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Legionnaires' Disease Hong Kong

John Herbert

A businessman figured 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 outbreak troubles 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.

Photograph: John Herbert Legionella Prevention Symposium Dec 2003, John Herbert in Centre  Hong Kong Legionella Conference (centre: John Herbert)


Hong Kong Legionella Cases Rising

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 every month, with many patients immediately treated with general antibiotics further masking the real number of cases.



Prevention 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 and is found in soil and compost.  In this case the government press release clearly states Legionella Pneumophila infection which is water, not soil based species.


Cooling Towers

Cooling towers are a known Legionella source. Many of the largest Legionella outbreaks have been traced to cooling towers because they provide the right conditions to harbour, breed, and disseminate Legionella into the community.

In Asia the open, bottle type cooling tower is 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, they then  provide opportunities for Legionella proliferation.

Wet cooling systems can favour the growth of Legionella by maintaining 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 aerosol, called drift, and in some cases has been identified 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)

click to view larger image

In Hong Kong an government EMSD study found that approx. 30% of cooling towers tested were in poor condition, so the risk is clear.


2011 Legionella Tamar

In December 2011, Micheal Suen HKSAR Education chief contracted Legionairres Disease from the new HK$ 5.5 Billion dollar Tamar Government Offices and was hospitalised.

legionella consultant, John Herbert, Kelcroft


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 Jan. 2102

Director John A. Herbert is cited in the SCMP front page report about the ongoing Legionella infection of the HKSAR governments flagship Tamar building. Click inmage to enlarge.





What Next?

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