Charles P. Gerba, PhD
Departments of Soil, Water and Environmental Science &
Epidemiology and Environmental Health
University of Arizona
Tucson, AZ

 Norovirus
 When and where it occurs
 Case histories
 Data you can use with your administrators/school boards

Help reduce disease incidence, absenteeism
2

 80% spread via air, water, food, fomites
 @ 800 million cases of respiratory and enteric infections annually (U.S.)
 Being around kids means more illness




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.
3


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
4

 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
5

Role Of Fomites In Transmission
Of A Disease
Pathogen falls on fomites e.g. phone, computer
Person picks up pathogen through contaminated fomite .
Person touches nose or eyes with contaminated fingers, becomes infected with pathogen.
Sick person sneezes, coughs and pathogens falls on fomite or get aerosolized.


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
7

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)
8


Adults touch their faces 15.5 times per hour

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
Te ac he rs
A c cou nt ant s
B a nk er s
R a di o
Average All Sites
D oc tors
Te le vi si on
C on s ul ta nt s
P ub lic is ts
La w y er s
Phone, Desk, Computer, Mouse
Highest bacteria per square inch on surfaces commonly touched
11

Frequently Contaminated Sites
In Schools
 Door knobs, handles, push plates
 Athletic equipment
 Teaching manipulatives
 Textbooks/other shared classroom items
 Locker handles
12

Setting
Long-term care facility
School
Other/Multiple settings 114
Hospital
Day care
Restaurant
2
1
574
Foodborne
No.
%
12
13
1
1
13
0.2
0.1
64
Catering or banquet facility
Private residence
All settings
151
37
904
17
4
100
Nonfoodborne†
No.
%
2,060
148
80
6
137
115
52
38
5
4
2
1
8
32
2,590
0.3
0.1
100
13

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
1.00E+07
1.00E+06
Figure 1
Top Three Contaminated Sites in All Schools
4.77E+06
1.70E+06
8.60E+05
1.00E+05
1.00E+04
1.00E+03
1.00E+02
Average
Toilet Seat
Cafeteria Table Computer Mouse Desk

Impact of Disinfectant Wipes on
Absenteeism -Seattle
 Study

Two school semesters

3 rd and 4 th graders
 Intervention

Children’s desk wiped with a disinfectant wipe at the end of each school day
 Results

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?
17

 Details

Two school semesters

3 rd and 4 th graders
 Classroom 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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 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
19

 Schools closed

Lost school days

Make-up days might be needed
 High absenteeism

State reimbursements lost
 Teachers and staff ill

Replacement personnel needed
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cont’d
 Custodial staff often become ill
 Schools must be disinfected to stop the outbreak

Outside services

Extra cleaning materials/supplies
21

 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
22



Staff members and students quickly ill
25
+ staff members absent multiple days
 Spread to other schools and the parochial school in the community


Team activities
Extracurricular activities at church (choir, Boy Scouts, first communion instruction)


Closed 11 schools for one week (school days, one holiday)
5000
+ enrollment
23

DIRECT=@$93K
 Disinfection = $45K

Outside haz mat vendor =$25K


Supplies = $10-15K
Janitorial staff overtime=$5K
 Personnel = $7875


Cost of substitute teachers =$105/day per sub
25 teachers x 3 days
 Cancelled class trip=$40K
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INDIRECT = $1,015,050
 School operations = $335,000 per day

Three lost days of school= $1,005,000
 State reimbursements = $10,050

3350 x 3+ days out (plus earlier absentees)
25

 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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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

Custodial staff and outside custodial used
 Disinfected the school, buses
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Real World Case II
DIRECT COSTS=$43K+
 Disinfection= $25,000
 Staff costs =$18,000
 Substitute teachers $100/day
 36 subs/5 days
28

Real World Case II
Indirect Costs
 Hospitalizations
 Parents lost time (minimum of six days) from work
29

 Bleach works, but is hard on surfaces

Requires personal protective gear (PPG)
 Quat-based products are available as liquids, ready-to-use and wipes

Can be used on keyboards, mice, all nonporous surfaces

Do not corrode metal

PPG is generally not needed
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 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

Bacteria grow on them, esp in human environments


Cloths and other organics reduce disinfectant concentration
Hard to get them clean
31

 Cleaning -“the removal of unwanted matter”
 Hygiene -“reducing the risk of infection”
 Cleaning alone may increase risks by spreading pathogens.
32

 93% of reusable cleaning cloths contained bacteria before use

Average number of bacteria = 17,000
 37.5 % of the disinfectant soak buckets contained bacteria

Average number of bacteria = 523

Organism Cotton Microfiber P-value
Total bacteria
1,995 24,547 0.01
Coliforms
Molds
1
1
6
47
0.0002
0.001

 Reuseable cleaning/towels/cloth can contain opportunistic pathogens
 Washing practices affect microbial loads in reusable cleaning cloths/towels
 Microfiber cloths contain more bacteria than cotton
 A wide range of enteric bacterial types are present in cleaning cloths

 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
36

 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

 Virus 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

Intervention
 Give maids antimicrobial products, disinfectant wipes for key surfaces
 Hand sanitizers for attendees
Results
 Reduce spread between rooms by 90%
 Reduce virus on hands by 50%

 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
40

 “Quats” on the market for 60+ years

Thousands of products but not all work for all pathogens!
 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
41

 Products with this
EPA-registration
• Labels indicate which products kill which pathogens http://tiny.cc/norovirus-products
42

 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

 Teacher and custodial training is important

Must understand their role in school health

Must know the difference between disinfecting, sanitizing and cleaning
 Disinfecting is needed the moment illness strikes

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
44

 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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