norovirus ppt
DESCRIPTION
Noroviruses in foodsTRANSCRIPT
NorovirusesNoroviruses
Viruses?
• Viruses are nonliving agents that are associated with all forms of life.
• The sizes of the longest viruses are same to the smallest bacteria cells.
• Size and genome content of viruses with compare other cells.
Size (Diameter)/nm Genome content
Smallest virus 20 4-5 gene
Largest virus 300 150-200 gene
E. coli cell 1,000 3,000 gene
Human cell 20,000 <60,000
Difference between virus and cellsViruses Living cells
Growth Grow only within cells, outside cell metabolically inert
Most free living
Nucleic acid content Contain either DNA or RNA, never both
Always contain both DNA and RNA
Enzyme content Have very few if any enzymes Have many enzymes
Cell components Lack ribosome and enzymes to generate energy
Contains ribosome and enzymes for generation of energy
Morphology of virus:
Oyster accumulate with Noro Virus
What are Noroviruses?
• Noroviruses are a group of viruses that cause the “stomach flu” in people.
• The term norovirus was recently approved as official name for this group of viruses. Several other names have been used for norviruses, including;– Calcivirus– Norwalk-like viruses (NLVs)– Small round structured viruses.
• Norovirus are resistant to environment changes.
• They can survive in up to 10 ppm chlorine, present in public water systems.
• They can bare freezing, can survive temperature as high as 1400F (600C). They have been associated with illness after steamed in shellfish.
• Noroviruses occur all over the world but data are not enough based on annual medicine of disease
How to identify?
• Antigen detection method.• Enzyme immunoassay.• Polymerase chain reaction (PCR).• Electron microscopic methods.
Food borne diseases?
• Not reported in Norovirus diseases in Sri Lanka.
• At the recent publication of food focus magazine, New Zealand has indicated that Norovirus take important role for food borne diseases at year 2005.
Mean incidenceSalmonella 16,800Yersinia 7,900Campylobater 123,000E. coli 340Listeria 24Norovirus 108,000
What are the symptoms of illness?• Usually
– Nausea– Vomiting– Diarrhea– Stomach cramping
• Sometimes additionally have– Low-grade fever– Headache– Muscle aches– General sense of tiredness
How to infected?
• Eating contaminated food or drink.• Touching surface or objects contaminated
with norovirus, and then placing hand in mouth.
• direct contact with another infected person
What are the treatments?
• Currently, there in no antiviral medication and no vaccine to prevent infection.
• Only giving dehyration fluid to prevent dehydration.
How to prevent?
• Frequently wash hands, before eating or prepare foods.
• Wash fruits & vegetables, steam oysters before eating.
• Thoroughly clean & disinfected food processing surface.
• Infected person should not prepare food 3 days after recover.
THNAKKS !THNAKKS !