H7N9 - What Is It?

There are 3 types of influenza viruses: A, B and C.

Type A viruses can infect humans, birds, pigs, horses and other animals, and wild birds are the natural hosts for these viruses. They are subject to gradual mutations (known as antigenic drift) as well as sudden changes in their surface proteins (known as antigenic shift). They are very dynamic and are continuously changing. Current vaccines may not be able to work to prevent or cure the disease, hence global surveillance is critical to monitor for their evolution. Because of their variability, type A viruses can cause major pandemics (spread over large areas).
Type B viruses can usually only infect humans. They undergo only gradual antigenic drift and cause only centralised epidemics (spread over small localised areas).
Type C viruses can only infect and cause mild illness in humans and are antigenically stable (i.e. they do not undergo any antigenic drift and antigenic shift). They cause only sporadic diseases and do not cause epidemics or pandemics.

Influenza type A viruses are further classified into subtypes on the basis of two proteins on the surface of the virus: hemagglutinin (H) and neuraminidase (N). There are 16 different hemagglutinin subtypes (H1 to H16) and 9 neuraminidase subtypes (N1 to N9). Various combinations of hemagglutinin (H) and neuraminidase (N) subtypes are possible. Following are some known influenza type A viruses:

H1N1 - Spanish flu pandemic of 1918 and swine flu pandemic of 2009
H2N2 - Asian flu pandemic of 1957
H3N2 - Hong Kong flu pandemic of 1968
H3N8 - frequently found in horses
H5N1 - bird flu
H5N2 - highly capable to produce diseases in chickens
H7N7 - 2003 poultry epidemic
H7N9 - new bird flu in China of 2013

Influenza type B and type C viruses are not classified into subtypes.

The influenza virus recently found in China is rightly named as Type A H7N9 virus because it is of the Type A influenza virus with hemagglutinin 7 and neuraminidase 9 subtype proteins. It was first reported to have infected humans in March, 2013.

(Information are mostly sourced from 'Influenza Viruses, November 2005, Centre of Disease Control USA')

A Random Act of Kindness

I recently read an article in my son's school magazine, the Knoxonian. It was an extract of an email from a father of a Year 7 boy to the Headmaster in which I quote below. Charlie is the name I use for the Year 7 boy for the sake of this story.

'Good morning.
I just want to let you know of a very positive experience that my son, Charlie in Year 7, encountered at school yesterday. Actually, it was Charlie himself who asked me if I could email you to let you know about what took place.
The Year 7s had only just received their ID cards this week. I told Charlie he could get his lunch from the canteen yesterday by using his new card, however I had forgotten to register his ID number on the Flexischools website.
Charlie went to the canteen and ordered his lunch, only to be told his card was not working and he then thought he would have to go without lunch. Then to his surprise, a lovely Year 12 boy (or Year 11) told the canteen staff that he would pay for his lunch. Charlie thanked him profusely and before he could ask his name the boy told Charlie not to worry as "sometimes it happens".
Charlie was obviously very grateful to this boy, as it was the first thing he told me about his day when I picked him up yesterday. I'm sure it is something Charlie will remember for many years to come, and that should he ever come across a new boy or any other person in the future that requires a helping hand, he remembers this kind act shown towards him in his early days in Year 7.
I was hoping there might be some way of thanking this mystery boy, as I think this young man should be acknowledged for his thoughtfulness.
It is also a wonderful example of the type of young man that Knox Grammar sends out into our community.'

The story was indeed a very simple one, and yet the significance has been profound. A lovely 'mystery' boy did something which he regarded as natural as something "sometimes it happens". But he probably wasn't aware that the seemingly unimportant matter could have caused an overwhelming effect on a Year 7 boy, and to the father of the Year 7 boy. It could be totally out of his imagination that his random act of kindness had so much enhanced the image of the school and encouraged a selfless, good-spirited and more connected community. There are plenty of such (good) stories happening around us everyday provided we have the time and heart to observe.

茶餐廳事件‏

噚日晌茶餐廳食晏, 睇完一輪餐牌後叫伙記落單.

我話, "咖哩雞飯, 唔該."
伙記話, "講英文吖, 唔該."
我心諗, "嘩! 你明明同我講中文. 點解要我講英文㗎." 我繼續諗, "哦! 佢可能喺 ABC (Australian Born Chinese), 可能唔明."
於是我決定就就佢. 用純正嘅英文同佢講, "Curry chicken with rice, please."

伙記睜大雙眼望住我, "我問你要 A, B, C 淨 D 餐咋."