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Legionnaires Disease And Legionella in Hong Kong

John A. Herbert
John Herbert
Legionella Risk Assessment

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.

Centre: John Herbert - Legionella Prevention Symposium December 2003
Hong Kong Legionella Conference John Herbert

Hong Kong Legionella Cases Rising

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)

John Herbert

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.

Legionnaires Disease Outbreak Feb 2020

Breaking news - February 2020 devleoping Legionnaires Disease outbreak around Choi Hung, Hong Kong.


Legionnaires Disease 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 consultant, John A. Herbert

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.

John Herbert, Legionnaires Disease, Tamar, Hong Kong

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.

John Herbert, Legionnaires Disease, Tamar, Hong Kong

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!

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tags: legionella, Hong Kong, Legionnaires disease, longbeachae