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Post on 10-May-2015
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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!!
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