Avian influenzaAvian influenza

A simple introduction

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What is avian influenza? What is avian influenza?

Bird flu highly species-specific , birds Occasionally, pigs and human 2 types

low pathogenic go undetected

high pathogenic ~100% mortality within 48 hours

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Structure of avian fluStructure of avian flu

Type A influenza virus

Classified by different proteins on the surface

Influenza A virus, the virus that causes Avian flu. Transmission electron micrograph of negatively stained virus particles in late passage.

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Structure of avian fluStructure of avian flu

Negative sense, single-stranded, segmented

Have 10 genes on eight separate RNA

Colorized transmission electron micrograph of H5N1 (golden) grown in Madin-Darby canine kidney cells (green).

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Structure of avian fluStructure of avian flu

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Structure of avian fluStructure of avian fluThis transmission electron micrograph (TEM), taken at a magnification of 150,000x, revealed the ultrastructural details of an avian influenza A (H5N1) virion, a type of bird flu virus which is a subtype of avian influenza A. At this magnification, one may note the stippled appearance of the roughened surface of the proteinaceous coat encasing the virion.

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Structure of avian fluStructure of avian flu

This transmission electron micrograph (TEM), taken at a magnification of 108,000x, revealed the ultrastructural details of two avian influenza A (H5N1) virions, a type of bird flu virus, which is a subtype of avian influenza A. At this magnification, one may note the stippled appearance of the roughened surface of the proteinaceous coat encasing each virion.

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Human infectionHuman infection

How do people become infected? direct contact with infected poultry intake of infected poultry contact with contaminated water

source consumption of inadequately

cooked poultry

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SymptomsSymptoms

Diarrhoea ( 腹瀉 ) Vomiting Abdominal and chest pain Bleeding from nose and gums High fever > 38oC Respiratory symptoms

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Country

Report datesTotal

2003 2004 2005 2006

cases deaths cases deaths cases deaths cases deaths cases deaths

 Azerbaijan   7 5 71.4 % 7 5 71.4 %

 Cambodia   4 4 100 % 1 1 100 % 5 5 100 %

 People's Republic of China

  8 5 62.5% 8 6 75.0% 16 11 68.8%

 Indonesia   17 11 64.7% 12 11 91.7% 29 22 75.9%

Confirmed cases of avian Confirmed cases of avian influenza of type A (H5N1)influenza of type A (H5N1)(Updated on (Updated on March 24, 2006March 24, 2006))

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Confirmed cases of Confirmed cases of avian avian influenza of type A (H5N1)influenza of type A (H5N1)(Updated on (Updated on March 24, 2006March 24, 2006))

 Iraq   2 2 100 % 2 2 100 %

 Thailand   17 12 70.6% 5 2 40.0%   22 14 63.6%

 Turkey   12 4 33.3% 12 4 33.3%

 Vietnam 3 3 100 % 29 20 69.0% 61 19 31.1%   93 42 45.2%

Total 3 3 100 % 46 32 69.6% 95 41 43.2% 42 29 69.0% 186 105 56.5%

Source World Health Organization (WHO) :Communicable Disease Surveillance & Response (CSR).

Total cases

Total deaths

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Highly pathogenic H5N1 Highly pathogenic H5N1

 →  Countries with poultry or wild birds killed by it

 →  Countries with humans and poultry or wild birds killed by it

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Why is it fatal to human?Why is it fatal to human?

Only H5N1 is fatal to human no scientific confirmation yet multi-organ dysfunction difficulty in breathing intravascular coagulation

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Pandemic risk Pandemic risk

When ... a new influenza virus subtype emerge

s it infects humans, causing serious illn

ess it spreads easily and sustainably am

ong humans.

A pandemic can start!

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Pandemic riskPandemic risk

H5N1 has reached 2 conditions it is a new virus for humans it has infected more than 100

humans, killing over half of them

We are now in danger!

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H5N1 as a pandemic virus H5N1 as a pandemic virus 2 ways to become a pandemic vi

rus reassortment

result in a fully transmissible pandemic virus

adaptive mutation a slower process can be prevented

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Prevention - PersonalPrevention - Personal

Avoid contact with live birds Wash hands after any poultry contact Cook poultry well done before eating Avoid crowded places with poor ventilati

on Wear gloves, a mask, goggles and a dispo

sable gown when contact poultry

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Prevention - GovernmentPrevention - Government

Provide vaccine injection Kill birds infected with avian flu Stop transport of poultry

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TreatmentTreatment Western Medicine

oseltamivir (Tamiflu) / zanamivir (Relenza)

reduce the severity and duration of illness

useful with early administration(48 hrs) improve prospects of survival

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Treatment (for interesting Treatment (for interesting /reference ONLY...)/reference ONLY...)

Chinese medicine - herbal remedy

It is still uncertain if it works...

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Thanks for your attention!