Listeriosis in the United States

Benjamin J. Silk, PhD, MPHStaff Epidemiologist

Enteric Diseases Epidemiology Branch, CDC

Public meeting on the Interagency RetailListeria monocytogenes Risk Assessment

May 22, 2013

National Center for Emerging and Zoonotic Infectious DiseasesDivision of Foodborne, Waterborne, and Environmental Diseases

Listeria monocytogenes

Found in soil and water

Grows at refrigeration temperatures

Transmitted to people by food

Infection (listeriosis) causes severe disease in vulnerable groups

Higher-risk Groups

Higher-risk Group Illnesses/outcomes

Pregnant women Febrile illness, fetal loss

Newborn infants Bloodstream infection, meningitis

Persons with immunocompromising conditions

Bloodstream infection, meningitis

Older adults Bloodstream infection, meningitis

Incidence by Risk Group, 2004–2009

Pregnancy-associated

Scallan E et al, Emerging Infectious Diseases, 2011

Pathogen Illnesses Deaths Case-fatality rate

Listeria 1,600 260 16%

Campylobacter 1,300,000 120 0.1%

Salmonella 1,230,000 450 0.5%

Shiga toxin- producing E. coli O157 96,000 30 0.5%

Listeriosis is rare, but deadly

U.S. Listeriosis Incidence, 1986-2011

Data from sentinel site surveillance (FoodNet since 1996)

Progress in late 20th Century

Detection of Processed Meats as Source, 1989

U.S. Listeriosis Incidence, 1986-2011

Data from sentinel site surveillance (FoodNet since 1996)

New regulatory policies and industry efforts begin targeting meat processing

Hot Dog Outbreaks, 1998–2011:A Regulatory Success

Years No. cases No. deaths/fetal losses1998 112 141999 4 0

2000-2011

0 0

Cartwright E et al, Emerging Infectious Diseases, 2013

Deli Meat Outbreaks, 1998–2011: A Regulatory Success

Years No. cases No. deaths/fetal losses1998 0 01999 7 22000 30 42001 28 02002 54 82003 0 02004 0 02005 13 12006 0 02007 0 02008 0 02009 0 02010 8 22011 0 0

Cartwright E et al, Emerging Infectious Diseases, 2013

U.S. Listeriosis Incidence, 1986-2011

Data from sentinel site surveillance (FoodNet since 1996)

New regulatory policies and industry efforts begin targeting meat processing

Advent of PulseNet, 1998

PFGE patterns

National database

Participating laboratories

Before PulseNet 1978-1997 (20 years)5 outbreaks (2 multistate)Average 54 cases/outbreak

Era of PulseNet 1998-2004 (7 years)13 outbreaks (4 multistate)Average 22 cases/outbreak

Advent of PulseNet

New Opportunities in 21st Century

U.S. Listeriosis Incidence, 1986-2011

Data from sentinel site surveillance (FoodNet since 1996)

New regulatory policies and industry efforts begin targeting meat processing

Lack of progress

Healthy People 2020 Goal

Developed in 2004 Enhanced surveillance for all cases Nationally-standardized food

history interviews Integration with PulseNet Expedites identification of

common food sources during outbreak investigations

Listeria Initiative

Outbreak from Whole Cantaloupe, 2011

Newly Recognized Sources of Listeriosis, from Outbreaks, 1998–2011

Implicated food vehicle Year No. cases No. deaths/fetal losses

None 1998-2005 0 0 Taco/nacho salad 2006 2 0 Tuna salad 2008 5 3 Sprouts 2008 20 20 None 2009 0 0 Pre-cut celery 2010 10 5 Whole cantaloupe 2011 147 34

Cartwright E et al, Emerging Infectious Diseases, 2013

Mexican-style Cheese Outbreaks, 1998–2011:A Continuing Problem

Year No. cases No. deaths/fetal losses

1998 0 0

1999 0 0

2000 13 0

2001 0 0

2002 0 0

2003 12 1

2004 0 0

2005 12 0

2006 0 0

2007 0 0

2008 8 0

2009 26 0

2010 6 1

2011 2 0

Cartwright E et al, Emerging Infectious Diseases, 2013

Incidence by Ethnicity, 2004–2009

Illnesses per 100,000 people

Outbreak from Imported Cheese that Cross-Contaminated Other Cheeses, 2012

Imported, contaminated ricotta salata was outbreak source

Cross-contamination of other cheeses propagated the outbreak

First U.S. listeriosis outbreak associated with cut and repackaged cheeses

Summary

Progress in late 20th Century• Interventions targeted processed hot dogs and deli meats• Enhanced outbreak detection

New Opportunities in 21st Century• Identify sources of sporadic cases via continued enhancement of

outbreak detection (e.g., Listeria Initiative, whole genome sequencing)• Newly recognized raw produce sources• Persistent sources, especially Mexican-style cheese

• Pasteurized and unpasteurized

• Targeting contamination and cross-contamination in retail settings

Public Health Approach to Prevention

Surveillance

Epidemiological Investigation

AppliedResearch

Prevention Measures

For more information please contact Centers for Disease Control and Prevention

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The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

National Center for Emerging and Zoonotic Infectious DiseasesDivision of Foodborne, Waterborne, and Environmental Diseases