What's for dinner? Current issues in foodborne illness

Transcription

1 What's for dinner? Current issues in foodborne illness Alicia Cronquist, RN, MPH Foodborne/Enteric Disease Epidemiologist Colorado Dept. of Public Health and Environment

2 Today s Goals What s new in foodborne disease epidemiology and outbreaks in Colorado Understand some of the forces that cause epidemiology of foodborne illness to be constantly changing

3 Changing epidemiology of foodborne disease Developments in lab techniques New pathogens; new ways to detect outbreaks Antibiotic use (humans and animals) Changes in human population Food safety regulation changes Globalization of food supply Centralized production Changing food preferences

4 What is foodborne disease? Infections Intoxications Enteric illness = diarrheal disease; can be from food, water, animal contact, person-to-person transmission

5 Types of foodborne / enteric illness Infection Bacteria: Campylobacter Listeria Salmonella Shigella STEC (O157 and non-o157) Vibrio Viruses: Norovirus Hepatitis A virus Parasites: Cryptosporidium Giardia Intoxication Clostridium botulinum Clostridium perfringens Staphylococcus aureus Bacillus cereus

6 More than vomit and diarrhea Listeria monocytogenes miscarriage, 20% mortality in immunocompromised STEC O157 (aka E. coli O157) Hemolytic uremic syndrome Campylobacter Guillian-Barré syndrome C. botulinum respiratory failure, death Vibrio vulnificus amputations, death

7 Determining the source of illness: Foodborne diseases??? STEC O157/non-O157 Salmonella Campylobacter Giardia Cryptosporidium Shigella* Norovirus* Food? Water? Person to person? Animal contact? *Shigella and norovirus do not have animal reservoirs

8 Examples of non-foodborne outbreaks with foodborne pathogens Salmonella Typhimurium associated with unchlorinated drinking water, Alamosa, 2008 STEC O157 outbreak associated with elk droppings, Evergreen, 2008 STEC O157 outbreak, National Western Stock Show, Denver, 2009

9 Reported Cases of Enteric Pathogens Colorado, Organism Campylobacter species Salmonella species Giardia lamblia Shiga-toxin E. coli Cryptosporidium Shigella species Hepatitis A Listeria monocytogenes Clostridium botulinum Note: Individual cases of illness caused by the following organisms are NOT reportable (but outbreaks are): - Bacillus cereus - Clostridium perfringens - Staphylococcus aureus - Norovirus Source: CEDRS database

10 Pyramid of reporting Reported to Health Dept Culture-confirmed case Lab tests for organism Public health surveillance Specimen obtained Person seeks care Person becomes ill Exposure in the general population

11 Rates of Enteric Illness by Age Group Cases Reported in Denver Metro Area, 2010 Rate/100, < Age in Years Campylobacter Salmonella Shigella STEC O157

12 Reported Cases of STEC O157 in Colorado 35 Number of Cases Jan-97 Jul-97 Jan-98 Jul-98 Jan-99 Jul-99 Jan-00 Jul-00 Jan-01 Jul-01 Jan-02 Jul-02 Jan-03 Jul-03 Jan-04 Jul-04 Jan-05 Jul-05 Jan-06 Jul-06 Report Month

13 Hepatitis A Rates in Colorado, cases Hepatitis A vaccine available Rate per 100, cases Report Year

14 Incidence of Infection with FoodNet Pathogens, Metro Denver*, Campylobacter Salmonella Shigella E. coli O157 Rate per 100, Year *Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, Jefferson Counties

15 Case investigation All reported cases Prevent further spread Work / child care restriction Patient education Identify outbreaks Do you know of other ill persons? Exposure history Travel, foods, animals, child care.

16 Disease control for reported cases High risk workers / settings Food handlers Child care attendees or workers Health care workers Require 2 negative stools and resolution of diarrhea before return to work/childcare STEC / E. coli O157 Shigella

17 Foodborne Outbreaks

18 What is an outbreak? CDC definition of a foodborne outbreak: Two or more cases of a similar illness resulting from the ingestion of a common food in the United States Operationally: Unexpected # of illnesses occurring in a cluster by time, place, person Priority on commercially prepared foods Priority when 2 or more people from different households

19 Detecting and investigating outbreaks Complaint call outbreaks Often a defined cohort (e.g. wedding party) Defined exposure period May not know disease agent Reported by providers, public, schools, employers, child care centers Surveillance outbreaks Agent is known Rarely a defined cohort Any exposure possible, ask about all exposures during incubation period

20 Why investigate foodborne / enteric illness? Remove an ongoing source of infection Foodhandler / contam. food / water / animal Correct faulty food prep practices Prevent further person-person spread Health care, child care, food workers, etc Understand enteric illness better New vehicles New routes of transmission Drive regulatory change

21 Reported Foodborne Outbreaks in Colorado, by Year Number of Reported Outbreaks Year of Outbreak

22 Agents causing foodborne outbreaks in CO, (N=206) Viral (norovirus) 41% (84) Bacterial infection 27% (55) 30 Salmonella, 17 STEC, 7 Campylobacter, 1 Listeria Bacterial intoxication 14% (28) Other 3% (7) 5 Scombroid Unknown 16% (32)

23 Errors Causing Colorado Foodborne Illness Outbreaks ( , N=206) Time/Temp Abuse Other 7% 2% Unsafe source 2% Ill worker 17% Unknown 55% X-Contam 1% Contam Product 16%

24 Norovirus outbreaks due to ill workers Michigan, 2006 Worker vomited into kitchen waste bin Kept working ~360 illnesses Data mounting about persistence of virus and duration of viral shedding Need to exclude ill workers for longer (72hrs?) CDPHE currently recommends at least 48 hours Surface decontamination with bleach in 25ft radius of vomiting May need to close restaurant for cleaning

25 A foodborne epi tasting menu Revolutions in the lab Good, bad and ugly Recurring outbreak themes Produce Drug-resistant Salmonella Raw milk

26 Foodborne surveillance and the laboratory Clinical lab Initial patient testing (usually culture) Cases must be reported to public health Tests should be sensitive and specific State lab Subtyping of specimens sent by clinical lab Primary testing during outbreaks

27 Lab Techniques and Outbreak Detection PFGE (pulsed field gel electrophoresis) PulseNet: National databases for sharing PFGE patterns between states and CDC Allow epidemiologists to recognize that geographically separated cases may have common source Surge in multi-state outbreaks directly attributable to PulseNet Genetic sequencing: used for primarily for viruses (norovirus and hepatitis A)

28 PulseNet in Action: Matching PFGE Patterns for Colorado and Minnesota Case-Isolates of Escherichia coli O157 PFGE: Xba 1 PFGE: Bln 1 Case Standard CO 1 CO 2 CO 3 CO 4 CO 5 CO 6 CO 7 CO 8 CO 9 CO 10 CO 11 CO 12 CO 13 MN 1 MN 2 MN 3 MN 4 MN 5 MN 6 MN 7

29 Eat your veggies? Recent produce-associated outbreaks Tomatoes At restaurants, Roma, sliced on sandwiches Lettuce Bagged lettuce, shredded on tacos Spinach Scallions Sprouts Jalapeños/serranos Cantaloupes

30 Why produce? Many opportunities for contamination lots of handling; irrigation water; fertilizer; grown near animals Changes in food processing / distribution Shipping longer distances Produce from multiple sources mixed together Nature of produce itself Good growth medium; low salt; high sugar More and more produce imported

31 Result of increased centralization of food processing Small deviations from good food handling practices may have large implications Results in a new kinds of outbreak: Large number of dispersed victims Lower attack rates (< 5% of those who eat the contaminated food) Larger proportion of cases among the elderly and immune-compromised

32 Multi-drug resistant Salmonella Associated with more severe illness Not considered an adulterant in meat Ground beef First recalls summer 2009 Two outbreaks within one month Ground turkey April 2011: Salmonella Hadar Aug 2011: Salmonella Heidelberg, 36 million lbs

33 What s old is new Raw milk outbreaks Sale of unpasteurized milk illegal in Colorado Herd share programs are legal Belief that raw milk is healthier Outbreaks: 2005 Campylobacter, 22 cases 2009 Campylobacter, 81 cases 2010 E. coli O157 and Campylobacter, 30 cases, 2 kids with kidney failure (HUS)

34 Rise of non-culture based testing (AKA Culture-independent testing) Wide variety of antigen-based tests available: Shiga toxin Campylobacter Cryptosporidium Giardia Others in development

35 Challenges posed by non-culture based testing False positives Tests often have lower specificity Used in real-world settings of low prevalence Increased false positives (low PPV) Potential for the tests to be used with different patient populations or for different indications Potential loss of isolates for subtyping Outbreak detection Trends in subtypes Loss of antimicrobial susceptibility testing Individual Population trends

36 Impact of Shiga toxin testing Reported cases of STEC in Colorado

37 Impact of non-culture testing on surveillance data Number of cases Campylobacter Cases in Colorado by Year of Report Non-culture Culture 14.5% of 2010 total

38 So, what is for dinner? Individual consumers: Handwashing, handwashing, handwashing Cook, Clean, Separate, Chill Buy pasteurized milk/juice or consume at own risk Consider avoiding certain foods if in a high risk group Washing produce may not help

39 So, what is for dinner? State/federal level Use the recently enhanced recall authority Better produce tracking Leafy greens action plan / other produce safety initiatives Allow reg agencies to share findings with public health Advocate for resources necessary to manage new lab testing challenges

40 Risky Foods/Risky Critters Sprouts Undercooked meats Raw shellfish/seafood Undercooked eggs Any unpasteurized milk/juice Reptiles Other animals (cattle, chicks )

41 Groups at Risk for Particular Pathogens Pregnancy and Listeria Deli meats Unpasteurized milk/cheese Liver Disease and Vibrio Raw oysters Seawater contact with bare skin

42 THANK YOU!