Listeria monocytogenes : The Burden of Illness and the Public Health Challenge

1. Listeria monocytogenes: The Burden of Illness and the Public Health Challenge Robert V. Tauxe, MD, MPH Foodborne and Diarrheal Diseases Branch Centers for Disease Control and Prevention, Atlanta, Georgia Food and Drug Administration, December 4, 2003 Unpublished data in this presentation is preliminary

2. Background on organism and infection Current public health burden Trends in incidence of listeriosis Conclusion Unpublished data in this presentation is preliminary Objectives

3. Listeria monocytogenesCharacteristics of the organism • Small rod shaped bacterium • Lives in soil, ubiquitous • Thrives in moist, cool locations • Grows slowly at refrigerator temperatures • In the animal or human, can be invasive • Survives inside white cells

4. Listeria monocytogenesCharacteristics of the infection • Perinatal infections • Pregnant woman may have fever, or not have a defined illness • Spread to the fetus • Sepsis • Miscarriage • Stillbirth • Spread to the newborn baby • Meningitis

5. Listeria monocytogenesCharacteristics of the infection • Non-perinatal infections, compromised host • Malignancy • Organ transplant • Immunosuppressive medications • HIV/AIDS • Elderly • Can produce invasive disease • Sepsis • Meningitis • Encephalitis

6. Listeria monocytogenesCharacteristics of the infection • Normal host • Most often is asymptomatic • Can produce diarrheal illness with fever • Rarely can lead to invasive disease • We track invasive illness

7. Estimated annual burden of selected foodborne diseases, United States* (1997 estimates) * Due to foodborne and other transmission routes Mead, EID Journal, 1999

8. Tracking listeriosis with active surveillance • 1985: Large outbreak in California: 142 cases, 40 fatalities, traced to Mexican style soft cheese, queso fresco • 1986: Active surveillance began in sentinel locations • Staff contact clinical laboratories to identify cases • 1996: Expanded to other foodborne infections as FoodNet, with support of USDA and FDA

9. Year Pop’n (million) 1996 14.3 1997 16.1 1998 20.7 1999 25.9 2000 30.5 2001 34.1 2003 36.0 13% of U.S. population FoodNet Sites 1996-2003

10. Has mortality of listeriosis changed over time? Case- fatality data from active surveillance, United States

11. Rate of invasive listeriosis infection in different population groups, United States*, FoodNet (1996-2000) • 4 per million persons in general population • 2 per million among White, non Hispanic • 2 per million among African-Americans • 4 per million among Asians • 2 per million among non-Hispanic • 7 per million among Hispanics

12. Rate of invasive listeriosis infection in different population groups, United States*, FoodNet (1996-2000) • Among infants • Incidence rate 12 fold higher among Hispanics than among non Hispanics • Among women of childbearing age • Incidence rate 11 fold higher among Hispanics than among non-Hispanics

13. Hot dog outbreak; PulseNet began subtyping Turkey frank case, New regulatory policies, Industry efforts Queso fresco outbreak Deli meat outbreak Incidence of reported cases of listeriosis in the United States, 1986-2002* *Data from active surveillance systems, FoodNet since1996. 2002 data are preliminary

14. PFGE patterns Participating laboratories National database Laboratory coordination

15. 12 Death or miscarriage Recall 11 Survived 10 9 Number of Patients 8 7 Plant Construction 6 5 Serotype 4b 4 3 2 1 0 6/27 8/2 9/6 10/11 11/15 12/20 1/24 2/27 4/3 Date Multistate listeriosis outbreak,1998-1999 • 101 cases in 22 states, 84 non-pregnant adults • 15 deaths (all adults), 6 miscarriages • Epidemiological investigation implicated eating hot dogs from Plant A

16. 12 cases in North Carolina All Hispanic 10 were in pregnant women 5 stillbirths Epidemiological investigation: queso fresco purchased from door-to-door vendors homemade queso fresco made using local raw milk Strains of serotype 4b, with a single PulseNet pattern, from patients, cheeses, and raw milk State banned sale of raw milk, launched education program MMWR 50:560, 2001 Cheese-associated outbreak of listeriosis, North Carolina, 2000-2001

17. 54 patients in 9 states 42 non-pregnant adults 8 deaths, 3 miscarriages/stillbirths Serotype 4b Outbreak was caused by turkey deli meat Post-processing contamination likely USDA-FSIS issued new microbial sampling policy Increased environmental testing Can base recall on environmental test results Preliminary data Multi-state outbreak of listeriosis, 2002

18. Hot dog outbreak; PulseNet began subtyping Turkey frank case, New regulatory policies, Industry efforts Queso fresco outbreak Deli meat outbreak Incidence of reported cases of listeriosis in the United States, 1986-2002* *Data from active surveillance systems, Some data are preliminary

19. PulseNet begins subtyping Listeria Multistate outbreak One state outbreak Outbreaks of listeriosis, United States, 1978-2003* * Data for 2002 and 2003 are preliminary

20. Listeriosis outbreaks in the United States 1979-2003* *Preliminary data 2002, 2003

21. General conclusions from the epidemiological data • Outbreaks caused by: • Processed ready-to-eat meats, especially turkey and hot dogs • Fresh soft cheeses made with raw milk • Typically contaminated after initial processing • Locus of contamination in the processing plant • Sporadic cases associated with: • Study #1: 1988: Unreheated hot dogs, undercooked poultry • Study #2: 1992: Foods from a deli, soft cheeses

22. General conclusions from the epidemiological data • Overall incidence has declined from 8 per million to 2.7 per million in the last decade • Mortality remains high at 20% • Risk groups include • Immunocompromised persons • Elderly • Pregnant women • Hispanic population

23. General conclusions from the epidemiological data • With PulseNet, ability to detect and investigate Listeria outbreaks has improved in the past 5 years • Investigating outbreaks leads to immediate and longer term control measures • Efforts to reduce contamination are followed by declines in incidence of human illness

24. Listeriosis control • National action plan • Reduce incidence of reported cases to below 2.5 per million per year = 700 cases per year • Measured through active public health surveillance of invasive cases (FoodNet) • Nationwide surveillance with enhanced subtyping and patient interviews for outbreak detection, investigation and control

25. FIN