Dr Tore Godal is Ex-Director of the WHO Special Programme for Research and Training in Tropical Diseases (TDR) and Executive Director of the Global Alliance for Vaccines and Immunization (GAVI)

Pictures from round the world:

The Pumphandle Lecture series always features a great lecturer and the speaker for the sesquicentenary, Dr Moren, was very appropriate, demonstrating that epidemiology is now a pan-European expertise. Training is essential to maintain and improve the skills of future epidemiologists and EPIET provides courses and training attachments across the “island and the continent” of Europe.

Dr Moren praised the critical thinking of Snow whose exceptional approach was demonstrated by features that were highly controversial in his time, although now forming the foundation of what is now considered the ideals for public health epidemiology:

• Challenging accepted knowledge.
• Field investigation – Snow demonstrated the need for what is known at CDC Atlanta as ‘shoe leather epidemiology’.
• Statistics and comparison of groups with and without a disease
• Cartography – which has led to the geographic information systems to plot disease distributions
• The importance of ‘outlying cases’ (such as the Widow of Hampstead) and anomalies such as the low number of cases at the Broad Street brewery (they had a private well with uncontaminated water)
• Communication – including writing up his theory and investigations
• Research
• Intervention – the removal of the pumphandle now symbolises the ideal public health preventive act.

The challenges are different, not less, in our era. Challenging accepted knowledge has become, possibly, more honoured in theory than in action and bureaucracy, ever a limiting factor on independent thought, can often take up so much time that field investigation and research may suffer. Establishing an epidemiological network across Europe has been a remarkable achievement, although much needs to be done and adequate funding is hard to maintain against other priorities. The concept of a ‘Europe of Health’ is not just a desirable ideal, but a practical necessity for a world with increasingly blurred boundaries, frequent travel and transport of foods from one side to the other. A coordinated epidemiological network is particularly important for communicable disease, which ignores political borders and can cause a rapidly escalating crisis. It took a long time to establish the need for EPIET: the Treaty of Rome for the European Union was in 1957, while the decision to finance European epidemiological surveillance was made by an EC decision numbered 2119 only six years ago, in 1998. The network is poised for another major development in 2005, when the European Centre for Disease Prevention and Control will open in Stockholm. Decision 2119 featured some important key words:

• Surveillance of communicable disease
• Early warning and response
• A permanent link between the Commission [EC] and responsible structures/authorities in Member States

There are now many networks for particular diseases, such as AIDS/HIV (the oldest, started by France), measles, hospital infection (HELICS), Legionella infection – and with a network for listeria due to start next year. Up to 51 nations participate in each network, with funding for independent networks provided by Member States and the coordination funded by the EC. ENTERNET, the surveillance system for gastrointestinal infection, has played an essential role in the control of salmonella outbreaks: to give just once example, an epidemic of over 4000 cases of Salmonella agona was achieved through networking between England and Wales, Canada, Israel and the USA.

Despite the success of the networks, they remain fragile, a patchwork still struggling to be firmly ‘joined up’: the threats including competition for funds (the surveillance of HIV and TB, for example, temporarily depended on independent funding by Member States); bureaucracy that swamps coordinators with paperwork; and, not least, yearly contracts that prevent long-term planning. Add to this the different approaches to epidemiological method, varying scientific terms and languages – and it seems remarkable that the networks have done so well. Field-orientated training, providing practical experience, has been based on several European strengths: the excellent universities, national schools of public health, the strong public health tradition of the UK and links between several countries, notably France, with CDC Atlanta. The existence of field epidemiology training programmes in several European countries (e.g. UK, Hungary, Italy, Spain, Germany) fuelled the idea for exchanges between countries – and so EPIET was born.

ET has several training objectives:

1. To plan, implement and evaluate a European surveillance system;
2. To perform outbreak investigations;
3. To develop research projects and to examine public health issues;
4. To enhance oral and written scientific communication skills;
5. To acquire teaching skills.

There is a 2 year practical training which starts with a 3 week introductory course and includes six one week training modules that rotate between European states. The emphasis is on ‘learning by doing’, with on-site supervision by a senior epidemiologist: an important corollary is that the ‘fellows’ will go on to train others. One problem is that EPIET fellows often enjoy their attachments in another country so much that they are reluctant to return, or are recruited to the World Health Organisation (WHO): this has created some funding dilemmas for the states that funded their training. On the other hand, the existence of EPIET has had a ‘snow ball’ effect by inspiring the establishment of field epidemiology training programmes (FETPs) in Nordic countries, the Middle East and Romania. Courses are open to external participants: some 400 from all over Europe have benefited, while 119 EPIET fellows have now graduated and many hold senior positions. There are now 19 training sites, with 27 nations and the WHO participating.

Recent successes for the network include coordination of the SARS outbreak in 2003 (the subject covered in last year’s Pumphandle lecture), a large outbreak of Salmonella typhimurium 204b in 2000 and, in 2004, control of an outbreak of Hepatitis A in tourists returning from Egypt. The Hepatitis A outbreak involved over 200 cases in 14 countries. Another outbreak of Hepatitis A in 2001, affecting mainly German tourists, was traced to Ibiza and required investigation of restaurants, shops, secondary cases and other factors involved in the chain of transmission. In the UK, the network also helped to investigate Clostridium infection in IV drug users in England, Scotland and Ireland in 2000. Such investigations have raised the issue of the need for coordination of communications: we are still a long way from the CDC Atlanta example of ‘everything in one phone call’: ensuring that all relevant staff have been informed is an extremely time consuming exercise for all Member States, not least in the UK.

The European network has also supported international missions to countries outside Europe: SARS in Asia in 2003; investigating infant deaths following immunisation in Egypt; Ebola in Uganda, the Congo, Gabon and Sudan; tularaemia in Kosovo. Strong administrative back up is needed for such missions, as well as ways of working with bureaucracy to ensure appropriate dissemination of results. In addition, there are issues such as security and independence of the doctors and scientists on the missions – and the socioeconomic implications such as the impact on tourism. Investigation may continue long after the outbreak has subsided: for example, further investigation of the SARS cases in Hong Kong. Speed is of the essence for an efficient epidemiological network, something that Snow demonstrated so well in his rapid assessment of the cholera outbreak in 1854. Bias and misinterpretation by others of his results was a problem for Snow – and it still occurs, when evidence of a possible cause is pounced on and prevents further analysis of other factors.

The network has undoubtedly proved valuable to the participating Member States and partners, for example in:

• Complementing university teaching
• Promotion of field epidemiology in Europe
• Training the trainers
• Promotion of national training programmes
• Increased mobility of epidemiologists with the EU
• Cross border – and international – investigations
• Coping with emergencies and bioterrorism.

Nevertheless, there is room for improvement. In 2002 the Byrne Commission Report concluded that Europe is not fully prepared for epidemics, hence the impetus for the coordinating centre in Stockholm. This ‘Eur-CDC’ will have links with laboratories, investigation, research, training, decision making and communications. It is the first important step to the ‘one stop shopping’ concept that CDC has been able to achieve in the USA. The Director of this new centre has yet to be appointed, but there may be news by the time this article appears. To conclude his lecture, Dr Moren eloquently described the benefits of a Europe that has now been a ‘space for peace’ for 50 years, with increasing harmony of human rights and economic exchange: time surely to advance Europe as a space for human networking. Dr John Snow would surely have taken up the challenge of epidemiology in Europe: meanwhile, you can find out more about EPIET on the website.

On 22 September 2003, Dr Mike Ryan gave the 11th annual John Snow Society Pumphandle Lecture at the London School of Hygiene and Tropical Medicine.

In the last half of the 20th century, following the development of modern antibiotics and vaccines, there were confident predictions that infectious disease would soon be vanquished – and no longer be a priority issue for public health. While there have been success stories, we know now that such optimism was sadly misplaced, particularly when considering the continuing global impact of infections. To date only one infection, smallpox, has been eliminated in its natural environment: the WHO announced official eradication of smallpox virus in 1980. In the decades following this magnificent achievement, several epidemics of new harmful micro-organisms (pathogens) have emerged, such as, legionnaires’ disease, cryptosporidiosis (the parasite associated with animal and water spread), AIDS/HIV, resistant bacteria in hospitals and campylobacter, now the commonest cause of bacterial intestinal infection. Newly emerging pathogens have been accompanied by re-emerging pathogens such as cholera and tuberculosis. The zeitgeist of globalisation, a term which could be said to characterise the modern age, includes the much increased potential for rapid spread of pathogens through food imports, travel and in the very air we breathe. So the epidemic in 2003 of another new disease, SARS (Sudden Acute Respiratory Syndrome) was a particularly appropriate topic for the 11th Pumphandle lecture, delivered by Dr Mike Ryan for the John Snow Society on 22nd September at the London School of Hygiene and Tropical Medicine. Dr Ryan is the coordinator of the Global Alert and Respiratory Unit of the World Health Organization (WHO), a unit formed in 1996 to counter infections of global importance, such as Ebola – and now, SARS.

The SARS story started quietly in a remote part of China (Table 1). In February 2003, local health workers made unofficial reports of cases of atypical pneumonia with a high death rate. A few days later this was officially confirmed and similar cases were identified in Hong Kong and Viet Nam. The illness started with fever and dry cough, not unlike influenza, but rapidly progressed in some cases to difficulty in breathing: up to 10% needed mechanical ventilation and up to 20% required treatment in intensive care units. Many people also developed diarrhoea, a point which helped in the epidemiological detective work later. Within a month, evidence of ‘globalised’ infection came from Ontario and Singapore and increasing concern about the role of international travel in spreading the infection. By this stage, the WHO Global Alert & Respiratory Unit had already coordinated teams to affected areas and was under intense pressure from the media. Mostly existing with only a few hours sleep, the team at the WHO painstakingly unravelled the epidemiology of this new infection, traced to a previously unknown type of corona virus. Thanks to email, teleconferencing and other forms of communication, rapid progress was made by linking with units around the world: this is the first epidemic where new communications technology played a major role. The team also worked to basic public health principles, trying to find answers to those key questions familiar to outbreak investigators: what is the infection; what does it do to people; how does it do it – and how do we stop it? With no vaccine and no specific treatment, the answer to that last question rests on public health measures: quarantine of known cases and avoiding contact with those infected. The team composed advice based on simple but effective rules – how do we detect it, how to we protect people from it. The epidemic has raised questions about facilities for artificial ventilation and for the prevention of infection by air filters and quarantine.

During the early stages of the outbreak, there was inevitably criticism of lack of progress and decisions: many preliminary decisions about intervention measures had to be made with limited information. The advice about international travel was controversial, for example the removal of Ontario from tourist itineraries at one stage. Thus Canada and other countries experienced yet another blow to tourism, still not recovered after the 11 September atrocities of 2001. Yet a glance at the chronology shows that continual progress was made throughout the epidemic. Research investigations in Hong Kong were particularly helpful, showing the potential for airborne spread in the high number of affected health workers and in the cases in a hotel and an apartment block. In the latter, a block in the Kowloon Bay area of Hong Kong, 41% of cases were associated with just one wing and two thirds had had diarrhoea. Environmental investigation revealed a combination of a cracked sewage pipe and contamination of the ‘U-bend’ trap in toilets. This was believed to have infected people in apartments on different levels of the wing via aerosol and droplet spread. While not a typical way in which SARS spread, it provided a neat ‘water-associated’ link for the Pumphandle Lecture: Dr John Snow would surely have approved of this detective work!

Now that the SARS information is much more complete, several important preventive measures have emerged. First, the virus is highly infective and rapid isolation with barrier nursing is essential. Second, there is clear evidence that it was spread by travel, so restrictions on journeys, particularly by air, will be essential if SARS re-emerges. Smallpox is now known to have spread throughout the world, centuries ago, via the silk trading route. Thirdly, there is potential to develop a vaccine. However, vaccines are not without problems and during the eradication of smallpox the vaccine side effects included death or disability. Perhaps one of the strongest messages is that we lose our traditional public health skills and tools at our peril – when a new infection emerges, the tried and tested ways of controlling epidemics are our best defence. In the final part of Dr Ryan’s fascinating lecture, he placed the SARS epidemic into the perspective of the way public health – and its threats – have developed over the last two centuries. Prevention methods based on the miasma theory (disease spread by ‘evil vapours’ in overcrowded or poor conditions) led to improvements in sanitation and ventilation that reduced the spread of microbes, although the ‘miasma’ emphasis, combined with the limited understanding of microbial spread in the early days of the germ theory, led to a possibly over-militarised approach. Now that the complexities of environmental spread are more clearly understood, we should be in a strong position for the current set of potential threats (Table 2). Global public health campaigns have reduced levels of some of the old enemies: guinea worm, poliomyelitis, measles, leprosy and neonatal tetanus. But the resurgence of many others, such as malaria and TB, is partly due to the patchy and, in some countries, declining state of public health services. Basic core standards of surveillance need to be matched by global partnership in the fight to counter those bugs that respect no borders. SARS has taught us “what should be in there”, such as enhanced surveillance, coordination of a “network of networks”, rapid response and attention to emerging issues such as animal-human transmission of infection. The SARS experience also showed that the coordination and intervention required does not come cheap: the overall cost of the public health work on the epidemic was an estimated $22 million dollars, way over the modest budget of the WHO unit. Considerable powers of persuasion and diplomacy were needed to raise the funds required: but another lesson of SARS was that the price of uncoordinated or tardy action would have been an even greater economic cost to airlines and hotels. It is a measure of the success of the measures taken that there was rapid recovery of the impact on tourism. Delayed recognition and reporting of this type of epidemic remains a difficult issue: the first major revision of the International Health Regulations since 1969 has been making slow progress over the last five years. Meanwhile, Dr Ryan and his colleagues in the Global Alert and Response Unit continue to build on three basic pillars of public health: containment of known risks, responding effectively to the unexpected and improving awareness.

This well attended Pumphandle lecture finished in the traditional way with the ceremonial removal of the pump handle on the Society’s pump – and a lively discussion and Annual General Meeting afterwards at the John Snow pub.

Ros Stanwell-Smith
Hon Secretary, John Snow Society

Date	Event
11 February	Unofficial reports of deaths from an unusual pneumonia in Guangdong Province, China
14 February	Official confirmation of epidemic by Chinese Government: 305 cases, 5 deaths
19 February	Two cases of Avian Flu (H5N1) in Hong Kong, linked to contacts in mainland China
26 February	Cases in Hanoi, Viet Nam
4 March	77 cases in medical staff at a hospital in Hong Kong
5 March	7 cases in medical staff at a hospital in Hanoi
8 March	WHO teams arrived in Hanoi & Hong Kong
12 March	First Global Alert
14 March	4 cases in Ontario, Canada & 3 in Singapore
15 March	Urgent Global Alert & broadcast of the case definition: advice re: travel risk given to international travellers
17 March	Establishment of ‘virtual’ research networks using communications technology
31 March	Outbreak of SARS at hotel in Hong Kong: confirmation of potential airborne threat
2 April	Passengers advised to postpone non-essential travel to Hong Kong or Guangdong Province.
April-August	Epidemiological and laboratory investigations confirmed the mode of spread, incubation, course of the illness and the nature of the virus, a new corona virus
21 September	Latest toll of cases: 8097, of whom 774 had died. 30 countries involved, although 92% of known cases were infected in China.

Type of infection threat	Example	Key points for public health
Emergence of new pathogens	AIDS/HIV, Legionella, SARS	The unexpected nature of emerging/resurging infectionsUnstable or poorly understood types of transmission
Resurgence of ‘old’ pathogens	Tuberculosis, Malaria, Cholera, Dengue fever, Ebola, Rift Valley Fever, West Nile Fever, Anti-microbial resistance	Large potential impact on economies and public health facilitiesCollapse of public health infrastructure in areas of conflictIncreasing urbanisation, exploitation & degradation of the environment
Accidental release	Bovine Spongiform Encephalitis/ CJD	Better understanding of the interface between animals and humans and the potential for ‘cross-species’ spread
Deliberate/ malicious release	Anthrax, smallpox	Need for sensitive surveillance systems

The 10th annual John Snow Society Pumphandle lecture, given by Dr David Salisbury, focused on the public’s concern for vaccine safety; where this fear comes from and how the Department of Health tackles these problems.

Dr David Salisbury is a Principal Medical Officer of the Communicable Disease Branch, the Department of Health, London, where he leads the group responsible for immunisation and communicable diseases. In addition to his UK responsibilities, he works extensively for the WHO on the Global Programme for Vaccines. He serves on three Regional Commissions for the Certification of Elimination of Poliomyelitis. Dr Salisbury graduated from London University in 1969. He trained as a paediatrician at Oxford and at the Hospital for Sick Children, Great Ormond Street, London.

He also has an honorary Senior Lectureship in Child Health at Kings College, London. He is an honorary visiting fellow at the Wellcome Centre for Infectious Disease Epidemiology, University of Oxford, is a Fellow of the Royal College of Physicians, Fellow of the Royal College of Paediatrics and Child Health, and a Fellow of the Faculty of Public Health Medicine.

Dr Salisbury was made a Companion of the Order of the Bath in the Queen’s 2001 Birthday Honours.

Dr Salisbury stressed that serious adverse reactions to vaccines occur extremely rarely. However, when they do occur they are a cause for concern and attract considerable media attention. He discussed how vaccine safety scares often arise from reports (often presenting data collected through active searching) where a series of cases of the adverse vaccine reaction have occurred. These reports, referred to by Dr Salisbury as ‘stamp collections’, often get published in professional journals, despite having little relevance to the background risk, and should not be taken as evidence in support of an association. However, said Dr Salisbury, they may form the basis of a hypothesis that should be then tested by a properly designed study against the criteria of biological plausibility.

Dr Salisbury gave the following example to highlight the significance and major knock-on effects of these ‘stamp collections’: In 1994 the UK’s Department of Health ran a nationwide immunisation campaign for the measles-rubella vaccine. All school children, aged 5 up to 16, were immunised in the space of six weeks. However, there was a cluster of cases of the disease Guillain-Barré syndrome occurring post-immunisation. These cases were picked up by media journalists, who made it into headline news and this is where the hypothesis that there might be a causal association between measles vaccination and Guillain-Barré syndrome began. This then became a scare over the measles vaccination and individual stories of the vaccination victims with adverse effects came to light. In response to this particular scare, Dr Salisbury explained how the department of Health tested the hypothesis independently by setting up a collaborative study with the Pan America Health Organisation. In response to this particular scare, Dr Salisbury explained how the Department of Health tested the hypothesis independently. The tests were carried out here in the UK and in the Americas. The risk of Guillain-Barré syndrome, detected through acute flaccid paralysis surveillance, was compared in both measles campaign periods and non-campaign periods. The results from this study demonstrated that there was no significant risk of Guillain-Barré syndrome following measles vaccination. So, concerns start in the professional press, but it doesn’t take long before these seep into the wider media. Extensive reportage in the media gives any vaccine scare story the potential to travel extremely fast all over the world. However, negative results do not attract media attention and these are poorly represented in the newspapers.

As the Principal Medical Officer of the Communicable Disease Branch at the Department of Health, Dr David Salisbury needs to deal with all of the above on a regular basis. The strategy the Department has in place is to try to predict scares, then try to prepare for them, alongside aiming to be proactive and achieving positive responses. Although they cannot always predict vaccine safety scares, the Department of Health does have a reasonable idea of the topics that are likely to attract public interest. These, not surprisingly include autism, multiple sclerosis, multiple vaccines and immune overload, which all share the common features of uncertain manifestation and long latency that the public fears. The public expects authorities to prove that studies claiming vaccine risks are false, or the theories stand unchallenged.

In preparation, it is critical to gather as much information as possible and to find out if adequate data already exists that can answer the problem. If not, how feasible is it to collect new data? If the answer is we are awaiting results from these studies, then this does not reassure the public!

It is necessary to be proactive during a vaccine safety alert. Health professionals must be alerted promptly about the scare before the media reach them. However, this can often be difficult because of embargoes on publications. It is very easy for journalists to find a doctor who may give unhelpful comments, often based on ignorance, but that the public will believe. The Department of Health prepares information materials for all audiences. References are given to parents to add credibility. The information is targeted to the right health professionals and to the right parents at the right time.

In times of vaccine safety scares, positive responses from authoritative bodies are essential. The most important thing is to tell the truth and give clear messages. Parents do want to feel that they are making a choice, but very few will have sufficiently detailed knowledge to actually be making a fully informed decision. Dr Salisbury believes that a choice of risks should not be offered because it is very difficult to put into realistic terms the risks and benefits. In addition, it is important not to patronise parents by being the ‘expert’. Professional support has been shown to help reduce scares dramatically and, therefore, it is necessary to have contacts in these fields. For example, if a media doctor, especially one appearing regularly on morning TV, informs the public that a vaccine is safe, they will believe and trust this doctor.

As part of their communication research programme, the Department of Health carries out two nationwide surveys each year. One thousand mothers, with children under the age of three, answer a series of questions related to vaccines, where they get information from and who they trust in relation to vaccine information. The surveys are geographically representative and question mothers from all walks of life. An additional two surveys have been added to the annual programme which ask questions specifically related to the MMR vaccination. The results from these surveys help the Department predict, prepare, and be proactive.

In conclusion, Dr Salisbury said that the internet had become a ‘battle ground’ of information to be picked up by eager journalists, emphasising the point that poor scientific reports, that may not have been properly scrutinised, are now immediately available for all to see on the internet. We must concentrate on presenting the truth to parents, said Dr Salisbury, to allow them to remain confident with our vaccination programmes.

Following his excellent lecture Dr Salisbury took numerous questions from the audience. Members of the John Snow Society then gathered in the John Snow pub in Soho for the annual general meeting of the society.

Professor David Bradley gave the ninth in the series of Pumphandle lectures of the John Snow Society on 5 September 2001 at the London School of Hygiene and Tropical Medicine (LSHTM).

The subject of the lecture was particularly appropriate to the memory of Dr John Snow and to the ‘pumphandle’ theme celebrating interventions and innovations in epidemiology and public health. Professor David Bradley’s long association with the LSHTM includes becoming Director of the Ross Institute in 1974 and he has an international reputation for his work on malaria and also on water. It was water that dominated his lecture on this occasion, with a summary and update of the classic study of domestic water use in East Africa (White, Bradley and White 1972). Professor Bradley paid tribute to Dr John Snow as the father of evidence based environmental health, for example in Snow’s emphasis on the importance of good drainage and on ample supplies of water free from sewage contamination. This goal still eludes over 2 billion people in developing countries (WHO 2001), nearly 150 years after the outbreak in Broad Street, which Snow used to complete his analysis of the spread of cholera in contaminated water in 1854. Professor Bradley argued convincingly for the unification of approaches to health and the environment and concluded his reflections on water with the symbolic importance of water in art, beautifully illustrated by drawings and paintings from around the world.

The study in East Africa 30 years ago was the first comprehensive survey of domestic water use, involving households and sites in Uganda, Kenya, Tanzania and Rwanda. The important findings included the high cost of water and the wide range of water volume used, with marked differences between those receiving piped and unpiped supplies. Those with piped water used between 10-650 litres per head, compared with 4-40 litres per head in areas with no piped supply. The cost of water was high: for example, 10% of the income of unskilled workers in Mulago (Uganda). Piped water in Africa cost the equivalent of 26 days’ salary a year, whereas in water-rich USA it cost only 1-2 days’ salary a year. Water consumption was closely linked to distance from the water supply and the study showed that it fell only when the users were more than a mile away. The study also examined cultural aspects of water use, for example restriction of bathwater in the home to men and the role of children in carrying water. The outcome of the study was a revision of the agenda for water, going beyond traditional water quality issues to ex-amine improvements and to categorise water related disease by type of source and water use/access.

Thirty years later, John Thompson of the International Institute for Environment and Development in the UK and colleagues in East Africa conducted a follow-up study Drawers of Water II. Astonishingly, many of the old records used in Drawers of Water I were still available to be used as comparison. While revealing some changes for the better, such as a doubling of the years of education of the water users, the follow-up survey found that water cost had risen and the time taken to collect water, for those with unpiped rural supplies, had risen from an average 15.8 minutes to 25.3 minutes. The volume of water use had doubled and the number of trips per day had risen slightly, while the average distance to the water source was much the same. By contrast, the volume of piped urban water used had fallen. While the population in the study areas had increased, water use was in general more efficient and there had been a cultural shift in water carrying. Women carried the old style containers on the head: with new large plastic containers, it had become more acceptable for men to carry water to supplement supplies. The study also examined environmental changes in water use and storage, showing for example that changes to papyrus swamps in Uganda had encouraged breeding of Aedes gambii mosquitoes.

Drawers of Water I and II demonstrated the value of repeat studies and the ‘long focus’ needed to assess the impact of water on health and the environment. While environmental health action is still dominated by legal enforcement issues, comprehensive studies such as Drawers of Water I and II show the importance of cultural ‘hard points’ that restrict change, the effect of loss of community and the changing baselines that determine the water-health relationship. Social justice becomes as important a factor as epidemiological evidence when trying to improve water-related public health.

In the final part of his lecture, Professor Bradley explored why water appears so often in landscape painting and other forms of art. At one level, water represents a refuge or pleasant prospect; at an environmental level, the frequent portrayal of water in art also suggests recognition of the importance of water to our habitat. He finished by agreeing with the medical writer René Dubois that we should not try to conform to the environment created by social and technical innovations; but that we should instead design environments adapted to our nature. This was an inspiring conclusion to a brilliant lecture combining water themes of science, art, medicine, epidemiology, history, public and environmental health.

As for most previous lectures, it was standing room only in the lecture theatre and afterwards at the John Snow pub, where members gathered to celebrate the memory of Dr John Snow and to hold the annual general meeting of the Society. It was also an important occasion for the Royal Institute of Public Health (its name from January 2002), as the first lecture held since relocation of the John Snow Society to the Institute. The annual ceremony of removing and then replacing the pump handle was a reminder of the continuing challenges remaining to public health in water and in other fields.

References

• White GF, Bradley DJ, White AU. Drawers of Water: Domestic Water Use in East Africa. Chicago, USA: University of Chicago Press, 1972
• World Health Organization. Water for Health: taking charge. Geneva: WHO, 2001 (WHO/WSH/ WWD/O1.1). See also www.worldwaterday.org and www.who.int/water_sanitation_health

The Influenza story has parallels with the search for the origin of many other infections. Cholera, still present in Europe at the turn of the twentieth century, was the subject of huge debate about its origins. Dr John Snow’s methodical approach in the 1850s solved the mystery of its transmission, laying the way open for future microbiological discoveries, culminating in the publication, in August 2000, of the cholera pathogen sequence (Nature, 3 August)

Dr John Snow would have been delighted, although little realising that it would take this long and that cholera would still be a major infection problem in many countries in the late 20th century. In reaching a full understanding of the pathogen, it is not so much an end to cholera as an ‘end to the beginning’. Snow’s major contribution in cholera was, of course, the demonstration of the water link. Water plays a part in the Influenza story too, not least in its origins. Influenza was possibly an early example of a virus jumping between species. It appears to have moved from an aquatic bird to humans around 10,000 years ago.

By the late nineteenth century, ‘flu was a familiar winter visitor although the viral cause was not understood. The epidemic of 1899 was known as “Russian Flu” and coincided with another wave of cholera in Europe. Recently Professor Oxford and his colleagues have been given permission to exhume some of the victims of the 1899 epidemic, to attempt to identify the nature of the Influenza virus responsible. This is not merely an academic exercise: no laboratory samples survive from the 1899 wave of the disease. This makes it very difficult to be precise about the specific virus responsible.

Most of the epidemics and pandemics are due to shifts or drifts in the Influenza A virus types, and the modern issue is when or whether another major shift will occur, causing widespread illness, since neither vaccination nor immunity to previous Influenza types would afford adequate protection. The 1918 pandemic, following so closely the exhausting end of the First World War, was devastating in its effects. In epidemiological terms, it was a huge natural experiment, and its study helps in the understanding of this pandemic disease, just as Dr John Snow’s scientific approach assisted in the control of cholera. To help us to imagine the times of the “Forgotten Plague”, Professor Oxford showed the page of deaths from the London Hospital’s children’s ward in November 1918, at the start of the pandemic. In addition to deaths from ‘marasmus’ (severe malnutrition), there were several listed as “Influenza-pneumonia”. One, Ivy Goddard, was only eight when she succumbed to the disease. The combination of widespread malnutrition and a new infection was inevitably lethal for this East London population, as in many other countries hit by the pandemic. Typically, death was heralded by cyanosis (blue appearance) of the lips and ears. This was matched by grave pathology in the lungs, resembling the effects of gassing, a problem familiar to the pathologists of the time from examination of war victims. The predominant theory was that the disease was due to a bacterial infection. The rapid deterioration of victims was also a reminder of the bubonic and pneumonic plague years of the distant past: a Breughal painting from the time of the Black Death (Plague), The Triumph of Death, showed Death on a pale horse, striking randomly with his scythe. The 1918 pandemic inspired many such images in cartoons and contemporary reports; it was also vividly described in the novel, ‘Pale Horse, Pale Rider’ by Katherine Anne Porter. Families were parted by death, including many couples who married shortly after the First World War, leaving widows and widowers all over the world. Worldwide, it is estimated that the pandemic caused 40 million deaths, the largest outbreak ever experienced.

The death toll did not stop with the decline of the pandemic: the ‘drift year load’ of subsequent epidemics, with slightly different types of the virus, also had high fatality. The famous actress and royal mistress, Lily Langtree, was one of the later victims. A cartoon of the Millennium Dome being punctured with needles was a reminder of the continuing drift year loads: around 19,000 deaths were attributed to Influenza over the 1999-2000 New Year period.

In 1933, there was a major breakthrough in understanding Influenza, when Charles Stuart Harris, Wilson Smith and their team isolated the virus in North London. This meant that physicians and scientists could now go back and examine fixed specimens from previous epidemics, as well as investigating the possibility of exhuming people who had died. Because the virus deteriorates rapidly in dead tissue, this latter route produced little initial success. What was needed was deep frozen tissue, where the virus might have survived or to have persisted, at least, in a state to allow identification. So began the story of the research into a group of miners who died from the pandemic in Spitzbergen, in the far north of Norway. Spitzbergen was a small mining community well used to Arctic hazards: citizens kept rifles to hand in case of attacks by polar bears and accident-related mortality was high. In October 1918, a ship arrived with miners to serve in the mines in the area. They caught ‘flu en route and seven of the miners died before arrival, 10% of those on board. These victims were hurriedly buried in the frozen ground. Decades later, a Canadian researcher, Dr Kirsty Duncan identified the probable location of the graves. Ground penetrating radar was used to pinpoint the site, picking up signals from the victims’ bones.

The next step was to obtain sponsorship and permission to exhume the bodies. A project of this type required considerable sensitivity and respect for the deceased miners, as well as permission from surviving relatives and the Norwegian authorities: it also needed research sponsorship of around £250,000. An international team returned to the site with 17 tons of equipment, and with expertise ranging from virology to professional grave digging. Local people were amused to find that the equipment taken to this polar region included a large fridge: but this was not a case of ‘coals to Newcastle’: any specimens would need to be kept at a constant low temperature (-20°C) during the research and return journey. A BBC documentary showed the disappointment of this team when they discovered that the Influenza victims had not been buried as far down as the permafrost, the permanently frozen layer. The bodies were higher up, in a layer that froze and thawed each year. But all was not lost. Previous experience with exhumations had shown that viruses could survive in identifiable form within sealed lead coffins, in formalin fixed specimens and in frozen bodies. Despite the deterioration during the thaws, some tissue had survived. In later examinations of specimens, signals of RNA – the nucleic acid of the virus – were detected. The celebration of this, in an issue of Esquire as “Virus beaters: the answer is buried in the ice”, belied the months of painstaking research required to uncover the secrets of the 1918 virus. While the RNA signal was detected in parts of the lungs and kidneys, the best signal was from brain samples. Research is underway to see whether the 1918 virus (Influenza A HA1/HA2) had an extra ‘pathogenic’ sequence giving it additional virulence. A sample from a surviving victim of the encephalitis lethargica epidemic of the 1920s (as fictionalised in the 1990 film ‘Awakenings’), suggested that this virus could have caused the strange disease, with its propensity for the brain. Because of the widespread pathology and severe pneumonia, possible early outbreaks of this strain were not attributed to ‘flu. Thus an outbreak in France in 1917 was described as “purulent bronchitis”: the virus responsible was Influenza and, to match the Spanish Lady of 1918, this one has been dubbed “The French Lady”. The strain that hit the Spitzbergen miners in October 1918 was particularly lethal: it may be no coincidence that the bodies of victims in Alaska and Carolina, also exhumed for viral study, relate to deaths in the same month.

Articles on emerging diseases often include the possibility of another pandemic. If it comes, have we made sufficient progress? What, in short, have we been doing to fight ‘flu since 1918? This is a question that perhaps the victims, like little Ivy Goddard, would have asked. Apart from vaccination, which necessarily has to be based on previous circulating strains, there have been developments that offer hope of effective treatment. The neuraminidase molecule was identified in the 1970s, leading to the development of a drug against Influenza, acting by binding to the amino acid on the neuraminidase spike of the virus. Its safety is still being tested on a large scale, but animal and human studies already suggest it could act as a prophylactic (preventing infection in around 90% of cases) as well as a treatment. In general, we are also far better nourished than the victims of 1918, so that the progress of the disease would be less rapid and less fatal in its course.So, vaccines and advanced drug therapy may be the future ‘Pump Handle’ for this virus, along with the established public health lessons regarding respiratory transmission in crowded spaces and the need to keep up surveillance and early warning systems. This was a worthy topic and lecture in the John Snow Society tradition, and Professor Oxford concluded the talk with the accustomed ritual of removing the Handle from the Society’s ceremonial Pump. The Handle was then returned to the Pump, as neither Influenza, nor many other diseases, have been vanquished yet. The meeting ended with another regular ritual: celebrating the memory of Dr John Snow at the John Snow Pub in Soho.

The following paper from Professor Pennington is based on a lecture he gave for the John Snow Society at the London School of Hygiene and Tropical Medicine in September 1997.The following paper from Professor Pennington is based on a lecture he gave for the John Snow Society at the London School of Hygiene and Tropical Medicine in September 1997.

At the end of a week of myth-making, with the funeral of Diana Princess of Wales only two days before, I felt it appropriate to start the Pump Handle Lecture by looking at John Snow through the eyes of the artist who painted his portrait in 1851, because of its vivid contrast with the well-known photograph by Maull and Polybank taken not long before he died. The idealised image of the former showed no signs of the ravages of hypertension and bad kidneys that can be read into the latter.

To continue with the theme of images, Snow’s 1855 “On the mode of communication of cholera” was revolutionary not only in what he said but in the way that he said it. The significance of the pump handle removal apart, the force of the street map showing the location of cases around Broad Street is overwhelming, not only in its originality in its historical context but for its strength as an investigative and demonstrative tool. Its heuristic power continues. What about Wishaw? What lessons has the 1996 Scottish E. Coli 0157 outbreak taught us? The legal process there is still active with all the constraints that that brings. To protect myself against an inadvertent breach of the sub judice rules I describe the events there through the eyes of the press.

The first cases in the outbreak came to the notice of the local public health department on Friday 22 November 1996. The hidden hand, which determines that the earliest – and therefore the most important – events and activities in an outbreak always occur over a weekend, was clearly acting with full force here! Its evolution over the next fortnight was marked by the headlines: “Town in fear” (25 November, 35 cases), “Food bug outbreak spreading” (26 November, 65 cases), “Traders warned, killer meats still a threat” (29 November). At this point 120 cases had been reported in Lanarkshire, 13 in Forth Valley (30 miles away), 2 in Glasgow, and 1 in Edinburgh, and five attendees at a meal provided for the frail elderly at the Wishaw parish church hall on 17 November had died. By this time it was clear that the butcher’s shop at the centre of the outbreak supplied not only Wishaw, a small run down industrial revolution town in th Lanarkshire badlands, but used its 40 staff to prepare meat and meat products for many outlets across central Scotland.

At this point, the Secretary of State for Scotland asked me to chair an expert group to enquire into the circumstances of the outbreak, learn lessons from it, and make recommendations. Needless to say, this administrative move had no effect on the evolution of the outbreak. Neither did it diminish press coverage. Rather, it intensified it and made it more, rather than less, political, with headlines like “Cutback fears of the food doctors” (30 November, 173 cases; expressing the fear that the categorisation of public health doctors in Scotland as administrators would make them even easier targets for downsizing) and “Raw deal from food police” (1 December, 232 cases; a right-wing attack: “food police already have enough powers … what is needed is a more sophisticated intelligence system to track the when and how of sporadic outbreaks”). The cartoons were also appropriate (figure 1). By mid-December the outbreak was over (figure 2), and the hogmanay my expert group’s interim report with priority recommendations was on the Secretary of State’s desk. It was published in mid-January and accepted in toto by the government. How was it received? To quote my actual words “there’s been an enormous amount of jumping up and down and shouting about what was being done and what wasn’t being done … but as soon as it was suggested that butchers should tighten up their act, especially with the physical separation of raw and cooked meats, we got some moderately hostile publicity” (figure 3). Events moved on, particularly on the policial scene – a row about the alleged rewriting of an official report on conditions in abattoirs received full media coverage. Without a doubt this publicity was good for the expert group (figure 4). Our final report was published on 8 April. It has 32 wide-ranging “plough to plate” recommendations.

At this point I addressed the title of my lecture, which was about the philosophical principles underpinning our work. I epitomised a particular and critical view of epidemiology by quoting Macaulay’s 1837 analysis of Bacon’s scientific method: a plain man finds his stomach out of order. He’s never heard of Lord Bacon’s name but he proceeds in the strictest conformity with the rules laid down in the second book of the Novum Organum, and satisfies himself that minced pies have done the mischief. “I ate minced pies on Monday and Wednesday, and I was kept awake by indigestion all night,” “I did not eat any on Tuesday and Friday, and I was quite well.” “I ate very sparingly of them on Sunday, and was very slightly indisposed in the evening. But on Christmas day I dined on them, and was so ill that I was in great danger.” “It cannot have been the brandy, which I took with them, for I have drunk brandy daily for years without being the worse for it.” Our invalid then proceeds to what is termed by Bacon the Vindemiatio, and pronounces that mince pies do not agree with him.

After raising the issue that much of epidemiology is obliged to rest on such old-fashioned inductive scientific principles – with all the problems attendant on that approach – I went on to ride a personal hobby-horse, which is to emphasise the power of another scientific principle first enunciated by the Victorian polymath, William Whewell. He called it the Consilience of Inductions. Whewell proposed that where “inductions from classes of facts altogether different have jumped together … [this] impresses us with a conviction that the truth of our hypothesis is certain. No accident could give rise to such an extraordinary coincidence. No false supposition could, after being adjusted to one class of phenomena, exactly represent a different class, where the agreement was unforeseen and uncontemplated. That rules springing from remote and unconnected quarters should thus leap to the same point, can only arise from that being the point where truth resides”. The relevance for epidemiology of the Consilience of Inductions is that through its application conclusions cannot just be further supported, but enormously strengthened. This happens when supplementary, non-epidemiological evidence is found that independently supports an epidemiological conclusion. For E. coli 0157, evidence of this kind is produced when strain typing is done by pulse-field gel electrophoresis – a variant of the new classical genotyping approach which compares the bar-code like patterns obtained by cutting the DNA in a gel. During the 1996 outbreak this method of clonal analysis allowed a clear and unequivocal distinction to be made between strains linked epidemiologically to the outbreak and the others that were being isolated in central Scotland at the same time. All the outbreak strains (>200) that were isolated had identical gel profiles.

Did William Whewell and John Snow ever become acquainted? Maybe. They were both members of the Royal Medico-Chirurgical Society in London in the 1850s. Whether they met or not, they lived parallel lives with many similarities.

	Whewell	Snow
Born	Lancaster 1794	York 1831
Father	Carpenter	Labourer
Siblings	Oldest of 7	Oldest of 9
Patron	Local headmaster (scholarship to Cambridge 1812)	Uncle (apprentiship Newcastle 1829)
Position at death	Master of Trinity College Cambridge	Anaesthetist in London
Cause of death	Fell from a horse 1866	Stroke 1858

Was Whewell interested in public health? Despite his polymathic tendencies (he wrote books on mechanics, gothic architecture, moral philosophy, the history and philosophy of science, translated Plato, was ordained, preached regularly, wrote poetry and science fiction, and at one time was a Professor of Mineralogy) probably not. Nevertheless, the relevant anecdote about him, Cambridge, toilet paper, and Queen Victoria still amuses. Queen Victoria, standing on a bridge over the Cam: “What are all those pieces of paper floating down the river?” The Master of Trinity (Whewell): “Those Ma’am, are notices that bathing is forbidden”.

I felt obliged to finish my lecture with a Scottish connection because I come forth of there. Two came readily to hand. The Aberdeen University Library copy of John Snow’s account of the 1854 cholera outbreak and the Broad Street pump is not on the open shelves because it bears John Snow’s signature. It was presented by Snow to Sir John Forbes. Forbes trained in Aberdeen and Edinburgh, eventually becoming a physician to the Royal household. He was a pioneer stethoscopist. I speculated that this background and these connections may have helped and influenced Snow. I concluded by commenting on John Snow’s explanation of the different patterns of cholera seasonality in Scotland and England – that it could be due to the English preference for beer and the Scots for spirits – by paying tribute to the continuing importance of the symbolism of the pump and the removal of its handle, and I reinforced this by physically removing the handle of a pump placed before me by the Pump Handle President.