the role immunocompromised people play in FBI
Write a one to two page summary of the following learning objectives:
Understand:
- the overall 2011 FBI (foodborne illness) estimates and the most common FBI’s
- how FBI’s from last century compare to today
- the roles of USDA, FDA, and CDC in food safety
- the number of foodborne pathogens (total versus common)
- the impact of Norovirus on foodborne illness
- the impact of unidentified FBI and implications on emerging pathogens
- the cost of FBI
- the leading causes of FBI deaths
- the role immunocompromised people play in FBI
- the role of the bodies defense in who gets ill and how many microorganisms are required to get an infection
- the difference between infection and intoxication
- the leading causes of FBI outbreaks these past two years
- some key factors leading to FBI increases
- emerging FB
CDC estimates renewed in 2011 indicate that each year roughly 1 in 6 Americans (or 48 million people) gets sick. 128,000 are hospitalized. And, 3,000 die of foodborne diseases. According to the 2011 estimates, the most common foodborne illnesses are caused by the bacteria Salmonella, Clostridium perfringens, and Campylobacter, and by the virus Norovirus.
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A century ago, typhoid fever, tuberculosis and cholera were common foodborne diseases. Ina few isolated cases botulism wiped out entire families. Improvements in food safety, such as pasteurization of milk, safe canning, and disinfection of water supplies have conquered those diseases. However, new foodborne infections have taken their place. For example in 1972 we first described Campylobacter and its foodborne illness. In 1982 we first described E. coli O157:H7 foodborne illness. In 1996, the parasite Cyclospora suddenly appeared as a cause of diarrheal illness related to Guatemalan raspberries. In 1998, a new strain of the bacterium Vibrio parahemolyticus contaminated oyster beds in Galveston Bay and caused an epidemic of diarrheal illness in persons eating the oysters raw.
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In the US, the USDA is responsible for ensuring safety of meat, poultry, and some egg products.
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The US FDA is responsible for all others foods including seafood and coordinating retail and foodservice operations.
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The CDC is responsible for the ship sanitation program or cruise ship food safety and for all epidemiological functions regarding foodborne illness. Most of the data presented in this presentation comes from the US CDC.
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There are over 250 different food pathogens identified to date. However, most are rarely encountered and little data is available on them. There are 31 more highly known foodborne pathogens. Most of these pathogens are tracked by local, state, and federal public health officials. Data in 2006 shows that Norovirus causes approximately 40% of all foodborne illnesses. The remaining four pathogenic viruses are not tracked in this figure. Bacteria including 21 different bacterial pathogens makes up 23% of all foodborne illnesses. Five different parasite pathogens account for just 1% of foodborne illnesses. Chemicals cause approximately 5% of foodborne illnesses. At least 29% of foodborne gastroenteritis illnesses have no cause. This may be due to insufficient data or unidentified pathogens. There is no data on potential foodborne pathogens causing non‐gastroenteritis symptoms.
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This slide shows the percentage change in the 2010 illnesses versus 1998. Note that Yersinia, E. coli O157:H7, Shigella, Listeria and Campylobacter are all down from 27 to 57 percent. However Vibrio has jumped 115% and Salmonella is up 3%.
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This chart shows the costs, in billions, of foodborne illness to just five states – California, Texas, New York, Florida, and Pennsylvania. In fact, contaminated food products caused more deaths each year than the combined totals of all 15,000 non-food products regulated by the U.S. Consumer Product Safety Commission.
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CDC data from 2011 indicate that there are approximately 5,461,731 cases of Norovirus per year. [read slide].
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The 2011 data from the CDC indicates that there are approximately 149 deaths attributed to Norovirus annually. While this may seem high compared to the others on this table, it is out of over 5 million illnesses. Most likely those that died were highly immuno‐compromised and Norovirus contributed to their death rather than caused their death. Salmonella is considered the most deadly at 378 deaths per year. Toxoplama gondii a unicellular parasite is implicated in 327 deaths annually. Listeria monocytogenes causes 255 deaths per year and this is out of only approximately 1500 illnesses. This is the pathogen with the highest percentage of death. Clostridium perfringens causes 26 deaths per year. Campylobacter causes 76 deaths per year. The Shiga toxin producing E. coli like E. coli O157:H7 only cause 20 deaths per year. Shigella causes 10 deaths per year. Yersinia enterolcolitica causes 29 deaths per year. The combined group of Vibrios cause only 48 deaths per year. No deaths were attributed to Trichinella illness. And lastly, one of the deadly toxin producers, Clostridium botulinum only causes 9 deaths annually.
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Deaths almost always occur in people who are immuno‐compromised. These include the very young, very old, infirm, and pregnant.
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The nature of a persons immune system and their intestinal health have a large impact on whether a pathogen can cause an infection or not. Most healthy people consume foodborne illness pathogens and never have any symptoms. This is due to the bodies defense mechanisms including the acidity of the stomach, intestinal flora competition and immune inflammatory response. In some cases the multiplicity of infection, or the number of pathogens needed to produce symptoms can be large enough to overcome the bodies defenses. Most toxins will result in illness symptoms despite the health of the individual because there is no intestinal flora competition and little immune response to them.
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There are two modes of foodborne illness. The first is a standard infection. In this case bacteria are consumed and they interact directly in the intestines. Most infections are countered by the immune system with inflammation. A food intoxication is where a pathogen produces a toxin. The toxin is an illness causing chemical. The toxin reacts with the bodies cells to produce a reaction.
When two or more people get the same illness from the same contaminated food or drink, the event is called a foodborne outbreak. C. botulinum illness is the only foodborne illness that only requires one person to constitute an outbreak. This slide depicts the major US multistate outbreaks in 2011. Take a moment to analyze the foods involved in outbreaks. Two types of food should be prevalent. These same foods have appeared in many of the outbreaks in the past years. If you were in charge of US Food Safety, where would you concentrate resources?
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For food safety for this decade we will continue to see the governments goals for the reduction in major outbreaks and illnesses. However, we will have to acknowledge that an ever increasing amount of foods are being imported. We also have to realize that consumers are seeking more fresh foods that have not been processed. That includes things like an increase in fresh produce consumption. Lastly, an eye must be kept out for new and emerging pathogens.
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The US is a globally active country. Over 500 million visitors come and go each year. Approximately 38,000 animals are imported. More than 11.2 million truckloads and 2.2 million railcars of goods enter the US. Finally some 51,000 ship loads of goods enter our ports. A large portion of these imports are foods. How do we control the safety of food grown in another country?
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Here is example of a research project that cultured Salmonella or Shigella from imported produce. Note the very high level of positives encountered. Fresh imported produce strikes two of the major food safety concerns for this next decade – global food production and consumers wanting more fresh produce in their diets.
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Is this the epidemiology of an emerging foodborne illness? Several years back a wave of Avian influenza cases were sweeping Asian countries. Most were from direct contact with avian species. A few were believed related to avian food sources. What if it were to get introduced into US poultry stocks? Note the high death percentage based on total cases.
The remainder of the course will take an in‐depth look at these fourteen different foodborne illness pathogens or pathogen groups.
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For each foodborne illness we’ll start with a case study outbreak and typical outbreak. We’ll then look at the symptoms. Next is the pathogen including its biology, mode of infection or intoxication, morbidity and mortality. After that we’ll look more closely at the implicated foods in the illness; and finally, we’ll look the preventative measures or controls.
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