Legionnaires Disease Corby

WHAT DARK SECRETS LAY BEHIND CLOSED DOORS IN CORBY?

LATEST INFORMATION ON CORBY AS OF
8th JULY 1998

UPDATE 3rd. AUGUST 1998

UPDATED 17th AUGUST 1998

Communicable Disease Report

Legionnaires' disease in Northamptonshire

Six cases of legionnaires' disease associated with an industrial estate in Corby, Northamptonshire arose during two weeks in August 1996. No deaths occurred among the flve men and one woman, all of whom have now left hospital and are convalescing. Environmental investivations at the estate were carried out by the Health and Safety Executive, environmental health offlcers, and the PHLS Water and Environmental Microbiology Research Unit. Legionella pneumophila serogroup (sg) 1 was isolated from 11 cooling towers serving eight cooling systems on six sites in the part of the estate where the cases worked or had links. Three of the cases, all of them men aged 49 ta 65 years who worked in different factories on the industrial estate, flrst came to light ln mid August. None had recently travelled.
Their infections were confirmed on the basis of fourfold rises in antlbody titres. Two further cases were confirmed on the basis of single high titres. and urlne from the sixth case (and one of the first three) was positive for L. pneumopbila sgl urinary antigen using an enzyme linked irnmunosorbent assay. Data soon to be published from the National Survefllance Scheme for Legionnaires' Disease show that the number of cases acquired in the community in 1995 was similar to recent years, and lower than in the late 1980s. The 1ntroduction of statutory notification of coollng towers and evaporatlve condensers in 1992 may explain why fewer large community outbreaks have been reported in recent years (CDR Rev 1996 (ln press)).

Volume 7 Number 3 17 January 1997 Communicable Disease Report Legionnaires' disease in Corby, Northamptonshire

Two outbreaks of legionnaire`s disease in Corby, Northamptonshire, in August (see CDR Weekly 1996; 6: 329) and in December 1996, are believed to be associated the with an industrial estate. The industrial estate covers an area of about 1.5 square miles to the east of Corby, and includes large and small lndustrlal premises. Fourteen cases were Identified in the first outbreak; ten worked on the Industrial estate, two were drlvers who visited the estate regularly, and two often drove through the estate. All 14 cases became ill between 4 and 28 August 1996, and all recovered. Twelve were men and two were women, and there ages ranged from 29 to 83 years. Infection with Leglonella pneumophila serogroup 1 was diagnosed by urinary antigen detectlon and/or a four fold rise in antibody levels in seven cases, and by a single high antibody titre in the other seven. Legionellas were not cultured from any of the eases. All industrial premises on the estate were inspected, and samples were taken for microbiologteal analysis from 48 weekscoollng towers or evaporatlve condensers on 15 premises. Control rneasures were taken at all premises on the estate. Legionellas were cultured from 18 samples from seven premises. No clinical isolates were obtalned for comparison wlth these environmental isolates. Seven cases have been detected so far in the second outbreak, all of whom became ill between 1 December 1996 and 1 January 1997. Flve cases either work on or regularly visit the industrial estate, and the other two travel through the estate to visit nearby shopping centres. Five are men and two are women, and their ages range from 42 to 64 years. One case is currently in an intensive care unit. Legionella pneumophila serogroup I has been isolated from one case. The PHLS Leglonella Reference Unit is carrying out subgrouping and subtyping studies of this isolate and of environmental isolates from the industrlal estate. Local clinicians, general practitioners, and occupatlonal health departments are helping to identlfy further cases, and the local media have been informed about the outbreaks. The consultant in communicable disease control (CCDC), Corby Environmental Health Department, the local Health and Safety Executive, and other publlc health professlonals are lnvestigating suspected sources of infection. All premises visited ln the ffrst outbreak are betng revisited and retested and control measures revlewed. Other sites are also being Investigated as possible sourees of infection. The investigatlon of the outbreak is being coordinated by Dr Patrick Morgan, CCDC, Northamptonshire Health Authority (tel 01604 615 394), who would welcome reports of cases of legionnalres' disease that might be associated with Corby.

Legionnaire`s Outbreak, Corby.

June, 1997.

In 1996 an outbreak of Legionnaire`s Disease in Corby killed one person and caused serious illness to another twenty-one. Fed up with rumours about infected factories, the unwillingness of the Northants Health Authority to discuss the situation openly, and the resulting lack of public information, victims of Legionnaire`s formed a group called GILD (Group Investigating Legionnaire`s Disease) whose purpose was to dig into the mire of secrecy and expose the facts inside.
The group has been assisted by Mr Dunning and Mr Lowe, both experts in the Legionella Bacterium and in industrial heating and cooling systems.
Their contribution has proved invaluable in getting at the truth and the facts surrounding this terrible outbreak.

On 17 March, 1997, Mrs Preston (partner of Patrick, the deceased) strode into the Council offices and asked to see the Chief Executive; she had a list of specific questions that she wanted answers to. She was met by Councillors Tom Simmons (then Chief Exec), John Murray (Leader) and Mark Pengelly, (Councillor for the Environment), who said they were as much in the dark about the disease as she was, despite Corby Council supposedly being on the Outbreak Control Team. In an effort to appease Mrs Preston they telephoned the Northants Health Department who point-blank refused to give them any information on her list of questions (this is should have been anticipated as no professional body would give such sensitive information over the telephone). It would appear that councillors had done very little research, even though the disease had been raging for months. In fact, the people of Corby were left to discover the truth for themselves. Guild called the public meetings, Guild bought the matter to the attention of the wider public, and Guild continue to fight for compensation for the victims.

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February, 1998.

MP Phil Hope is addressing a seminar organised by the HSE at Aston University about the problems experienced in Corby. He is expected to warn water treatment companies on the devastating impact that Legionnaires disease had on the town. Whilst Phil Hope is thus engaged, he should not forget that members of his constituency were struck down by law-breaking factories that had breached cooling tower regulations.

So often we see politicians capitalising on a tragedy, yet innocent victims are left fighting an up-hill battle for compensation. Curiously GILD was not informed that Phil Hope was speaking on the legionnaires outbreak. Whatever the outcome of his address, he should do his best to make sure all victims receive justice.

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Unknown to residents, the East Lloyd's Estate was well within the danger zone of fallout from factories on the Earlstree Industrial Estate. Borne on microscopic droplets of water, blown into the atmosphere from defective cooling towers, the legionella bacterium could travel for up to five miles and possibly more given the right conditions. The factories are less than a mile away from residential houses.

Because the legionella bacterium readily re-infected factories that had previously been cleaned and disinfected, Mr Dunning suggested that it could be thriving in slime trapped in the main water pipes. He pointed to an article in the New Scientist called Slime City, 31 August 1996, Vol.151, which described vast colonies of bacteria cohabiting in the sludge that accumulated in such pipes. More properly known as biofilms or mucilages, this slime thrives wherever there is water — in the kitchen, on contact lenses, in the gut linings of animals. When the urban sprawl is extensive, biofilms can be seen with the naked eye, coating the inside of water pipes or dangling slippery and green from plumbing.

In the past few years have scientists learnt how to observe the inner structures of biofilms using powerful microscopy techniques. What they are now discovering is sending shock waves through microbiology. Research shows that in nature, bacteria seldom if ever grow in single-species colonies. Instead, different species live cheek-by-jowl in slime cities (see article above), helping each other to exploit food supplies and to resist antibiotics through neighbourly interactions. Toxic waste produced by one species might be hungrily devoured its neighbour. And by pooling their biochemical resources to build a communal slime city, several species of bacteria, each armed with different enzymes, can break down food supplies that no single species could digest alone.*

The fear is that if the main water pipes leading to the factories are infected, it will make it virtually impossible to fully eradicate the bacterium from factory cooling towers. Colonies of legionella and other dangerous micro-organisms exist untreated within the slime, ready and waiting to contaminate whatever site the water is piped into. Mr Dunning pointed this out in an open letter to the Evening Telegraph, March 2, 1997 (see below), yet no action has been taken regarding the mains water pipes leading to factories and people's homes.

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4 May, 1998.

KILLER BUG STRIKES AGAIN AS PREDICTED BY MR DUNNING

We have learned that a 57 year old Corby woman was stricken with Legionnaires last week. She works in Chemence on the Earlstrees Industrial Estate, the focal-point of previous legionella infections, and is recovering from the disease in Kettering hospital. Duty Manager sister Gill Jones said: "The woman is now off intensive care, on a normal ward, and is doing very well." Doctors and GPs have been alerted and told to watch out for anyone showing signs of the symptoms. A top level meeting was called on Saturday by Corby Borough Council officials and councillors, with MP Phil Hope and the Northamptonshire Health and Safety Executive (HSE). John Murray, Council Leader, said: "The people of Corby can have every confidence that everything possible is being done." However, the HSE says that 'this case has got to be taken into context and they don't want anyone to panic'. One of the water towers at Chemence have been closed and an investigation launched, but an HSE spokesman said 'that doesn't mean that is the cause — we are looking at everything possible'. Phil Hope said: "I am very concerned that there has been another case but I am glad the decision has been made to take additional measures and the agencies got of the mark so quickly." Government environment secretary Michael Meacher was being kept updated on the situation.

We repeat that people living on the Lloyd's East Estate are in particular danger from cooling tower fall out. The factories on the Earlstrees Estate are close by and when the wind blows from the North, it carries with it microscopic droplets of possibly contaminated water. Hopefully the officials will get on top of it this time, after all it's what they promised to do last year. If this outbreak had occurred in London or some other high profile place, it would never have been allowed to continue. Heaven and earth would have moved to prevent further infection. It just shows what the authorities think of us here in Corby — one dead and twenty three infected and the disease is still with us a year later.

5 May, 1998.

In an effort to calm the anxious public, Phil Hope MP said, "Everything should be done to ensure there are no more cases of the potentially fatal Legionnaire’s disease". He made the call for action following the hospitalisation of the latest victim A Health and Safety Executive spokesman said inspectors would continue to visit factories on the estate today and possibly tomorrow. Mr Hope said: "If this is now under control, we have to look at the wider question of how we can prevent this happening again. I have made it my business to make sure the agencies work together and effectively. They are continuing to meet and have already closed one cooling tower at the factory and have been visiting other factories in the area making sure they are safe."

Marylyn Preston, Widow of Pat Preston who died of the disease in February last year said: "This is devastating. It seems lessons are not being learned. We have been saying it would happen again and now it has. My heart goes out to the family."

6 May, 1998.

Tony Helps, 58, spent three days at his wife Mary’s bedside as she lay in intensive care at Kettering General Hospital, critically ill. He said: "I was very worried for her. I was in tears. I feel so angry that this has happened again."

Mrs Helps visited her doctor but was told to continue taking her medication for arthritis. Two days later when her condition worsened her husband called an ambulance and she was taken to hospital. Mrs Helps, who works as a packer at the Chemence superglue factory, in Corby, was critically ill for three days.

A cooling tower at the factory has been closed as a precaution by health and safety experts investigating the cause of the latest outbreak.

Four days after being admitted to hospital Mrs Helps was tested for Legionnaire’s disease, after her husband told doctors that she worked on a Corby industrial estate. He said: "I felt angry when I was told what the diagnosis was. I felt it should have been picked up earlier. "I am sure something more could have been done. They should be checking the factories more often.

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New Scientist called Slime City, 31 August 1996, Vol.151,

We wrote to Phil Hope MP expressing our concern.

Mr Dunning's letter to the Evening Telegraph

What is legionnaires Disease?

How to prevent it?

Leaked local authority Information

Northamptonshire Health Authority

New Scientist, 31 August 1996, Vol.151 No.2045 Page 32

Slime city - Chic, urbane, sophisticated and sometimes deadly, such are the inhabitants of the world's weirdest metropolis. Andy Coghlan reports from the underworld

Through the murky gloom, you can just make them out to be shadowy towers shaped like mushrooms. Circulating through and around them, apparently suspended in mid-air, there are ducts and channels of swishing liquid. Just for a moment, the murk clears. In the distance, you see skyscrapers of ghostly spheres piled one on top of the other.

The set of a futuristic movie on some distant planet? Not quite. This is slime city, a sprawling metropolis very much of this world. Inside, shielded from harm and replete with every creature comfort, live beings whose cosmopolitan lifestyle is only now coming to light.

Amazing cityscapes like this have existed on Earth for billions of years, built and populated by plain, humble bacteria such as Escherichia coli and salmonella. More properly known as biofilms or mucilages, slime cities thrive wherever there is water; in the kitchen, on contact lenses, in the gut linings of animals. When the urban sprawl is extensive, biofilms can be seen with the naked eye, coating the inside of water pipes or dangling slippery and green from plumbing.

Yet only in the past few years have scientists learnt how to observe the inner structures of biofilms using powerful microscopy techniques. What they are now discovering about those ghostly cityscapes is sending shock waves through microbiology.

Toxic food

For decades, microbiologists have based virtually all their ideas about bacteria — how fast they can grow, how they react to antibiotics, what they can eat, and so on, on the behaviour of colonies grown from single species on laboratory plates. But research now shows that in nature, bacteria seldom if ever grow in single-species colonies. Instead, different species live cheek-by-jowl in slime cities, helping each other to exploit food supplies and to resist antibiotics through neighbourly interactions. Toxic waste produced by one species might be hungrily devoured its neighbour. And by pooling their biochemical resources to build a communal slime city, several species of bacteria, each armed with different enzymes, can break down food supplies that no single species could digest alone.

The problem is that not all scientists have taken the new findings on board. "Serious errors have arisen from extrapolation of data from single-species laboratory cultures to explain bacterial behaviour in real ecosystems," warns Bill Costerton, a pioneer of slime research at the Montana State University in Bozeman. What's more, mistakes are still being made. Single-species cultures are still routinely used to assess the sensitivity of biofilm bacteria to antibiotics, says Costerton. And this despite the fact that biofilms can be 1500 times more resistant to antibiotics than a single colony, because they shelter their bacterial inhabitants so effectively.

If biofilms were rare, none of this might matter so much. But Costerton estimates that more than 99 per cent of all the planet's bacteria live in biofilm communities. Some do vital jobs. Sewage treatment plants, for instance, rely on biofilms to remove contaminants from water, while cows use them to digest grass in their forestomachs. But biofilms also wreak much havoc. Some are implicated in diseases as various as cystic fibrosis and the blood poisoning caused by infected catheters. Others secrete acids that nibble away at the toughest of metals and minerals, corroding anything from the legs on oil rigs to the teeth in your mouth.

Biologists have known about biofilms ever since bacteria were first studied. But in the past researchers were blinded by two flawed assumptions. The first was that, biochemically speaking, biofilm bacteria must behave much like solitary, free-roving microorganisms. The fact that many biofilm dwellers and free-rovers belong to the same bacterial species simply served to reinforce that view. It didn't seem likely that something as simple as an E. coli or salmonella bacterium could have two distinct modes of biochemical behaviour, one suited for the solitary life of scouring the waterways and bloodstreams, the other for structured group living.

But that is precisely what researchers are now discovering. While it's true that city dwellers have exactly the same genetic makeup as their free-roving cousins, their biochemistry is very different because they switch to using a different set of genes. It's a type of genetic flexibility that multicellular organisms simply don't have.

The second assumption was that biofilms contain disorderly clumps of bacteria located in no particular structure or pattern. Again, nothing could be further from the truth. Costerton, working with Zbigniev Lewandowski, a Bozeman colleague, and Douglas Caldwell's team at the University of Saskatchewan have dispelled that myth by using a high-powered microscopy technique to spy on biofilms as if viewing a city from a satellite.

The technique, confocal scanning laser microscopy, was first developed by cell biologists 15 years ago, but it was only taken up by biofilm researchers in the early 1990s. Its great advantage over other microscopic techniques is that it can magnify biofilms without destroying them. Previously, samples had to be dried out or treated with chemicals. What researchers didn't realise was that these methods were destroying the gel-like structures of biofilms.

They do now. When Costerton and his colleagues first used the confocal microscope in 1992, the complexity of what they saw astonished them and others alike. Since then, the researchers have examined a vast range of biofilms from sources as diverse as catheters, sewage pipes and the gut linings of animals.

In most cases, says Costerton, the base of the biofilm is a bed of dense, opaque slime 5 to 10 micrometres thick. It is a sticky mix of polysaccharides, other polymeric substances and water, all produced by the bacteria. Soaring 100 to 200 micrometres upwards are colonies of bacteria shaped like mushrooms or cones. The more plentiful the food, the more crowded the bacterial skyscrapers.

Above street level comes more slime, this time of a more watery and variable consistency. Its chemical makeup varies, depending on the identity of the bacterial species making it. In most cities, says Costerton, you'll find a rich mix of species, each living in their own chemical ghettos or "microzones".

Similar cityscapes have been popping up on microscope computer screens elsewhere. At the Centre for Applied Microbiology and Research at Porton Down in Wiltshire, Bill Keevil and his colleagues have been using a microscope technique they invented in 1991 to study slime samples from North Sea oil rigs, dental plaques and other sources. Sparkling with reflections from the microscope's light beam, their skyscrapers resemble a city at night. "It looks like Manhattan when you fly over it," says Keevil.

Every city needs an infrastructure, and these little manhattans are no exception. According to research in Costerton's laboratory, the biofilms are permeated at all levels by a network of channels through which water, bacterial garbage, nutrients, enzymes, metabolites and oxygen travel to and fro. Gradients of chemicals and ions between microzones provide the power to shunt the substances around the biofilm, as do currents from water flowing overhead. Individual bacterial species form microcolonies wherever their staple diet is in abundance. Often, their food is the waste product from a neighbouring microcolony and wafts in through one of the channels. The origin of these connecting channels is a mystery the researchers are itching to solve. Water alone might create the channels by pushing through weak spots in the slime structure. Or the bacteria might be involved in some way. "We don't know yet," says Costerton.

The researchers' microscope technique can also produce "movies". Some simply show the bacteria moving around the cities. More Big Brotherishly, Lewandowski and his colleagues have used fluorescent chemical markers to pry into which genes the bacteria are switching on and off and which proteins they're producing. "You can watch the critters at work," says Costerton. And what's clear in these movies is that bacteria are not the only inhabitants of slime city.

In many cases, fungi stake out their own turf, as do the algae that give some slimes their lurid green colour. And protozoans that consume bacteria can be seen scavenging for an easy meal. Video footage from Keevil's laboratory shows disc-shaped protozoa hunting for bacteria, and other kinds of protozoa spinning like Ferris wheels to suck in their prey.

Spying on slime cities is just the beginning. Biofilm researchers have their sights on a deeper issue=BEhow organisms as simple as bacteria can produce such apparently complex worlds. The first requirement, plainly, is a surface. Biofilms, like cities, are born when individuals settle permanently in one place. Some bacteria settle because the surface, such as cellulose in grass, is edible. Others put down roots because the fluid washing over a surface, such as sewage in a pipe, is rich in nutrients the bacteria can digest.

Exactly how these "pioneer" bacteria anchor themselves to surfaces, nobody knows. Keevil thinks they rely on electrostatic forces. Costerton, on the other hand, thinks they glue themselves to surfaces with an unusually sticky form of slime called alginate. Using confocal scanning laser microscopy and a fluorescent chemical to track gene activation, Costerton's team has studied how Pseudomonas aeruginosa, a species of bacteria that clogs the lungs of people with cystic fibrosis, forms biofilms. The instant the bacteria dock to glass, they switch on certain genes involved in the synthesis of alginate, switching them off again once the bacteria are engulfed in alginate.

But sticking to a surface is not enough. The pioneer bacteria must also be persuaded to adapt their biochemistry to group living, giving up the selfish habits of the lone vagrant. Here, there's more agreement about the trigger. A bacterial chemical called homoserine lactone swings dramatically into action, signalling the pioneers to turn into stationary city dwellers (see "The secret language of bacteria", New Scientist, 16 September 1995, p 30).

The key role of this chemical first came to light in the early 1990s, thanks to teams led by microbiologists such as Gordon Stewart, of the University of Nottingham, and Pete Greenberg of the University of Iowa. Bacteria constantly discharge low levels of homoserine lactone, even when they are roving. They are equally capable of sniffing it out, by capturing the molecule on surface receptors. But the lactone's dramatic effects on bacteria only kick in when its concentration exceeds a certain threshold. Nothing happens until there's a critical mass of pioneer bacteria discharging the lactone all in one place. Only then will a biofilm form.

Towers of Babel

"The lactone is the communication signal that holds the city together," says Costerton. "The fascinating thing is that it works between species, so lots of different species can get together without it becoming the Tower of Babel."

Now, researchers are close to understanding precisely how it works. When the lactone concentration reaches a threshold level it signals the bacteria to produce proteins called "sigma factors". Vital for changing vagrants into city dwellers, these powerful proteins are subunits of the enzyme RNA polymerase, which helps to transcribe the information present in genes into a form that cells can use. Acting inside bacteria, each sigma factor will switch on a job lot of up to 40 genes simultaneously.

Entire biochemical pathways, dormant in free-roving bacteria, spring to life, enabling bacteria to produce the sugary polymers, like alginate, on which slime cities are founded. At the same time, sigma factors shut down many genes required by free-rovers. New arrivals in the city no longer need such tough cell walls, so they close down genes involved in making cell-wall proteins

In all, as many as 30 to 40 per cent of the proteins present in bacterial cell walls differ between city dwellers and free-rovers, says Costerton. "Some of the targets for antibiotics are not there any more either, so the bugs become desperately difficult to kill," he says. In many cases, they become resistant to penicillin and even powerful chlorine-based disinfectants.

This newfound genetic hardiness, combined with the physical shelter provided by slime cities, explains why biofilms that form on the surfaces of prosthetic devices, contact lenses and catheters are such a problem. It also explains why biofilms in sewage works, water pipes and cooling towers provide such safe havens for bugs like Legionella pneumophila, the cause of Legionnaire's disease, and Cryptosporidium parvum, a protozoan parasite that causes severe stomach upsets.

If researchers can discover a "reverse" sigma factor, or a chemical that neutralises homoserine lactone, it might be possible to dissolve biofilms by sending in the equivalent of an evacuation signal. At present, the only chemical that reliably lays the cities to waste is plain old bleach, which turns the slime into carbon dioxide and water and kills the bacteria. But milder alternatives are in prospect.

Costerton has found that methyl cellulose, a chemical discharged by bacteria when they return to vagrancy, can evacuate an entire city if the concentration is high enough. A further option is alginate lyase, a bacterial enzyme that dissolves slime. Researchers have also dislodged the cities using pulses of sound. Marianne Walch of the US Naval Surface Warfare Center in Silver Spring, Maryland, will reveal details of this latest technique at an international meeting on biofilms next month at Snowbird in Utah.

Order or anarchy?

However, the key question for most biologists is not how to destroy slime cities. It's about who=BEor rather what=BEgoverns the form and apparent orderliness of their structures. Maybe their street plans and infrastructure are the result of specific genetic programmes that have evolved in bacteria to make them cooperate in specific ways when the conditions are right=BEprogrammes, perhaps, that are activated at the same time as sigma factors. Or maybe the orderliness is an illusion, the fortuitous outcome of opportunist organisms randomly exploiting whatever niches are available. Opinions remain divided.

The bacteria simply go where the food is, says Julian Wimpenny of the University of Wales in Cardiff. "Don't say the cells are responsible for this design=BEit's a haphazard result of concentrations of nutrients." But Costerton, for one, thinks there's more to it than that. He sees biofilms less like colonies of self-serving automatons and more like the cells of tissues of multicellular organisms, where selfish instincts must be subordinated to the wider interests of the group. "All of a sudden, instead of individual organisms, you have communication, cell cooperation, cell specialisation and a basic circulatory system, as in plants or animals," says Costerton. "It's a big intellectual break."

To back up his argument, Costerton points to the inhospitable terrain of the cow's rumen, home to one of the first biofilms he and his colleagues investigated. At least five different species of bacteria are needed to digest cellulose in the rumen. Only by collaborating in slime cities can these bacteria succeed in the complex task of breaking down cellulose.

On one side of the biofilm=BEthe cellulose "coalface", as Costerton puts it=BEFibrobacter succinogenes bacteria break down the cellulose into glucose. On the other side are mushroom-shaped colonies of butyrovibrio bacteria that specialise in breaking down this glucose into butyrate. In turn, the butyrate is degraded into acetate by a clump of neighbouring bacteria that are different again. And in the final step, the acetate is converted into methane by a nearby ball-shaped colony of specialist methanogen bacteria. "What's waste for one bacterial colony is the nutrient for the next," says Costerton.

But the collaboration seems to run even deeper than that. Since oxygen normally poisons methanogens, these bacteria need help to survive in the oxygen-rich environment of the biofilm. That help comes from a fifth species of bacteria, which forms a protective seal around each methanogen colony.

It's hard to imagine all these interactions arising from random opportunistic mechanisms, argues Costerton. Whatever the truth, there's no denying that slime cities have a distinctly social ring to them. After all, they seem to be founded on the familiar trade-off between individual and collective needs that governs all good cities and societies. Citizenship carries a price. The bacteria must use some of their resources and energy to produce sticky slime and infrastructure that will in the end be used by many different species. But the dividends of group living can=BEwhen the conditions are right=BEmake this investment worthwhile even for individuals that are purely selfish.

A few years ago, all this would have seemed fanciful. But now the secrets of the city are leaking out, and microbiology is slowly turning a new, slimy corner.

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Phil Hope MP,
House of Commons,
London,
SW1A 0AA.

4 May, 1998.

Dear Mr Hope,

RE: NEW CASE OF LEGIONNAIRE`S DISEASE

You may be interested to learn that Mr Mark Dunning (expert on cooling towers and airborne bacteria) predicted on March 2, 1997, that legionnaires would break out again in Corby. Today we read in the Telegraph that a fifty seven year old woman has fallen ill with the disease and is in Kettering hospital. It is extremely worrying that yet another case of legionnaires has been reported — worrying because it means the authorities have not yet got to grips with the problem despite the possible answers being available over a year ago; and because the Lloyd's East Estate is in the danger zone from bacterium fallout which can travel five miles or more in the atmosphere given the right conditions.

The text below was cut and pasted from my web site, and has been on the Internet for a year, along with Mr Dunning's open letter to the ET.

Sincerely

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The Editor,
Evening Telegraph,
Northfield Avenue,

Kettering,
NN16 9TT

4 March, 1997,

Sir,

I was very perturbed to learn of the recent cases of Legionnaire`s Disease in Corby. It appears distinctly possible, given the number of people that have fallen ill during cold weather, that the source of the infection could be found in the hot and cold water services of buildings on the Weldon North and Willowbrook Estates (cooling towers and systems do not operate at full capacity during the winter months). Legionella bacteria are frequently found in small quantities in mains water supplies and will, in the right conditions, proceed to contaminate all the water systems in a building, not just the cooling system. Hot and cold water systems now account for the majority of identified cases of Legionnaires Disease in the UK.

The Health and Safety Executive issued guidelines, HS(G)70, in 1991, revised in 1993, to reduce the risk of Legionellosis. These guidelines advocate the use of temperature regimes (at least 60°C for hot water and 20°C maximum for cold) as the primary method of Legionella control. There have always been concerns regarding the effectiveness of this method of treatment.

Because of these concerns the Government commissioned the Building Services Research and Information Association in 1994 to carry out a two year project, comparing control by temperature regimes with another method of water treatment, copper and silver ionisation. This project was designed to replicate actual rather than laboratory conditions. The HSE were represented on the Steering Group for this project.

The results of this project, compiled in January, 1996, and published in April, were very significant. Not only did they demonstrate that there were serious deficiencies in the effectiveness of HS(G)70, they also proved that the only way to determine whether any water system was infected with Legionella bacteria or not was through regular sampling and testing of the water. Installing a regime of temperature control, even in accordance with HS(G)70, in no way of itself guarantees the prevention or elimination of Legionella bacteria.

Given the seriousness of these findings the HSE undertook to publish a technical amendment to HS(G)70 last September. It was not issued. Despite various meetings, correspondence and telephone calls since, despite the urgent need to recommend regular microbiological testing of hot and cold water services and despite several promises, the HSE have still not published any such amendment. This is now more than a year after the HSE were made aware of the ineffectiveness of their recommended method of Legionella control. In the meanwhile people have still not been alerted to the dangers of relying on HS(G)70 to protect them, and people are still falling ill. We are right to be concerned.

Yours faithfully,

Mark Dunning.

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NORTHAMPTONSHIREI HEALTH AUTHORITY

DIRECTORATE OF PUBLIC HEALTH & HEALTH STRATEGYENVIRONMENTAL IIEALTH/COMMUNICABLE DlSEASE CONTROL
Direct dial: (01604) 615211

March 5th 1997Fax No: (01604) 615295

To: All companies,Earlstrees Industrial Estate,

Corby Northants

To whom it may concern,

As you may know there have been a number of cases of Legionnaires’ Disease reported in Corby. Of these 15 took place during August 1996 and could be linked to the Willowbrook and Weldon North Industrial Estates. There have also been 8 cases reported during the winter of 1996. Most of these could also be linked to the Willowbrook and Weldon North Industrial Estates, but recently one case has come to our attention which is linked to the Earlstrees Industrial Estate. Because of the high level of public concern about Legionnaires’ Disease in the north of county, we have produced an information sheet for anyone who requests information about the illness This was distributed to all general practitioners and pharmacists in the area in January 1997. At this time it was also distributed to all employers in the Willowbrook and Weldon North Industrial Estates. As employees in Earlstrees Industrial Estate may also now have questions about the illness, we are distributing an updated version of the information sheet to all employers on the Earlstrees Industrial Estate.

A copy of this has been enclosed. Please photocopy this for distribution. Unfortunately it is not practical for the Health Authority to provide a large number of copies for everyone who might require it.

Dr Marshall

Specialist Registrar in Public Health,Highfield,
Cliftonville Road,
Northampton,
NN1 5DN.

Tel: 01604 615000 Fax: 01604 615010

Chairman: Simon Schanschieff OBE, FCA, JP Chief Executive:
Lynda Hamlyn BA(Hons)

Information about Leqionnaires’ Disease issued by Northamptonshire Health Authority March, 1997

What is Legionnaires’ Disease?

Legionnaires’ Disease is a kind of pneumonia. It was named after an outbreak of severe pneumonia which affected a meeting of the American Legion in 1976. It may be a mild illness or more serious.

The illness occurs more frequently in men than women. It usually affects middle-aged or elderly people and it more commonly affects smokers or people with other chest problems. Legionnaires’ disease is uncommon in younger people and is very uncommon under the age of 20. Some UK cases of Legionnaires’ Disease are caught abroad, others are a result of outbreaks in this country.

How do people get it?

The germ which causes Legionnaires’ Disease is a bacteria called Legionella pneumophila People get Legionnaires’ Disease by inhaling droplets of water which contain the legionella bacteria. However, most people who are exposed to legionella do not become ill.

Legionnaires’ Disease does not spread from person to person. (?)

How is it treated?

The illness is treated with an antibiotic called erythromycin or a similar antibiotic.

What measures are there to control Legionnaires’ Disease?

The bacteria which causes Legionnaires’ Disease is widespread in nature. It mainly lives in water, for example in ponds, where it does not usually cause problems. Previous outbreaks have been associated with cooling towers, evaporative condensers, showers, Jacuzzis and even fountains. Most outbreaks in the UK have been linked to installations such as cooling-towers or evaporating condensers which can spread droplets of water. These are found in air-conditioning systems and in industrial cooling equipment. To prevent the occurrence of Legionnaires’ Disease, companies which operate such equipment must comply with regulations for the management of their cooling systems.

What are the symptoms?

The symptoms of Legionnaires’ Disease are similar to the symptoms of the flu: high temperature, feverishness and chills, cough, muscle pains, headache. If you develop these symptoms and you are worried, see your General Practitioner Because it is similar to the flu, it is not always easy to diagnose. A blood test may be helpful in deciding whether an illness is or is not Legionnaires’ Disease. When doctors are aware that the illness is present in the local community, they have a much better chance of diagnosing it earlier

Legionnaires’ disease 5 March 1997

Outbreak Control Team - Corby Borough Council Environmental Health Department, Health & Safety Executive, Northamptonshire Health Authority, Communicable Disease Surveillance Centre/Public Health Laboratory Service.

What is Legionnaires’ disease? What are the symptoms and can it be fatal?

Legionnaires’ Disease is a form of pneumonia caused by the bacteria Legionella pneumophila. (It is not a virus). It usually affects adults and more commonly those who are middle-aged or elderly. It may be a mild illness (some patients are not admitted to hospital) or a more serious illness. In previous outbreaks, some patients have died as a result of Legionnaires’ Disease. (More on this below). It begins with symptoms which are similar to the flu, a high temperature, feverishness and chills, muscle pains, headache and cough. Because it is similar to the flu, it is not always easy to diagnose. A blood test may be helpful in deciding whether an illness is or is not Legionnaires’ Disease. Legionella may also cause a much milder flu-like illness called Pontiac fever. This does not cause pneumonia or serious illness and patients recover within 2 to 5 days.

How do people get it? How does it get into buildings?

People get Legionnaires’ Disease by inhaling droplets of water which contain legionella.The bacteria which causes Legionnaires’ Disease is widespread in nature. it mainly lives in water, for example in ponds. Outbreaks have been associated with air-conditioning cooling towers, evaporative condensers, showers, Jacuzzis and even fountains. Because cooling towers and evaporative condensers are known to be a potential source of Legionella, companies are required to register these with the local authority. In addition there are guidelines for managing and treating cooling towers and evaporative condensers.

What type or person is most likely to catch it? Who is most at risk?

Legionnaires’ Disease is very rare in people under the age of 20. It more commonly affects those in their middle years or the elderly. It is more common in smokers than non-smokers and in those who suffer from chest problems.

Does it cause lasting damage?

Following recovery, lasting damage as a result of the illness can occur, but it is not usually the case. However it should be remembered that in the UK each year a number of people die from Legionnaires’ Disease.

Can it pass from person to person? Do people need to be isolated?

Legionnaires’ Disease does not pass from person to person. Patients do not need to be isolated.

How is it treated? How long does it last?

Legionnaires’ Disease is treated with the antibiotic erythromycin or one of a similar group of antibiotics. Recovery from the infection usually takes two to three weeks, but it may take many weeks or even months for patients to feel that they are fully recovered

If you have had it are you more likely to get it again?

This is not thought to be the case.

How long do you have to be in contact with the bug?

This is not really known. It probably depends on how much bacteria you have been exposed to. If a cooling tower is spreading very large amounts of Legionella, it is possible to be infected by being in the area for only a short period of time.

How many cases were reported locally in the past year?

There were 20 cases reported in Northamptonshire in 1996. Fourteen cases were associated with the outbreak in Corby in August and 5 with the recent outbreak (the sixth one was reported on 1 January 1997).

During the month of August 1996 there were 15 "probable" or "definite" cases of Legionnaires’ disease. Most of these spent some time in hospital and all recovered following treatment. All of these cases could be linked to the Willowbrook and Weldon North Industrial Estate. Following the action taken by the Outbreak Control Team, no further cases were detected. At the beginning of December 1996 two further cases were picked up. Following this a number of other cases were reported, bringing the total to 7 cases. Most of these could also be linked to the same estate. Since then a further case has been reported. This person works at a company in the Earlstrees Industrial Estate.

Are other communities nationwide affected now?

There was an outbreak of Legionnaires’ Disease in the West Midlands in November 1996 which we believe involved two cases. As it takes time for reports of Legionnaires’ Disease to be confirmed we are not yet certain whether other communities are experiencing similar outbreaks at the present. In 1995 (for comparison) there were 160 people in England and Wales reported as having had Legionnaires’ Disease, of these 20 died. About half of these were acquired abroad and half in this country.

What action was taken last summer to control the outbreak?

After cases were reported by local hospitals in the summer, the Environmental Health Department of Corby Borough Council, the Health and Safety Executive and Northamptonshire Health Authority formed an Outbreak Control Team to take action.

More than 100 premises were visited by officers of HSE and the EHO to identify any cooling

towers or evaporating condensers. Previous experience has shown that cooling towers or

evaporating condensers are the most likely potential sources of infection. As a result of this,

samples were taken from about 50 cooling towers and evaporating condensers on 15 sites. In

addition the procedures for the management of cooling towers and evaporating condensers were examined to ensure that this complied with guidelines for the running of such systems.

Following sampling, all companies were told to disinfect their systems. Those cooling towers and evaporating condensers which gave positive results were re-tested until they gave satisfactory results. The HSE also took enforcement action against those companies who were not maintaining their legal responsibilities under the Health and Safety at Work Act. All companies were again

I reminded of their responsibilities under the Health and Safety at Work Act and the Control of Substances Hazardous to Health Act.

Despite all the action which was taken at the time, the source of the outbreak was not identified. This is common in such outbreaks.

In total at least thirty staff from HSE, Northamptonshire Health Authority and Corby Borough Council were involved on a day to day basis in the control of this outbreak. In reality many more were less directly involved.

Why was this not enough to put an end to it?

We believe that this outbreak was brought under control. There were no new cases after the end of August 1996. However, it appears that the recent cases are a new outbreak. We are working hard to try and find out why this has happened.

What action was taken to control the winter outbreak?

Companies on the Willowbrook and Weldon North Industrial Estate have been visited again and samples taken from their cooling systems. Cooling-towers and other sources of water in a wider area were also tested at this stage. Following sampling the companies were again advised to disinfect their systems. Those companies which tested positive have been re-tested and disinfected on a regular basis. The results of those tests are now all considered satisfactory, but re-testing and inspection will continue for a further six months.

What action has been taken since a case was identified in the Earlstrees

Industrial Estate?

Since a case was identified on the Earlstrees Industrial Estate, all registered cooling towers in the estate have been inspected by Health and Safety Executive and have been sampled by the Environmental Health Department of Corby Borough Council. In addition, Environmental Health Officers have visited sites on the estate to ask about cooling towers which companies have failed to register. These have also been tested and inspected. Following testing, all companies were requested to disinfect their cooling systems. The Outbreak Control Team will meet again on 10 March to discuss the results of inspection and testing and to decide what needs to be done next.

Should people who visit the industrial estate be concerned?

Tens of thousands of people either work on, visit or pass nearby these industrial estates every week. Of these there have only been 15 cases in the first outbreak and 8 in the more recent outbreak. Clearly, for those who suffer from the illness this is very serious and distressing. Nevertheless, most people who are exposed to Legionella do not become ill. So for most people the risk from visiting either estate is very small. However, anyone who experiences flu-like symptoms and who has links with either industrial estate should consult their general practitioner.

What can people do to lessen their chances of catching the disease? What can companies do to protect their workers?

Because of the nature of the illness there is no specific action which you can take which will guarantee that you will not get Legionnaires’ Disease. It is of note that Legionnaires’ Disease more commonly affects smokers or those with these conditions.

Companies have a legal duty to make sure their cooling systems are properly installed, managed and maintained, in accordance with health and safety guidelines. If they are uncertain about this they should contact the Health and Safety Executive in Northampton.

How long is this outbreak likely to last?

It is impossible to predict how long this will last, but we are taking every possible measure to bring it under control as quickly as possible.

Is there any chance of either industrial estate being closed?

We cannot envisage any circumstances under which either industrial estate would have to be closed. However, legal action could be taken to prohibit the use of plant or process at any particular premises if it was considered necessary.

Are we happy that everything possible has been done locally to combat it?

The Outbreak Control Team is taking all the action it can to minimise the risk to public health. It meets regularly to review progress and consider any new action which may be appropriate The last meeting was today when thirteen new points for action were agreed and a further meeting will take place on Monday.

Will a higher health authority have to be brought in?

As a matter of routine, the Public Health Laboratory Service, the Communicable Disease Surveillance Centre in London and the Department of Health have been informed about the outbreaks. Experts from these centres are members of the Outbreak Control Tes1.

Legionnaires' Disease

Recommendations for Prevention of Nosocomial Legionnaires' Disease

I. STAFF EDUCATION AND INFECTION SURVEILLANCE

A. Staff Education

Educate (1) physicians to heighten their suspicion for cases of nosocomial Legionnaires' disease and to use appropriate methods for its diagnosis, and (2) patient-care, infection-control, and engineering personnel about measures to control nosocomial legionellosis.(659-661) CATEGORY IA

B. Surveillance

1. Establish mechanism(s) to provide clinicians with appropriate laboratory tests for the diagnosis of Legionnaires' disease.(386,414,415,419,704) CATEGORY IA

2. Maintain a high index of suspicion for the diagnosis of nosocomial Legionnaires' disease, especially in patients who are at high-risk of acquiring the disease (patients who are immunosuppressed, including organ-transplant patients, patients with AIDS, and patients receiving systemic steroids; are >65 years of age; or have chronic underlying disease such as diabetes mellitus, congestive heart failure, and chronic obstructive lung disease).(385,386,400,402-406,412) Refer to the accompanying background document for definition of nosocomial legionellosis. CATEGORY II

3. No Recommendation for routinely culturing water systems for Legionella spp.(271,385,429,433,435,436,438-440,456,705) UNRESOLVED ISSUE

II. Interruption of Transmission of Legionella Spp.

A. Primary Prevention (Preventing Nosocomial Legionnaires' Disease When No Cases Have Been Documented)

1. Nebulization and other devices

a. (1) Use sterile (not distilled, nonsterile) water for rinsing nebulization devices and other semicritical respiratory-care equipment after they have been cleaned and/or disinfected.(258,271,706) CATEGORY IB

(2) No Recommendation for using tap water as an alternative to sterile water to rinse reusable semicritical equipment and devices used on the respiratory tract, after they have been subjected to high-level disinfection, whether or not rinsing is followed by drying with or without the use of alcohol. UNRESOLVED ISSUE

b. Use only sterile (not distilled, nonsterile) water to fill reservoirs of devices used for nebulization.(241,252,258,271,706) CATEGORY IA

c. Do not use large-volume room-air humidifiers that create aerosols (eg, by venturi principle, ultrasound, or spinning disk) and thus are really nebulizers, unless they can be sterilized or subjected to high-level disinfection daily and filled only with sterile water.(252,706) CATEGORY IA

2. Cooling towers

a. When a new hospital building is constructed, place cooling tower(s) in such a way that the tower drift is directed away from the hospital's air-intake system, and design the cooling towers such that the volume of aerosol drift is minimized.(422,707) CATEGORY IB

b. For operational cooling towers, install drift eliminators, regularly use an effective biocide, maintain the tower according to manufacturers' recommendations, and keep adequate maintenance records. (See Appendix D.) (422,464,708) CATEGORY IB

3. Water-Distribution System

a. No Recommendation for routinely maintaining potable water at the outlet at = 50°C or < 20°C, or chlorinating heated water to achieve 1-2 mg/L free residual chlorine at the tap.(385,429,440,447-450) UNRESOLVED ISSUE

b. No Recommendation for treatment of water with ozone, ultraviolet light, or heavy-metal ions.(391,460-463,466) UNRESOLVED ISSUE

B. Secondary Prevention (Response to Identification of Laboratory-Confirmed Nosocomial Legionellosis)

When a single case of laboratory-confirmed, definite nosocomial Legionnaires' disease is identified, OR if two or more cases of laboratory-confirmed, possible nosocomial Legionnaires' disease occur within 6 months of each other (refer to background document for definition of definite and possible nosocomial Legionnaires' disease.):

1. Contact the local or state health department or the CDC if the disease is reportable in the state or if assistance is needed. CATEGORY IB

2. If a case is identified in a severely immunocompromised patient such as an organ-transplant recipient, OR if the hospital houses severely immunocompromised patients, conduct a combined epidemiologic and environmental investigation (as outlined from II-B-3-b-1 through II-B-5, below) to determine the source(s) of Legionella spp. CATEGORY IB

3. If the hospital does not house severely immunocompromised patients, conduct an epidemiologic investigation via a retrospective review of microbiologic, serologic, and postmortem data to identify previous cases, and begin an intensive prospective surveillance for additional cases of nosocomial Legionnaires' disease. CATEGORY IB

a. If there is no evidence of continued nosocomial transmission, continue the intensive prospective surveillance (as in II-B-3, above) for at least 2 months after surveillance was begun. CATEGORY II

b. If there is evidence of continued transmission:

(1) Conduct an environmental investigation to determine the source(s) of Legionella spp. by collecting water samples from potential sources of aerosolized water, following the methods described in Appendix C and saving and subtyping isolates of Legionella spp. obtained from patients and environment.(241,258,422-428,452,454) CATEGORY IB

(2) If a source is not identified, continue surveillance for new cases for at least 2 months, and, depending on the scope of the outbreak, decide on either deferring decontamination pending identification of the source(s) of Legionella spp., or proceeding with decontamination of the hospital's water distribution system, with special attention to the specific hospital areas involved in the outbreak. CATEGORY II

(3) If a source of infection is identified by epidemiologic and environmental investigation, promptly decontaminate it.(466) CATEGORY IB

(a) If the heated-water system is implicated:

i. Decontaminate the heated-water system either by superheating (flushing for at least 5 minutes each distal outlet of the system with water at 65ºC), OR by hyperchlorination (flushing for at least 5 minutes all outlets of the system with water containing > or = 10 mg/L free residual chlorine).(450,452,456,457) Post warning signs at each outlet being flushed to prevent scald injury to patients, staff, or visitors. CATEGORY IB

ii. Depending on local and state regulations regarding potable water temperature in public buildings,(458) maintain potable water at the outlet at 50ºC or <20ºC, or chlorinate heated water to achieve 1-2 mg/L free residual chlorine at the tap in hospitals housing patients who are at high risk of acquiring nosocomial legionellosis (eg, immunocompromised patients).(385,429,440,447-450) (See Appendix B.) CATEGORY II

iii. No Recommendation for treatment of water with ozone, ultraviolet light, or heavy-metal ions.(391,460,461,463) UNRESOLVED ISSUE

iv. Clean hot-water storage tanks and waterheaters to remove accumulated scale and sediment.(393) CATEGORY IB

v. Restrict immunocompromised patients from taking showers, and use only sterile water for their oral consumption until Legionella spp. becomes undetectable by culture in the hospital water.(430) CATEGORY II

(b) If cooling towers or evaporative condensers are implicated, decontaminate the cooling-tower system using the protocol outlined in Appendix D.(464) CATEGORY IB

(4) Assess the efficacy of implemented measures in reducing or eliminating Legionella spp. by collecting specimens for culture at 2-week intervals for 3 months. CATEGORY II

(a) If Legionella spp. are not detected in cultures during 3 months of monitoring, collect cultures monthly for another 3 months. CATEGORY II

(b) If Legionella spp. are detected in one or more cultures, reassess the implemented control measures, modify them accordingly, and repeat decontamination procedures. Options for repeat decontamination include the intensive use of the same technique utilized for initial decontamination, or a combination of superheating and hyperchlorination. CATEGORY II

(5) Keep adequate records of all infection control measures, including maintenance procedures, and of environmental test results for cooling towers and potable-water systems. CATEGORY II

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LEGIONNAIRE`S DISEASE, CORBY.

During September 1996, Corby Borough Council was notified by the Health Authority of several cases of Legionnaires disease in people working in particular areas of Corby.

Legionnaires disease is a severe pneumonia illness caused by bacteria which can readily be treated by antibiotics once diagnosed. The bacteria is found widely in nature, particularly in warm water, where it does not usually cause any problems. If the disease is spread it can be through inhalation of affected droplets of water in an aerosol, it is NOT spread person to person.

As of mid October 1996 there have been nine cases of the disease in persons who have links with industrial areas to the north east, of the town. All of these cases showed symptoms around mid August indicating a similar time of exposure to potentially affected water droplets. The time delay between different cases being identified was as a result of differing speeds of diagnosis and retrospective checking of patients who had pneumonia symptoms previously.

As already detailed the Legionella bacteria may be found in warm water and previously they have been identified in water from cooling towers etc where water is used to cool machinery or air. As this fact is known it had been a requirement for several years that all operators of cooling towers register them with their local authority.

When Environmental Services were first notified of cases of the disease it became apparent there was a geographical connection with the three industrial areas of Weldon North, Willowbrook North/East and Willowbrook South. The register of cooling towers revealed a number of companies with such systems and an intensive survey of the areas identified a few unregistered systems. All the systems from the register and those identified by the field based survey had water samples taken for analysis which were taken by officers of the Environmental Services team and sent to the Public Health Laboratory at the University Hospital, Nottingham.

At the time of taking samples, Environmental Services Officers instructed that steps should be taken to shock dose disinfect all systems as soon as possible as a precautionary measure.

In all 48 water samples were collected from 33 systems at 15 different companies over a period of about two and half working days. When all the results were known there were 17 of the 48 samples taken showing a positive result for the presence of Legionella bacteria. It was considered that eleven of the seventeen positive results had the potential for causing human infection on the basis they contained 10,000 c-- more colonies of the Legionella bacteria per litre of water. These eleven water samples were obtained from eight systems at five separate companies.

Upon conclusion of collecting water samples, investigations of water- cooling systems and the maintenance thereof began. All hut one of the companies involved has the Health and Safety Executive as the enforcing authority for health and safety matters, therefore considerable liaison with that organisation, as well as the Health Authority, took place.

The Health and Safety Executive drafted in officers from various locations in order to carry out inspections and investigations at all companies as quickly as possible. As a result of investigations the Health and Safety Executive served several deferred and Immediate Prohibition Notices, as well as a larger number of 'Notices of Intention' to serve an Improvement Notice with respect, in the main, to matters of routine repair and maintenance. The conditions found at the large company for which Corby Borough Council is the Health and Safety enforcement authority did not warrant the service of any Notices and water samples from those premises gave a negative result.

Once all results for the first round of water samples were received, Corby Borough Council instigated a second phase of sampling from systems where positive results were gained from first samples and certain other systems at the request of the Health and Safety Executive and the Health Authority. In the second phase, 22 samples were taken from seven separate companies with only three of those samples producing a positive result with NONE over 10,000 colonies per litre, in fact, two of the positive samples had results of less than 300 colonies per litre, whilst the third was considerably less than half of the noted figure of 10,000. These three remaining positive results have been conveyed to the Health and Safety Executive which is the enforcing authority for the two companies concerned and are still considering further actions in relation to possible prosecutions and further educationally based campaigns over the county as a whole.

The integrated actions of Corby Borough Council Environmental Services, the Health Authority and the Health and Safety Executive served to allay public fears, educate individuals and companies, identify potentially infected systems, have those systems treated so as to remove or reduce the risk of further cases and to consider the need for further action either educationally or in some cases by means of prosecution of certain parties for failing to ensure public safety.

(DCS

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NORTHAMPTONSHIREI HEALTH AUTHORITY

DIRECTORATE OF PUBLIC HEALTH & HEALTH STRATEGYENVIRONMENTAL IIEALTH/COMMUNICABLE DlSEASE CONTROLDirect dial: (01604) 615211

March 5th 1997Fax No: (01604) 615295

To: All companies,Earlstrees Industrial Estate,

Corby

Northants

To whom it may concern,

Dr Marshall

Specialist Registrar in Public Health,Highfield,

Cliftonville Road,

Northampton,

NN1 5DN.

Tel: 01604 615000 Fax: 01604 615010

Chairman: Simon Schanschieff OBE, FCA, JP Chief Executive: Lynda Hamlyn BA(Hons)