Illness Outbreaks Linked to Nonpasteurized (Raw) Milk

Transcription

1 National Center for Emerging and Zoonotic Infectious Diseases Illness Outbreaks Linked to Nonpasteurized (Raw) Milk Megin Nichols, DVM, MPH, DACVPM Enteric Zoonoses Activity, Outbreak Response and Prevention Branch Division of Foodborne, Waterborne, and Environmental Diseases National Association of Dairy Regulatory Officials July 11, 2017

2 What is an outbreak? An incident in which two or more people experience a similar illness after contact with a common exposure, and an epidemiologic analysis implicates the exposure as the source of the illness

3 Outbreak investigations are a major driver for reducing disease burden Prevent additional cases in current outbreak Identify a new pathogen or problem Determine what occurred to prevent future similar outbreaks Define risks associated with ownership of certain animals Identify areas for education of consumers Stimulate further specific research Develop new processes or regulations

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5 Cases Identified to Public Health The Tip of the Iceberg Pathogen Under-reporting/ under-diagnosis multiplier* Listeria monocytogenes 2.1 Shiga toxin-producing Escherichia coli O157 Salmonella spp., nontyphoidal Scallan et al.foodborne Illness Acquired in the United States Major Pathogens. EID 2011

6 Detecting Outbreaks with PulseNet National network of 87 state public health and regulatory laboratories, established in 1996 When bacteria are collected from an ill person, labs create DNA fingerprints using pulsed-field gel electrophoresis (PFGE) and other techniques PFGE banding pattern Bacteria with the same DNA fingerprint are more likely to come from a common source =

7 Strengths and Limitations of PFGE-based Subtyping Successful over the last 20 years in detecting highly disseminated outbreaks Would not have otherwise been detected Would have been detected later Limitations to PFGE-based subtyping Some PFGE patterns are common, limiting utility PFGE patterns are indirectly reflective of underlying genetic relatedness of bacteria Related bacteria can appear different by PFGE and vice versa

8 Whole Genome Sequencing (WGS) Provides a higher resolution view of the bacterial genome Cut Sites All Positions PFGE only gives information at a cut site via the banding pattern WGS has the ability to give us information at (nearly) every position in the bacterial genome

9 Detecting Outbreaks with PulseNet Laboratory data from illness-causing bacteria uploaded to the PulseNet USA database Monitored for temporal and geographic clustering When a cluster is identified, PulseNet notifies epidemiologists

10 Outbreaks Linked to Nonpasteurized Milk United States, Number of outbreaks linked to drinking nonpasteurized milk increasing 30 in in Sickened nearly 1,000 people 73 people hospitalized More than 80% of outbreaks occurred in states where selling nonpasteurized milk was legal Mungai EA, Behravesh CB, Gould LH. Increased outbreaks associated with nonpasteurized milk, United States, Emerg Infect Dis [Internet] Jan [date cited].

11 Outbreaks Linked to Nonpasteurized Milk United States, Campylobacter Salmonella Coxiella burnetii E. coli Multiple Foodborne disease outbreaks with implicated food Mungai EA, Behravesh CB, Gould LH. Increased outbreaks associated with nonpasteurized milk, United States, Emerg Infect Dis [Internet] Jan [date cited].

12 Microbiological Hazards Found in Raw Milk Bacillus species Campylobacter jejuni Coxiella burnetti Cryptosporidium parvum Eschericia coli Helicobacter pylori Listeria monocytogenes Mycobacterium species Paenibacillus Salmonella enterica Staphylococcus aureus Yersinia enterocolitica Davis BJK, Li CX, Nachman KE (2014) A Literature Review of the Risks and Benefits of Consuming Raw and Pasteurized Cow s Milk. Johns Hopkins Bloomberg School of Public Health. Oliver SP, Jayarao BM, and Almeida RA (2005) Foodborne pathogens in milk and the dairy farm environment: food safety and public health implications. Foodborne Pathog Dis 2[2]:

13 Despite Risks, Raw Milk Consumption Continues Why? Perceived health benefits Lactose intolerance Allergies Asthma Fewer estrogenic hormones Vitamins/nutrients Misperception of risk Taste and texture preference Animal welfare concerns Davis BJK, Li CX, Nachman KE (2014) A Literature Review of the Risks and Benefits of Consuming Raw and Pasteurized Cow s Milk. Johns Hopkins Bloomberg School of Public Health.

14 Lactose Intolerance True or False: Drinking raw milk can attenuate the effects of lactose intolerance Studies show pasteurization does not substantially change the lactose content in milk (Ijaz, 2013; Lejeune, 2009) Randomized control pilot study to observe effects of raw milk on lactose intolerance and malabsorption (Mummah, 2014) Individuals drinking raw milk showed higher lactose malabsorption when compared to pasteurized milk Davis BJK, Li CX, Nachman KE (2014) A Literature Review of the Risks and Benefits of Consuming Raw and Pasteurized Cow s Milk. Johns Hopkins Bloomberg School of Public Health. Lejeune JT and Rajala-Schultz PJ (2009) Food safety: unpasteurized milk: a continued public health threat. Clin Infect Dis 48(1): Ijaz N Unpasteurized milk: Myths and evidence. In: Grand Rounds Presentation, (BC Centre for Disease Control, ed). Mummah S, Oelrich B, Hope J, Vu Q, Gardner CD Effect of raw milk on lactose intolerance: A randomized controlled pilot study. Annals of family medicine 12:

15 Allergies and Asthma True or False: Raw milk protects against the development of allergies Case-control study on school-age children residing in rural areas of Germany, Austria, and Switzerland (Loss, 2011) Questionnaire, took milk samples, assessed asthma, atopy and hay fever Raw milk consumption had inverse association with all three allergic conditions when compared to pasteurized milk (UHT) Selection bias and study did not measure life-long exposure Epidemiologic studies evaluating relationship of raw milk to allergies caution against consuming raw milk Loss G, Apprich S, Waser M, Kneifel W, Genuneit J, Buchele G, et al The protective effect of farm milk consumption on childhood asthma and atopy: The gabriela study. The Journal of allergy and clinical immunology 128: e764.

16 Concentration of Estrogenic Hormones in Milk True or False: Estrogen content is higher in pasteurized milk than raw milk Estrogen is naturally secreted in lactating cows Concentrations of estrogen in raw and pasteurized milk related to cow pregnancy status (Malekinejad, 2006) Estrogen concentration associated with fat content in milk Davis BJK, Li CX, Nachman KE (2014) A Literature Review of the Risks and Benefits of Consuming Raw and Pasteurized Cow s Milk. Johns Hopkins Bloomberg School of Public Health. Malekinejad H, Scherpenisse P, Bergwerff AA Naturally occurring estrogens in processed milk and in raw milk (from gestated cows). Journal of agricultural and food chemistry 54:

17 Vitamins and Nutrients True or False: Raw milk has more vitamins and nutrients Meta-analysis compared vitamin concentrations in raw and pasteurized milk (Lejeune, 2009; Macdonald, 2011) No significant change: Vitamins D/K after pasteurization Increase: Vitamin A increased after pasteurization Decrease: Vitamin B2/B12/E Milk not considered a significant source of B12/E Other foods supplement B2 Davis BJK, Li CX, Nachman KE (2014) A Literature Review of the Risks and Benefits of Consuming Raw and Pasteurized Cow s Milk. Johns Hopkins Bloomberg School of Public Health. Lejeune JT and Rajala-Schultz PJ (2009) Food safety: unpasteurized milk: a continued public health threat. Clin Infect Dis 48(1): Macdonald LE, Brett J, Kelton D, Majowicz SE, Snedeker K, Sargeant JM A systematic review and meta-analysis of the effects of pasteurization on milk vitamins, and evidence for raw milk consumption and other health-related outcomes. Journal of food protection 74:

18 Misperception of Risk True or False: Infection and outbreak rates for pasteurized and raw milk are similar, or are lower for raw milk Does not take into account substantial differences in consumption frequency Current estimates indicate raw milk consumed by approximately 3.5% of the U.S. population (Committee on Infectious Diseases and Committee on Nutrition of the American Academy of Pediatrics, 2014; David, 2012) If consumption increased then number of illness outbreaks linked to raw milk would likely increase Committee on Infectious Diseases and Committee on Nutrition of the American Academy of Pediatrics Consumption of raw or unpasteurized milk and milk products by pregnant women and children. Pediatrics 133:

19 Findings from Review of Literature No scientific evidence to support statements that benefits of consuming raw milk outweigh health risks Pregnant women, young children, older adults, people with weakened immune systems more susceptible to severe outcomes of infection Pasteurization reduces risk of disease Additional studies regarding biologic mechanisms behind raw milk and reduced allergies needed; not a causal relationship Davis BJK, Li CX, Nachman KE (2014) A Literature Review of the Risks and Benefits of Consuming Raw and Pasteurized Cow s Milk. Johns Hopkins Bloomberg School of Public Health.

20 Nonpasteurized Milk Regulation Michigan 1948: 1st statewide requirements enacted Dairy products pasteurized FDA 1987: Interstate sale or distribution of nonpasteurized milk prohibited Laws regulating intrastate sales are set by each state Regulations for intrastate sales vary Complete ban bans Sale on farm Herd share Retail (Online) In states in which sale of nonpasteurized milk is illegal, milk often obtained through other means Mungai EA, Behravesh CB, Gould LH. Increased outbreaks associated with nonpasteurized milk, United States, Emerg Infect Dis [Internet] Jan [date cited].

21 Internet Sale of Raw Milk Classified advertisement websites Online retailers Online buyers clubs

22 Listeria Illness Outbreak Linked to Interstate Shipment of Raw Milk United States

23 Initiation of the Investigation November 2015: International Raw Milk Symposium held in Anaheim, California Sample of raw chocolate milk produced by Dairy Farm X in Pennsylvania and collected at conference FDA isolated Listeria from milk Whole genome sequencing conducted Listeria bacteria from the raw chocolate milk isolated in 2015, was closely related genetically to Listeria bacteria from two people isolated in 2014

24 People infected with the outbreak strain of Listeria monocytogenes, by state of residence, March 15, 2016

25 Listeriosis Surveillance State/local health departments attempt to interview all listeriosis patients

26 Public Communication

27 Recommendations and Lessons Learned: Before an Outbreak Become familiar with the regulations in your jurisdiction Production, sale and distribution of raw milk Get to know regulatory and enforcement agency officials Identify farms producing and stores distributing raw milk On-farm activities (e.g. school field trips) Retail outlets selling milk from out-of-state Milk from animals other than cows Report entities selling nonpastuerized milk interstate for consumption to FDA

28 Recommendations and Lessons Learned: During an Outbreak One Health Approach Engage partners from multiple sectors and agencies Engage laboratory partners in product testing Consider both common and uncommon pathogens (e.g. L. monocytogenes and L. ivanovii) Advance molecular detection methods can be useful in characterization of isolates

29 Resources Raw milk questionnaire template Raw milk letter

30 Recommendations and Lessons Learned: After an Outbreak Share information Publications Zoonoses and One Health Updates Call Local newsletters and public health reports Report to National Outbreak Reporting System (NORS)

31 Essential elements to most effectively respond to human illness of potential animal origin On-going relationships between human health and animal health agencies Have access to integrated human and animal surveillance Protocols for conducting joint response investigations Agreements for sharing biological samples and lab results Established lines of communication with agriculture and animal industry Plans for unified communication messaging Need to build linkages and TRUST before an outbreak

32 Future Opportunities for Collaboration

33 Acknowledgements Outbreak Response and Prevention Branch-CDC Amanda Conrad Laura Burnworth Ian Williams Food and Drug Administration Susan Lance USDA-FSIS Kristin Holt Pennsylvania Department of Health Andre Weltman Erica Smith Pennsylvania Department of Agriculture Lydia Johnson Florida Department of Health California Department of Public Health

34 Thank you Megin Nichols, DVM, MPH, DACVPM For more information, contact CDC CDC-INFO ( ) TTY: 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.

35 Resources and References Raw milk questionnaire template Raw milk letter CDC Website

36 Select publications Committee on Infectious Diseases and Committee on Nutrition of the American Academy of Pediatrics Consumption of raw or unpasteurized milk and milk products by pregnant women and children. Pediatrics 133: Davis BJK, Li CX, Nachman KE (2014) A Literature Review of the Risks and Benefits of Consuming Raw and Pasteurized Cow s Milk. Johns Hopkins Bloomberg School of Public Health. Ijaz N Unpasteurized milk: Myths and evidence. In: Grand Rounds Presentation, (BC Centre for Disease Control, ed). Lejeune JT and Rajala-Schultz PJ (2009) Food safety: unpasteurized milk: a continued public health threat. Clin Infect Dis 48(1): Loss G, Apprich S, Waser M, Kneifel W, Genuneit J, Buchele G, et al The protective effect of farm milk consumption on childhood asthma and atopy: The gabriela study. The Journal of allergy and clinical immunology 128: e764. Macdonald LE, Brett J, Kelton D, Majowicz SE, Snedeker K, Sargeant JM A systematic review and meta-analysis of the effects of pasteurization on milk vitamins, and evidence for raw milk consumption and other health-related outcomes. Journal of food protection 74: Malekinejad H, Scherpenisse P, Bergwerff AA Naturally occurring estrogens in processed milk and in raw milk (from gestated cows). Journal of agricultural and food chemistry 54: Mummah S, Oelrich B, Hope J, Vu Q, Gardner CD Effect of raw milk on lactose intolerance: A randomized controlled pilot study. Annals of family medicine 12: Mungai EA, Behravesh CB, Gould LH. Increased outbreaks associated with nonpasteurized milk, United States, Emerg Infect Dis [Internet] Jan [July 27, 2016]. Oliver SP, Jayarao BM, and Almeida RA (2005) Foodborne pathogens in milk and the dairy farm environment: food safety and public health implications. Foodborne Pathog Dis 2[2]: Scallan et al.foodborne Illness Acquired in the United States Major Pathogens.EID 2011