Agents of Foodborne Zoonoses Foodborne Diseases Active ...
Transcript of Agents of Foodborne Zoonoses Foodborne Diseases Active ...
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Agents of Foodborne Zoonoses • Illness caused by
– Campylobacter spp. – Escherichia coli O157:H7 – Salmonella
• 80-95% cases from these bacteria estimated to be foodborne; probably of animal origin
• FoodNet data (repeat) – PulseNet: Molecular epidemiology
• Outbreaks and investigations • Carriage by food animals and food • Risk
Foodborne Diseases Active Surveillance Network (FoodNet)
• Principal foodborne disease component of CDC's Emerging Infections Program
• Active surveillance for foodborne diseases and related epidemiologic studies (PulseNet) to better understand the epidemiology of foodborne diseases in the United States.
• “Active” surveillance system, meaning public health officials frequently contact laboratory directors to find new cases of foodborne diseases and report these cases electronically to CDC.
FoodNet Disease Monitoring • Bacteria
– Campylobacter – Escherichia coli O157 – Listeria monocytogenes – Salmonella – Shigella – Vibrio – Yersinia enterocolitica
• Parasites – Cryptosporidium – Cyclospora
• Viruses – Hepatitis A – Noroviruses
FoodNet
• 1995, FoodNet surveillance began in five locations: California, Connecticut, Georgia, Minnesota and Oregon
• New York and Maryland in 1998, Tennessee in 2000, Colorado in 2001 and New Mexico in 2004). – The total population of the 2004 bacterial
catchment is 44.5 million persons, or 15.1% of the United States population.
Mead et al (1999)
Reported and Estimated Illnesses: Foodborne pathogens--US
Mead et al (1999)
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Foodborne Disease - US (1998-2002) (Reported)
From FoodNet and Mead et al (1999)
(Estimated)
Relative Rates vs 1996-1998 Baseline
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5714a2.htm
Vibrio
Listeria
Salmonella Campylobacter O157
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5714a2.htm
FoodNet 2007
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5714a2.htm
Pathogen Incidience/105 National Health Obj.
Campylobacter 12.79 12.30
Salmonella 14.92 6.80
STEC O157 1.20 1.00
Outbreaks 1998-2002
After FoodNet After FoodNet
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Campylobacteriosis
FoodNet
Foodborne Illness Cases (Top 10 Salmonella Serotypes)
FoodNet www.fsis.usda.gov/PDF/Serotypes_Profile_Salmonella_Tables_&_Figures.pdf
Frequency of some Salmonella Serotypes Isolated from some Commodities
Kimura et al (2004)
Foodborne Disease Outbreak Investigations
• Reported foodborne outbreaks (FoodNet) • Subtyping • PulseNet • E. coli O157
– Hamburger – Spinach
• Salmonella • Campylobacter
– Manning et al (2003)
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Reported Outbreaks and Cases—US (1998) Subtyping Issues • ID cases likely to be part of an outbreak • Eliminate sporadic cases (background noise) • Difficult to select appropriate method
– Tenover et al. (1997)
• Salmonella – Bender et al (2001) – McQuiston et al (2004)
• E. coli O157:H7 – Samadpour (1995)
• Campylobacter – Manning et al (2003)
Some Methods Used for Typing E. coli O157:H7 Strains
Toxin gene screening Thomas et al., 1996; Ostroff et al., 1989 Plasmid profiling Ostroff et al., 1989; Paros et al., 1993;
Meng et al., 1995; Radu et al., 2001 Phage typing Ahmed et al., 1987; Khakhria et al.,
1990; Barrett et al., 1994 Antibiotic susceptibility testing Kim et al., 1994; Farina et al., 1996;
Radu et al., 2001; Restriction fragment length polymorphism with phage λ (λ -RFLP)
Paros et al., 1993;Samadpour et al., 1993
Ribotyping Martin et al., 1996; Roberts et al., 2001
Pulsed-field gel electrophoresis (PFGE) Bohm and Karch, 1992;Barrett et al., 1994;Meng et al., 1995;Radu et al., 2001
PCR using randomly amplified polymorphic DNA (RAPD) sequences Swaminathan and Barrett,1995; Radu et
al., 2001 PCR using highly repetitive sequences (rep-PCR) None specific for E. coli-O157:H7;
Johnson and O’Bryan, 2000 Amplified fragment length polymorphism analysis (AFLP)
Iyoda et al., 1999; Zhao et al., 2000
How Does PulseNet Work? 1. PFGE 2. Pattern electronic database at local,
state or federal level 3. Uploaded to national database at CDC 4. CDC searches for clusters of patterns 5. Local cluster searches 6. Clusters posted to Listserve.
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Changes in Outbreaks
• Food consumption and practices in US have changed during the past 20 years
• Shift from the typical point source, or “church supper” outbreak, which is relatively easy to detect to the more diffuse, widespread outbreaks that occur over many communities with only a few illnesses in each community.
Changes in Outbreaks Continued • Large food producing facilities that disseminate
products throughout the country • Some few outbreaks that some low level
contamination of food products • Products are distributed among many states • Only a few illnesses occur in each community, • New laboratory and statistical tools, such as
PulseNet and the surveillance outbreak detection algorithm (SODA), impact ability to identify and investigate these new types of outbreaks
How does subtyping help in epidemiologic investigations?
• Identifies cases within an outbreak • Distinguishes outbreak cases from concurrent
sporadic cases • Reduces misclassification • Detects outbreaks through surveillance • Links apparently sporadic cases
– Cases may be too widely dispersed to detect – Organism too common to notice small increase – Identifies related cases and separates them from
unrelated ones • DNA “fingerprinting” methods have greatly
increased sensitivity of subtyping
Increases sensitivity of outbreak detection
Rangel, J.M. et al. Emerg. Infect. Dis. 11: 603-609 (2005)
Num
ber o
f Out
brea
ks/Y
ear
outbreak detected 1993
Meat recall
1993 Western States E. coli O157 Outbreak
732 cases 4 deaths
39 d
outbreak detected 2002
18 d
Swaminathan
Occurence in Food Products
• E. coli O157:H7 – Beef – Fruits and vegetables
• Salmonella – Poultry, beef, hogs – Eggs, fruits, vegetables
• Campylobacter – Poultry
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Fresh Produce Outbreaks--US
(1977-1999)
Sivapalasingam et al. (2004)
Some Pathogenic E. coli (Simplified)
LT/ST enterotoxigenic stx+
eae+
EHEC
O157:H7
E. coli Verotoxin =
Shigatoxin
stx Assay on Vero Cells Filtrate Control
Speirs et al (1977)
E. coli O157:H7 Outbreak--1993
• Western states • >500 laboratory-confirmed infections • 4 deaths • O157:H7 known in hamburger since 1982
– Wells et al. (1983) • Prompted FSIS to declare O157:H7 an
adulterant in raw ground beef (1994) – Product often undercooked
Leafy Greens Outbreaks
Buchanan
MMWR
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MMWR
Salmonella poona: Cantaloupes
• April—June 2000 – 47 cases; 5 states
• April—May 2001 – 50 cases; 5 states
• March—May 2002 – 58 cases; 14 states and provinces
Anderson et al. (2002)
PR/HACCP Salmonella “A” Sets (1998-2006)
After: http://www.fsis.usda.gov/science/Progress_Report_Salmonella_Testing_Tables/index.asp http://www.fsis.usda.gov/PDF/Salmonella_9year_Figures.pdf
Sarwari et al. (2001)
Broilers Ground Turkey
Hogs Ground Beef
Rigney et al. (2004)
1998-2000
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Salmonella Farm and Processing Plant
McCrea et al. (2006) Heinitz et al (2000)
Campylobacter Farm and Processing Plant
McCrea et al. (2006)
Strains
Campylobacteriosis in Iceland
Stern et al. (2003)
Campylobacter Prevalence (US)
Top: Stern and Pretanik (2006); Bottom: FoodNet
2004 2003
Chicken Carcass Rinses
Outbreaks
Campylobacter Prevalence (US) Chicken Carcass Rinses
Stern and Pretanik (2006)
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Risk Factors
• Mostly exposure to food • Exposure to animals
Risk Factors S. enterica serotype Enteritidis (FoodNet 02-03)
Marcus et al. (2006)
Friedman et al (2004)
Transfer of Campylobacter
Luber et al. (2006)