Avian influenza A simple introduction
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
Structure 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.
Structure 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).
Structure of avian flu
Structure of avian flu This 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.
Structure 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.
How do people become infected? Human 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
Symptoms Diarrhoea (腹瀉) Vomiting Abdominal and chest pain Bleeding from nose and gums High fever > 38oC Respiratory symptoms
People's Republic of China Confirmed cases of avian influenza of type A (H5N1) (Updated on March 24, 2006) Country Report dates Total 2003 2004 2005 2006 cases deaths Azerbaijan 7 5 71.4 % Cambodia 4 100 % 1 People's Republic of China 8 62.5% 6 75.0% 16 11 68.8% Indonesia 17 64.7% 12 91.7% 29 22 75.9%
Confirmed cases of avian influenza of type A (H5N1) (Updated on March 24, 2006) Iraq 2 100 % Thailand 17 12 70.6% 5 40.0% 22 14 63.6% Turkey 4 33.3% Vietnam 3 29 20 69.0% 61 19 31.1% 93 42 45.2% Total 46 32 69.6% 95 41 43.2% 186 105 56.5% Source World Health Organization (WHO) : Communicable Disease Surveillance & Response (CSR). Total cases Total deaths
Highly pathogenic H5N1 → Countries with poultry or wild birds killed by it → Countries with humans and poultry or wild birds killed by it
Only H5N1 is 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
A pandemic can start! Pandemic risk When ... a new influenza virus subtype emerges it infects humans, causing serious illness it spreads easily and sustainably among humans. A pandemic can start!
We are now in danger! Pandemic 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!
2 ways to become a pandemic virus H5N1 as a pandemic virus 2 ways to become a pandemic virus reassortment result in a fully transmissible pandemic virus adaptive mutation a slower process can be prevented
Prevention - Personal Avoid contact with live birds Wash hands after any poultry contact Cook poultry well done before eating Avoid crowded places with poor ventilation Wear gloves, a mask, goggles and a disposable gown when contact poultry
Prevention - Government Provide vaccine injection Kill birds infected with avian flu Stop transport of poultry
Treatment Western Medicine oseltamivir (Tamiflu) / zanamivir (Relenza) reduce the severity and duration of illness useful with early administration(48 hrs) improve prospects of survival
Treatment (for interesting /reference ONLY...) Chinese medicine - herbal remedy It is still uncertain if it works...
Thanks for your attention! END Thanks for your attention!