Transcript Slide 1

Communicable
Disease Prevention
and Management in
Schools
Charles P. Gerba, PhD
Departments of Soil, Water and Environmental Science &
Epidemiology and Environmental Health
University of Arizona
Tucson, AZ
We’ll Cover
 Norovirus
 When
and where it occurs
 Case histories
 Data you can use with your
administrators/school boards

Help reduce disease incidence, absenteeism
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Common Infections
 80%
spread via air, water, food, fomites
 @800 million cases of respiratory and
enteric infections annually (U.S.)
 Being around kids means more illness
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
Unmarried males = one cold per year
Unmarried women = 1.3 colds per year
Couples with school aged kids = 2.3 colds
each
School children =3.5 colds per year.
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Norovirus in the U.S.


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21 million people
1.9 million outpatient visits
400,000 ER visits, esp. in young children
71,000 hospitalizations
800 deaths mostly young children and the
elderly
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Norovirus Is One Of The
Worst Viruses
 Highly
contagious
 Spreads in schools via high touch surfaces
 Persists on hard surfaces up to 30 days
 Schools quickly get contaminated
 Occurs October-May
 Most school cases go unreported/
unconfirmed
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Role Of Fomites In Transmission
Of A Disease
Pathogen falls on fomites
e.g. phone, computer
Person picks up pathogen
through contaminated fomite.
Sick person sneezes, coughs and pathogens
falls on fomite or get aerosolized.
Person touches nose or eyes
with contaminated fingers,
becomes infected with pathogen.
Schools –The Perfect Storm
 Lots
of individuals, confined spaces
 Winter incidence—closed windows
 High touch areas often not effectively
disinfected
 Busy hands touch EVERYTHING


Kids touch faces, eyes, mouth 5+ times a
minute
Hand washing is not thorough
 Viral
transfer–up to 50% of viruses on a
surface are picked up by the hand
when the surface is touched
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The Perfect Storm, cont’d
 Most
school cases are NOT food-borne
 Hugh amounts of virus are shed before
symptoms occur

Virus on dust particles in the air, settles on
surfaces
 Disease

transmission via 1-10 virus particles.
1 trillion per gram of feces (size of peanut)
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The Hand is Quicker Than
The Sneeze
Hand Contact
 Adults
hour
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

touch their faces 15.5 times per
2.5 eyes
5 nose
8 lip
 Children
touch their faces
5 times per minute
Teaching: The “Germiest” Profession
Germs per square inch by occupation
20500
18500
16500
14500
12500
10500
8500
6500
4500
2500
500
s
Te
lev
isi
on
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Pu
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La
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Ba
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Ac
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Average All Sites
Highest
bacteria per
square inch
on surfaces
commonly
touched
Phone, Desk, Computer, Mouse
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Frequently Contaminated Sites
In Schools
 Door
knobs, handles, push plates
 Athletic equipment
 Teaching manipulatives
 Textbooks/other shared classroom
items
 Locker handles
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Reported Norovirus Outbreaks
Setting
Long-term care facility
School
Other/Multiple settings
Hospital
Day care
Restaurant
Catering or banquet
facility
Private residence
All settings
Foodborne
No.
%
12
1
13
1
114
13
2
0.2
1
0.1
574
64
Nonfoodborne†
No.
%
2,060
80
148
6
137
5
115
4
52
2
38
1
151
17
8
0.3
37
904
4
100
32
2,590
0.1
100
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The Most-Frequently Contaminated
Sites in Schools
Site
Desks
Computer mouse
Cafeteria table
Library table
Bathroom sink faucets
Water fountain
Keyboards
Bathroom paper towel dispensers
% sites
positive for
fecal bacteria
59
57
55
53
36
33
33
29
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School Study (Grade K thru 12)- 2009
Figure 1
Top Three Contaminated Sites in All Schools
Total Bacteria/approximate 100 cm sq
1.00E+07
4.77E+06
1.70E+06
8.60E+05
1.00E+06
1.00E+05
1.00E+04
Average
Toilet Seat
1.00E+03
1.00E+02
Cafeteria Table
Computer Mouse
Desk
Impact of Disinfectant Wipes on
Absenteeism -Seattle
 Study
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Two school semesters
3rd and 4th graders
 Intervention
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Children’s desk wiped with a disinfectant wipe
at the end of each school day
 Results
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50% reduction in absenteeism
From Bright et al, 2010; J. School Nursing
Our Ohio School Study
 Compared
classrooms using
disinfecting wipes at end of day on
each desk
 Could
we lower incidence of
gastroenteritis by treating
hard surfaces?
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The Study
 Details
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Two school semesters
3rd and 4th graders
 Classroom
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surfaces
Influenza A virus on up to 50% contaminated
Norovirus on up to 22% contaminated
 Intervention

Quaternary ammonium-based disinfectant
wipes registered for norovirus by EPA
 Used by teachers on desks at the end of each
school day
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Results
 Use
of disinfecting wipes reduced
detection of norovirus on hard classroom
surfaces
 Classrooms that did not use disinfecting
wipes had a higher incidence of
gastroenteritis
Absenteeism reduced by 50%
in classrooms using disinfecting wipes
with EPA registration for norovirus
efficacy
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What Do Outbreaks Cost?
 Schools
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Lost school days
Make-up days might be needed
 High

closed
absenteeism
State reimbursements lost
 Teachers

and staff ill
Replacement personnel needed
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Outbreak Costs, cont’d
 Custodial
staff often become ill
 Schools must be disinfected to stop the
outbreak
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Outside services
Extra cleaning materials/supplies
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Non-School (Hidden) Costs
 Parents
stay home from work to care
for sick students

Siblings fall ill in sequence
 Parents
become ill, lose more work
time
 Virus spreads to work place,
community facilities, other schools
 Total hidden costs hard to estimate but
very high to communities
 Medical expenses
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A Real-World Outbreak

Staff members and students quickly ill
 25+ staff members absent multiple days
 Spread to other schools and the parochial
school in the community
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Team activities
Extracurricular activities at church (choir, Boy Scouts, first
communion instruction)

Closed 11 schools for one week (school
days, one holiday)
 5000+ enrollment
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Real-World Outbreak Costs
DIRECT=@$93K
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Disinfection = $45K
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Personnel = $7875
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Outside haz mat vendor =$25K
Supplies = $10-15K
Janitorial staff overtime=$5K
Cost of substitute teachers =$105/day per sub
25 teachers x 3 days
Cancelled class trip=$40K
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Real-World Outbreak Costs
INDIRECT = $1,015,050
 School operations = $335,000 per day
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Three lost days of school= $1,005,000
 State

reimbursements = $10,050
3350 x 3+ days out (plus earlier absentees)
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Real-World Outbreak Costs
 TOTALS
for 2013--Direct and Indirect
$1,093,000
 TOTALS--If
This Had Occurred In 2014
$2,200,000
(based on state reimbursement policy
changes and increased snow days used)
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Norovirus Outbreak
Real World Case II
 Virus
active one week before closure
 50% of student body and staff ill (479
people)
 Closure “recommended” by the Public
Health Department
 Closed 7 days for disinfecting
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Custodial staff and outside custodial used
 Disinfected
the school, buses
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Norovirus Outbreak
Real World Case II
DIRECT COSTS=$43K+
 Disinfection= $25,000
 Staff costs =$18,000
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
Substitute teachers $100/day
36 subs/5 days
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Norovirus Outbreak
Real World Case II
Indirect Costs
 Hospitalizations
 Parents lost time (minimum of six days)
from work
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What to Use for Norovirus
 Bleach

works, but is hard on surfaces
Requires personal protective gear (PPG)
 Quat-based
products are available as
liquids, ready-to-use and wipes
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Can be used on keyboards, mice, all nonporous surfaces
Do not corrode metal
PPG is generally not needed
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What Custodians
Probably Don’t Know
 Reduce
illness sharply by disinfecting high
touch areas early and often
 Buy the right type of product—not all kill
norovirus and flu
 Read the label and use correctly
 Reusable cleaning cloths can spread illnesses
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Bacteria grow on them, esp in human environments
Cloths and other organics reduce disinfectant concentration
Hard to get them clean
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Cleaning vs. Hygiene
 Cleaning
-- “the removal of unwanted
matter”
 Hygiene -- “reducing the risk of infection”
 Cleaning alone may increase risks by
spreading pathogens.
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Disease Spread in Offices
(Similar to Schools)
 Tracer
virus on entry door push plates in
80-person office
 Within 2-4 hours, 40% to 60% of fomites
sampled had virus
 Coffee break room is the first to be
contaminated
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A Real-World Outbreak: Hotels

Tracer virus (MS-2 virus)
added to hotel room
surfaces (i.e. nightstand,
desk, doorknob
 Sample rooms after
maids clean
 Sample conference room
end of day
 Conference attendees’
hands
Hotel Results
 Virus
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detected
Next 4 rooms cleaned by the maid
On surfaces (table tops) in the conference
room
On 1/3 of the conference attendees’ hands
On the coffee pot handle
of the break room
Hotels -- Intervention


Intervention
Give maids antimicrobial
products, disinfectant
wipes for key surfaces
Hand sanitizers for
attendees
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Results
Reduce spread between
rooms by 90%
Reduce virus on hands
by 50%
Hospital Cleaning
Cloth Study Results
 93%
of reusable cleaning cloths contained
bacteria before use

Average number of bacteria = 17,000
 37.5
% of the disinfectant soak buckets
contained bacteria
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Average number of bacteria = 523
Cleaning Cloth Material
Makes a BIG Difference
Organism
Total
bacteria
Coliforms
Molds
Cotton
1,995
Microfiber
24,547
P-value
0.01
1
1
6
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0.0002
0.001
Conclusions
 Reuseable
cleaning/towels/cloth can
contain opportunistic pathogenic bacteria
 Washing practices affect microbial loads in
reusable cleaning clothes/towels
 Microfiber clothes contain more bacteria
than cotton
 A wide range of enteric bacterial types are
present in cleaning clothes
Products That Kill Norovirus
Also Kill Ebola In Schools
 Nine
Texas school districts spent
$117,000 to clean schools
 $36,000 for cleaning and closed school for
three days
 $13,000 spent by one school to purchase
all new aerosol germicidal sprays
 $32,000 spent on supplemental cleaning
in one school
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Which Quat-Based Products?
 Products
with this
EPA-registration
• Labels indicate
which products kill
which pathogens
http://tiny.cc/norovirus-products
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Quat-Based Products
 “Quats”
on the market for 60+ years
 30+ quat-based EPA-registered
formulations in 1500 products that control
norovirus
 Our studies in schools show disinfecting
with a norovirus-specific quat-based wipe
prevents illness

These wipes also kill flu virus and other
pathogens
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Annual Costs for Quat
Wipes for Norovirus/Flu
 180
school days
 30 desks per class

1 wipe for two desks
 15
wipes per classroom per day (2700 per
year)
 Canister is $8.72, contains 160 wipes =
5.45 cents per wipe
 Cost per year is $147 per classroom
Communication Is the Key

Teacher and custodial training is important
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Disinfecting is needed the moment illness
strikes
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Must understand their role in school health
Must know the difference between disinfecting,
sanitizing and cleaning
The school nurse should be empowered to help
determine when and which high touch areas need
to be disinfected
Your districts should see cost savings
associated with illness reduction
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Take Home Messages

Norovirus and flu are major causes of school
closures, absenteeism
 Use quat-based disinfectant formulations
registered for efficacy for norovirus and flu


Labels state specific pathogens killed by the
product
Norovirus is a surrogate for enterovirus, Ebola,
other emerging viral diseases

Simple interventions are cost effective ,
reduce transmission of common schoolbased infections
 Follow label directions
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Questions?
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