# 4444
When it comes to influenza surveillance, few places in the world can match Hong Kong. Located next to mainland China – regarded as the `cradle of influenza’ by many – Hong Kong has often been the first place where new respiratory viruses are detected.
From the Wikipedia.
This enhanced surveillance network it probably why we learned of a Swine Flu reassortment in a butchered pig last month (see Hong Kong: Swine Flu Reassortment) and why, on a half dozen occasions, local doctors have picked up on mild cases of H9N2 infections over the past decade.
Hong Kong is also very good about publishing their findings, on their CHP Website, which makes them an important sentinel site for what is going on in Asia.
As mentioned on March 4th (see Hong Kong: Uptick In Flu Cases), Hong Kong is beginning to report an increase in influenza activity. Roughly half of the cases being tested are coming back as pandemic H1N1 flu, and half are seasonal `B’ influenza.
This is the time of year when seasonal influenza would be expected to peak in Hong Kong, and so a spike in cases is not unexpected. That said, the numbers are still far lower than those seen last fall.
First a press release, then some excerpts from their latest weekly update.
March 18, 2010
Hong Kong has entered the traditional peak period for seasonal influenza, with flu detections rising from 177 in the week ending March 6, to 268 in the week ending March 13.
The Centre for Health Protection today said influenza virus isolation in the Public Health Laboratory Centre showed a steady rise. Virus isolates are mainly either human swine influenza (49%) or influenza B (50%).
Reports of influenza-like illness outbreaks in institutions also surged from 24 in the week ending March 13, to 31 from March 14 to 18.
The consultation rate for influenza-like-illness among sentinel private doctors increased in recently. During the week ending March 13, the consultation rate for influenza-like-illness at private clinics was 51 per 1,000 consultations.
The centre's surveillance system also showed high seasonal activity of respiratory syncytial virus. The number of respiratory syncytial virus detections in the week ending March 13 was 134. The figure is consistent with the trend recorded in the past few years.
The centre will closely monitor the situation and has sent letters to doctors, schools and institutions alerting them to the upcoming flu season and providing advice on prevention and control.
Local situation on Human Swine Influenza (Pandemic influenza H1N1(2009))
(as of Mar 17, 2010)
- As indicated by the latest surveillance data, HSI activity in the community has increased when compared to the previous week.
- As of Mar 17, 2010, 51 patients with HSI infection remained in public hospitals. The weekly number of severe cases recorded in week 11 (Mar 7 to 13, 2010) was 2. As of Mar 17, 2010, a total of 263 severe cases were recorded.
- These severe cases included 160 males and 103 females with ages ranged from 30 days to 95 years (median: 51 years).
- In week 11 (Mar 7 to 13, 2010), one fatal case was recorded. As of Mar 17, 2010, a total of 74 fatal cases were recorded. They were 52 males and 22 females, age ranged from 1 to 95 years (median: 55.5 years).
- The latest surveillance data showed an increasing number of laboratory influenza isolates and institutional outbreaks of influenza-like-illness, which signal that Hong Kong has entered the traditional peak season for seasonal influenza (Fig 4 and 7).
The Magenta line shows ILI (Influenza-Like-Illness) reported for 2010, and while climbing, it remains below the levels seen in 2008, but above that seen this time last year.
And lastly, the age distribution of positive HSI cases continues to be skewed heavily towards those under the age of 60, with the most affected age groups being children and teenagers.
