The relationship between cleaning and hygiene

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The relationship between cleaning and hygiene
Sally Bloomfield, International Scientific Forum
on Home Hygiene Hon. Professor, London School of
Hygiene and Tropical Medicine
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Cleaning and hygiene - whats the difference?

• Terms cleaning and hygiene often used
  interchangeably
• Significant overlap, also significant
  differences
• Cleaning - process which - remove dirt and soil -
  make environment aesthetically clean (i.e
  provides a satisfactory /acceptable environment
  to work and live in) but
• may not make sites or surfaces hygienically
  clean (i.e reduce microbial or other
  contaminants to a level which is not harmful or
  potentially harmful to health).
• Home provides a simple model, applicable to all
  environments, for explaining difference between
  cleaning and hygiene.
• Microbes, allergens, particulates are all
  potentially harmful to heath

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The International Scientific Forum on Home
Hygiene (IFH)

• Established 1997 as a professional, not-for
  profit, non-government organisation.
• Primary objectives
• Raise awareness of the fundamental role of
  hygiene in preventing infectious disease in home
  and community
• Promote understanding of hygiene practice in the
  home as the means to control such disease
• Ensure home hygiene is based on the scientific
  evidence

www.ifh-homehygiene.org
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A risk assessment approach to home hygiene

• HACCP (Hazard Analysis Critical Control Point)
  has successfully controlled microbial risks in
  food and other manufacturing environments
• HACCP means identifying critical points and
  targeting hygiene at these risk points
• To devise a hygiene policy which has real health
  benefits it is accepted that a risk-based
  approach must also be developed for the home
• For IFH the risk assessment approach to home
  hygiene has come to be known as the targeted
  hygiene

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Developing a targeted approach to home hygiene

• Pathogens (germs) are introduced continually into
  the home via
• people, food, domestic animals - also
  water, insects, air
• Also - sinks, sink and basin U-tubes, toilets,
  wet cleaning cloths can support growth of some
  types of bacteria and fungi and become a
  secondary source/reservoir of infection

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Chain of infection in the home
Source of pathogens People, pets (colonised or
infected), contaminated food or water
Recipient all are at risk, but some are at
higher risk of infection
Exit route Faeces, vomit, mucous, wound
exudates, skin scales, juices from food
Portal of entry mouth, nose, conjunctiva,
damaged skin or mucous membrane
Spread of pathogens via hands, hand and food
contact surfaces, cleaning cloths and other
cleaning utensils, clothing, linens, etc.
aerosols
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Developing a targeted approach to home hygiene

• Risk assessment is based on assessing the
  microbiological data related to the infection
  transmission cycle in order to identify the
  critical control points for preventing spread
  of infection.
• In any situation, assessing whether there is a
  risk depends on
• whether the site or surface likely is likely to
  be contaminated with pathogens/germs
• whether the pathogens are likely to be spread
  from the site or surfaces such that family
  members are exposed
• If the answer to both questions is yes, then
  there is a need for hygienic cleaning to reduce
  the risk of spread

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Identifying critical points
Hands
Hand contact surfaces
Food contact surfaces
Cleaning cloths/ utensils
Clothing and household linens
Toilets, baths, sinks,washbasins
Floors, walls, furniture etc
Increasing risk
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• Hygiene is not
• a daily or weekly clean to get rid of dirt and
  germs,
• Hygiene is not a state
• Hygiene is
• about identifying high risk sites and situations
  and targeting hygiene measures appropriately (i.e
  as and where it is necessary) to reduce exposure
  to microbes which could be harmful
• Hygiene is an ongoing set of interventions to
  break the chain of infection transmission

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Hygienic cleaning procedures in the home -
reducing the risks
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What do we mean by hygienically clean

• a level of germs which is not harmful
  to health
• But
• infectious dose varies
• viruses 1-100 particles
• bacteria may be 10 --gt as high as 106
• Salmonella amplified following transfer to food
• depends on the susceptibility - may be lower for
  at risk groups
• Without precise data it seems reasonable that
• where there is significant risk of germs
  spreading (e.g. during food preparation)
• aim should be to get rid of as many germs as
  possible

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What methods are available for hygiene cleaning

• Detergent-based hygienic cleaning
• In many situations - hands, cooking/ eating
  utensils, hygiene achievable using
  detergent-based cleaning.
• To be effective it must be applied in conjunction
  with a thorough rinsing process - to wash germs
  away from the surface
• Disinfection
• In other situations germ kill process is
  needed
• - chemical disinfectant products or alcohol
  hand sanitizers
• - NB. Soiled surfaces should be cleaned before
  disinfection
• - heat (e.g boiling or gt60C)
• or Combined removal and kill
• - laundry - removal, heat and bleach kill
• - dishwashing - removal, heat kill

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Risks associated with preparation of a meal using
a chicken contaminated with Salmonella or
Campylobacter
Bacterial counts ranged from 1 togt 1000
cells/sample area
Cogan, Bloomfield and Humphries, Letters in
Appl.Microbiology 1999, 29,354-358
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Contaminated foodstuffs as a source of infection
in the home

• Prevalence in meat products
• UK - raw chickens ve
• Salmonella 3.6, Campylobacter 66
• Up to 1 in 30 homes every day
• (Beef lamb products ve for E. coli O157 0.4
  and 0.8)
• Survival
• 4 - 24hrs on surfaces
• Infectious dose
• Salmonella 102 to 106cfu - risk amplified by
  transfer to food or wet cloths
• Campylobacter 100-500cfu
• E. coli O157 10-100 cells
• Outcome
• --gt600,000 cases per annum 40 at home 20
  salmonella cases not foodborne

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Influenza

• Viral shedding
• People infected with influenza shed virus-laden
  mucous - up to 107 infectious particles/ml
• Particles can travel gt3m to contaminate
  surrounding surfaces.
• Survival in the environment
• Survival times vary between 1 h and 24 h
• but viable virus on hands ----gt low level within
  5 min.
• US daycare centres during flu season, flu virus
  detected on 50 of hand contact surfaces
  including telephone receivers, computer
  keyboards, kitchen taps, light switches, TV
  remote controls, door knobs, baths and taps and
  toilet handles.
• Wiping surfaces with S,Wcloth can spread viruses
• Infectious dose
• Nasal ID 100-1000 particles
• lung ID 1-3 particles

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Why is hygiene an important part of public health?
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• In 1970, the Surgeon-General of the United
  States of America stated
• it is time to close the book on infectious
  diseases, declare the war against pestilence won,
  and shift national resources to such chronic
  problems as cancer and heart disease".

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Why is hygiene important?

• Last 40 years shows optimism misplaced
• Mortality from killer ID has declined - but
  morbidity is a significant burden of health and
  prosperity of the community
• Last 2 decades has seen ID moving back up health
  agenda
• New emphasis on developing strategies to prevent
  spread of IDs
• Increasingly this includes promotion of hygiene
  in public health
• Why?

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Infectious Intestinal Disease

• Foodborne disease
• remains at unacceptable levels
• UK notifications gt70,000 per year actual
  several millions
• Spain 9,000 notifications
• Foodborne illness almost 100 preventable (WHO)
• hygiene from farm to fork
• Food is by no means the only cause of IID
• Community based studies in UK and NL indicate
  burden
• UK 9 million cases/y (1 in 5 of population)
• UK norovirus cases in the community - 3 million/y
  (97 non-fb)
• 19 of Salmonella gt50 of E. coli O157
  outbreaks non-fb
• good hygiene prevents person to person transfer

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Common infections in the community are mainly
viral?

• Not treatable - prevention through hygiene is key
• Infectious intestinal diseases
• norovirus - 3 million rotavirus 0.5 million
  cases/y
• Respiratory tract infections
• rhinovirus, RSV, flu
• Increasing evidence of spread via hands and
  surfaces
• tend to be regarded as merely a nuisance - but
• significant burden on economy through absence
  from work/school
• serious/fatal for at risk groups - may need
  hospitalization
• norovirus most common cause of hospital ward
  closures
• clinical sequelae

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Pathogens can act as co-factors/ triggers in
other diseases
Lindsay, J.A. 1997, Emerging Infectious Diseases
3, 443-452
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Emerging infections

• Since 1980 - norovirus, Legionella, Campylobacter
• More recently - SARS, Avian flu - and now swine
  flu
• Hygiene the first line of defence
• Global flu pandemic preparedness plans
• - include action on community hygiene advice
• - good respiratory hygiene
• - decontamination of hand contact surfaces

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At risk groups in the hospital and community

• Up to 1 in 5 people in population at increased
  risk of infection
• Those at increased risk include
• Elderly, very young
• pregnant mums, etc
• underlying disease - HIV/AIDS, diabetes
• Healthcare associated infections (hospital and
  community)
• C. difficile
• drug treatment (e.g chemotherapy)
• Transplant patients
• catheterisation, inhalation systems
• surgical wounds etc

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Control of healthcare-associated infections

• Governments increasingly under pressure to fund
  the level of healthcare that people expect.
• Success of advanced treatments severely
  undermined by increased risks of infection
• Although shorter hospital stays mean reduced
  hospital costs, gains likely to be undermined by
  inadequate infection control associated with care
  at home.

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Spread of antibiotic resistant strains in the
home and community

• Good hygiene means fewer infections, means fewer
  patients demanding antibiotics from GP, means
  fewer resistant strains in the community
• Community MRSA strains (some are PVL-producing)
• ESBL-producing enterobacteria
• Fewer resistant strains in the community means
  fewer resistant strains entering healthcare
  facilities
• ICPs realise managing HAI hampered by colonised
  or infected people that walk into their
  facilities.

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In summary

• Infectious disease remains a key issue -
  significantly affects our ability to deliver
  health and well-being
• Hygiene is a key component of ID prevention
• If ID is to be contained in a manner which is
  economically sustainable, it must be a
  responsibility shared by everyone
• Risk-based approach (targeted hygiene) offers
  means/ framework to develop effective hygiene
  strategies (and effective products and processes)
  for preventing infection transmission
• To achieve change we need to change perception
  about hygiene
• Distinguish between cleaning and hygiene
• re-position hygiene as part of achieving health
  and well being

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We shouldnt be too clean ?

• Hygiene hypothesis proposes lack of exposure
  to infectionin early childhood is linked to the
  rise in allergic disease
• Significant evidence that microbial exposure
  is a factor - but not infection
• No evidence that hygiene (the things we do
  to protect ourselves from infectious diseases) is
  a factor

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Targeted hygiene is simpler - and healthier

• Targeted hygiene offers the means to deliver
  messages which make sense
• offers the means to maximise protection against
  infection whilst reducing the impact on our human
  and natural environment to the least extent

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IFH website www.ifh-homehygiene.org
IFH website www.ifh-homehygiene.org
All IFH materials are downloadable from the IFH
website
IFH reviews,
Guidelines, Training materials
Fact/hygiene advice sheets,