Epidemiology and
Outbreak Report
Josh Rounds, MPH
Epidemiologist
Minnesota Department of Health
Norovirus Update
 Continue to see a lot of norovirus activity
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32 Nursing home outbreaks reported since
December 1st
8 confirmed foodborne norovirus outbreaks
since December 1st
Outbreak of E. coli O157:H7 associated
with Sally Jackson Cheese
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8 cases in Oregon, Washington, Vermont and
Minnesota (2) from September to November
Made from unpasteurized goat, sheep and cow
milk
Wrapped in grape and chestnut leaves gathered
from a neighbor's orchard and tied with twine
No labels listing ingredients, no pull dates
Very expensive ($30 per pound)
Outbreak of E. coli O157:H7 associated
with Sally Jackson Cheese
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Gross contamination issues
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no sanitizing of cheese-making utensils, old milk
residue in a milk chiller, mold-like substances on an
aging table and above a draining table, a dirty floor,
peeling ceiling plant, cobwebs, rodent droppings and
one dead mouse.
E. coli and Unpasteurized Cheese
 E. coli O157 Bravo Farms
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38 illnesses linked to raw milk Gouda cheese
 Is the 60 day aging period adequate?
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Using raw milk in cheeses that are aged for at
least 60 days is permitted under federal law
Outbreak of non-O157 STEC
associated with venison
 MDH received a report of 2 students from
same class hospitalized with bloody
diarrhea
 7 deer provided by students
 Butchered under the football stadium
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Small amt of additional venison not butchered
at school also provided by students
 Made into kabobs
 Grilled
Outbreak of non-O157 STEC
associated with venison
 117 (52%) students interviewed
 28 cases identified
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6 laboratory confirmed STEC infections
O103:H2 and O145:NM
 20 students ill not meeting case definition
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Evidence of norovirus infections
Outbreak of non-O157 STEC
associated with venison
Outbreak of non-O157 STEC
associated with venison
Exposure
Odds Ratio 95% CI
Undercooked “Pink
” Venison
Pink”
3.27
P value
% Cases Exposed
1.18-9.03 0.02
39
Not washing hands after contact 21.43
with raw venison or cleaning
on November 23
1.90-562
21
Not wearing gloves during
November 17 class
1.01-35.6 0.03
 Students in 4th
6.00
0.003
14
period class more likely to
become ill than students in 1st or 5th period
classes
Outbreak of non-O157 STEC
associated with venison
 Cross-contamination
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Not washing hands after bare-hand contact
with raw venison
Using same plate for raw and cooked venison
Same tongs used to handle raw and cooked
 Skewers could introduce contamination
into interior of meat
Outbreak of non-O157 STEC
associated with venison
 Venison from two students homes positive
for E. coli O103:H2
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Venison butchered at school
 No evidence of cross-contamination with
beef
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Butcher’s tools had never been used on beef
 Novel pathogen vehicle combination?
 Previous E. coli O157:H7 outbreaks
involving deer
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1995 OR outbreak traced to venison jerky
1996 WA outbreak traced to unpasteurized
apple cider
• Deer feces at orchard + for O157
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2000 Connecticut case report
• Case and venison + for matching O157
Prevalence of STEC in Deer
 Studies of O157 prevalence range from
0.25% (Nebraska) to 2.4% (Kansas)
 Non-O157 STEC 5% of deer sampled
from MN and WI wildlife management
areas
 International studies found carriage rates
of non-O157 STEC ranging from 7.5% of
roe deer meat in Germany to 22% of
fallow deer meat in Belgium
 Deer and cattle can inhabit the same
environments
 Possible factors contributing to
contamination
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Gut shot
Contamination during field dressing
 Environmental contamination during
transportation
 Stored in conditions promoting bacterial
growth
 Cross-contamination during butchering
 Marinated in 5 gallon buckets
Other Factors
 Testing for non-O157
 Non-O157 STEC infections are under
recognized
 Many clinical laboratories don’t test for
non-O157 STEC
 Need to use a rapid shiga toxin PCR
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11% of clinical labs in FoodNet study
 Outbreak may not have been detected
through clinical testing alone
Questions