Transcript Food and Water Borne Diseases

Food Poisoning
Dr. Sabir
Fecal-Oral Route
 Pathogen
is shed in feces
 Transmission occurs when another
person comes in contact with this
feces (food or person)
EX: Food handler use the restroom,
does not wash hands well makes
salad  customer eats the salad, gets
sick
General Measures of Prevention
Clean & store food properly
 Prepare food properly cooking
adequately
 Restrict carriers from food preparation
 Protect food from insects, rodents
 Use pure water

Staphylococcal Food Poisoning

Staphylococcus aureus
Humans harbor these organisms, present
in boils, skin lesions
 Food poisoning is caused when staph is
transferred from person to food

 Could
come from an open boil, lesions,
sneeze, etc
Staphylococcal Food Poisoning
Intoxication caused by 3 toxins
 “True” food poisoning
 Exotoxins are heat stable proteins known
as enterotoxins
 second  inhibit water absorption from
the intestine & induce diarrhea & vomiting
 Third one damages the intestinal lining
colitis

Symptoms
Nausea, vomiting, abdominal cramps,
diarrhea
Onset 1-6 hours after eating the
contaminated food
Key Feature absence of fever, this
distinguishes it from other food borne
diseases

Prevention
1.
2.
Reduce the possibility of food
handlers contaminating food
( education in general hygiene)
Keep cold foods cold, hot foods hot
( serve foods when prepared or
keep refrigerated, do not allow
foods to sit at room temperature)
Clostridium botulinum &
Botulism
 C.
botulinum Gm(+) ,
endospore forming organism,
anaerobic
 Present in soil, ponds and lakes
Botulism
 Infrequent,
but fatal
 Caused by exotoxins produced
by C. botulinum most deadly
biological toxin neurotoxin
and affects the CNS
Botulinum Toxin
8
types  3 affect humans
 Exotoxins are readily destroyed
by heat
 Boiling for 3 mins will inactivate
the toxin( 10-20 min recom.)
Botulism
 Associated
with home or commercial
canned low acid foods, ex: veggies &
fruits
 Smoked meat
 Toxin is preformed & acts readily
 Vomiting, diarrhea, constipation may
occur BUT neurological symptoms are
inevitable w/in 12-36hrs
Neurological Symptoms
 Blurred
or double vision, slurred
speech, dyspnea, dysphagia, dry
mouth
 Evidence of paralysis and reflect
loss of ability to transmit nerve
impulses
 Death may occur w/in 12-24h
from respiratory failure
Diagnosis & Therapy
 Fatality
rate is low due to accurate
diagnosis and supportive therapy
 Suspected cases must be
hospitalized and give IM or IV
antitoxin and respiratory support.
 Recovery may be slow months to
years
Prevention
 Endospores
may not be removed
by washing
 Proper canning
 After canning avoid bulging
can/jar
Clostridium perfringes
Anaerobic spore former
 Present in soil & intestines of humans
and animals hence also in sewage
 Typical illness diarrhea, abdominal
cramps, nausea and vomiting
 Sickness lasts a day, incubation period is
usually 6-24 hours


Prevention: refrigerate food and cook
adequately
Bacillus cereus
Anaerobic spore former present in soil
 Produces a heat stable toxin
 Common in uncooked rice rice is cooked
and left at room temp, spores germinate
& produces the toxin that is not
destroyed by brief cooking )
 Symptoms & Prevention  same as C.

perfringes
Salmonella
 Gm(-)
rod
 Facultative anaerobe
 Causes salmonellosis
 Two strains S. enteritidis, S.
typhimurium
Salmonellosis
 Infection
caused by salmonella
transferred in food (fecal
contamination)
 Bacteria enter & adhere to the
intestinal mucosa
 Infection is limited to the
intestinal mucosa
Symptoms
Headache, chills, vomiting, nausea,
abdominal cramps & fever
 Onset: sudden and violent after ingestion
of contaminated food
 12-36 hrs incubation period
 Lasts for 1 wk can cause severe
dehydration in infants
 May eventually spread to the blood
stream

Reservoir
 Wide
variety of animals poultry,
cattle, swine, rodents
 Pets chicks, dogs, cats, reptiles
Transmission
 Raw
undercooked foods
 Meat, poultry, eggs, milk
 Person-person
 Fecal-oral route
Prevention
 Thaw
meat in refrigerator
 Cook eggs & meat well
 Salmonella is destroyed by
conventional cooking
Escherichia coli
Gm(-) rod, facultative anaerobic
 Causes gastroenteritis, bladder
infections, Kidney infections, gall
bladder infections, septicemia,
pneumonia
 Urine infection in 90% of non hospital
patients, 30% in nosocomial patients

4 Major Types
 Enteropathogenic E.coli
 ETEC Enterotoxigenic E.coli
 EIEC  Enteroinvasive E.coli
 EHEC  Enterhemorrhagic
 EPEC
E.coli
EPEC
 Associated
with severe diarrhea,
 Outbreaks most often affect
infants, especially those that are
bottle-fed
ETEC
 Associated
with “travelers diarrhea,
 Produces 2 toxins
 Results in fluid loss& copious watery
diarrhea
 Disease is usually self-limiting,
infants, elderly appropriate
electrolyte replacement therapy may
be necessary.
EIEC
 Affects
the large intestine
 Illness known as bacillary
dysentery
 Penetrates the epithelial cells
 Multiplies & destroys cell
 Results in bloody mucus stools
 Often
mistaken for dysentery caused
by Shigella species
EHEC
 Present
in undercooked meat, also
in fruit juices
 Causes severe abdominal cramps,
copius bloody diarrhea with no pus
 Produces a powerful exotoxin
 GI disease can lead to kidney
damage
Foodborne & Waterborne Viruses
Rotavirus most common cause of
severe dehydrating diarrhea
 Hepatitis A Virus
 Enteroviruses
 Norwalk Agent winter vomiting
disease
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