Outbreak of Listeria Infections Associated with Whole Cantaloupe

Outbreak of Listeria Infections Associated with Whole Cantaloupe – United States, 2011 Donald J. Sharp, MD, DTM&H Deputy Director, Food Safety Office Division of Foodborne, Waterborne, and Environmental Diseases National Center for Emerging Zoonotic and Infectious Diseases Centers for Disease Control and Prevention Jeff Mc. Collum, DVM, MPH Colorado Department of Public Health and Environment Communicable Disease Epidemiology Program The findings and conclusions in this presentation are those of the author and do not necessarily represent the views of the Centers for Disease Control and Prevention

Listeria monocytogenes (LM) q Annual public health impact — United States § 1, 591 illnesses § 1, 455 hospitalizations § 255 deaths q Foodborne pathogen § <1% bacterial foodborne illnesses § 19% food-related deaths q 94% hospitalization rate § Highest among foodborne pathogens q 15. 9% overall case-fatality rate § 25– 50% among newborns Scallan E et. al. , Emerging Infectious Diseases; 2011 Jan; 17(1); 7 -15.

Estimated Annual Health Burden — Select Bacterial Foodborne Pathogens, United States Pathogen Illnesses Deaths Fatality Rate Salmonella 1, 027, 561 378 0. 04% Campylobacter 845, 024 76 0. 01% E. coli O 157 63, 153 20 0. 03% Listeria 1, 591 255 16% Scallan E et. al. , Emerging Infectious Diseases; 2011 Jan; 17(1); 7 -15.

LM: Epidemiology q q q Ubiquitous in soil and water Animal reservoirs Typical food vehicles § § § q q Unpasteurized (raw) milk Raw-milk cheeses Hot dogs Deli meats Smoked seafood Growth during refrigeration Mostly sporadic illness § 2– 3 U. S. outbreaks annually

LM Outbreaks: Historical Perspective Coleslaw 41 cases Canada Mexican-style cheese 142 cases California 1981 1983 1985 Pasteurized milk 49 cases Massachusetts 1998 2000 2002 2008 2009 2010 2011

LM Outbreaks: Historical Perspective Coleslaw 41 cases Canada Turkey deli meat 30 cases Multistate Mexican-style cheese 142 cases California 1981 1983 1985 Pasteurized milk 49 cases Massachusetts Turkey deli meat 54 cases Multistate 1998 Hot dogs 108 cases Multistate 2000 2002 Mexican-style cheese 13 cases North Carolina 2008 2009 2010 2011

LM Outbreaks: Historical Perspective Coleslaw 41 cases Canada Turkey deli meat 30 cases Multistate Mexican-style cheese 142 cases California 1981 1983 1985 Pasteurized milk 49 cases Massachusetts Chopped celery 10 cases Texas Turkey deli meat 54 cases Multistate 1998 Hot dogs 108 cases Multistate 2000 2002 Mexican-style cheese 13 cases North Carolina 2008 2009 Alfalfa sprouts 20 cases Multistate 2010 2011 Cantaloupe 146 cases Multistate

Relative rate (log scale) Relative Rates of Laboratory-confirmed Infections with Listeria Compared with 1996 -1998 Rates, by Year, Food. Net 1996 -2010* The position of each line indicates the relative change in the incidence of that pathogen compared with 1996 -1998. The actual incidences of these infections cannot be determined from this graph. *

LM: Clinical Manifestations q q Long incubation: 3– 70 days (median: 21 days) “Healthy” individuals § Asymptomatic § Febrile gastroenteritis q High-risk groups § § q Immunocompromised Older adults (≥ 60 years) Pregnant women Newborns Invasive disease § Septicemia § Meningitis

Cantaloupe-Associated Outbreaks — United States, 1973– 2003 q 28 outbreaks § 1, 615 illnesses § 57 hospitalizations § 2 deaths q Causative pathogen § § q 11 (39%) Salmonella 7 (25%) Norovirus 1 (4%) Campylobacter 1 (4%) E. coli O 157 21 (75%) linked to prepared cantaloupe § 17 (61%) restaurant or caterer § 4 (14%) grocery store Bowen A et. al. , Epidemiol. Infect. (2006), 134, 675– 685.

LM in Cantaloupes? q q No documented Listeria outbreaks linked to whole fresh-cut cantaloupes Sporadic illnesses § Associated with eating commercially-prepared melons § Retail environments’ role in contamination and amplification of LM q Research § LM survives on cantaloupe rind ≤ 15 days with refrigeration § Fresh-cut cantaloupe pieces positive for LM after inoculation of rind at ≤ 15 days refrigerated storage

Multistate Outbreak of Listeriosis Linked to Whole Cantaloupes from Jensen Farms, Colorado — 2011

Investigation Methods q Case definition § Illness onset July 31–October 31, 2011 § Culture-confirmed Listeria clinical infection § Isolate indistinguishable from any of four outbreak strains by pulsed-field gel electrophoresis (PFGE) q Pulse. Net § PFGE pattern repository q q Patient interviews Listeria Initiative data Product traceback On-farm environmental assessments

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 8) q September 2 — CDPHE notifies CDC § 8 cases reported since August 15 § 7 cases reported since August 29 § 3 distinct PFGE patterns among cases Number of Illnesses q Expect 1– 2 cases in August in Colorado 10 Colorado cases 8 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 11) q September 5 Number of Illnesses § CDPHE collects cut and whole cantaloupe from a single ill patient’s home for Listeria testing 10 Colorado cases 8 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 13) q September 6 Number of Illnesses § Pulse. Net defines outbreak strains § Two additional illnesses in Nebraska and Texas § 7/7 Colorado patients report consuming cantaloupe ≤ 30 days before onset 10 Colorado cases 8 Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 15) q September 7 Number of Illnesses § CDC begins coordinating multistate investigation 10 Colorado cases 8 Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 15) q September 8 Number of Illnesses § CDPHE collects cantaloupes from retail stores for Listeria testing 10 Colorado cases 8 Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 15) q September 9 Number of Illnesses § Significantaloupe association rapidly determined using Listeria Initiative data and case-case analysis (p = 0. 02) § CDPHE issues consumer warning § FDA collects cantaloupes from retail 10 Colorado cases 8 Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 15) q September 10 Number of Illnesses § CDPHE and FDA conduct joint on-farm environmental assessment of two Colorado cantaloupe producers § Environmental and product samples are collected § Jensen Farms halts harvest and distribution 10 Colorado cases 8 Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 15) q September 11 Number of Illnesses § CDPHE successfully cultures Listeria from a patient’s whole and cut cantaloupe collected September 5, and from Jensen Farms’ cantaloupes from retail stores 10 8 § Preliminary interview and traceback implicate cantaloupes Colorado cases marketed as “Rocky Ford” Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 28) q September 14 Number of Illnesses § Ongoing traceback investigations converge on Jensen Farms § Jensen Farms voluntarily recalls all cantaloupe 10 Colorado cases 8 Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 41) q September 16 Number of Illnesses § Jensen Farms’ cantaloupes collected by CDPHE at retail September 8 yield outbreak strains of Listeria 10 Colorado cases 8 Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 53) q September 19 Number of Illnesses § Samples collected at Jensen Farms September 10 yield several outbreak strains of Listeria § Fourth outbreak strain of Listeria identified 10 Colorado cases 8 Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 73) q September 22 Number of Illnesses § FDA conducts root cause environmental assessment at Jensen Farms § CDPHE, Colorado Department of Agriculture, Prowers County Public Health 10 Colorado cases 8 Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 131) q October 19 Number of Illnesses § FDA announces findings of Jensen Farms root cause environmental assessment conducted September 22– 23 10 Colorado cases 8 Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 145) q October 27 Number of Illnesses § Illness onsets for the final two outbreak-associated cases occur 10 Colorado cases 8 Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Timeline of Events: Multistate Listeriosis Outbreak Linked to Whole Cantaloupes — July–October, 2011 (n = 145) q October 31 Number of Illnesses § Last day of the outbreak period determined by CDC § Illness onsets during July 31–October 31 due to outbreak strains of Listeria considered part of outbreak 10 Colorado cases 8 Non-Colorado cases 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 August September Date of Illness Onset October

Number of Patients by Date of Illness Onset — All States, July–October, 2011 (n = 145) 10 Colorado cases Jensen Farms recalls all Non-Colorado cases Number of Illnesses 8 6 4 2 0 31 3 6 9 12 15 18 21 24 27 30 2 August 5 8 11 14 17 20 23 26 29 2 September Date of Illness Onset 5 8 11 14 17 20 23 26 29 October

Final Case Finding: Pulse. Net q 146 cases identified in residents of 28 states § Colorado: 40 cases q Bordering states east and south of Colorado have high numbers of reported cases § § q Texas (18) New Mexico (15) Oklahoma (12) Kansas (11) Four different PFGE patterns

Persons Infected with Outbreak Strains of LM, by State* MT 1 OR 1 ND 2 ID 2 WY 4 NV 1 CA 4 UT 1 SD 1 PA 1 IA 1 NE 6 CO 40 NY 2 WI 2 IL 4 KS 11 MO 7 OK 12 NM 15 IN 3 TX 18 AR 1 AL 1 LA 2 1 -4 cases 5 -9 cases 10 -19 cases ≥ 20 cases * n= 146 for whom information was reported to CDC on December 2, 2011 WV 1 VA 1 MD 1

Characteristics — All Patients (n = 146) Characteristic Number (%) Age, median years (range) 77 (<1– 96) ≥ 60 years of age 126 (86) Female 85 (58) Hospitalized* 142 (99) Died 30 (21) Pregnancy-associated 6 (4) * Among 144 patients with available data

Number of Patients by Age — All Affected States (n = 146) ≥ 60 Years 86% 10 Number of Patients 8 6 4 2 0 <1 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78 81 84 87 90 93 96 Age in Years

Jensen Farms Cantaloupe Field

Jensen Farms Packing Operations

Summary of LM PFGE Pattern Data Among Cantaloupe and Environmental Samples PFGE Outbreak Pattern Cantaloupe 1 2 3 Patient X X X Retail X X X JF cooler Swabs, JF processing X X 4 X X X

Summary: Jensen Farms Root Cause Environmental Assessment q Multiple Listeria outbreak strains found § Food contact surfaces § Whole, processed cantaloupes q q Processing facility most likely source of cantaloupe contamination Deficiencies § § Inadequate sanitation Facility design and use Equipment Lack of postharvest cooling

Conclusions q q Whole cantaloupes produced and packed by Jensen Farms caused outbreak First reported Listeriosis outbreak associated with whole cantaloupe § Ready-to-eat and processed foods previously q q q Older adults ≥ 60 a majority of patients Few pregnancy-associated cases Largest documented U. S. outbreak of Listeriosis § Deadliest U. S. foodborne outbreak in >90 years

Thank You!

Cantaloupe Association and The Listeria Initiative* Date Cantaloupe Ham Sept 9 OR (95% CI) = 8. 54 (1. 32 -∞) Cases: 11/11 (100%) Controls: 54/85 (64%) P=0. 02 OR (95% CI) = 2. 01 (0. 51– 9. 44) Cases: 7/11 (64%) Controls: 360/774 (47%) P=0. 41 Sept 12 OR (95% CI) = 10. 13 (1. 60–∞) Cases: 13/13 (100%) Controls: 54/85 (64%) P=0. 01 OR (95% CI) = 2. 58 (0. 71– 11. 58) Cases: 9/13 (69%) Controls: 360/774 (47%) P=0. 18 Sept 14 OR (95% CI) = 14. 93 (2. 43–∞) Cases: 19/19 (100%) Controls: 54/85 (64%) P=0. 001 OR (95% CI) = 1. 44 (0. 50– 4. 24) Cases: 10/18 (56%) Controls: 360/774 (47%) P=0. 60 * In controls, cantaloupe exposures limited to those with isolation dates in August. Controls are nonpregnancy associated sporadic cases among persons 60 years or greater. ** Cases initially limited to PFGE patterns 1 and 2.