Legionnaires Disease Outbreak Hong Kong update 18 Feb 2020


Two (2) more Legionnaires Disease infections were reported on 18-2-2020, bringing the total number of Hong Kong cases to twenty two (22) and sixteen (16) of those reside near Choi Hung. The new cases report by CHP include:

  1. A male patient, aged 94 with underlying illness, who lives in Hung Shek House, Ping Shek Estate, Kwun Tong
  2. A female patient, aged 52 with underlying illness, who lives in Block 2, 22 Wing Ting Road, Ngau Chi Wan (Fire Service Married Quarters)
Legionnaires Disease Outbreak Location Map

The CHP report [link] lists fourteen (14) cases, attributing two cases (12 and 13) as residing in a different area, although physically close to the Choi Hung area, approx. 1000m from the buildings implicated in Choi Hung, Kowloon.

In earlier CHP reporting it’s noted that the Choi Hung MTR station has four cooling towers samples were taken before they were disinfected on 4 and 12 Feb 2020. And these match specimens from six (6) patients in the Choi Hung Area.

The novel coronavirus covid19 epidemic has increased awareness and heightened surveillance in Hong Kong. Since both diseases present with similar symptoms and both involve pneumonia, further Legionnaires Disease infections will be detected and diagnosed in the coming months.

legionella, legionnaires disease outbreak, Choi Hung, Ping Shek, cooling towers, Kowloon, pneumonia, Hong Kong

previous update:

Legionnaires Disease Outbreak Hong Kong update 17 Feb 2020

CHP reported one (1) additional Legionnaires Disease case on 17-2-2020, including the two nearby Kwun Tong cases, that brings the total number of cases to fourteen (14) so far in the Choi Hung and Ping Shek area. As reported by CHP all 14 cases involve persons with unspecified underlying illness.

The new case is a 72 year old male residing in Kam Shek House, Ping Shek Estate, the same building as previous case numbers 4, 5 and 8 (refer to map) reported more than ten days ago, that’s significant because the incubation period is normally 2-10 days.

Given the typical 2-10 day incubation period, this gentleman probably contracted the disease between 7 and 15 Feb. 2020, which is after the date CHP reported the Choi Hung MTR cooling towers were allegedly disinfected on the 4 Feb. 2020.

So far CHP has reported that six (6) cases match the specimens taken from the Choi Hung MTR station cooling towers before 4-2-2020, the exact date is not clear.

And MTR staff were witnessed working on one set of the Choi Hung MTR cooling towers on Sunday 16-2-2020, near the Leung Chung road / Ngau Chi Wan village sitting-out area (refer photo below)

Legionnaires Disease and novel coronavirus covid19 have similar presentations, considering the heightened surveillance and awareness surrounding the novel coronavirus covid19 it is inevitable that previously undiagnosed and unreported cases of Legionnaires Disease will be also be discovered.

Additional Hong Kong Legionnaires Disease Cases

In addition to the ongoing Choi Hung / Pink Shek outbreak, three (3) new cases were reported on 17-2-2020 residing in different areas of the city.

  1. A male patient, aged 56 with underlying illnesses, who lives in 1H Sands Street, Central and Western District (Kennedy Town)
  2. A male patient, aged 85 with underlying illnesses, who lives in Ma Tong Tsuen, Chuen Lung, Tsuen Wan;
  3. A male patient, aged 52 with underlying illnesses, who lives in 7 Sau Fu Street, Yuen Long.

Outside Choi Hung, there are six (6) cases in total with no apparent connection to the Choi Hung Outbreak. However, it must be said that the CHP reporting is vague.

legionella, legionnaires disease outbreak, Choi Hung, Ping Shek, cooling towers, Kowloon, pneumonia, Hong Kong

previous update:


Legionnaires Disease & the Built Environment

Legionnaires Disease Oubreak in Cold Weather

There are countless poorly informed commentators that promulgate the myth that Legionnaires Disease is only warm-weather / summer time disease, it’s not, and never has been.

It’s winter in Hong Kong and we have an ongoing Legionnaires Disease Outbreak with patients admitted between 1 Feb. 2020 – 14 Feb. 2020 so far.

Lets assuming ten (10) day incubation period, what was the weather during that period of time? The Hong Kong Observatory records daily weather data, and the following minimum and maximum air temperatures were in recorded at Kwun Tong, the nearest weather station to the outbreak:

  • 22 Jan 2020 between 16.9 C and 24.4 deg C
  • 23 Jan 2020 between 19.8 C and 25.5 deg C
  • 24 Jan 2020 between 18.4 C and 22.6 deg C
  • 25 Jan 2020 between 17.9 C and 21.9 deg C
  • 26 Jan 2020 between 12.2 C and 20.1 deg C
  • 27 Jan 2020 between 9.8 C and 16.9 deg C
  • 28 Jan 2020 between 9.9 C and 16.4 deg C
  • 29 Jan 2020 between 10.1 C and 17.9 deg C
  • 30 Jan 2020 between 10.3 C and 17.6 deg C
  • 31 Jan 2020 between 11.7 C and 17.8 deg C
  • 1 Feb 2020 between 13.4 and 17.7 deg C
  • 2 Feb 2020 between 15.0 and 17.7 deg C

The HKO data shows the typical range of wintertime temperatures experienced during the cold weather season in Hong Kong.

In conclusion, the evidence demonstrates that during cold weather Legionnaires Disease outbreaks do occur, contrary to literature this disease is NOT limited to warmer climate conditions, and during the winter Legionnaires Disease cases, clusters, and outbreaks may occur.

HKO cold weather warning symbol

#legionella #outbreak #winter #legionnaires #disease #hongong

Legionnaires Disease Outbreak Hong Kong update 14 Feb 2020

Legionnaires disease outbreak

Update 2 14-2-2020 @ 21:35

CHP reported on 14-2-2020 that 6 out of the eleven (11) cases apparently match the sequence type identified in two of the four MTR Choi Hung station cooling towers, effectively confirming the MTR cooling towers are one source of the Legionella.

CHP also reports two further Legionnaires Disease SP1 cases on 14-02-2020 although attributing these new cases to a new cluster in Kwun Tong district.

  • A male patient, aged 56 with underlying illness, who lives in Choi Hay House, Choi Fook Estate
  • A male patient, aged 62 with underlying illness, who lives in Wang Kwong Building, 33 Ngau Tau Kok Road

These new two cases reside approx 1000m from the first eleven (11) cases, probably part of the same outbreak, a very popular wet market is located over the Choi Hung MTR station.

CHP link

Legionnaires disease outbreak

Updated 14-Feb-2020 @ 2:27 am

MTR Choi Hung Cooling Towers shutdown

One additional Legionnaires Disease case was reported by CHP bringing the total number of confirmed cases to eleven (11) cases, all located the area around the Ping Shek / Choi Hung estate area in Hong Kong [CHP link].

Legionnaires disease outbreak

The 11th patient is an 82-year-old male living in Kam Hon House that is very close to a previously reported case in the adjacent Kam Wan House, Choi Hung Estate.

MTR Cooling Towers Implicated

CHP reports that three (3) out of the four (4) cooling towers at the Choi Hung MTR station had Legionella Pneumophilia count above the action level!

Presumably, 1,000 cfu/ml, however, no data is given in the CHP report, and the Legionella outbreak is not mentioned on the EMSD website, the MTRC website or in local media (checked 1:10 am on 14-2-2020).

In the CHP press release at 23:55 PM on 13-3-2020, CHP recommended closing and disinfecting all the cooling towers today (13-3-2020) due to the high Legionella pneumophilia count in the samples collected before the first disinfection on 4 February 2020. Remember that the first CHP report issued on 1 Feb 2020 confirmed four cases in that area [CHP link].

12 Feb 2020

updated 12-2-2020 7.22 pm

Still no reporting in the media, and also no update from CHP so far.

11 Feb 2012 (first published)

Legionnaires disease outbreak

Whilst the novel coronavirus attracts headlines, Hong Kong has a Legionnaires’ disease outbreak in progress, centered around Ping Shek/Choi Hung Estate, Hong Kong.

Legionnaires’ Disease is a serious, pneumonia type illness ( learn more about Legionella )

There are ten confirmed cases so far, all are reported to be living near the Ping Shek/Choi Hung Estate area of the city, and confirmed cases within the last eleven days.

Legionnaires disease outbreak

There are also three other confirmed Legionnaires disease cases, one located in Lee Uk Tsuen, one located in Tung Tau Tsuen, Yuen Long, and one in Deep Water bay Road, which has not been connected to the main cluster so far.

CHP update 11-2-2020 [ link ]

legionella, legionnaires disease outbreak, Choi Hung, cooling towers Kowloon, pneumonia Hong Kong

Legionella Outbreak caused by Retail Display Hot Tubs Again

In the US, the North Carolina Department of Health and Human Services released its final report into an outbreak of Legionnaires’ disease that occurred 6 – 15 Sept. 2019.

This outbreak caused 136 confirmed cases of the disease, with four fatalities.


This outbreak was surely predictable and preventable, there are countless examples of hot tubs / spas / etc. filled with water in retail display setting often during trade shows causing Legionnaires’ disease outbreaks, some examples:

1999 – Trade Show Display, Kappellen, Belgium

1999 – Retail display at Flower show, Netherlands https://www.ncbi.nlm.nih.gov/pubmed/11749746/

2002 – Retail Display, Bagshot, Surry

2012 – Retail display, Stoke on Trent, UK https://www.ncbi.nlm.nih.gov/pubmed/22995431

#legionella #preventable #legionnaires #hottub #spa

BEAM PLUS Neighbourhood v1 by John A. Herbert


Neighbourhood v1 is the new member of the BEAM suite of rating tools, this tool unlike it predecessors, which examines the final project, Neighbourhood is specifically designed to assess and rate the master planning stage. If the master plan changes another assessment is required.

If you are familiar with BEAM family and NB, you will recognise framework and credits structure, indeed twenty of the credits listed in the following table are similar to (almost copied from) BEAM NB v1.2 credits

About the Author

John A. Herbert is a veteran professional with more than 30 years solid construction experience, educated in the United Kingdom he has been working across Asia for the last two decades, serving international, and local companies. And involved with the development of Hong Kong Green Building for a decade. He is a Hong Kong Registered Energy Assessor (REA), and a BEAM Professional.

BEAM Neighbourhood BEAM Pro

Green but not the colour for cooling towers by John A. Herbert

The world is catching on, the Green Building concept, where Green equates with Good, but not for cooling towers. Cooling towers need to be audited every year in Hong Kong, here is an example of a very poor Hong Kong cooling tower, with algae covering the entire floor of the cooling tower cell1 and cell2 … Legionella risk: severe

Kelcroft conducts the annual EMSD cooling tower audits in accordance with EMSD code for annual audit requirements, call the experts today.

About the Author

John A. Herbert is a veteran professional with more than 30 years solid construction experience, educated in the United Kingdom he has been working across Asia for the last two decades, serving international, and local companies. And involved with the development of Hong Kong Green Building for more than a decade. He is a Hong Kong Registered Energy Assessor (REA), and a BEAM Professional.

Seven dead, 86 infected as New York officials identify and disinfect cooling towers filled with Legionnaires bacteria

Legionella risk assessment

The Washington Post USA (http://tinyurl.com/ofmzeme) reports that so far the New York city Legionella outbreak has claimed the lives of seven (7) people, and eighty six (86) people are sick after contracting Legionairres’ Disease, probably from an infected cooling towers.


Update 20 August 2015

Since the original reports regarding the New York City Legionella outbreak report above, the death toll has risen to twelve (12) people, with more than 100+ diagnosed with Legionnaires’ Disease.

During the course of the outbreak it transpired that New York City USA, lagged behind Hong Kong, with administrators having no legislative powers for monitoring and enforcing cooling tower operations, that changed on 19 August 2015 when the NY Mayor pushed through legislation [link] requiring improved cooling tower operation and maintenance.

During the course of this legionella outbreak apparently five (5) cooling towers were discovered with Legionella contamination, although the precise source of this outbreak has not been established.


Legionella cases under reported

by John A Herbert

legionella under reported hong kong

In Hong Kong a case of Legionnaires’ disease (LD) affected a man aged 62. The government reported (1) that the patient, with underlying illnesses, presented with fever, headache, cough with sputum and shortness of breath 7 July 2014 and was admitted to Queen Elizabeth Hospital on 8 July  for management. His clinical diagnosis was pneumonia and he was discharged on 15 July in stable condition.

24 July 2014

Nine (9) days after the patient was discharged, the positive for Legionella pneumophila serogroup 1 antibody was reported (according the government on 24 July 2014) and ONLY then can the Legionnaires’ disease (LD) investigation commence. This case adds to the evidence that Legionnaires’ disease is often mis-diagnosed as pneumonia.

Risk Management

Legionella is a potentially fatal disease and building owners need to be vigilant.


  1. http://www.news.gov.hk/en/categories/health/html/2014/07/20140724_182119.shtml
  2. http://www.chp.gov.hk/en/view_content/35733.html

Kelcroft’s John A. Herbert WSD lecture on Legionella

green building consultant John Herbert Hong Kong Legionella prevention

Kelcroft’s director John A. Herbert conducted a Legionella briefing for Hong Kong’s Water Services Dept. (WSD) on 7th March 2012 with assistant directors attending. The Q&A, always the most interesting part in my view, covered all aspects of water storage and distribution.

Relevant Links:
4 Jan 2012 –  Kelcroft’s director John A. Herbert interviewed for South China Morning Post news regarding Legionella