Handwashing and Hands, Big Questions and Answers
Hands as Vehicles for Flu and Infectious Disease Transmission
Sep 15, 2009
Why wash those hands? Concerns abound about the flu, or many other potential, infectious (transmissible) diseases. This brief inquiry promotes better thinking about hands, handwashing and infectious disease.
How Important are the Hands and Fingers in Disease Transmission?
That is a big, important question — it deserves a closer look.
Watch any group of people. Notice the many human interactions. Hand shakes, "high fives", common door handles, elevator buttons, shared drinking cups and bottles, pens, pencils, food, desks, computers, phones or items of various kinds — it is obvious, hand interactions abound. See someone sneeze or cough into cupped hands, or elbow site (preferred), wipe a nose or mouth with a tissue — now laden with exudate that may transfer directly onto fingers and hands. Because hands contact surfaces, people, and often one's own eyes, mouth and nose with such great frequency, whatever is on the hands can be transferred. Watch how often some people touch their eyes, mouth, forehead and hair.
The importance of hands in disease transmission, and handwashing in disease prevention, comes from many epidemiological studies in hospitals and clinics.
Hospital-acquired (nosocomial) infections may be traced to some negligent hospital aides, nurses and doctors, who routinely omit adequate handwashing. Modern-day observers such as Pittet (Emerging Infectious Diseases, 7(2):234-40. March-April, 2001.) document routine incidences of 50% or greater, non-compliance with handwashing protocols by hospital personnel. Dramatic reductions of transmissible, infectious diseases occur everywhere (homes, schools, hospitals, businesses), whenever good handwashing is rigorously practiced and enforced.
What Kinds of Infectious Disease Agents Survive on Hands and do They Grow There?
Hands are never sterile, because skin is never sterile. Microbes may survive on the hands for varying periods of time. Microbial survival for a few minutes to many hours is a wide and true range. Factors such as temperature, moisture, and frequency of cleansing or washing of the hands influence how much and what is there. Some microbes seem to stick better to skin than others, and some studies have shown that certain bacteria may grow and multiply on the very moist palms of some people.
Microbes that survive on the hands include: Staphylococcus, Streptococcus, Pseudomonas, enterics (e.g., E.coli, Klebsiella, Serratia), Candida and herpes, influenza, enteroviruses and others.
When Should Handwashing be Done and How Does Anyone Handwash Well?
Handwashing rules have existed, it seems like, forever. Wash
- before eating,
- just before preparing a meal,
- after using a bathroom, or changing a diaper, or
- after touching any obviously dirty, or potentially microbially-contaminated, object, person or surface.
Many human infections are acquired by contaminated hands contacting eyes, nose or mouth. A basic and good rule: Avoid touching fingers to mouth, eyes or nose.
To wash effectively with water:
- Wet your hands thoroughly with clean (preferably warm), running water,
- Add plenty of soap,
- Rub both hands together for at least 20 seconds and rotate and wash one hand with the other,
- Rinse thoroughly,
- Dry by disposable towel, or forced air.
If no water is available, use:
- Gel or foam ethanol (minimum 62%). Place 1 inch or 2.5 cm amount on your one palm and rub and rotate the hands together covering the top and bottom of hands in all areas until there is no more. It works!
- Disinfectant towelettes may be used. Tear open small packet. Wipe both hands thoroughly for about 20 seconds. Appropriately discard in waste basket or trash can.
Handwashing is a proven, necessary ritual. Science and medical records show that bad things happen when good handwashing is omitted. Thorough, frequent, and timely handwashing is imperative for a good and healthy life, and its practice is a sign of being a wise person.
Resource
Timmreck, Thomas C.1994.The Epidemiology of Childbed Fever in a Lying-In Hospital pp.68-70 in An Introduction to Epidemiology. Jones and Bartlett Publishers, Boston. 484 pp
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