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Why is home hygiene important? – Hygienerelated disease in the home and community
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. The target audiences for this briefing material
are is healthcare professionals, the media and others who are looking for background
understanding of this issue.
As good health and well-being underpins a good quality of life, controlling infectious
disease is a public health priority. Not only is infectious disease a significant cause of
death – globally it kills 13 million people each year – it also works to keep families in
poverty and, especially in the developing world, threatens economic development
In the past 20 years or so, concern about 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 in this fact
sheet.
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education in schools has been replaced by other subjects deemed more important.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 2009, IFH carried out a review of hygiene-related diseases, focusing on the spread
of these diseases in the home and family.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 hygienerelated. 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.
An assessment of the global burden of infectious disease is also given in a report by
the Rudolf Schulke Foundation in 20082 Further information on the incidence and
prevalence of food borne infection can be found European Centre for Disease
Prevention and Control Annual Epidemiological Report.3
Gastrointestinal disease
Despite significant investment at all levels, food-related, waterborne, and other nonfood-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. Gastrointestinal diseases may be either foodborne (due to
consumption of contaminated food), waterborne, or non foodborne (person to
person).
Most data on GI disease comes from outbreaks reported to national
surveillance. The annual Community Summary Report by the European Food Safety
Authority (EFSA) and European Centre for Disease Prevention and Control (ECDC),
gives an overview of the latest trends and figures on the occurrence of zoonoses and
zoonotic agents in humans, animals and foodstuffs in the 27 European Union (EU)
Member States and the European Free Trade Association (EFTA) countries.4
In reality only a small proportion of the total cases (which includes outbreaks and
sporadic (individual) infections) are reported to surveillance. An estimate of the true
GI infection rates comes from a UK study of the incidence of GI in the UK in the
community which indicates that there are up to 17 million sporadic community cases
of IID and 1 million GP consultations annually. Of these, norovirus accounts for 3
million cases and 130,000 GP consultations, and Campylobacter is responsible for
500,000 cases and 80,000 GP consultations.5 The data suggest that up to 1 in 4
people in the UK suffer from a GI illness every year. This community-based study,
estimated that only one in 147 cases of gastrointestinal illness is detected by
surveillance and that, for every one reported case of Campylobacter, Salmonella,
rotavirus and norovirus, another 9.3, 4.7, 43 and 288 cases, respectively, occur in the
community.
In the UK, the estimated cost of infectious intestinal disease alone is £745 million/y. 6
In the USA health-related expenditure on food-borne illness costs $152 billion
annually ($1850 per illness), which far exceeds previous estimates of $6.9-35 billion.7
Preventing food-related infections relies on a combination of good hygiene
practices during food preparation, cooking and storage:
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The EFSA/ECDC Zoonoses Report in 2007 estimated that one third of the
population in developed countries are affected by food-borne disease every year.
The 2012 EFSA/ECDC Zoonoses Report4, based on data collected in 2010,
estimated that 31.7% of reported food-borne outbreaks occur in private homes.
As stated in the 2003 World Health Organisation (WHO) report “foodborne illness
is almost 100% preventable”.8
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
GI (foodborne and non-foodborne) circulating in the community is difficult. National
and international ssurveillance systems mostly focus on food-borne disease, but
ccommunity-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.7
 The incidence of non-food-borne infections in the UK is estimated at over 4
million cases per year, the largest proportion of which are norovirus infections,
which are transmitted easily from person-to-person within community groups.
 Norovirus, which is mainly spread from person-to-person, is now the most
significant cause of gastrointestinal infections in the developed world, 9 whilst
rotavirus is the leading cause of gastroenteritis in children under 5 years of age.10
 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 promotion of handwashing alone could lead to a reduction in the
incidence of diarrhoeal infections by 48-57%.11
Further data on incidence of GI infections can be found in Section 3 of the 2009 IFH
review.1
Respiratory infections
Increasingly the evidence suggests that not just coughs and sneezes, but also hand
and surface play a part in the spread of respiratory infections such as colds and
probably also influenza. Evidence summarised in a 2013 IFH review shows that
respiratory hygiene plays a part in limiting spread of respiratory infections.12
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The common cold is reported to be the most frequent, acute infectious illness to
humans.
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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 3.5–5.5.13
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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.
 In response to the threat posed by emerging pandemic strains such as SARS and
swine flu, hygiene is an important first line of defence.14
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 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.
 It is estimated that promotion of handwashing could lead to a significant reduction
in the incidence of respiratory infections. A systematic review of respiratory
infections in community settings (i.e, excluding health care-related and military
settings) indicated reductions due to handwashing ranged from 20%-51%.7
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.
Further data on incidence of GI infections can be found in Section 3 of the 2009 IFH
review.1
Emerging pathogens
One of the key factors which has raised awareness of the importance of community
hygiene Is ongoing problem of emerging infections. 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. International and
national agencies such as WHO, CDC as well as the UK HPA, now recognise that,
where there is emergence of a new pathogen, good hygiene may be a first line of
defence before other measures can be put in place.
 The threat posed by emerging diseases such as avian influenza and SARS which
demand an immediate response, has prompted the realisation that, in the event of
a pandemic, hygiene will be a first line of defence during the early critical period
before mass vaccination becomes available.13 “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 PVLproducing strains of Staphylococcus aureus).
- have acquired the ability to resist the action of antibiotics e.g methicillin
resistant Staphylococcus aureus (MRSA).
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Further data on incidence of GI infections can be found in Section 8 of the 2009 IFH
review.1
The spread of antibiotic resistance
Antibiotic resistance represents a major threat which severely undermines our ability
to control infectious diseases. As antibiotic resistance continues to reduce our ability
to treat infections, infection prevention through hygiene in hospitals and the
community becomes of even greater importance:
 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. Increasingly it is recognised that reducing
the spread of resistant strains in hospitals and other healthcare settings cannot
be achieved without also reducing spread in the healthy community.
 In the community, healthy people can become persistent skin carriers of MRSA or
faecal carriers of enterobacteria strains that carry multi-antibiotic resistance
factors such as NDM-1 or ESBL-producing strains. Risks are not apparent until
they are, for example, admitted to hospital where they can become “self-infected”
with their own resistant organisms. Other patients may then become infected. As
persistent nasal, skin or bowel carriage in the healthy population spreads
“silently” across the world, the risk from resistant strains in both hospitals and the
community rises. It is thought that the major source of healthcare-associated
infections is the patient’s endogenous flora.
 Sometimes these infections occur in the community, as happened in 2005 when
a young soldier acquired what should have been an easily treatable skin infection
from a PVL-producing strain of MRSA, but subsequently died.15
The e-Bug project (www.e-bug.eu). 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. This resource which includes
teaching manuals and an interactive website is ow translated into 27 European
languages.
In 2013, the US Center for Disease Control and Prevention (CDC) and UK
Department of Health published five year strategy plans (2013-2018) for tackling
Antimicrobial Resistance. These can be found at
http://www.cdc.gov/drugresistance/threat-report-2013/ and
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/23887
2/20130902_UK_
The increasing importance of viral infections
Novel identification techniques are 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.
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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
of studies have demonstrated situations in which pets were identified as a risk factor
for infection in the home, for example:
 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.
Further data on infection risk associated with pets and domestic animals can be
found in section 10 of the 2009 IFH review.1
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.
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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.
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Further data on infection risk associated with pets and domestic animals can be
found in section 10 of the 2009 IFH review.1
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, under pressure to fund the level of healthcare that people
expect, are looking at prevention as a means to reduce health spending. 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. Much of the care is carried out by family members.
 Trends in social behaviour, eating habits, availability and use of home
appliances etc can affect risks of transmission of IDs in the home.
 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.
Much of the care of “vulnerable” groups is carried out by the family who thus need an
understanding of infection prevention, which includes protecting family members
against foodborne and respiratory infections. Healthcare workers now accept that
reducing the burden of infection in healthcare settings cannot be achieved without
also reducing the circulation of pathogens such as norovirus and MRSA in the
community. As standards of IC in healthcare setting improve, it exposes hygiene in
home and everyday life settings as the weak link in the chain
Further data on infection risk associated with pets and domestic animals can be
found in section 12 of the 2009 IFH review.1
Social inequality
Social inequalities result in inequitable distribution of disease. Populations with a low
education level, income level or occupational class are at higher risk of infection.
These factors initiate a “vicious cycle” of infection predisposing to malnutrition and
growth faltering, which in turn leads to increased risk for further infection.16,17
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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 and
sanitation, but also 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). 18
 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.
Are we too clean for our own good?
How, and to what extent, parents should protect infants and children from infectious
illness has been the subject of much debate in recent years. In the last 30 years we
have seen an epidemic of chronic inflammatory diseases in the industrialized world.
For young children the major concern is asthma, hayfever, food and other allergies,
but, in reality, the problem extends to a broader range of diseases including Type 2
diabetes, inflammatory bowel disease, and autoimmune diseases like multiple
sclerosis. The concept of a link between reduced “infection” exposure and increasing
levels of allergic diseases, as first proposed in the 1990s, was named the hygiene
hypothesis. This fuelled the idea that we have become too clean for our own good,
and still persists, despite the fact that the hypothesis has been substantially revised.
A more rational explanation, the ‘Old Friends’ hypothesis, is now becoming more
widely accepted and argues that the vital exposures are not colds, influenza,
measles and other common childhood infections which have evolved relatively
recently over the last 10,000 years, but the microbes already present over 2 million
years ago in hunter-gatherer times when our immune system was developing.
Although we cannot be sure precisely what microbes are involved, current thinking is
that the Old Friends organisms include harmless commensal microbes found on the
human and animal body and in the gut, and organisms from the natural environment.
It also includes some infections such as parasitic worm infections that can persist as
relatively harmless carrier states.
This suggests that, on one hand it is important not to become hygiene-obsessed, but
on the other to maintain good hygiene practices. Babies are inevitably exposed to
some micro-organisms in their environment which, in addition to some germs, will
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also include some of the Old Friends which need to become established as their
normal gut flora, on their skin etc. Gradual exposure to small numbers of a wide
range of microbes is also important for priming the immune system.
Hygiene practices are important because they focus on protecting against exposure
to “infectious doses” of harmful organisms which our immune systems are not
equipped to deal with.
The latest findings on this issue can be found in a 2012 IFH review.19
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