Five keys

1.INTRODUCTION

Food borne diseases-(intoxications and infections) covers illnesses acquired through consumption of contaminated food-i.e food poisoning

Food borne disease outbreaks-occurrence of 2 or more cases of similar illness resulting from ingestion of common food OR when observed number of paticular disease exceeds expected number

Most cases-sporadic but need investigations for control

1.INTRODUCTION –BURDEN

Global burden-high morbidity and mortality

Infectious diarrhoea-3 to 5 billion cases and 1.8 million deaths annually

CDC-76 million cases of food borne diseases in US annually with appx.5000 deaths

Infections-Bacterial/Viral/parasite

Invade and or multiply in lining of intestine

Incubation period-hours to days

s/s-diarrhoea,nausea,vomitting,

abdominal cramps,fever

Transmission-spreads from person to person

Factors-inadequate cooking,cross contamination,poor personal hygiene,bare hand contact

Intoxications-toxins (natural/preformed bacterial/chemical)

No invasion or multiplication

Incubation period-minutes to hours

s/s-vomitting,nausea,diarrhea,diplopia,weaakness,resp.failure,numbness,sensory/motor dysfunction

Not communicable

Factors-inadequate cooking,improper handling temperatures

FOOD BORNE INFECTIONS VS INTOXICATION

SOME IMPORTANT FOOD-BORNE PATHOGENS,TOXINS AND CHEMICALS

1.Bacteria-Bacillus cereus,brucella,campylobacter,clostridium sp,e.coli,Salmonella sp,listeria,staph aureus,,vibrio cholera and parahemolyticus

2.viruses-hepatitis a and e,rotavirus,norvovirus,

3.protozoa-cryptosporidium,cyclospora,entamoeba,giardia,t gondii

4.trematodes,cestodes and nematodes

FOOD BORNE PATHOGENS-TOXINS AND CHEMICALS

Toxins-marine biotoxins,tetrodotoxin(pufferfish),pyrrolizidine alka,mushroom toxins,shellfish toxins,mycotoxins,plant toxicants

Chemicals-pesticides(opp,sb),radionuclides,nitrites(food preservatives),toxic metals-cd,cu,hg,pb,sn,fluoride,MSG

PATHOGENESIS AND TRANSMISSION

Infectious agent or contaminant

Inoculum/size of infective dose-can be as small as 10-100 bacterial cysts for shigella,EHEC,giardia,E.histolytica or 10^ 5-10^ 8 for vibrio cholera,variable for salmonella

Animals or humans harbouring infectionshed in fecescontaminate water,fruits,vegetablesinadequate cooking/improper storageinfection

Warm temperature(10-50 degree cent.)-multiplication of pathogens

SOME COMMON BACTERIAL FOOD POISONSIncubation period

cause symptoms Common foods

1-6 hours Staph aureus(enterotoxin)

Nausea,vomitting,diarrhea

Milk n milk products,ham,poultry,salads,custards

Bacillus cereus(enterotoxin)

Nausea,vomitting,(emetic form)

Fried rice

SOME COMMON BACTERIAL FOOD POISONS

Incubation period

Cause symptoms Common foods

8-16 hours

Clostridium perfringes(spores)

Abd.cramps,diarrheaNausea andvomitting-rare

Meat,poultry,legumes.gravies

Bacillus cereus(diarrheal form-preformed n stable toxins)

Diarrhea,abd.pain,nausea,No vomitting/fever

SOME COMMON BACTERIAL FOOD POISONSIncubation period

cause symptoms Common foods

>16 hours Vibrio cholera

Rice watery stools

Water and ice creams,sea food

Salmonella spp

Inflammatory diarrhea

Meat,milk n milk products,poultry

Shigella sp dysentry Potato/raw eggs-salad

EARLY DIAGNOSIS AND INVESTIGATIONS1.Initial assessment of cases-Detailed

clinical history including time of onset,duration of illness,symptoms,h/o travel,recent meals,cooking and refrigeration,details of others with similar complaints

2.Detailed clinical examination-vitals and degree of dehydration,systemic signs

LAB DIAGNOSIS

Main objectives-

a)To confirm clinical diagnosis by isolation of causative agent from proper samples,eg-stool,vomitus/gastric aspirate,food specimens

b)Ensure proper identification of disease

c)Determine causative agent if present in food sources with relevant epidemiological markers-eg Biotyping,serotyping,pcr,phage typing etc

THE SOLUTION!!