An investigation into the causes of the recent UK foot and mouth outbreak, which resulted in the slaughter of at least 60 cattle, yields the lesson that biosecurity and high-grade plumbing go hand in hand.
Six years ago a foot and mouth epidemic in the UK crippled farms across the country, costing the economy an estimated £8.5 billion (US$17.3 billion).
The clean-up was extensive and heartbreaking for farmers, requiring the slaughter of between 6.5 million and 10 million animals. The long-term effect was an incalculable loss of trade and confidence in the UK farming community.
This year, with farmers still haunted by the 2001 outbreak, the disease was again detected in cattle at several farms in Surrey, south-west of London. The government immediately acted to isolate the disease with a ban on the movement of livestock across the country – at a time when farmers were likely to be transporting animals in preparation for autumn and winter conditions.
National Farmers Union spokesman Anthony Gibson told the BBC the new outbreak would have severe financial implications.
“The longer we keep getting these outbreaks, the longer it will take to get the export ban lifted. And that’s costing at least £2 million (US$4 million) a day. Since the foot and mouth outbreak was confirmed in August, we think the total cost to the farming industry is about £250 million (US$510 million). That’s in terms of lost exports and lower meat prices.”
A recent report by the Health and Safety Executive (HSE) was able to isolate the source of the outbreak and investigate likely causes. Poor plumbing installations at the nearby research facility Pirbright may have contributed, and the occupants of the facility were potentially in breach of strict biosecurity Standards.
The report was triggered when the Department of the Environment, Food and Rural Affairs (DEFRA) established that the foot and mouth virus that infected the cattle in Surrey was not naturally found in the environment. It was a laboratory strain and was not known to be in circulation anywhere else in the world.
This was the strain being researched at Pirbright by three occupants of the facility at the time – a government agency and two private companies.
The report investigated various ways the disease could have leaked from Pirbright, including airborne release, human movement, solid waste removal and liquid waste disposal. It found no evidence to suggest the disease was leaked from the site into the atmosphere or through solid waste disposal, as the appropriate bio-control systems were in place. But liquid waste disposal was a different matter.
Most liquid waste from the facility passed through two chemical effluent inactivation treatment processes on site before joining the public sewer. However, the report notes that wastewater from human showers was not treated before it entered the site drainage system. It was therefore possible for small quantities of live virus to enter the plumbing from workers.
It was also possible that one on-site operator, which was testing the virus in much higher volumes than the other two, flushed waste containing the virus into the effluent sump and this passed into the drainage system. Waste in the drainage system was routinely given a final effluent treatment before release into the public sewer, and these incidents in isolation were not considered to be in breach of biosecurity regulations.
However, at some stage in the drainage process before the second and final treatment phase (where caustic soda should have neutralised any live viruses), infected wastewater leaked out of the pipework, contaminating the surrounding soil. In other words, the report concludes, the site’s plumbing network failed to contain the virus.
In its assessment of the condition of the ageing drainage system, the report noted weaknesses in the containment standard of effluent drains across the Pirbright site. These included displaced joints, cracks, debris build-up and tree root ingress.
Unsealed manholes were also investigated, and the report concluded it was very likely that a poorly fitted and neglected manhole, with gaps around the edges, had allowed virus-laden effluent to escape and infect surrounding soil during a period of particularly heavy flooding.
An independent review presented to the Secretary of State for Environment, Food and Rural Affairs and the Chief Veterinary Officer concurred with the report, adding there had been concern for several years about the maintenance of plumbing and drainage on site, which seemed not to have had regular inspections. No money was made available for a replacement system.(1)
The report considered record-keeping, maintenance and inspection regimes at Pirbright to be inadequate for a biosecurity-critical facility. One of the operators was found to be using bowsers and hoses in the intermediate site effluent drains to clear blockages without a standard operating procedure, which was a breach of biosecurity even though it was unlikely that the practice caused the spread of the virus in this instance.
So how did the virus reach the farm from the Pirbright facility about 2½ miles (4km) away? At the time, roadworks were being done in the vicinity. Four 32-tonne trucks removed soil from an on-site trench and transported it along a route that included a lane close to the first infected farm and known to be used by the farmer and visitors. This coincided with a period of heavy flooding of the Pirbright site and roads in the area.
This movement took place about the time of the initial exposure of cows to the foot and mouth virus.
The report recommended that the drainage system at the facility be improved to meet biosecurity containment standards, and that better record-keeping, monitoring regimes and plumbing maintenance procedures be enforced.
Robert Burgon is World Plumbing Council deputy chairman, and director of the Scottish and Northern Ireland Plumbing Employers Federation.
“Attention needs to be drawn not only to the effects of this devastating disease but to the cause in this instance,” he says.
“This incident should provide a reminder that properly installed, well-maintained plumbing is vital to public health and good biosecurity.
“The UK is the poor relation of other developed countries when it comes to plumbing Standards and regulations. There are two issues – certification of those who install the systems, and regulations governing maintenance.
“Anyone can install a drainage system here. This makes us susceptible to poor plumbing practice, and it’s worrying that this applies to high- risk facilities like hospitals and research centres.
“The situation at Pirbright seems to have been caused by neglect of the drainage system, and it might have been avoided had regular maintenance and record-keeping procedures been in place.
“Although it is sad that it takes serious bad news to highlight the importance of good, well-maintained plumbing systems, the reality is that stories like the spread of SARS in Hong Kong and now the apparent breaches of biosecurity at Pirbright in England have raised public awareness of the consequences of badly installed or neglected plumbing.
“We hope there will be a review of plumbing practices in the UK.
“The World Plumbing Council’s mission includes raising awareness of the health and environmental roles of the plumbing industry – issues that are often taken for granted.
“It seems inadequate attention to plumbing maintenance in this episode may have been a factor in the spread of a virus from what should have been a secure testing facility. And it proves that poor plumbing can also affect economies.
“We must all hope the lessons of such events lead to a greater understanding that good plumbing and maintenance are important in every aspect of society.”
1. Independent Review of the safety of UK facilities handling foot and mouth disease virus, chaired by Professor Brian G. Spratt, 31 August 2007, page 9.
Appeared in the online and print editions of World Plumbing Review.
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