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Legionnaires' Disease And Legionella Hong Kong
John Herbert
Legionella Risk Assessemnt Legionnaires Disease Expert
A businessman thought that a decorative fountain would be a
great feature for his restaurant. However, maintenance was not a high
priority, it never is. Unfortunately, the lack of maintenance allowed
the growth of Legionella and subsequently caused a Legionnaires disease
outbreak many of the customers fell ill.
After dinner death was not an expected outcome, so news of the legionella
outbreak spread rapidly in the local community and press.
The business was closed by health officials. After the necessary investigation,
testing, and cleaning, etc. and the media hype had subsided, he reopened restaurant
but the damage was already done, his customers never returned, eventually
without any business he was forced to close the doors. Don't let your
business suffer the same fate.
Hong Kong Legionella Conference (centre: John Herbert)
Hong Kong Legionella Cases Rising
2015
Hong Kong recorded the highest number of Legionella cases in recent years, 66 cases were reported in 2015.
August 2009
During the period Jan 2009 - August 2009 a total of twenty four cases of confirmed Legionella
infection have been officially reported (14/08/2009
report).
However, Legionella species infection including Legionnaires Disease requires a specific laboratory
test procedure for detection, and is generally NOT carried out by the clinical staff. Therefore
Legionella infection is widely under-reported here and around the globe. So we are left in dark,
and the number of cases is higher than officially reported.
In Hong Kong we experience approximately 5,000 unexplained cases of pneumonia with many
patients immediately treated with general antibiotics further masking the real number of cases.
Government Preventitive Advice?
The HKSAR government press release for example 14/08/2009
[PDF
version] has a bizarre warning.
Strangely it focuses attention on the risk of contracting Legionella infection from soil
or compost, and provides precautionary instructions, to avoid inhaling dust, wash hands, etc.
Now whilst it is possible to contract Legionnaires' Disease from compost, to
my knowledge there are no recorded cases of infection in Hong Kong.
Legionella Longbeachae is the causative agent, it is found in soil and compost
and could be inhaled. But the Government press release clearly states
Legionella Pneumophila infection which is water, not soil based Legionella
species.
Cooling Towers
Cooling towers are a known source for Legionella, many of the largest Legionella
and most explosive outbreaks were been traced back to cooling towers because
they provide the right conditions to harbour, breed, and disseminate
Legionella into the larger area of the community.
In Asia the open, bottle type cooling tower is very popular, however this design
easily allows debris to accumulate in the fill and in the basin. It also has
exposed surfaces, permitted sunlight and allowing algae growth.
Couple that with the humid warm environment, poorly and inadequately
maintained, opportunities for Legionella proliferation are abundant.
Wet cooling systems favour the growth of Legionella because they
operate with water temperatures of up to 35°C (temperatures in
the range of 20°C to 45°C favour the growth of aqueous
Legionella species) and also by holding high levels of organic
material and protozoa.
Approximately 2% of the water circulated in wet cooling systems
escapes outside the tower, as an aerosol, called drift, and in
some cases has been identified carrying Legionella several kilometres
from the source.
When combined with poor maintenance and under-dosing of biocide, these
systems can foster extensive growth of bacteria including Legionella
pneumophila. Below is a table from EWGLINET mapping Legionella
spp. cases involving cooling towers across Europe (click image for larger
version)
In Hong Kong an government EMSD study found that approx. 30% of cooling towers tested were in 'poor' condition, so the legionella risk is very real.
Legionella Tamar
Legionella Tamar - December 2011
In December 2011, Micheal Suen HKSAR Education chief contracted
Legionaires' Disease from the new HK$ 5.5 Billion dollar Tamar
Government Office complex and he was hospitalised.
Legionella Tamar 3 Jan. 2012
CHP report more positive test results. initially testing was focused on
the area around Micheal Suen's office (from a common tank I believe) on
11/F - 15/F cited by CHP as the source. Now in fact samples from both
wings, first floor to 23/F has a positive test results.
Legionella Tamar 4 January 2012
Director John Herbert is cited in the SCMP front page report about
the ongoing Legionella infection of the HKSAR governments flagship Tamar
building. Click image to enlarge.
It appears that private bathrooms were provided, and un-used water stagnated.
Legal and Regulations
In Hong Kong there are essentially three legal requirements, as follows:
1. Legionaires' Disease is a reportable disease in Hong Kong, and Government health department
issues brief report when a case is uncovered. Beyond that few details of the cases are
reported to the public.
2. In 2006 the Government introduced a code of practice, updated in dated in 2007, and in 2016 for design, operation,
and water treatment of cooling towers. part 2 operation, requires owners of cooling towers to
undertake independant cooling tower audit every
year, with the report issued to Government (EMSD), and the audit requires site inspection of
the facility and review of the records.
3. EMSD conducts water sampling of cooling towers in Hong Kong, and will issue public
notice when legionella is found. Although common, there is no reporting mechanism
for legionella discovered in water storage tanks at present.
What Next? Call us to order a Legionella audit today!
