bacterial food born diseases
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Dr. Dalia El-ShafeiLecturer, Community medicine department,
Zagazig university
Food born infections
Viral• Poliomyelitis• Hepatitis A&E
• MCD
Bacterial• Typhoid &
paratyphoid• Brucellosis• Diarrheal diseases:• Food poisoning• Dysentery• Diarrhea diseases in
children• Cholera
Parasitic• Ascariasis• Entrobiasis• Amoebic dysentery• Heterophiasis• Fascioliasis• Hydatid cyst• Giardiasis• Toxoplasmosis
Salmonellae have more than 2000 serotypes, of which pathogens of Human disease is:
*Typhoidal salmonellae: S. typhi, & S. paratyphi A, B, C.
*Nontyphoidal salmonellae, of salmonella food poisoning and salmonellosis.
Causative Organism :
Reservoirs
Carrierscholecyst
itis & urinary lesions
Incubatory
Last days of IP
(faeces)
Convalescent
Temporary 10%Chronic 2-5%
Contact 2 wks
Healthy Sub-clinical
infection2 wks
Cases
Foci and exit of infection :
Small intestine (Peyers patches) & gall-bladder: faeces (faecal carrier).
Kidney: urine (urinary carrier). Faecal carriers:more common than
urinary Urinary: more frequent in endemic
Schistosomiasis Haematobium.
Susceptibility
• Summer
• Relative
• Male• Femal
e (faecal carrier)
•10-30 ys
AGE SEX
SEASON
IMMUNITY
classical untreated typhoid (4 weeks)
Prodroma • FHMA (stepladder, evening, low pulse)• Rash (macular rosy spots , abdomen,7th
day , 25%)
Advance• High fever, worse physical & mental
condition,• Abdominal distension & tenderness
Decline• Gradual improvement• Drop of temperature
Convalescence• Relapse(s) after one to two weeks: 10-
20%, usually mild.
Atypical presentation:infection by antimicrobial resistance strains & in children (respiratory symptoms & diarrhea)
Case fatality: 15-30% in untreated cases &
decreases with treatment to 1-2%.
Bl. culture1st wk
• Bacteremia
Widal test
2nd wk
• Agglutination test (rising titer)• High titer O & low titer H → Recent
infections• High titer H & low titer O → Past
Infections
Stool & Urine
culture 2nd & 3rd
wk
• 3 times, • Practically valuable to detect
carriers, rather than diagnosis
TAB (TABC) vaccine • Parenteral heat-killed• Adults: 2 doses of 0.5 & 1.0ml SC, 4 weeks
apart. Children over 2 years can be given smaller dosage.
• Booster Doses: adult dose of 1.0 ml (smaller for children) is given every 3 years.
• Protective Value: moderate (50-75%)/and may not be protective on exposure to heavy infection Typhoid Oral Vaccine
• Protective value is around 65%• 4 oral doses on alternate days
Polysaccharide vaccine• Parental vaccine containing Vi Ag in single
dose
Vaccination in endemic areas is given to (indications):
*Occupational groups at-risk: Food handlers, Lab workers, HCW, waste
disposal. *Camps & other closed communities.
*Slum areas. *At-risk communities during epidemics &
outbreaks. *Travelers to endemic areas & pilgrims.
CONTROL CASES
Release: 3 -ve cultures of stools & urine, 24 or
more hours apart. 1st sample: 2 weeks after drop of
temperature to normal (to exclude possibility of relapse).
Control of Carriers
• Diagnosis especially among food handlers & during pre-employment examination: by Widal test for Vi antigen, if +ve: stool & urine culture can be done (repeated cultures are indicated). • Health education. - Not to be licensed to work in food handling.
For chronic gall-bladder carrier: Ampicillin for 1-3 months until 3-ve successive samples.cholecystectomy is indicated. For chronic urinary carrier:Foci surgical removal.
Endemic in Egypt even with increasing incidence because of
animals' importation from different countries.
No man-to-man infection
Incubation Period: varies, usually 6-60 days.
Case fatality of untreated cases is 2% or less & usually results from endocarditis
Brucellin test: ID hypersensitivity test (survey studies), to show prevalence of
infection in man.
Prevention Man
Milk & Meat
sanitation
Occupational
control
Airborne infection
Animals
Veterinary care
Sanitary wastes disposal
Vaccination
Vaccination (live attenuated) of young calves by strain 19 or RB51 of B.abortus and of young sheep & goats by
Rev-1 strain of B.melitensis in endemic areas.
Agglutination survey: +ves are infected animals, to be slaughtered if of small percent, otherwise to be
segregated.
DIARRHEAL DISEASE
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DIARRHEAL DISEASE
- Increased bowel motions than the usual own pattern of individual.
OR the passage of 3 or more abnormal loose stools that may be associated with fever, vomiting & change in color & presence of blood, pus or mucus.
Etiology: infective & no infective.
Infective include: 1- Cholera
2-Infectious food poisoning3-Infective diarrheal disease of
children (GE)4-Dysenteries.
2315 case (2007)
Bio-type
Sero-group
Sero-type
Vibrio choleraO1
Classical
3
El-Tor
3
O139
Causative agent:
The organisms liberate potent exotoxins (enterotoxins). That remain in intestine causing
destruction of mucosa.
Current 7th pandemic: O1 sero-groups El-Tor biotype.
Resistance : V. cholera O1 & O139 can persist in water
for long periods & multiply in moist leftover food.
Killed within 30 minutes by heating at 56 C & within few seconds by boiling.
El-Tor biotype is more resistant The classical vibrio cause more virulent & cause
more severe clinical cases while El-Tor biotype is less virulent causing mild cases, subclinical cases
with high carrier rate &Infectivity
Reservoir: Man is the only source of infection either case or carriers.1-Cases: inapparent, subclinical or clinical.2-Carriers: incubatory, contact & convalescent. Usually temporary but in El-Tor biotype tend to be more chronic.
Exit: Stool and vomitus of cases. Stool of carriers.
Mode of transmission:
1. Ingestion of contaminated water or food.2. Beverages prepared with contaminated water, ice and even commercial bottled water have been incriminated
Susceptibility
• Summer
• Autumn
• Type-specific• HCL• O group
• Low •Children
AGE &
SEX Socio-economic
SEASON
IMMUNITY
Clinical picture:
• In most cases it may be asymptomatic or causes mild diarrhea, especially with El-Tor
biotype.
• Profuse painless watery stool (rice water stool).
* Nausea & profuse vomiting early in the course of illness.
Complications Dehydrati
on
Acidosis
Hypoglycemia RF
Circulatory collapse
Fatality :
- Case-Fatality is high (exceeding 50%) among severe dehydrated cases,
- But greatly declined (less than 1%) due to: better diagnostic facilities, better management through dehydration and effective chemotherapy.
Koll's vaccine•Heat killed phenol
preserved•2 Doses (0.5&1 ml) 4 wks
apart-booster every 6 ms.•Partial protection (50%
efficacy)•Short duration (3-6
months)•Only antibacterial & not
antitoxic immunity•Not prevent asymptomatic
infection & carrier state.•Associated with adverse
effect. •Not recommended by WHO
Oral vaccines•Live vaccine (strain CVD
103-HgR) & a killed vaccine(inactivated vibrios + B-subunit of the cholera
toxin)•2 dose regimen•O1 strain•Significant protection•Several months •Safe•Travelers from industrialized
countries
ChemoprophylaxisTetracycli
ne•500
mg/6 hours
for 3 days
•Single dose of
1gm
• ½dose for children
•Contacts
•Travelers
•Pilgrims
Doxycycline
•Single daily dose of 300 mg for 3 days
International measures:
1- Notification to WHO.2-Chemoprophylaxis: Tetracycline or
Doxycycline for travelers coming from endemic or infected areas.
Vaccination certificate is not required internationally since the
vaccine is not potent
Cases : Early case finding and confirm diagnosis. Report to LHO & WHO. Isolation in fever hospital, quarantine or cordon. Disinfection: Concurrent disinfection of all
soiled articles & fomites, stool and vomitus using heat & carbolic acid. Terminal cleaning is sufficient.
Treatment: Adequate dehydration therapy using OR in mild cases, IV rehydration in severe cases. Treatment of hypoglycemia.
Release after 3-ve successive stool sample.
Food poisoning
Bacterial Food poisoning
Presence of bacteria or other microbes which infect the body after consumption.
Ingestion of toxins contained within the food, including bacterially produced exotoxins
Food infection Food intoxication
Food intoxication: staphylococcal, botulism & others (Clostridium Perfringes & Bacillus-cereus).
Food infection: salmonella & others.
Bacillus Cereus Found in soil, vegetation,
cereals & spices
Staphylococcus Aureus
Found in human nose & throat
(also skin)
Clostridium Perfingens
Found in animals & birds
SalmonellaFound in
animals, raw poultry & birds
Clostridium Botulinum
Found in the soil &
associated with vegetables &
meats
Salmonella Botulism STAPH- Outbreaks- Egypt
- Rare - sporadic cases
- Commonest- Outbreaks
Pattern
Non typhoidalSalmonella (S.typhimurium & S.enteritidis)
Exotoxin of Cl .Botulineum neurotoxinBotulus= Latin for sausage
Performed thremostableEnterotoxin (Exotoxin)
Causative agen
t
- Animals: Rodents &cattle - Man: Cases&carriers
- Soil: grownvegetables,
fruitscontaminated
withspores- Animals:
excretaof cattle, pigs&others
1. Man :Case or carrier(skin or resp. infec) > 5% of population having foci of skin or nose infection
2. Cattle: (staph.mastitis
contaminate milk)
Reservoir of infection
Salmonella Botulism STAPH1. Ingestion of
food from infected cattle or swine.
2. Ingestion of foodcontaminated with excreta of animals or rodents3. Water polluted with excreta of man or animal4-Hand to mouthInfection “auto-infection”
Ingestion of foodcontaminated with Performed exotoxin of Cl.Botulieum(preserved vegetables without proper sterilizationpacked or canned meats or sausages or fish)*packing of salted raw fish (fessikh)
Ingestion of enterotoxin contaminated food or milk by resp. discharge of food handlersFavored by: much handling& sufficienttime between contamination &consumption withoutRefrigeration “koshary, belela”
Mode of trans
mission
38 hs 12-36 hs
2-6 hs IP
Salmonella Botulism STAPH1. Outbreaks:
GE2. Sporadic:
salmonellosis
3. Enteric likePicture: self-limited disease
Paralysis of occulo-motor & other cranial ns causing visual disturbances as diplopia, loss of accommodation, dysphagia, dysphonia & resp. paralysis case-fatality is high (70%) in few days due to resp. failure
abrupt onset of GE (for hours then recoveryslight or no fever Case-fatality is almost nil
C/p
- Mainly Clinically - Culture: Stool, Vomitus& Food remains (-ve results not exclude staph. as organism may be destroyed while the enterotoxin is not).
Diagnosis
Salmonella Botulism STAPHGeneral preventive measures of food borne
diseases Prevention
In case of botulism:1.Proper processing, packing, canning of food after
sterilization2. Food preservation at home
3. Suspected canned food to be spoiled (bulged from gas formation) rejected
4. Specific prevention: Trivalent Botulism antitoxin
As food borne infection & investigation of outbreak1. Sero-therapy by Trivalent Botulism
antitoxin :limited value (irreversible effect of exotoxin on CNS)
2.Seroprophylaxis for person sharing food with diagnosed cases but no manifestations
3. Food remnants: destroyed after sampling for bacteriological testing
Control
Botulism Death may occur due to
respiratory paralysis within 7 days.
Clostridium Welchii
(Cl.Perfrinqens type A)
Bacillus cereus
Anerobic spore formingpowerful enterotoxin
Aerobic spore forming 2 enterotoxins “heat
labile (diarrhea) & heat stable (vomiting)”.
Agent:
Animals (cattle, poultry &fish)
Man (cases &carriers).
Spores found in the soil “rice”.
Reservoir
Ingestion of spore-contaminated meat
Ingestion of spore-contaminated rice.
Mode of
Infection
6-24 hours. 1-6 hours in emetic 6-24 hours in diarrheal
cases.IP
intensive diarrhea, no vomiting “self-limited” - necrotizing enteritis
“highly fatal in the elderly”
GIT manifestations either Emetic or
Diarrhea “self-limited”C/P
Bacillus cereus
Incubation period < 6 hoursSevere vomitingLasts 1-6 hours
Incubation period > 6 hoursDiarrhea
Lasts 6-24 hours
EMETIC FORM DIARRHEAL FORM
Investigation of outbreak of food
poisoningReservoirs
Food
Cases
Outbreak
Features & Circumstances of Outbreak
Many cases.Share common food.Very short IP (hours).
Similar manifestations.
1. Enlistment & distribution of cases by TPP.
2. Proper history taking & examination.3. Culture of faeces & vomitus of cases.
4. Look for other cases.
Measures for cases:
1. Listening of food & remnants.2. Origin, preparation & storage.3- Culture of suspected food remnants4-Compare the attack rate Attack rate for food items eaten =
no. of cases among those ate certain food x100
all who ate the same foodFood items: Greatest difference in attack
rates between those ate this food and did not eat
Measures for food items:
Measures for reservoirs:
1. Food handlers: examination e.g. for staphylococcal infection: nose & throat swabbing for carriers, and examining
skin & nails for lesions
2. Other possible sources of contamination e.g. rodents & their
excreta
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Diarrheal Disease Of Children
(Gastro-enteritis)
Gastro-enteritis is diarrheal disease of children below 5 years (infants & young
children).
Bacterial Es
cher
ich
ia
Ente
roto
xige
nic
(ETE
C)Tr
avel
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diar
rhea
Ente
roha
emo
rrha
gic
(EH
EC)
Hem
orrh
agic
colit
is
Ente
ropa
thog
eni
c (E
PEC)
Neon
atal
di
arrh
eaEn
tero
inva
sive
( EI
EC)
Dyse
nter
y
Stap
hylo
cocc
us
aure
usNo
n-ty
phoi
dal
salm
onel
lae
Shig
ella
e
Cam
pylo
bact
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jeju
ni
Viral
Rota
viru
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spita
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Ente
rovi
ruse
s
Cock
sack
ie
viru
ses,
ECHO
vi
ruse
s, po
liovi
ruse
s, HA
VEn
teric
Ad
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irus
epid
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vira
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Mea
sles
Protozoal
Giar
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Dyse
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Reservoirs of Infection: 1- Man (cases or carrier)
2- Animals “non-typhoidal Salmonellae, Campylobacter jejuni, E.Histolitica, B.
coli”.
Underlying Factors:1.Community Underdevelopment: a) Insanitary environment. b) Illiteracy. c) Lack of effective health services2. Host factors: Malnutrition, especially protein-energy malnutrition (PEM). Persisting systemic infection “chronic otitis media & bronchitis”.3. Season: sporadic cases may occur all the year round.Monthly distribution of cases in developing countries shows 2 peaks:• A peak of higher morbidity & mortality in summer & fall• A small peak, with some rise of cases during winter months “increased incidence of acute respiratory infections”.
GE fo
rms
Epidemic diarrhea of the newborn “E-
coli”
Summer diarrhea
Flies.
Rapid multiplication of organisms in milk
& foodDiminished acid
secretion of stomach
Weaning diarrhea.
Staphylococcal enteritis-
Secondary enteritisPersistent systemic infection, specially the respiratory &
urinary
Recurrent diarrhea
Incubation Period: Vary according to the causative agents usually hours to 2-4 days.
Clinical Picture:*Mild cases: mild diarrhea (less than 5 times
throughout the day), no or mild fever, no vomiting, no or insignificant dehydration, and no or mild systemic manifestations (self-limited and clears up within days)
*Moderate & severe cases: abrupt onset, with fever (usually high), frequent liquid or rice-water stools (up to 20 or more in a day), vomiting and dehydration.
Basic Lines of Treatment:
1. Rehydration therapy: 1st line to replace loss of fluid & electrolytes, and restores fluid-electrolyte balance by oral rehydration, or parenteral route.a) Oral Rehydration Therapy (ORT): each of 5.5gm of sodium chloride, sodium bicarbonate (to correct acidosis), potassium chloride (to correct hypokalaemia) and glucose. it is dissolved in 200 ml water.b) Nasogastric Rehydration: repeated uncontrolled vomiting.c) Intravenous fluid Rehydration: hospitalized severe cases
2-Chemotherapy:for bacterial diarrhea cases.3. Diet Therapy:a) Cases having no dehydration: keep on usual feeding,
and give sufficient fluid. Supplementary vitamin B & C.b) Cases with dehydration:Mild cases: given ORS and milk, alternating, until cured.Moderate cases: initially given rehydration, with fasting
(water can be given if necessary) for some hours until dehydration improves, then milk, then other foods can be given.
- Symptomatic Treatment: especially fever.
Dysentery
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Dysentery
Inflammation of the colon (large intestine). Tenesmus
Abd. painFrequent stools “Bl. & mucus”
Agents
Bacterial “Shigella
e”
Protozoa “Entamib
a histolytic
a” Helminthis
“Scistosoma”
Shigellosis
Shigellosis (Shigella) Bacillary Dysentery
Acute infectious inflammatory bacterial disease of the colon. It is a worldwide disease. It is usually sporadic cases. Outbreaks occasionally occur, in confined groups.
Incidence is higher with seasonal breeding of flies (spring, early summer and the fall) important vector role.
Causative Organism4 groups of Shigella with no cross immunity. Group A: S.dysenteriae (Shigella shiga), most
virulent. Group B: S. flexneri Group C: S. bouydii
Group D: S. sonnei causing mild disease.Relatively resistant outside the body, but readily destroyed by heat & disinfectants.Locally: the exotoxin is enterotoxic, causing dysentery.* Toxaemia: the exotoxin is a neurotoxin, may be fatal
Reservoir of Infection: man, cases and carriers.
Carriers: number is several times the cases, and forms the main reservoir of infection. They are contact, healthy and convalescent carriers.
Exit: in faeces Infectivity: usually for few weeks, sometimes
longer, and rarely for one or more years.
Incubation Period 1 -7 days (usually less than 4).Clinical Picture:More than one attack may occur, due to different groups and serotypes. Infection is usually followed by type-specific immunity. Mild disease that may pass unnoticed.1-Acute cases : sudden onset, with fever, may be vomiting, and dysentery (tenesmus, squeezing pain of lower abdomen, and frequent loose scanty stools, mainly made of fresh blood, pus and mucus). Disease is usually self-limited, with recovery in few days.2-Severe fulminate disease: with dysentery, the case shows systemic manifestations, and may be dehydration and complications (uncommon), due to exotoxin and toxaemia, and some cases may be fatal (especially in the young, elderly and debilitated).
Case study
40 years old working female complained from headache, anorexia, vomiting, and constipation turned to diarrhea and upgrading fever few days ago. The fever is not responding to antipyretics.
a) What are the other signs you have to look for in this case?
b) What are the investigations you should do?c) What is the probable diagnosis?d) How will you manage this case?e) When can she return to work?f) What are the control measures you should do for
contacts?
Other signs
1) Fever increase at night (stepladder)2) Bradycardia( Pulse is relatively slower to
temperature. 3) Rosy spots on the abdomen
Investigations Blood culture: (the first week):positive culture conclusive, but the negative
not exclusive Widal test: (the 2nd week) agglutination test ,rising titer which is
diagnostic Stool and urine culture: in 2nd & third
week valuable to detect carriers, rather than diagnosis.
Management of case
Case-finding Notification to the local health office. Isolation: allowed at home when sanitary
requirements are fulfilled, otherwise must be at hospital.
Disinfection Treatment
Release
after 3 -ve cultures of stools & urine, 24 or more hours apart.
1st sample is taken 2 weeks after drop of temperature to normal (to exclude possibility of relapse).
measures for contacts
a) Family and Household contacts: Enlistment& Active immunization. Surveillance for two weeks, from date of last
exposure to the case, for case-finding. Food handlers: excluded from work, and
bacteriologic ally examined until prove not to be carriers.
b) Nursing personnel: Active immunization personal cleanliness precautions on nursing the case not to handle or serve food to the others.
Case study
Three persons from a family in rural area drinking underground water and have latrines for sewage disposal are complaining from acute attack of watery diarrhea with no fever.
a) What is the suspected diagnosis? Justify?b) How will you manage this case?c) How will you manage contacts?
suspected diagnosis
Cholera as Epidemics and pandemics of it strongly linked to unsanitary water supply, poor sanitary conditions
Cholera spreads easily in lower socioeconomic group
bad sanitary environment which act as favorite media for endemically.
management of case Case finding. Notification LHO and WHO. Isolation in fever hospital, quarantine or
cordon. Disinfection Treatment: Adequate dehydration therapy
using OR in mild cases, IV rehydration in severe cases. Treatment of hypoglycemia
Release after 3 -ve successive stool sample.
Management of contacts
Enlistment: H.E Isolation for 5 days calculated from the day of
exposure. Release after 3 negative successive stool sample. Chemoprophylaxis. repeated stool culture to prevent carrier state.
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