Outbreak of Salmonella Enteritidis
Infections Associated with Organic
Eggs, August-October 2011
Background
• 6 Salmonella Enteritidis isolates submitted
through routine surveillance with
indistinguishable PFGE patterns
• Initial investigation revealed high egg
consumption; two self-reported eating
organic eggs
– Re-interviewed all cases about specific
egg consumption
Investigation
• Conducted community case control study
– Organic eggs from Larry Schultz Organic
Farm statistically significant (sold under
brand name and store brands)
• 5/6 cases vs. 1/16 controls;
OR = 75; 95% CI, 3.9-1434; p = 0.004
• Minnesota Dept. of Agriculture visited farm
– Isolates from egg belt matched human
isolates
• Press release and recall issued on Oct. 19
Outbreak Summary
•
•
•
•
8 confirmed cases (7 received at MDH-PHL)
Onset dates August 12 to October 20
Median age 25.5 years (range, 5-70 years)
3 (38%) hospitalized
– Each hospitalized for 3 days
• All residents of seven-county metropolitan
area
All Salmonella Enteritidis Isolates Received
August-October 2011 (n=63)
No PFGE Subtyping
Number of Cases
8
7
6
5
4
3
2
1
August
September
October
Week of Specimen Collection
All Salmonella Enteritidis SE1 Isolates
Received August-October 2011 (n=32)
PFGE Subtyping – 1 Enzyme
Number of Cases
8
7
6
5
4
3
2
1
August
September
October
Week of Specimen Collection
All Salmonella Enteritidis SE1 Isolates
Received August-October 2011 (n=7)
PFGE Subtyping – 2 Enzymes
Number of Cases
8
7
6
5
4
3
2
1
August
September
October
Week of Specimen Collection
3 Months Later…
Outbreak Salmonella Enteritidis
Infections Associated with a
Restaurant, January 2012
Background
• January 26: MDH PHL notified epidemiology
staff of a Salmonella Enteritidis isolate with a
matching PFGE pattern to the fall 2011 egg
outbreak
• Case reported attending a private event at a
restaurant in St. Paul on January 12
– At least two other attendees ill
– Restaurant sources “organically grown
and sustainably raised local ingredients”
Outbreak Summary
• 7 cases (4 laboratory confirmed)
– 6 (3 confirmed) from January 12 event
– 1 (confirmed) from January 21 event
• Consumption of desserts containing
undercooked eggs associated with illness
– Restaurant discontinued the use of
unpasteurized shell eggs in uncooked
foods
• No Salmonella found on one farm sampled
by MDA in January
Outbreak of Cryptosporidiosis
Associated with a Hotel Waterpark,
March 2012
Background
• March 26: MDH foodborne/waterborne illness
hotline received a complaint that 6/8
individuals from two households became ill
with diarrhea and cramps 4-9 days after
swimming at a hotel waterpark in Duluth
– Illnesses consistent with cryptosporidiosis
• Outbreak investigation was initiated
– All pools at the waterpark were voluntarily
closed and superchlorinated
Health and Laboratory Alerts
Investigation Results
• Illness histories obtained from 229 waterpark
users
– 97 primary cases identified
• 22 laboratory confirmed Cryptosporidium
– 16 identified as C. parvum BGP3 at MDH PHL
• 31 visited a healthcare provider
– 7 emergency room visits
– 1 hospitalized for 3 days
• Reported exposure dates March 3-26
Investigation Results
• Onsite environmental health assessment and
pool records review showed high combined
chlorine levels on multiple occasions in the
previous month with no notes indicating any
corrective action
• Three additional facilities superchlorinated
as a result of individuals from the outbreak
swimming while ill
Outbreak Conclusions
• An infectious pool user most likely
introduced the parasite into the pool
• Improperly maintained chlorine levels helped
facilitate the survival of the parasite in the
pools, leading to a protracted amount of time
during which pool users were at risk for
becoming infected
Pathogen Inactivation Time for
Chlorinated Water
Pathogen
E. coli O157
Hepatitis A
Giardia
Cryptosporidium
Time
<1 minute
~16 minutes
~45 minutes
~15,300 minutes
Number of Laboratory Confirmed Cryptosporidium
Cases in Minnesota by Outbreak Status, 2000-2011
450
Number of Cases
400
350
Non-Outbreak Cases
Outbreak Cases
300
250
200
150
100
50
0
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
Year of Specimen Collection
Educating Patrons Not to Swim
with Diarrhea
• Add healthy swimming information to
website with other pool information
– Place it near the most popular information,
such as hours of operation
• Add a message to voicemail or automated
greeting
– Example: When a customer calls to get the
check the hours, add: “To keep the pool
healthy for everyone, remember not to
swim when you have diarrhea”
Educating Patrons Not to Swim
with Diarrhea
• Train staff to routinely educate patrons
• Add healthy swimming messages to all print
material around the pool
• Post signs at the front desk, front door,
locker rooms
• Include the information in your rules for
special event guests
www.healthyswimming.org