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

Click icon to add picture

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

ers’

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

er

jeju

ni

Viral

Rota

viru

sHo

spita

lized

Ente

rovi

ruse

s

Cock

sack

ie

viru

ses,

ECHO

vi

ruse

s, po

liovi

ruse

s, HA

VEn

teric

Ad

enov

irus

epid

emic

vira

l GE

Mea

sles

Protozoal

Giar

dia

lam

blia

GE

Enta

moe

ba

hist

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coli

Dyse

nter

y

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.