Norovirus Ppt

Viruses?

Noroviruses B.K.K.K.Jinadasa [email protected]

• 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 (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

• Size and genome content of viruses with compare other cells.

Difference between virus and cells Viruses

Morphology of virus:

Living cells

Growth

Grow only within cells, Most free living outside cell metabolically inert

Nucleic acid content

Contain either DNA or RNA, Always contain both DNA never both and RNA

Enzyme content

Have very few if any enzymes Have many enzymes

Cell components

Lack ribosome and enzymes Contains ribosome and to generate energy enzymes for generation of energy

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.

Oyster accumulate with Noro Virus

• 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. Salmonella Yersinia Campylobater E. coli Listeria Norovirus

Mean incidence 16,800 7,900 123,000 340 24 108,000

• At the recent publication of food focus magazine, New Zealand has indicated that Norovirus take important role for food borne diseases at year 2005.

What are the symptoms of illness?

How to infected?

• Usually – Nausea – Vomiting – Diarrhea – Stomach cramping

• Sometimes additionally have – Low-grade fever – Headache – Muscle aches – General sense of tiredness

What are the treatments? • Currently, there in no antiviral medication and no vaccine to prevent infection. • Only giving dehyration fluid to prevent dehydration.

• Eating contaminated food or drink. • Touching surface or objects contaminated with norovirus, and then placing hand in mouth. • direct contact with another infected person

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 !