Food borne EIDIs that burger safe E' coli O157:H7 and nvCJD

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Food borne EIDIs that burger safe? E. coli
O157H7 and nvCJD
Educational Objectives Understand the
factors that spread food-borne infectious
diseases Be able to discuss the publics
perception of food safety and how that affects
EID and food
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U.S. Consumer Confidence in Food Safety
Most Consumers are Confident but Confidence
trending down since 1996 About 1/5 doubt food
safety Virtually all consumers have specific
concerns
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Concern about Foodborne Pathogens is Justified
CDC estimates that each year -76 million cases
of food-borne disease each year -300,000
hospitalizations -5000 deaths -only 18 or 14
million cases are from known pathogens, 62
million from unknown agents USDA-ERS estimates
that each year -7 billion in medical costs and
lost wages
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Factors that Facilitate the Spread of Foodborne
Diseases

• Globalization of the food supply, particularly of
  
• perishable foods, like fresh produce
• Development of new food production industries in
• developing nations- meets the needs of export
  market
• 3) Centralized processing of human and animal
  foods,
• followed by widespread distribution
• 4) Expanded US market for ethnic foods
• 5) Increased international travel

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Disease Factors Associated with the Globalization
of Food
Water-if you dont have good water for drinking,
you dont have good water for agriculture
(irrigation and cleaning) Animal feed (mega feed
production e.g. BSE), and manure- lots of
countries use manure as fertilizer Workers-
labor intensive, lots of human contact and the
people dont have good bathroom
facilities Transportation-rapid
harvest/transport or dirty transporters Wildlife,
rodents, and insects Food processing-FDA cannot
inspect foreign facilities often, this
country it is only every 1 and 1/2 years
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Globalization of US Food Supply
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Imported Foods
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Percent of Produce Item from Mexico sold in the US
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Comparisons of Grocery Stores
In 1950, the average grocery store stocked about
200 items, 70 of which came from a 70 mile
radius Today the average supermarket carries
between 50,000 to 120,000 items from all over
the world
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Changes that Increase Foodborne Disease
Diet (increases in chicken and fresh fruit and
vegetables) -most foodborne disease is from
fresh produce (MN) -in 2009, 80 of our fish is
now imported, aquaculture Commercial food
service- 54 of food is spent on eating
out -70 of foodborne illness traced to food
service (MN) New methods of food production New
or re-emerging infectious agents High risk or
immunocompromised populations- the young, the
old, those with cancer, organ transplants,
diabetes, and AIDS are at risk for foodborne
illnesses -25 of the population More acres
going into corn production for ethanol (30 by
2010) In 2007 there was 78 miliion acres to 2009
about 90
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Per Capita Consumption in the U.S.
Food in Pounds 1970 1999
Change Whole milk 219 72 -67 Red Meat
132 118 -11 Low-fat milk 50
131 162 Cheese 11 30 173 Poultry 34
68 100 Fresh vegetables 79 129 63 Fresh
fruit 97 126 30 How are the new low-carb
diets effecting this? -20 of US adults have
tried a low-carb diet since 2002 -significant
decrease in orange juice consumption
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What are the Most Common Foodborne Microbes?
Campylobacter jejuni- now the most common
bacterial pathogen in food- Complicated by the
emergence of fluoroquinolone resistance
Listeria monocytogenes- kills 1 out of 5
infected E. coli O157H7- Estimated 73,000 cases
and 61 deaths in the U.S. each year. Norwalk
Virus- 23 million cases per year -top cause of
foodborne illness (could not detect until
1990) Parasites- CDC estimates 2.5 million cases
annually due to food and beverage parasites-
especially cysts
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E. coli 0157H7
Identified in 1982, became famous in 1993
outbreak at Jack in the Box, 732 cases with 4
death of children Most often transmitted in
uncooked ground beef Young children shed the
organism in their feces for 1-2 weeks after
their illness resolves (daycare centers and
pools) -July 2004 a Bronx daycare center had 26
cases linked Causes bloody diarrhea, and
abdominal cramping with no fever (5-10 days).
2-7 have hemolytic uremic syndrome (HUS when
RBCs destroyed, Kidney failure). Blood
transfusions and kidney dialysis needed There is
no evidence that antibiotics work, and the may
promote kidney problems
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E. coli 0157H7 cont.
Produces a toxin (from a phage) that is almost
identical to shiga toxin from Shigella
dysenteriae New processing technology and highly
consolidated meat processing has brought about
the emergence and distribution. About 1 of
healthy cattle have 0157H7 in their intestines
From outbreaks they have estimated the mean
infectious dose to be fewer than 50
organisms Most common in the U.S., Canada, and
the U.K. in ground beef In the U.S. it is more
in northern than southern states, and higher
incidence from June to September June 2007, 5.7
million pounds of fresh frozen ground beef
recalled
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Steaks and E. coli 0157H7
June 2003 there was a recall of 739,000 pounds of
frozen steak, because 5 cases were
linked. Steaks are usually not a high-risk
source, because bacteria usually exist on the
outside of steak, so searing kills it. These
special steaks were injected with tenderizers and
flavor-enhancing solutions that transfered the
bacteria to the inside of the steak.
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E. coli O157H7- Not Just in Meat
In 1996, there was about 70 cases (mostly
children) of O157 in Odwalla unpasteurized
apple juice The thought was that unpasteurized
juice was healthier slogan was Drink it and
thrive drop apples contaminated by cattle
manure Lab studies have shown that E. coli
O157H7 can survive up to 4 weeks in
unpasteurized apple cider Outbreaks have been
linked to petting zoos where children touch farm
animals, unpasteurized milk, and swimming
pools In Japan in 1996, radish spouts affected
gt6000 school kids In 2001 at a county fair in
OH, 19 people contracted O157 from sawdust in
the air at an exhibition hall, viable O157 10
months later in the rafters.
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Spinach is bad for you 2006
As of Oct. 3, 2006, 193 persons from 26 states
have been infected w/ E. coli O157H7 from baby
spinach Among the ill persons, 98 (51) were
hospitalized, 30 (16) had HUS. 1 adult in
Wisconsin died (most cases in WI). The
proportion of persons who developed HUS was 28
in children, 9 adults, and 14 gt60 years. 80
became ill between Aug 19th and Sept 5th, 2006.
31 became ill between Aug 30th to 1 Sept 1st,
2006. The number of cases of HUS in this cluster
has been higher than usual, especially since
most cases were not in young children. Investigat
ors have narrowed the source of the outbreak to
12 fields on 9 farms in CA Salinas Valley. E.
coli in pastures could contaminate nearby
spinach if it ends up in irrigation water.
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Salmonella saintpaul outbreak
May 22, 2008- New Mexico Health Department
reported 4 confirmed cases of Salmonella
saintpaul and 15 other Salmonella cases not yet
confirmed. Centered in the Texas and New Mexico,
but cases 43 states and Canada. Tomatoes were
initially blamed and maybe were a source early
on, but by June 30th, people were still getting
sick, so broadened search. 100s of millions in
lost in tomatoes. Jalapeno peppers were linked
as the main source of contamination. Linked to
US distributors that received produce from
Mexico. April to August, 1442 persons had
Salmonella saintpaul with the same genetic
footprint. Contributed to two deaths. In July
the FDA lifted its advice to avoid tomatoes, in
August it lifted its advice to avoid jalapeno
and serrano peppers
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Salmonella Saintpaul curve summer 2008
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Salmonella Saintpaul end of August 2008
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Salmonella Saintpaul sprouts 2009
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New Variant Creutzfeldt Jacob Disease-nvCJD
Like sporadic Creutzfeldt Jacob disease, nvCJD
is prion mediated Much younger patient
population Linked to bovine spongiform
encephalopathy (BSE). Likely high titer bovine
CNS tissue in human food-no social class
differences What dose is needed? Cows need 1
gram of PrPSc -we dont know the species
jumping ability.
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Prion Diseases in Mammals
Kuru Gerstmann-Straussler syndrome Creutzfeldt
Jacob disease Fatal familial insomnia Scrapie Tra
nsmissible mink encephalopathy Bovine spongiform
encephalopathy Chronic wasting disease Exotic
ungulate encephalopathy
Humans Other Mammals
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Unusual Properties of Prions
Resistant to UV, ionizing radiations, various
chemical and enzymatic treatments-not DNA or
virus Degrading and denaturing destroys
infectivity-protein Heterogeneous in size and
density with no unitary structure seen by EM-
not virus
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Prion Hypothesis
Proteinaceous infectious particles (prion)
composed of a modified host protein PrPSc is
derived from the cellular form PrPC the PrPSc
and PrPC share the same primary structure PrPSc
and PrPC have different conformations
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Other Facts About PrPSc
PrPSc is the only macromolecule consistently
identified in infectious prion
preparations Scrapie-associated fibrils
identified by EM PrPSc was purified from scrapie
infected sheep, N-terminal amino acids
determined, then oligo probed a cDNA library to
find the gene PrPC is normally on the cell
surface (2 TMD) but normal cellular function is
still unknown 7/30/04 published in Science that
synthetic prion causes disease in mice between
300-500 days. Brains from these mice cause the
disease in other mice.
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BSE Epidemic in the UK
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BSE in the UK
To date almost 200,000 cows known to be infected
statistical analysis predict that 1 million
cattle were infected, most entered the food
chain. UK still had about 200 BSE cases in 2005.
Portugal and Spain are still increasing in
numbers of BSE cases. Definitely Prion
mediated Epidemiologic studies suggest that the
source was cattle feed 1981 introduced a
process of preparing cattle feed from the
carcasses of dead ruminants (sheep)
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Creutzfeldt Jacob Disease-Age at Death
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nvCJD Cases
-Invariably fatal with no effective therapy
available -As of 8/4/06 156 deaths, 6 more cases
still alive in the UK -7 cases in France (may
have had 300,000 cattle infected) -1 each in
Canada, Italy, Ireland, Hong Kong, and the
U.S. -Median age at death is 28 -Median
duration of the illness is 13 months, sporadic
is 4 months Usually present as a psychiatric
illness for 6 months, then neurosymptoms 1 case
of nvCJD from a blood transfusion in the UK, so
donors who have received a blood transfusion can
no longer donate
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Deaths from nvCJD in the UK by year
Year Deaths 1995 3 1996
10 1997 10 1998 18 1999
15 2000 28 2001 20 2002
17 2003 18 2004 9 2005
5 2006 3 Total 156
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Increases in Sporadic CJD
Year nvCJD Sporadic 1995 3
35 1996 10 40 1997 10
60 1998 18 63 1999 15
62 2000 28
49 2001 20 57 2002 17
73 2003 16 43 2004
9 2005 5 2006 3
33 Total 156 Used to be about 30
sporadic cases a year, is there better reporting?

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Methionine at Codon 129
All examined cases are homozygous for Met at
codon 129 of PrPC, -40 of UK population is MM
at 129 One case of iatrogenic infection (blood
transfusion) in a MV at 129 Do they present
faster? Will we have a peak of cases later? Are
they the only polymorphism that gets nvCJD? Do
the others not get CJD or do they look like
sporadic? This year, 2 cases with VV at 129 (10
of UK population is VV) Kuru mouse model showed
than genotypes other than MM took longer Thus
blood and organ donation may sustain a low level
in the UK population
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New Treatment for vCJD?
A 19-year-old male from Belfast has been treated
with pentosan polysulphate by injection into
the brain After 8 months' treatment, he has
some improvement in neurological functions,
regaining the ability to swallow. He has become
more alert, responding to verbal instructions,
and trying to speak. Extended into 7
patientsseems to prolong life, but they still
die.
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What is Pentosan polysulphate?
Pentosan polysulphate is a large polysulphonated
polyglycoside. -The drug is relatively
inexpensive (made from beechwood). -Used since
1960 as an anticoagulant (like heparin) It is
currently used in US for treating interstitial
cystitis but not licensed in the UK. Injecting
pentosan polysulphate into the brains of sheep
infected with scrapie, slowed the accumulation
of prions. It has been suggested that pentosan
binds to heparan binding sites on infectious
prions, inhibiting further prion production.
Pentosan polysulphate is unable to cross the
blood-brain barrier.
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Mad Cow Disease in North America
In Canada in May 2003, a 6-8 year old cow, born
in Canada. age is important because of a
fed-ban in 1997 In the US in December 2003, a
6-8 year old cow, born in Canada. -June 2005 and
March 2006, 2 more with a rare variation of
BSE. Incomplete paper trail on both cows. Many
nations, (including the US to Canada at
first),banned the import of beef costing
millions a day and slaughtering thousands of
cows. Canadian officials have traced to 2 mills
the feed that probably caused North America's 2
cases. British cattle put into the feed before
1997. June 2004, USDA to test up to 400,000
animals over 18-monthsOf 388,000 only 3
rapid tests found, 2 confirmed (Texas-12 yr
old). By July 2006, Canada has found 7 BSE
positive cows through mass screening.
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What Can We Do About Food Safety?
Make sure our cattle are vegetarians. Change our
lifestyles to eat out less or no produce in
winter or only U.S. grown produce? How do you
know? Acceptance of ionizing radiation,
especially of poultry and red meat, can reduced
the risk of foodborne illness Decrease the
amount of imported foods? Go back to smaller
family farms? Eliminate cattle that have E.
coli 0157H7? Cleaner slaughter and grinding
facilities?