Download Disease Transmission and Control in the Home

Slide 1
Disease Transmission and Control in the Home Setting
Teleclass Presented by Dr. Charles Gerba, University of Arizona
March 20, 2003
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Disease Transmission and Control in the
Home Setting
Charles P. Gerba
Departments of
Microbiology and Immunology
and
Epidemiology and Biostatistics
University of Arizona
Tucson, AZ 85721
Webber Training Teleclass – March 20, 2003
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Slide 2
“W ater disinfectio n and personal
hygien e ended the age of ep idemics.”
“The develop ment of antibiotics and
vacc ines h ave had only a small
impact on mortality.”
V . G reene
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Slide 3
The Home is a Multifunctional
Setting
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A residence
restaurant
day care setting
a hospital
and animal shelter
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Teleclass Sponsored by Webber Training, www.webbertraining.com
Hosted by Paul Webber, [email protected]
Slide 4
Disease Transmission and Control in the Home Setting
Teleclass Presented by Dr. Charles Gerba, University of Arizona
March 20, 2003
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Significance of Hygiene in the Home
• Most foodborne infections occur in the home
• Cross contamination is the cause of 30% of the
Salmonella outbreaks
• 2/3 of all colds originate in the home setting
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Slide 5
Sources of Pathogens Within the
Home
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People
Pets
Food
Water
Air
Fomites (Inanimate Objects)
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Slide 6
The Germest Areas in the Home
• Kitchen
– cleaning tools (sponge or dishcloth)
– sink
– cutting board
• Bathroom
– sink
• Washing machine
• Playroom or child’s bedroom
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Teleclass Sponsored by Webber Training, www.webbertraining.com
Hosted by Paul Webber, [email protected]
Slide 7
Disease Transmission and Control in the Home Setting
Teleclass Presented by Dr. Charles Gerba, University of Arizona
March 20, 2003
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Ranking of Sites by Coliform Densities. The Four Most and
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4
3
2
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1
0
-1
Toilet seat
Bath countertop
Bath floor
Cutting board
Kitchen floor
Kitchen sink drain
Bath sink drain
-2
Sponge/dishcloth
Geometric mean per cm2 or per mL
Four Least Contaminated Sites Are Shown.
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Slide 8
Importance of Hands in Disease
Transmission
• A small child will bring their hands to their nose
or mouth once every three minutes
• A child will swallow the amount of household
dust found on six kitchen floor tiles per day
• A working adult will touch as many as 30 objects
in one minute
• The hands are the major route of transmission for
colds and many enteric diseases
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Slide 9
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Risk Model for Hard Surfaces
Number of organisms
per square centimeter
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% transferred to hand
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Contamination
of food
Growth in
the food
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% transferred to mouth
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Probability of becoming ill
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Teleclass Sponsored by Webber Training, www.webbertraining.com
Hosted by Paul Webber, [email protected]
Slide 10
Disease Transmission and Control in the Home Setting
Teleclass Presented by Dr. Charles Gerba, University of Arizona
March 20, 2003
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Bugs in Your Underwear
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The Hidden Secrets of Enteric Bacteria
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Slide 11
Occurrence of Coliforms and Fecal Coliforms in
Wash Water After Laundering
Coliform Arithmetic
Average
Per
Item
Fecal Coliform
Arithmetic Average
Washer
Load
Per
Item
4.5 x 105
5.6 x 105
7.4 x 104
1.07 x 105
1.5 x 104 2.24 x 103
Type of
Clothing
Washer
Load
Underwear
5.2 x 106
Jeans
7.2 x 105
Bath Towels 1.2 x 106
1.77 x 103
<1.6 x 104
ND
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Slide 12
Occurrence (%) of Coliforms and E. coli in
Washing Machines and Laundered Clothes*
Coliforms
E. coli
Surface of Drum+
Before cycle
After cycle
26
25
2
5
Cloth swatch
44
16
Final Rinse Water**
25
1.5
Sample
*Results from 140 samples collected from households
**10 ml samples
+swab of 10 cm2
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Teleclass Sponsored by Webber Training, www.webbertraining.com
Hosted by Paul Webber, [email protected]
Slide 13
Disease Transmission and Control in the Home Setting
Teleclass Presented by Dr. Charles Gerba, University of Arizona
March 20, 2003
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Transfer of Bacteria between Fabrics
CFU log10 Recovered
After Laundering
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CFU log10 Recovered
After Drying
Organism
Inoculated
Swatches
Sterile
Swatches
S. aureus
5.3
4.8
3.5
2.8
E. coli
6.0
5.2
<1.4
<1.4
S. typhimurium
6.0
4.2
1.2
<1.4
M. fortuitum
5.9
5.8
5.6
5.6
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Inoculated Sterile
Swatches Swatches
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Swatches contained 8.1 to 8.5 CFU log10 of organisms recovered before washing
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Slide 14
Risk of Rotavirus Infection from laundering
Concentration of Virus
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Assumption
2 x 107
The amount in 0.001 gr of feces
2 x 105
After washing 99% reduction sq. cm clothing
2x
104
1% transferred to hands
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10 % transferred to mouth
2
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After 28 min. drying
200
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Risk of infection ~ 1:10
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Slide 15
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E n v iron m e n ts M o st C on ta m in ated w ith
Bo d ily F lu id s (sa lv ia , u rin e, b lo od )
50
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46
% surfaces Positive
45
40
35
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29
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28
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26
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20
14
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11
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10
5
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0
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Teleclass Sponsored by Webber Training, www.webbertraining.com
Hosted by Paul Webber, [email protected]
Slide 16
Disease Transmission and Control in the Home Setting
Teleclass Presented by Dr. Charles Gerba, University of Arizona
March 20, 2003
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Occurrence of fecal bacteria on the
hand (United States)
Preparing a meal
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Greatest
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Children after playing
Doing the laundry
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Least
Person exiting a toilet
Slide 17
Most Contaminated Sites in Offices
(Total Bacteria)
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Desk Tops
Phone (mouth piece and handle)
Fax Keys
Computer Mouse
Computer Keyboard
60% of coffee cups contain coliform bacteria
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Slide 18
Public Toilets
• Diseases shown to be transmitted by public
toilets: Hepatitis A, Norwalk, Salmonella,
Shigella
• Pathogens are most likely found in the sink,
faucet, and bottom of toilet seat. Least likely on
door knob and stall latch
• Women’s restrooms contain more coliform on all
surfaces than men’s restroom, except the floor
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Teleclass Sponsored by Webber Training, www.webbertraining.com
Hosted by Paul Webber, [email protected]
Slide 19
Disease Transmission and Control in the Home Setting
Teleclass Presented by Dr. Charles Gerba, University of Arizona
March 20, 2003
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Public Toilets
• Institutional restrooms are the most contaminated,
while fast food restaurants and hospitals are the
cleanest
• E. coli and Salmonella most commonly isolated
from the restroom sink
• Salmonella found in 3% of the sinks tested
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Slide 20
Goals of Home Hygiene
• Identify those places where you are most likely to
come into contact with pathogens
• It is not to kill all microorganisms, but
• to target the reduction and killing of pathogenic
microorganisms to levels that present no
significant risk of infection
• To accomplish this goal is not by more cleaning,
but by the development of better cleaning tools
and products
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Slide 21
Types of Products that Aid Hygiene
in the Home
• Disposable cleaning tools (e.g. paper towels,
disinfecting wipes)
• Cleaning tools which prevent the growth of
bacteria (e.g. antimicrobial sponges)
• Self disinfecting or antimicrobial surfaces (e.g.
cutting boards)
• Products which both clean and disinfect
• Hand sanitizers (alcohol gels)
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Teleclass Sponsored by Webber Training, www.webbertraining.com
Hosted by Paul Webber, [email protected]
Slide 22
Disease Transmission and Control in the Home Setting
Teleclass Presented by Dr. Charles Gerba, University of Arizona
March 20, 2003
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Ranking of Sites by Coliform Densities. The Four Most and Four
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6
Contr ol Period
5
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1st Intervetion
4
3
2
2nd Intervention
1
0
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Toilet seat
Bath countertop
Flush handle
Bath sink drain
Kitchen countertop
Refrigerator handle
Sponge/dishcloth
Kitchen sink drain
Bath floor
Toilet seat
Kitchen floor
Bath sink drain
Bath countertop
Sponge/dishcloth
Kitchen sink drain
Kitchen faucet handle
Bath floor
Toilet seat
Kitchen floor
Bath countertop
Cutting board
Bath sink drain
-2
Sponge/dishcloth
-1
Kitchen sink drain
Geometric mean per cm2 or per mL
Least Contaminated Sites Are Shown for Each Period.
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Slide 23
Cleaning Protocols for Phase 3 of the Study
Kitchen
surface
Cleaning and
Disinfecting Method
Frequency
Sponge or
dishcloth
Soak in bleach 5 - 10 min.
3 / week
Countertop,
cutting board,
handles
Spray with disinfectant cleaner,
wipe clean after 30 sec.
daily
Floor around
kitchen sink
Spot clean with dinsifectant cleaner, daily
wipe clean after 30 sec.
Mop with disinfectant, let
stand 5 min., rinse
3/ week
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Teleclass Sponsored by Webber Training, www.webbertraining.com
Hosted by Paul Webber, [email protected]