hitherto unknown form of
spongiform encephalopathy, described by the report as “a bombshell”. Yet Keith
Meldrum, Britain’s chief veterinary officer at the time, said there was no
likely connection between this case and BSE. Meldrum had “no basis for this
degree of reassurance”, says Phillips.
Another key finding overlooked by scientists for too long was that only a
“peppercorn” of BSE-contaminated material could infect a cow. Research published
in 1988 by the Neuropathogenesis Unit showed that sheep could be infected by
just half a gram of infective BSE material. But scientists only widely accepted
that such a tiny dose was lethal six years later, following experiments by the
Central Veterinary Laboratory.
For five years, this ignorance led to slaughterhouses routinely breaking the
ban on BSE-contaminated cattle material, known as specified bovine offal (SBO),
entering the human and animal food chains. This perpetuated BSE on farms.
Experts in the government’s Spongiform Encephalopathy Advisory Committee
(SEAC) also took until November 1995 to realise that infective material had been
entering the human food chain in “mechanically recovered meat”, edible material
scraped from the spines of cows. Eventually, government ministers banned
mechanically recovered meat in December 1995.
When scientists did provide sound advice, the government let them down, says
the report. It didn’t communicate vital information about BSE to the public and
to non-government scientists, and it failed to coordinate and direct scientific
research into the emergence and spread of the disease.
For example, the Ministry of Agriculture, Fisheries and Food (MAFF) withheld
the publication in the scientific literature of the first report into BSE for
six months. With BSE spreading so fast in cattle feed, the delay may have
seriously damaged attempts to spot new cases and trace the epidemic.
Several lines of research should have been pursued earlier. Alarmingly, says
the report, the government took until 1997 to commission research testing
Wilesmith’s theory that BSE was the bovine form of scrapie.
Roy Anderson, then of Oxford University, told the inquiry that in 1991 a
mathematical analysis could have shown infections caused by SBO were continuing.
MAFF refused to give Anderson data to do the calculation.
Further delays occurred at the start of the crisis because Britain had cut
its research budget for agriculture and animal health by 20 per cent. According
to Phillips, this led to unacceptable delays in funding the Neuropathogenesis
Unit in Edinburgh, which had been studying spongiform encephalopathies since
1981.
Many of these gaps, delays and errors in the research programme could have
been avoided, says Phillips, if a research “supremo” had been appointed. But
“there was a reluctance on the part of the scientific community to be overseen
in this way”.
The findings of the Southwood report and Wilesmith’s conclusions should have
been regularly reviewed by independent experts. MAFF compounded the problems by
failing to release data and research material to independent researchers,
especially those outside Britain.
Malcolm Ferguson-Smith, a member of the inquiry team, said at last week’s
press conference that Britain should follow the example set by Canada and the US
and hold more scientific hearings about food safety in public. The advice given
to governments could also be improved if expert foreign researchers were allowed
to bid for contracts to perform key food safety research, he said.
Phillips’s overall message is that the government and the public must
re-evaluate their expectations of scientists. “żěè¶ĚĘÓƵs were expected to
provide all the answers when sometimes this was not their proper role,” he said
last week.
Crucially, the government must be totally open and willing to share bad
scientific news as well as good with the public. “Public trust can only be
established if communications about risk are frank and objective [and] in
particular, there must be openness about uncertainty,” said Phillips last
week.
“We have a real challenge about how we communicate comparative risk to the
public,” the Health Secretary, Alan Milburn, admitted. “The era of bland
reassurances has come to an end.” John Krebs, chairman of Britain’s Food
Standards Agency, said the inquiry had set a precedent for how the government
will communicate findings about risk. “Never again will vital information on
food safety risks be withheld from the public,” he pledged.
