International Scientific Forum on Home Hygiene s4

Why is home hygiene important? – Hygiene- related disease in the home and community October 2008

This information sheet takes an overview of hygiene-related disease and why hygiene promotion in the home and community plays a key role in reducing the global burden of infectious diseases. This briefing material has been produced for those who work in healthcare professions, the media and others who are looking for background understanding of this issue.

In the past 20 years or so, infectious disease (ID) has moved steadily back up the health agenda, prompting new emphasis on developing strategies for prevention and control. Increasingly this includes promotion of hygiene to the family, both at home and in their social and work lives outside the home. A number of factors/events contribute to this current situation which are summarised below.

There is no doubt that advances in hygiene during the 19th and 20th centuries, along with other aspects of modern medicine, have improved both the length and quality of our lives beyond all recognition. During the second half of the 20th century, however, following the development of vaccination and antibiotic therapy, and with serious epidemics of the “old” infectious enemies, such as diphtheria, TB and typhoid fever apparently under control, hygiene tended to lose its prominent position and the focus of concern shifted to degenerative, chronic diseases. In developed countries, hygiene education in schools has been replaced by other subjects deemed more important. Nowhere has the decline in concern about hygiene been more evident than in the home, where there has been a tendency to assume that, compared with the hospital setting, most people are “normal and healthy”, and the infection risk is minimal. Social changes across the world mean that women increasingly work outside the home and have had less time for childcare and housework. This has led to a more superficial approach to hygiene and home cleaning, with speed and aesthetic factors more important than disease prevention.

Indications are that a significant proportion of the global ID burden is caused by diseases which are hygiene-related (i.e. transmitted via food, water, faecal and other waste material, hands and other surfaces, and via the air) and that, within the home and other settings, standards of hygiene, in relation to handwashing, handling of food and water, disposal of faeces and other waste materials, care of at risk groups and people who are infected, are key factors which determines the ID burden within and between communities.

In 2008, IFH carried out a review of hygiene-related diseases, focusing on the spread of these diseases in the home and family (reference 1). The report evaluates the incidence and prevalence of hygiene-related diseases in the home and community, and summarises data indicating why and to what extent these diseases are hygiene- related. It also assesses what the benefits could be in terms of improving global health and well-being, if we could motivate people to take more responsibility for preventing the transmission of ID in their own home through better hygiene practice. The report covers both developed and developing countries and compiles data from epidemiological and microbiological studies. Further details and the sources of the information given in this fact sheet can be found in this report.

Gastrointestinal disease Despite significant investment at all levels, food-related, waterborne, and other non- food-related gastrointestinal diseases (GI) remain at unacceptably high levels, even in developed countries. This is despite the efforts of food producers to ensure the safety of the food chain. Preventing food-related infections relies on a combination of good hygiene practices during food preparation, cooking and storage:  'The Zoonoses Report', published by the European Food Safety Authority (EFSA) and the European Centre for Disease Control and Prevention (ECDC) in 2007, estimates that one third of populations in developed countries are affected by food-borne diseases every year.  The 2003 World Health Organization (WHO) report concluded that about 40% of reported food-borne outbreaks in the WHO European Region occur in private homes.  As stated in the 2003 World Health Organisation (WHO) report “foodborne illness is almost 100% preventable”.

Whereas there has been significant investment in reducing the burden of foodborne disease, through food hygiene campaigns, there has been little attempt to reduce the burden of non-foodborne GI disease. Obtaining a true picture of the total burden of gastrointestinal infections (foodborne and non-foodborne) circulating in the community is difficult. National and international surveillance systems mostly focus on food-borne disease, but community-based studies suggest that food-borne infections represent only a fraction of the total burden of gastrointestinal infections.  The 2003 WHO report stated that, of the total outbreaks reported in Europe during 1999 and 2000, 60 and 69%, respectively, were due to person-to-person rather than food-borne transmission.  A UK community-based study, carried out between 1993 and 1996, estimated that only one in 136 cases of gastrointestinal illness is detected by surveillance and that, for every one reported case of Campylobacter, Salmonella, rotavirus and norovirus, another 7.6, 3.2, 35 and 1,562 cases, respectively, occur in the community.  The incidence of non-food-borne infections in the UK is estimated at around 4.5 million cases per year, the largest proportion of which are norovirus infections, which are transmitted easily from person-to-person within community groups.

Non-foodborne gastrointestinal infections are transmitted from person-to-person via contaminated hands and surfaces, and to some extent (e.g. for norovirus) by inhalation of aerosol particles produced when an infected person vomits. Hygiene is thus also a vital factor in reducing the burden of these infections.  It is estimated that hand hygiene alone could reduce the incidence of diarrhoeal infections by up to 47%.

Respiratory infections Page 2/7 Increasingly the evidence suggests that not just coughs and sneezes, but also hand and surface hygiene play a part in reducing the spread of respiratory infections such as colds and probably also influenza.

 The common cold is reported to be the most frequent, acute infectious illness to humans.  In the USA, it is estimated that the mean number of respiratory illnesses experienced per year in adults is around 1.5–3.0, and in children under 5 years it is around 3.5–5.5.  It is estimated that the global burden of influenza epidemics is around 3–5 million cases of severe illness and 300,000–500,000 deaths per year.  Among those with influenza, who belong to an “at risk group”, a significant proportion develop pneumonia, and may require hospitalisation, whilst up to 1 in 10 can die of influenza-related complications.  Intervention studies suggest that hand hygiene alone could reduce the risk of respiratory infection by up to 23%.

Indications are, however, that knowledge and awareness of “good respiratory hygiene” needs to be improved if the public are to play their part in reducing the burden of respiratory infections.

 Whereas there has been a tendency to assume that the gastrointestinal (GI), respiratory and skin infections circulating in the community are a relatively minor concern, the burden related to these infections in terms of absence from work and school, together with increased pressure on health services, is considerable.

Emerging pathogens Experience now shows that, as soon as we begin to get one pathogen under control, another emerges:  Pathogens such as rotavirus, Campylobacter, legionella, E. coli O157 and norovirus, largely unknown before the 1980s, are now leading causes of morbidity. New pathogens can spread quickly through communities. Hygiene is an important first line of defence in limiting the spread of new pathogenic strains. Recent emergent pathogens include SARS and avian flu. In the event of a flu pandemic, it is likely that hygiene will be a first line of defence during the early critical period before mass vaccination becomes available. “Global Preparedness” means that respiratory hygiene needs to become part of our daily lives before the event.

New infectious agents infection can arise in a number of ways:  They may be species which are normally present in the environment, but have become pathogenic to humans as a result of changes in technology (food technology, building design and operation etc) or societal changes. An example of this is Legionella which is common and harmless in the environment, but can cause infection if inhaled e.g. through poorly-maintained air-conditioning systems  They may be new strains of well-established pathogens which: - have developed altered or enhanced virulence properties (e.g. they have acquired the ability to produce a toxin, or enhanced levels of toxin e.g PVL- producing strains of Staphylococcus aureus). - have acquired the ability to resist the action of antibiotics e.g methicillin resistant Staphylococcus aureus (MRSA). Page 3/7 The spread of antibiotic resistance Antibiotic resistance represents a major threat which severely undermines our ability to control infectious diseases. The implication from this is that, increasingly, we need to rely on hygiene strategies:  Good hygiene in the home and community means fewer infections, fewer patients demanding antibiotics from their general practitioner, and thus fewer resistant strains developing and circulating in the community. Reducing the reservoir of carriers in the community reduces the risk of these strains being carried into healthcare facilities by new patients.  Whereas pathogens such as methicillin resistant Staphylococcus aureus (MRSA) and Clostridium difficile (C. difficile) were once considered hospital-related problems, this is no longer the case. Those responsible for ensuring the public are protected from infection in healthcare facilities increasingly realise that their ability to manage infection outbreaks is hampered by spread of germs such as MRSA, C. difficile, and norovirus in the community and the home, which in turn determines the number of infected people or carriers that walk into their facilities.  Educating primary and secondary school pupils about antibiotic resistance and hygiene is the fundamental aim of the EU-sponsored e-Bug project. The aim of the project is to ensure that all children leave school with knowledge of prudent antibiotic use and how to reduce spread of infections for themselves and their children through hygiene.

The increasing importance of viruses The application of novel identification techniques is now showing the extent to which viral agents such as the norovirus, rotavirus and adenovirus are a cause of community-acquired infections, not only GI infections, but also respiratory and other infections. Since viral infections are not treatable by antibiotics, this reinforces the need for prevention through hygiene.

Pets and other domestic animals in the home The home is frequently a shelter to a range of different animals. Domestic pets have the potential to act as a source of infection in the home. More than 50% of homes in the English-speaking world have cats and dogs, with 60 million cats and dogs in the USA. Domestic cats and dogs can carry organisms such as Salmonella, Campylobacter, Staph. aureus (including MRSA and PVL-producing strains) and Clostridium difficile. Exotic pets such as reptiles can also be a source of infection e.g Salmonella:  In the USA, up to 39% of dogs may carry campylobacter, and 10–27% may carry Salmonella;  A London study isolated 19 species of Campylobacter spp. from 100 specimens of faeces obtained from a cattery, including C. upsaliensis and C. jejuni;  A Canadian study showed that C. difficile was the most frequently isolated pathogen from dogs, C difficile was isolated from 58 (58%) of 102 faecal specimens, of which 41 isolates were disease-causing strains.

Although there is little data indicating the extent of the infection risk from animals in the home (i.e. how often infections are acquired from animals in the home), a number Page 4/7 of studies have demonstrated situations in which pets were identified as a risk factor for infection in the home:  A study of 50 USA homes in which children under 4 years were known to be infected with salmonella spp. showed that, in 34% of homes there was also illness in another family member. The data indicated that environmental sources, infected family members and pets were more significant risk factors for development of salmonellosis in these children than contaminated foods.  In 3 studies, discharged MRSA-infected hospital patients and health care workers were successfully treated at home to eradicate the organism, but subsequently became re-colonised. In each of these cases the evidence suggested that the source of re-colonisation was a domestic dog.

Pathogens as co-factors in other diseases In addition to the threat posed by acute infections, pathogens are increasingly implicated as causative or as co-factors in cancers and degenerative diseases. Because these may manifest at a later date, the link to infectious disease may go unrecognised.

 Foodborne illness has been estimated to result in chronic sequelae in 2–3% of cases.  Mild viral infections can be important predisposing factors to more severe secondary bacterial infections.  Campylobacter jejuni has been linked to development of Guillain Barré syndrome  H. pylori is associated with peptic ulcer disease.  Childhood wheeze and asthma may be triggered by respiratory infections.  A 2008 UK study has shown that infection may be more significant in cot deaths (sudden unexpected death in infancy (SUDI)) than previously thought.

Demographic and societal changes The changing “hygiene climate” in the home and community not only reflects the constantly and rapidly changing nature and range of pathogenic micro-organisms to which we are exposed, but also the social, demographic and other changes which are occurring within the global population which affect home and community-based resistance to infection:  Demographic changes and changes in health service structure mean that the number of people in the home needing special care, because they are at increased risk of infection is increasing. Up to 1 in 5 people in the community is at increased risk of infection. The largest proportions are the elderly who have reduced immunity to infection which is often exacerbated by other illnesses such as diabetes, etc. It also includes the very young, patients discharged from hospital, taking immunosuppressive drugs or using invasive systems, etc. It also includes the estimated 40 million people in the community who are infected with HIV/AIDS.  Governments are under pressure to fund the level of healthcare which people expect. Care of increasing numbers of patients in the community, including at home is one answer, but can be fatally undermined by inadequate infection control in the home.  Trends in social behaviour, eating habits, availability and use of home appliances etc can affect risks of transmission of IDs in the home.

/7  The demand for different and “exotic foods” has stimulated increasing movement of foodstuffs from one region or country to another, but creates problems in controlling microbial quality.  Increasing population mobility due to factors such as air travel means that, as in the case of SARS, virulent pathogens can move rapidly across the world, making it difficult to contain epidemics related to novel pathogenic strains.

Hygiene-related diseases in the developing world For low income communities in the developing world, one of the main “drivers” for changing attitudes to hygiene in recent years has been the 2002 UN Millennium Development Goals, which have firmly established not only the issues of water, sanitation, but also more recently, hygiene, on the global agenda. For decades, universal access to water and sanitation has been seen as the essential step in reducing the preventable ID burden, but it is now clear that this is best achieved by programmes that integrate hygiene promotion with improvement in water quality and availability, and sanitation. The neglect of hygiene goes a long way to explaining why water and sanitation programmes have often not brought the expected benefits.  An analysis, presented in the 2006 Disease Control Priorities Project (DCPP) publication “Disease Control Priorities in Developing Countries” concluded that, for the “high burden” diseases such as HIV/AIDS, Malaria, diarrhoeal disease and TB, hygiene promotion is the most cost-effective intervention in terms DALYs averted (up to $10 per DALY averted due to diarrhoeal disease compared with e.g. up to approx $1,000 per DALY averted by anti-retroviral treatment of HIV/AIDS).  Trachoma is the world’s leading cause of blindness, which mainly affects poorer communities in developing countries. Trachoma, however, is completely preventable through hygiene (face washing breaks the infection cycle). - it is estimated that 92 million people suffer from trachoma and 8 million are visually impaired or blinded as a result of the disease. Up to 600 million individuals live in endemic areas and are at risk for contracting trachoma.

Sources of Information 1. The changing hygiene climate: a review of infectious disease in the home and community. International Scientific Forum on Home Hygiene 2008. http://www. ifh- homehygiene.org/IntegratedCRD.nsf/111e68ea0824afe1802575070003f039/29858aa 006faaa22802572970064b6e8?OpenDocument 2. European Centre for Disease Prevention and Control. The first European Communicable Disease Epidemiological Report. Available from: http://ecdc.eu ropa.eu/en/Health_Topics/. 3. The European Community Summary Report on Trends and Sources of Zoonoses, Zoonotic Agents, Antimicrobial Resistance and Foodborne Outbreaks in the European Union in 2006. Downloadable from: http://www.efsa .europa.eu/EFSA/efsa_locale- 1178620753812_1178671312912.htm. 4. World Health Organisation. Several foodborne diseases are increasing in Europe. Press Release EURO/16/03. Available from http://www.euro.who.int/ep rise/main/who/mediacentre/PR/2003/20031212_2x. 5. The e-Bug project. UK Health Protection Agency http://www.e-bug.eu/ebug.nsf/ Home?OpenPage. Page 6/7 6. Rudolf Schulke Foundation 1996. Infectious Diseases – need for reassessment and for a new prevention strategy in Germany Mhp-Verlag GmbH Wiesbaden, Germany. 7. Rudolf Schulke Foundation 2008 The threat posed by infectious diseases – need for reform of infection control. Mhp-Verlag GmbH Wiesbaden, Germany. 8. Cairncross S, Valdamanis P. 2006 Disease Control Priorities Project (DCPP). Disease Control Priorities in Developing Countries (2nd edn), Chapter 41. Downloadable from: www.dcp2.org/pubs/DCP.