Chapter six Food Borne Diseases

By Gugsa Nemera

Objectives

At the end of this session students will be able to

1. Discuss common food born diseases in terms of their source of infecction , manifestation , managements prevention and control

Food Borne Diseases

• Food-borne diseases are illnesses acquired by consumption of contaminated food

• Includes Food PoisoningFood borne IntoxicationsFood-borne infection

Food Poisoning contamination of food with chemical

contaminants /heavy metals and organic compounds

Food borne Intoxicationsbacterial growth in the food before

consumption (staphylococcus aurous and botulism)

Food-borne infection salmonellosis

Staphylococcal food poisoning (Intoxication)It is intoxication (not infection) of abrupt and

sometimes violent onset. Infectious agent (toxic agent)Several enterotoxins of staphylococcus aurous,

stable at boiling temperature, staphylococci multiply in food and produce the toxins

EPI:wide spread and relatively frequentReservoir:Humans in most instances; occasionally cows

Staphylococcal food poisoning -MT

By ingestion of a food product containing staphylococcal enterotoxin

Risk factors Poor food handling Inadequate heating or refrigeration

common sources are food source such as Saladsandwiches sliced meat meat products pastries etc

Staphylococcal food poisoning cont’d

IP30 minutes to 8hrs, usually 2-4 hrsPCNot applicable S/R Most people are susceptible

Staphylococcal food poisoning cont’d

Clinical manifestationSudden onset of vomiting and watery

diarrhoea Fever abdominal cramp

Staphylococcal food poisoning cont’d

• DiagnosisGroup of cases with characteristic acute

predominantly upper GI symptomsshort interval between eating a common food item

and the onset of symptoms Culture

staphylococcal recovery (greater than or equal to 10 organisms per gram of food)

detection of enterotoxin from an epidemiologically implicated food item confirms the diagnosis

Staphylococcal food poisoning -Rx

Depending on intensity of illness pt may require hospitalization

Fluid and electrolyte replacement if fluid loss is significant particularly in severe cases

Gastric resting

Staphylococcal food poisoning -Prevention and control Educated food handlers on

strict food hygiene sanitation and cleanliness of kitchens, proper temperature control, hand washing, cleaning of finger nails need to cover wounds on the skin.

Reduce food handling time to no more than 4hrs Keep perishable food hot (>600C or cold below 100C). Temporarily exclude people with boils, abscesses and other

purulent lesions of hands, face or nose from food handling.

Botulism food poisoning Definition A paralytic disease that begins with cranial

nerve involvement and progresses gradually to involve the extremities.

Infectious agent (Toxic agent)Toxin produced by clostridium botulinum

(Neurotoxin)

Botulism food poisoning -EPIWorldwide occurrence with home canned foods,

particularly vegetables, fruits and less commonly with meat and fish.

Outbreaks have occurred from contamination through cans damaged after processing.

Commercial products occasionally cause outbreaks but some of these outbreaks have resulted from improper handling after purchase.

Food born botulism can occur when a food to be preserved is contaminated with spores

Botulism food poisoning cont’dReservoir The bacteria found in the soil and in the intestine of animals MT- Food infection in which preformed toxin is found.I/P: Neurological symptoms of food borne botulism usually appear

within 12-36 hours, sometimes several days, after eating contaminated food

PC: not communicable S and R Susceptibility is general

Botulism food poisoning -Clinical Manifestations Illness varies from a mild condition to very severe

disease or death within 24 hours.Symmetric descending paralysis is characteristic and

can lead to respiratory failure and death.Cranial nerve involvement makes the onset of

symptoms, usually produces diplopia ,dysphasiaWeakness progresses' often rapidly, from the head to

involve the neck, arms, thorax and legs; the weakness is occasionally asymmetric.

Nausea, vomiting, abdominal pain may proceed or follow the onset of paralysis.

Botulism food poisoning -Clinical Manifestations

Dizziness, blurred vision ,dry mouth, and occasionally sore throat is common.

No fever; ptosis (abnormal dropping of upper eyelids) is frequent

Papillary reflexes may be depressed: fixed or dilated pupils are noted in half of patients

The gag reflex may be suppressed; deep tendon reflexes may be normal or decreased

Paralytic ileus (a decrease in or absence of intestinal peristalsis)

severe constipation and urinary retention are common

Botulism food poisoning -Diagnosis

Clinical- afebrile, mentally intact patients who have symmetric descending paralysis without sensory findings

Appropriate historyDemonstration of organisms or its toxin in

Vomitus, gastric fluid or stool is strongly suggestive of the diagnosis

Wound culture

Botulism food poisoning-Treatment

Hospitalize the pt and monitor closely Intubation and mechanical ventilation may be needed Antitoxin administration after hypersensitivity test to horse serumEmesis and lavage if short time after ingestion of food to decrease the toxin

Botulism food poisoning-Prevention and control

Ensure effective control of processing and preparation of commercially canned and preserved food

Education about home canning and other food preservation techniques regarding the proper time, pressure and temperature required to destroy spores.

The need for adequate refrigeration, storage, boiling home-canned vegetables for at least 10 minutes to destroy botulinum toxin.

Canned foods in bulging containers should not be used eaten or tasted.

Salmonellosis

Definition A bacterial disease commonly manifested by an

acute enterocolitis (inflammation involving both the large & small intestines)

Infectious agentSalmonella typhimurium and salmonella enteritidis

are the two most commonly reported EPI: It occurs world wide

Salmonellosis cont’d Reservoir Domestic and wild animals including poultry, swine, cattle,

rodents and pets (tortoises, dogs, cats, and humans) patients or convalescents are carriers esp. of mild and

unrecognized cases.MT ingestion of organisms in food derived from infected food

contaminated by faeces of an infected animal or person raw and under cooked eggs and egg products raw milk and its products poultry and its products consumption of raw fruits and vegetables contaminated during

slicing (cutting in to pieces)

Salmonellosis cont’d I/P:from 6-72 hours, usually about 12-36 hoursPC: extremely variable through the course of infection; usually

several days to several weeksS& R Susceptibility is general and increased by

achlorhydriaantacid therapyGI surgeryprior or current broad spectrum antibiotic Rxneo plastic diseaseImmuno suppressive Rxmalnutrition

Salmonellosis cont’d Clinical ManifestationSelf limited fever and diarrhoea (Bloody or dysenteric when

colon is involved)Nausea, vomiting and abdominal crampMicroscopic leukocytosisDXBlood culture initially Stool cultureRx Symptomatic If there is an underlying immunosuppressive disease ,treat the

underlying cause

THANK YOU

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