Foodborne diseases, also called foodborne illness, is an illness caused by eating contaminated food. Infectious organisms including; bacteria, viruses and parasites or their toxins are the most common causes of food poisoning

1. Foodborne diseases
By
Salam Khassaf

2. Overview
• Foodborne diseases, also called foodborne illness, is an illness
caused by eating contaminated food. Infectious organisms
including; bacteria, viruses and parasites or their toxins are the
most common causes of food poisoning.
• Food poisoning is a major cause of gastroenteritis, resulting in a
well-known set of unpleasant symptoms.
• Gastroenteritis is usually caused by viruses, bacteria, or
parasites; when the source of such infection is contaminated
food, it is called food poisoning. Gastroenteritis may also be
referred to as “gastric flu” or “stomach flu.”

3. Fast facts on gastroenteritis and food poisoning
• Most cases of gastroenteritis are caused by infection with bacteria,
viruses, or parasites
• Diarrhea, nausea, vomiting, and abdominal pain are typical
symptoms of gastroenteritis
• Gastroenteritis is usually self-limiting, and tests are not usually
necessary for a diagnosis
• The most serious complication of food poisoning and
gastroenteritis is dehydration, especially for vulnerable people
such as the very young and very old.

4. Signs and symptoms
- The main symptoms include:
• feeling sick (nausea)
• vomiting
• Diarrhea, which may contain blood or mucus.
• Stomach cramps and abdominal pain.
• A lack of energy and weakness
• Loss of appetite
• A high temperature (fever)
• Aching muscles
• Chills
• The symptoms of food poisoning usually begin within one to two days after eating
contaminated food, although they may start at any point between a few hours and
several weeks later.

5. Risk factors
High-risk groups include.
• Older adults. As you get older, your immune system may not
respond as quickly and as effectively to infectious organisms as
when you were younger.
• Pregnant women. During pregnancy, changes in metabolism and
circulation may increase the risk of food poisoning. Your reaction
may be more severe during pregnancy.
• Infants and young children. Their immune systems haven't fully
developed.
• People with chronic disease. Having a chronic condition such as;
diabetes, liver disease or AIDS or receiving chemotherapy or
radiation therapy for cancer reduces your immune response.

6. Complications
• The most common serious complication of food poisoning is
dehydration. A severe loss of water and essential salts and
minerals. If you're a healthy adult and drink enough to replace
fluids you lose from vomiting and diarrhea, dehydration shouldn't
be a problem.
• Infants, older adults and people with suppressed immune systems
or chronic illnesses may become severely dehydrated when they
lose more fluids than they can replace. In that case, they may need
to be hospitalized and receive intravenous fluids. In extreme cases,
dehydration can be fatal.

7. Prevention

8. Classification of foodborne disease
Foodborne diseases
Food infections
Food intoxication
• Caused by ingestion of viable
microorganisms in food.
• There are two types of food
infection i.e. invasive type
and enterotoxigenic type.
• May be caused by bacteria,
viruses and parasites.
• Usually characterized by
fever.
• E.g. includes: Salmonelosis,
Shigellosis.
• Caused by ingestion of pre-
formed toxin in food.
• Chemical poisoning
(Household products)
• Biological poisoning such as:
microbial, animal and plant
tissues.
• E.g. includes: disease caused
by Clostridium botulinum,
Staphylococcus aureus, etc.

9. ESOPHAGITIS
• Esophagitis is an inflammatory process that can damage the
esophagus.
• Inflammation caused by infection, typically by fungi such as
Candida or viruses such as herpes simplex virus, causes the
symptoms of esophagitis. Most cases occur in immuno-
compromised patients, especially those with reduced cell-mediated
immunity.
Clinical Manifestations
Odynophagia (pain on swallowing)
and dysphagia (difficulty in
swallowing) are the key clinical
manifestations of esophagitis.
Candida esophagitis. Note the many whitish lesions on the
esophageal mucosa seen on endoscopy

10. GASTRITIS
• Gastritis refers to inflammation of the mucosa of the stomach.
• A break in the gastric and adjacent duodenal mucosa defines
peptic ulcer disease.
• Pathogens:
• Infectious and noninfectious etiologies are possible. Among
infectious causes, H. pylori is the most important.
• Viruses such as cytomegalovirus and fungi such as Mucor may
rarely cause ulcer disease as well, particularly among immuno
compromised patients.
• Following ingestion of raw fish, larvae of Anisakis Nematodes
may become embedded in the gastric mucosa and cause severe
abdominal pain.
• Mycobacteria (tuberculosis and nontuberculosis mycobacteria),
Giardia, and Strongyloides may also cause gastritis.

11. Clinical manifestations of gastritis
• Patients with gastritis typically complain of dyspepsia (epigastric
pain, burning), nausea, and vomiting.
• In the case of peptic ulcer disease, epigastric pain is the primary
symptom.
• Gastrointestinal bleeding is a complication of peptic ulcer disease.
• Some patients with gastritis may be asymptomatic.

12. DIARRHEA(GASTROENTERITIS,ENTEROCOLITIS)
• Acute diarrhea may be classifies as non-inflammatory (watery, non-
bloody) or inflammatory (bloody).
• Bloody diarrhea is also known as dysentery.
• For example, bloody diarrhea caused by Shigella is often called
bacillary dysentery.
• Most of the infectious agents that cause diarrhea act at the small
intestine or the colon.
• The most common cause of acute diarrhea in the United States is
norovirus.
• The most common cause of fatal diarrhea is hospital-associated
Clostridium difficile.

13. Pathophysiology
• Pathogens or their associated toxins disrupt the normal absorption
and secretory processes in the small intestines.
• Acute diarrhea is usually caused by preformed exotoxins in food
or by the infectious agents in the intestinal tract.
• Pathogens that produce preformed exotoxins include
Staphylococcus aureus, Bacillus cereus, and Clostridium
perfringens.
• Other pathogens that cause non-inflammatory acute diarrhea by
enterotoxin production include enterotoxigenic Escherichia coli
(ETEC) and Vibrio cholerae.
• Pathogens that cause acute inflammatory diarrhea include
Salmonella, Shigella, Campylobacter (via mucosal invasion),
Shiga toxin-producing E. coli (STEC) such as E. coli O157:H7,
and C. difficile (via cytotoxin production).
• Antibiotic use predisposes to pseudomembranous colitis caused
by C. difficile.

14. Pseudomembranous colitis caused by Clostridium difficile.
• If bloody diarrhea is
associated with
antibiotic use,
laboratory tests for the
presence of the C.
difficile toxin in the
stool should be done.
• Colonoscopy may
reveal the characteristic
yellowish plaques seen
in pseudomembranous
colitis

15. DIVERTICULITIS
• Diverticulitis is inflammation of a sac-like protrusion of the
colonic wall, usually in the sigmoid colon.
• Colonic diverticula may occur following years of a diet deficient
in fiber.
Clinical Manifestations
• Patients usually present with dull,
aching, left lower quadrant
abdominal pain.
• This is often accompanied by a
low-grade fever,
• leukocytosis, nausea, and
vomiting. Diarrhea or
constipation maybe present.
Pathogens
• Bowel flora such as anaerobes,
that is, B. fragilis, and those in
the Enterobacteriaceae family,
such as E. coli, are typically
involved.

16. ENTERICFEVER SUCHAS TYPHOIDFEVER
• Enteric fever is a clinical syndrome comprised of constitutional
symptoms, such as fever and headache, and nausea, vomiting, and
abdominal pain.
• Although enteric fever can be caused by several Salmonella
species, “typhoid fever” refers to enteric fever caused by
Salmonella typhi. S. typhi is also known as Salmonella enterica
serotype Typhi.
• Typhoid fever is a significant global health problem.

17. Pathophysiology
• Following the consumption of contaminated food, Salmonella
bacteria enter through the intestinal mucosal epithelium by
transcytosis.
• The microbes then replicate in the macrophages of Peyer
patches, mesenteric lymph nodes, and spleen.
• Bacteremia then occurs with dissemination to lungs, gallbladder,
kidneys, or central nervous system.

18. Clinical Manifestations
• A prodromal phase is characterized by constitutional symptoms
• such as malaise, together with abdominal pain, constipation, and
headache.
• Fever increases over the next several days.
• During the second week of disease, a typical transient rash of
pink maculopapular lesions (rose spots) may be seen.
• Splenomegaly occurs more commonly than hepatomegaly, but
both may occur. Relative bradycardia and leukopenia are often
observed.
• Diarrhea is uncommon.
• The chronic carrier state occurs in approximately 3% of patients
with typhoid fever.
• The organisms typically reside in the gallbladder and are excreted
in the stool, serving as a source of infection for others.

19. Characteristicsof watery diarrheacomparedto bloodydiarrhea

20. Importantorganismsthattypicallycauseeitherwateryor bloodydiarrhea

21. Acute non-inflammatory diarrhea (watery, non-bloody stools;
usually no fever)
Bacteria
Staphylococcus aureus
Symptoms: vomiting, epigastric
pain, diarrhea (mild). Usually
within 6 hours of consumption of
infected food (dairy products,
mayonnaise, meat products).
Bacillus cereus
Symptoms: vomiting, epigastric
pain,diarrhea. Usually within 6
hours of consumption of infected
food (reheated rice).
Enterotoxigenic
Escherichia coli (ETEC).
Symptoms: Afebrile, watery
diarrhea. Traveler’s diarrhea.
Vibrio cholerae
Symptoms: Severe, watery
diarrhea with rapid fluid and
volume loss. Vomiting in early
disease. Suspect cholera if watery
diarrhea is associated with rapid
and severe volume loss or in an
outbreak setting.
Listeria monocytogenes
Symptoms: Often febrile,
vomiting, diarrhea. Acquired by
ingestion of unpasteurized soft
cheese, deli meats, and raw
vegetables. Can grow at
refrigerator temperature.

22. Acute non-inflammatory diarrhea (watery, non-bloody
stools; usually no fever)
Viruses
Protozoa
Norovirus & Astroviruses*
Symptoms: Afebrile, vomiting,
headaches, Cruise ship and
nursing home outbreaks.
Infection after consumption
contaminated food and water.
*Astroviruses (low grade fever)
Rotavirus
Symptoms: Low-grade fever and
vomiting prodrome, then diarrhea.
-Fecal oral route.
-Common in children can lead to
severe dehydration and death.
Giardia lamblia
Symptoms: Abdominal cramps, flatulence,
diarrhea (acute or chronic); stools are fatty,
foul smelling, and may float. Infection after
consumption contaminated food and water.
Diarrhea may persist for weeks.
Cryptosporidium hominis
Symptoms: Abdominal pain and cramps,
watery diarrhea. Cause of large
communitywide outbreaks from
contaminated water supply.
Important cause of diarrhea in AIDS
patients

23. Acute inflammatory diarrhea (stools can be bloody; can be febrile)
Bacteria
Shiga toxin–producing
E. coli (STEC),
esp. E. coli O157:H7
Symptoms: Bloody diarrhea,
abdominal pain, usually afebrile.
*Acquired by ingestion of undercooked
ground beef or fruits and vegetables
contaminated with cattle manure.
Clostridium difficile
Symptoms: Bloody diarrhea, fever.
Associated with frequent use of
antimicrobial drugs.
Pseudomembranous colitis
(inflammation of the large intestine).
Shigella spp.
Symptoms: Diarrhea with blood or
pus usually; abdominal
cramps; can be febrile.
*Person-to-person spread can occur;
humans are the reservoir; not found in
animals
Yersinia enterocolitica
Symptoms: Fever, diarrhea. Causes
mesenteric adenitis that can mimic
appendicitis. *Most often transmitted by
consumption of contaminated food (raw
or undercooked pork). untreated water, or
by direct or indirect contact with animals
Campylobacter jejuni
Symptoms: Fever, diarrhea.
*Acquired by ingestion of unpasteurized
dairy products or undercooked poultry.
Associated with Guillain-Barré
syndrome.
Salmonella
Symptoms: Diarrhea can be bloody; low-
grade fevers.
*Acquired by ingestion of
undercooked eggs, unpasteurized
dairy products, raw vegetables, or
undercooked poultry.

24. Acute inflammatory diarrhea (stools can be bloody; can be febrile)
Protozoa
Entamoeba histolytica
(Amebiasis)
- Bloody diarrhea, fever, and abdominal pain. Syndrome is called amebic
dysentery.
- Transmission is generally occurs by fecal excretion of cysts followed by oral
ingestion of contaminated food or water.
- Extra intestinal amebic liver abscesses are the most common manifestation of
extra intestinal amebiasis. Pleuropulmonary abscess, brain abscess, and
necrotic lesions on the perianal skin and genitalia have also been observed.

25. Non-infectious Diarrhea
• Non-infectious Diarrhea can be caused by toxins (e.g., certain
types of food poisoning), chronic diseases (e.g., cystic
fibrosis), inflammatory bowel disease or antibiotics (e.g.,
ampicillin)
• Non-infectious diarrhea DOES NOT spread from person-to-
person.

26. Summary
Inflammatory
• Invasive bacteria.
• Disrupt intestinal mucosa.
• Fever, pain, low volume, bloody.
• Fecal leukocytosis.
• Pathogens Salmonella,
Campylobacter, Shigella, EHEC
and C. difficile.
Non-inflammatory
• Usually viral or toxins
• Promote intestinal secretions
• Large volume, non bloody.
• Few or no fecal leukocytosis.
• ETEC, S.aureus, Giardia, V.
cholerae, Bacillus cereus and
Clostridium perfringens.
inflammatory VS Non-inflammatory diarrhea

27. Symptoms summary
Nausea, vomiting (Emetic
diarrhea) within 1-8 hours.
Watery diarrhea Bloody diarrhea
Abdominal cramps, diarrhea
within 8-16 hours.
Staphylococcus aureus
Bacillus cereus
Clostridium perfringens
Bacillus cereus
Vibrio cholerae
ETEC
Salmonella
Shigella
E. histolytica
Campylobacter

28. Bacterial species Common food that may be contaminated
Bacillus cerues Cooked rice, meat.
Campylobacter spp. Poultry, unpasteurized milk.
Clostridium botulinum Low-acid canned food
Clostridium perfringens Cooked meat, poultry.
Escherichia coli Meat, row milk
Listeria monocytogenes Raw vegetables, unpasteurized milk, Pâté and soft cheese.
Salmonellae Meat, poultry and eggs.
Shigella spp. Eggs and salads.
Staphylococcus aureus Ham, poultry and dairy products.
Yersinia enterocolitica Milk and poultry.
Common foodsources