NHS Legionella Report 2013

Cluster of Legionella longbeachae cases in Scotland

in September/October 2013

Report from a national Incident Management Team

Published June 2014

Acknowledgements The collaboration of those involved in this investigation is gratefully acknowledged. This includes Health Protection Teams, Environmental Health Teams, microbiologists, public analysts, the Growing Media Association and Horticultural Trades Association.

Health Protection Scotland is a division of NHS National Services Scotland.

Health Protection Scotland website: http://www.hps.scot.nhs.uk

Published by Health Protection Scotland, NHS National Services Scotland, Meridian Court, 5 Cadogan Street, Glasgow G2 6QE.

First published June 2014

© Health Protection Scotland 2014

Reference this document as: Health Protection Scotland. Cluster of Legionella longbeachae cases in Scotland in September/October 2013 Health Protection Scotland, 2014 [Report]

Contributing Authors: Alison Potts on behalf of the IMT

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Cluster of Legionella longbeachae cases in Scotland in September/October 2013 i

Table of Contents

Abbreviations -ii

1. Introduction 1

2. Background 2

2.1 Legionella bacteria and legionellosis 2

2.2 Legionnaires’ disease in Scotland 2

2.3 Legionnaires’ disease caused by L. longbeachae 2

3. Investigation 4

3.1 Timeline 4

3.2 Epidemiological investigation 6

3.3 Clinical microbiological investigation 9

3.4 Environmental investigation 11

3.5 Environmental microbiology investigation 13

3.6 AFLP typing 13

3.7 Whole genome sequencing 13

4. Risk management 15

4.1 Prevention of further exposure to hazardous agent 15

4.2 Care of cases 15

5. Risk communication 16

5.1 Communication with clinicians 16

5.2 Communication with the public 16

5.3 Communication with retailers 17

5.4 Communication with manufacturers 17

6. Discussion and conclusion 19

6.1 Discussion 19

6.2 Conclusion 22

7.Lessons learned and recommendations 24

7.1 Lessons learned 24

7.2 Recommendations 24

8. References 26

9. Appendices 27

9.1 Members of the national IMT 27

ii Cluster of Legionella longbeachae cases in Scotland in September/October 2013

AbbreviationsECDC European Centre for Disease Prevention and Control

ELDSNet European Legionnaires’ Disease Surveillance Network

ESS City of Edinburgh Council Scientific Services

GMA Growing Media Association

HPN Health Protection Network

HPS Health Protection Scotland

HPT Health Protection Team

HTA Horticultural Trades Association

IMT Incident Management Team

ICU Intensive Care Unit

NHS National Health Service

NHS NSS NHS National Services Scotland

PAG Problem Assessment Group

PCR Polymerase Chain Reaction

PHE Public Health England

PHNI Public Health Northern Ireland

PHW Public Health Wales

Sg1 Serogroup 1

SHLMPRL Scottish Haemophilus, Legionella, Meningococcus, Pneumococcus Reference Laboratory

TSS Dundee City Council Tayside Scientific Services

WGS Whole Genome Sequencing

Cluster of Legionella longbeachae cases in Scotland in September/October 2013 1

1. IntroductionIn the period August to September 2013, six confirmed and one probable case of Legionnaires’ disease caused by L. longbeachae were reported in NHS Lothian and NHS Tayside. The six confirmed cases were severely unwell and all required treatment in intensive care units, including ventilation. All cases survived. The majority of cases were keen gardeners and had exposure to growing media, soils and water in the garden during their incubation period. Prior to this cluster, eleven sporadic cases of Legionnaires’ disease caused by L. longbeachae infection had been reported to Health Protection Scotland, in the period 2008-2013. Given the unprecedented concurrent nature and close geographical proximity of these cases, an investigation was undertaken. Due to cases being identified in two NHS boards, the investigation was co-ordinated by HPS.1 This report details the investigation undertaken.

Members of the national IMT are listed in Appendix 1. This report has been approved by the IMT.

2 Cluster of Legionella longbeachae cases in Scotland in September/October 2013

2. Background

2.1 Legionella bacteria and legionellosis

Legionella bacteria are ubiquitous and are often isolated from water and soil samples. There are two forms of legionellosis, the illness caused by Legionella bacteria infection:

• Legionnaires’ disease (pneumonia characterised by fever, myalgia and cough); and

• Pontiac fever (a milder flu-like illness without pneumonia).

Legionnaires’ disease is recognised as an important cause of severe, sporadic community-acquired pneumonia. Pontiac fever is rarely reported outside outbreaks and is likely to be under ascertained. Pneumonias caused by Legionella species are not uncommonly associated with respiratory failure and thus have a relatively high mortality rate.

2.2 Legionnaires’ disease in Scotland

The detection of any member of the Legionella genus in a clinical sample by a microbiological laboratory has to be notified to the relevant NHS board and to Health Protection Scotland (HPS) under the Public Health (Scotland) Act of 20082. HPS undertakes enhanced surveillance of notified cases of Legionella infections in conjunction with NHS boards and the Scottish Haemophilus, Legionella, Meningococcus and Pneumococcus Reference Laboratory (SHLMPRL). The purpose of enhanced surveillance is to characterise the Legionella species causing infection and identify likely sources and exposures to the organism. Legionnaires’ disease is monitored by the European Centre for Disease Control (ECDC3) through the European Legionnaires’ Disease Surveillance Network (ELDSNet4). Guidelines on the management of outbreaks of Legionnaires’ disease have been developed by the Health Protection Network (HPN).5

The incidence of Legionnaires’ disease in Scotland is low. There are usually between 20 and 40 cases per year, the majority of who contract the infection overseas.6 Older age and male gender are both associated with increased risk, as are smoking and underlying respiratory disease. Cases range in severity from those who can be treated with antibiotics at home and make a full recovery, to those who require invasive ventilation for prolonged periods, to death. The mortality rate in Scotland is around 9%,7 which is slightly lower than that seen in the whole of Europe (10%).8 The majority of cases in Scotland are caused by L. pneumophila Serogroup 1 (Sg1).

There have been a number of outbreaks of Legionnaires’ disease in Scotland in the last few years. These include an outbreak associated with cooling towers in the south-west of Edinburgh and an outbreak of 12 cases in a residential area for which no source could be found, despite extensive investigation. In addition there was a significant outbreak of Pontiac fever associated with sports facilities in a hotel. All of these outbreaks were caused by different strains of L. pneumophila Sg1.

2.3 Legionnaires’ disease caused by L. longbeachae

L. longbeachae is an uncommon species of Legionella and like L. pneumophila, it can cause a wide range of symptoms from mild flu-like illness to acute atypical community acquired pneumonia and death. The major source of human infection is considered to be commercial growing media (soils and composts which are sold through garden centres and are a blend of some or all of: soil, peat, composted green waste, sand and minerals; used for growing plants) and other composted


materials such as bark and sawdust. Unlike other known strains of Legionella, L. longbeachae has rarely been identified in man-made water systems.9

Legionnaires’ disease caused by L. longbeachae may be missed or diagnosed late, as urine tests which are routinely used to identify most cases of Legionnaires’ disease do not detect L. longbeachae. Confirmed diagnosis of L. longbeachae infection requires culture of the organism from clinical specimens, whereas elevated specific antibody titre and detection by polymerase chain reaction (PCR) may be used to diagnose probable infection. These tests may not be routinely performed or available in routine diagnostic laboratories. The number of cases of Legionnaires’ disease caused by L. longbeachae in Europe is small but growing. However, in Australia and New Zealand up to half of Legionnaires’ disease cases are caused by L. longbeachae. Investigations into growing media in Australia have revealed that a large proportion of Australian growing medias are contaminated with Legionella bacteria10 – similar studies in other countries including the UK have corroborated these findings.11 A main difference between Australian and New Zealand growing media and those produced in Europe is that Australian and New Zealand growing media are made mostly from composted pine sawdust and bark, whereas in Europe growing media are mostly peat based.9 The proportion of peat and composted material in growing media in the UK is changing to support UK legislation13 to preserve peat resources. Peat is being replaced with composted green waste.

Bags of growing media in Australia and New Zealand are labelled with a warning about risk of exposure to L. longbeachae and advice to wear gloves and a facemask whilst handling the growing media.12 This labelling is described in industry standards which were introduced in 2003 (Australia) and 2005 (New Zealand). These standards are not statutory but there is widespread compliance. However, it is not clear that introduction of these standards has been effective, as there has been no decline in numbers of cases of Legionnaires’ disease caused by L. longbeachae, since their introduction.

Currently in the UK there is a British Institute of Standards for composted green waste – PAS 100.15 This standard states that:

“the following information about each consignment of conforming compost dispatched shall be printed on packaging or on a separate document supplied to the compost recipient ……..h) warning about product misuse, risks when handling and safety advice or symbols as appropriate;”

The Association for Organics Recycling recommends in their guidance on L. longbeachae16 that to meet the PAS 100 standard, a warning statement should be included in labelling which reads:

“SAFE HANDLING AND USE

Every effort has been made to ensure this compost contains no germs, sharp fragments, toxins or regenerative plant parts. However the compost producer cannot guarantee they will never be present. As with all products of this type, wear gloves when handling and wash hands after use. During handling avoid inhaling any dust or water vapour or droplets from it, or ingesting any of it”

Information from previous discussions with the horticultural industry suggests that general wording on a label may exacerbate liability issues and that a voluntary agreement to label products would be unlikely to be agreed among all manufacturers. This raises the issue as to whether labelling should be a statutory requirement.

The mechanism by which an individual can contract L. longbeachae infection from compost and growing media is not currently known but is assumed to be through inhalation of aerosolised dust or contaminated water.


3. Investigation

3.1 Timeline

This investigation was carried out from August to October 2013. The timeline below summarises the main events during the course of this investigation. Table 1 contains summary case characteristics and should be referred to when reading this section.

Week of 19 August 2013On 22 August Case 1 was confirmed by culture with L. longbeachae infection. Case 1 was male and in the ageband 80-90 years, who had been admitted to ICU in NHS Lothian on 18 August with community acquired pneumonia and a history of shortness of breath, haemoptysis and cough. This case required ventilation. This case has previously been treated in primary care, prescribed antibiotics and sent home. Investigation identified that this case was a keen gardener.

Week of 26 August 2013On 30 August Case 2 was diagnosed by culture with L. longbeachae infection. Case 2 was a 70-80 year old female who was admitted to ICU in NHS Lothian 22 August. This case had community acquired pneumonia with a history of diarrhoea and vomiting from one week before being admitted. This case required ventilation. Investigation identified that this case was a keen gardener.

Week of 2 September 2013On 5 September Case 3 was diagnosed by PCR as Legionella species positive. This case was a 60-70 year old male who had been admitted to hospital in NHS Lothian on 2 September with community acquired pneumonia. This case had previously been admitted to hospital on 29 August 2013 with community acquire pneumonia and discharged on 31 August following antibiotic treatment. On 2 September this case was admitted to ICU and required ventilation. This case was identified as a keen gardener.

Following this cluster of cases of the same organism in such a short period of time, NHS Lothian swiftly alerted HPS and local clinicians. On 6 September a letter was circulated to local clinicians and microbiological services increasing their index of suspicion. Case 3 was confirmed by culture on 6 September.

Week of 9 September 2013On 10 September Case 4 was diagnosed by PCR as Legionella species positive in NHS Lothian. This case was a 70-80 year old female who had been admitted to hospital in NHS Lothian on 7 September with community acquired pneumonia. This case was admitted to ICU and required ventilation. This case was identified as a keen gardener.

In NHS Tayside, Case 5 was confirmed by culture with L. longbeachae infection on 9 September. Case 5 was a 50-60 year old female, who was admitted to ICU with community acquired pneumonia on 3 September. This case was identified as a keen gardener. NHS Tayside informed HPS of this case on 11 September.


On 12 September NHS Lothian held a PAG and requested that HPS attend, who in turn invited NHS Tayside to participate. At this PAG it was agreed that an Incident Management Team (IMT) should be formed to investigate and manage this cluster of cases and given that more than one NHS board was involved, the role of co-ordinator was passed to HPS. HPS actions taken from this meeting involved sharing a modified enhanced surveillance form, starting a line listing and developing an outbreak database, developing case definitions, producing an alert for all NHS boards and developing reactive media lines.

Week of 16 September 2013On 16 September Case 6 was diagnosed as Legionella species positive by PCR at SHLMPRL, on a sample sent by NHS Tayside. On 17 September Case 6 was confirmed as L. longbeachae infection, by culture. Case 6 had been admitted to hospital in NHS Tayside with community acquired pneumonia on 13 September. This case was a 70-80 year old male, who also required ventilation in ICU. This case was not a keen gardener, but had recently spent time helping his wife digging and planting in their garden.

On 18 September, HPS chaired the first IMT, with NHS Lothian, NHS Tayside, relevant local authorities, local and reference microbiology services, Scottish Government and PHE in attendance. The main actions from this meeting were based around the environmental investigation being undertaken and tracing of growing media used by the cases during their two week potential incubation period.

Week of 23 September 2013Environmental Health Officers (EHOs) from the relevant local authorities met on 24 September to discuss best practice in respect to tracing growing media products, sampling methods and disposal of samples. Consensus was met and the need to develop a fuller sampling protocol following this investigation was agreed. A second IMT was held on 26 September.

Week of 30 September 2013A further IMT was held on October 2nd, where full clinical and environmental microbiological investigation results were discussed. No further cases had been identified for around two incubation periods following the date of onset of Case 6. It was agreed that no further investigation was required, but a further meeting including a de-brief session should be held when remaining details had been finalised.

Week of 7 October 2013Case 7 was identified in NHS Lothian. This case was male aged 50-60 years and was treated for pneumonia by his GP, in the community. This case was a keen gardener. The GP requested blood for immunological investigation after reading about the cluster of cases – the first serum sample had elevated titre, so this case was diagnosed following successful antibiotic treatment. A number of repeat blood samples were taken to identify a four-fold change in titre (decrease from 1:128 to 0) for this case.


Week of 25 November 2013A final IMT was held on 27 November, when the investigation was summarised and final results collated. The IMT was officially closed. It was agreed that Case 7 should be included in the cluster as a probable case. A de-brief session was held.

3.2 Epidemiological investigation

The epidemiological investigation for each case was undertaken by Health Protection Nurses within NHS Lothian and Tayside Health Protection Teams and by EHOs in the relevant local authorities. Following the submission of the standard legionellosis surveillance form, a trawling questionnaire developed by HPS following the IMT investigation into cases of L. longbeachae investigation in 201212, was administered to the case or if they were still severely unwell a close relative, followed up by a further interview when the case was fit enough to respond personally. This trawling questionnaire was used for the first time in this investigation. Additional questions were added to this form following its use for the first two cases. This form contained questions about water, soil and growing media exposures, types of gardening activity and hand hygiene practice in the garden and following gardening. Completed forms were sent to HPS who collated them, entered them into an outbreak database and reviewed descriptive epidemiology, which was subsequently reviewed by the IMT. The main case characteristics are detailed in Table 1.

3.2.1 Case definitionsThe case definitions (corresponding to ECDC case definitions) used by the IMT were:

Confirmed case

• clinical or radiological evidence of community acquired pneumonia with disease onset on or after 1 August 2013 AND

• evidence of having been exposed in Scotland to horticultural growing media (including composted material produced locally or domestically) in the 14 days prior to the onset of symptoms AND

• isolation of Legionella longbeachae from respiratory secretions

Probable case



• detection of Legionella species specific nucleic acid in respiratory secretions (accompanied by a negative urinary antigen test), or a detected change in Legionella longbeachae serum antibody levels of at least fourfold, or a single high titre of Legionella longbeachae serum antibody

Possible case




• no current microbiological evidence as to the causal agent

3.2.2 Descriptive epidemiologyThis cluster of cases, for the purposes of investigation, was treated as a single All-Scotland cluster as all cases were linked to the same time period. However, it is acknowledged that in space, there were two separate clusters, one within Lothian and the second within Tayside.

Distribution by case definitionThis cluster consisted of seven cases, including six confirmed cases and one probable case.

Distribution by severity of illnessAll confirmed cases were severely unwell and required hospitalisation and ventilation in ICU. The probable case had milder illness and was treated in the community by primary care. All cases survived. Further details are available in Table 2.

Distribution by age/sexThe cases included three females and four males. The mean age was 67.7 years (range 50-90 years). The median age was 71 years.

Distribution by placeCases were in two NHS board regions – NHS Lothian and Tayside. Cases were distributed across four local authority areas – Angus, East Lothian, Edinburgh City and West Lothian. Five of the cases were retired and were not exposed to high or medium risk sources outside their own home and garden.5 The cases were not known to each other and had not visited the same places.

Table 1: Summary of case characteristics

Number of cases

Case typeDate of onset

Sex Age Organism Smoker?Relevant hobbies

76 confirmed

and 1 probable

11/08/2013 to

11/09/2013

4 male and 3 female

50-90 yearsLegionella

longbeachae 1

2 smokers3 ex-

smokers2 non-

smokers

Gardening

Table 2: Summary of dates of onset, admission and reporting of cases

Number of cases

Case typeDate of onset

Date of admission

Ward typeLength

of stay in hospital

Date reported

Days from onset to diagnosis

76 confirmed

and 1 probable

11/08/2013 to

11/09/2013

18/08/2013 to

13/09/2013

6 ICU (1 not hospitalised)

11-43 days23/08/2013

to 10/10/2013

7-16 days for those hospitalised

30 days for case not hospitalised


Distribution by date of onset The epidemiological curve by date of onset is presented below in Figure 1. Cases were clustered over a calendar month, between 11 August and 11 September 2013.

Figure 1: Epidemiological curve for this cluster of L. longbeachae cases (by date of onset)

0

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/2013

Distribution by risk factors5/7 cases had significant morbidity and underlying risk factors which may contribute to underlying immunosuppression (for one case risk factors were not known).

One case was a smoker, three were ex-smokers and one was an occasional smoker. Two cases were not smokers.

Distribution by potential exposurePotential exposures were categorised as:

• travel and stay away from home;

• hospitalisation;

• Jacuzzi/whirlpool spas;

• Showers;

• Use of water sprays in the garden;

• Use of soils/growing media/composts/manures/bark/mulches;

• Handling of recently purchased plants.

Lifestyle and occupationNone of the cases had a stay away from home, through travelling or in hospital, in the two weeks prior to onset. None of the cases had used a shower other than that in their own home; and none of the cases had used a Jacuzzi or whirlpool spa in the two weeks prior to onset. None of the cases reported recent works on the water systems within their homes.

All cases were interviewed about potential exposures to water, growing media, soil and other garden products in their home and garden. All seven cases had spent time in the garden or outdoors in the two weeks prior to onset. 4/7 cases had exposure to water spray in the garden – this included use of garden taps, hoses and electric garden fountains. One case had an irrigation


or sprinkler system, which was located in a potting shed. No cases collected rainwater in butts for use on the garden.

There is evidence to suggest that dripping hanging baskets can increase risk of legionellosis.14 4/7 cases had hanging baskets which hung outside. For 2/4 cases, these hanging baskets dripped when they were watered.

Use of growing media and related gardening practicesPossible infection pathways from a contaminated source (growing media) to case were hypothesised. The route of infection might include a case breathing in growing media dust or contaminated water vapour whilst handling contaminated growing media. It is likely that handling growing media indoors or in an enclosed space can lead to a build up of contaminated aerosol/particles around the user. Alternatively it is possible that contaminated growing media could be passed from hand to face/mouth/nose where it is inhaled (or ingested).

6/7 cases had recently bought growing media and had used it in the two weeks prior to onset. No cases had used farm produced compost or manure. One case had a garden compost heap, but had not disturbed the heap during the two weeks prior to onset.

6/7 cases used growing media/potted outside; one case used growing media/potted in the greenhouse/potting shed; and 2/7 cases used growing media/potted in the house. 4/7 cases wore gloves whilst using growing media. No cases wore a mask whilst using growing media. 5/7 cases had access to hand washing facilities close to where they worked with growing media; and washed their hands before undertaking other activities. 2/7 cases ate, drank or smoked whilst undertaking gardening activities.

Analytical studyNo analytical study was undertaken in relation to this cluster. This was discussed at IMT meetings, but the number of cases was deemed too small.

3.3 Clinical microbiological investigation

All local diagnostic laboratories in Scotland provide urinary antigen testing for Legionella, which will detect L. pneumophila Sg1; and all provide a culture service and refer Legionella isolates to SHLMPRL for further characterisation. One diagnostic laboratory (NHS Lothian Department of Laboratory Medicine, based at the Royal Infirmary of Edinburgh) also uses two molecular screening tests for Legionella – specifically PCR for L. pneumophila and a second for Legionella species (that is all species except L. pneumophila). These tests were introduced in 2010.

SHLMPRL provides a reference service for samples from across Scotland. For cases of Legionnaires’ disease to be confirmed in Scotland all positives are verified by SHLMPRL. Specific tests offered by SHLMPRL include: a variety of urinary antigen tests; PCR tests specific for L. pneumophila Sg1, other L. pneumophila serogroups and Legionella species (all species except L. pneumophila); serology testing with a wide range of species specific antibodies; and strain typing.

It is well recognised that L. longbeachae cases test negative with urinary antigen testing, which may be used by some clinicians as a test to rule out legionellosis. Diagnosis of L. longbeachae infection requires respiratory samples (for example sputum or broncho-alveolar lavage) to test positive for Legionella species by PCR or culture; or for blood samples to have an elevated titre


to L. longbeachae specific antibody. Following urinary antigen testing which is negative, additional samples may not be requested. Clinical microbiology testing results are summarised in Table 3.

Detection in NHS LothianCases 1-4 were detected in NHS Lothian principally though the PCR screening test employed in the diagnostic laboratory. Samples taken early in the hospital stay for each case met the laboratory criteria for testing of lower respiratory samples by PCR (community acquired pneumonia, severe illness, unknown exposure) and tested positive for Legionella species. In all cases, samples were forwarded to SHLMPRL for confirmation and any remaining sample was cultured. Colonies obtained by culture were characterised by SHLMPRL. The positive PCR test informed the clinical management of the cases before confirmation of strain species was available. These cases may not have been identified if this PCR test was not used in the local diagnostic laboratory.

Case 7 was detected after recovery from illness using serological confirmation. It is likely that this case would not have been detected if information materials had not been circulated to NHS Lothian primary care clinicians.

Detection in NHS TaysideCases 5 and 6 were detected in NHS Tayside though culture and additionally for Case 6, by PCR for Legionella species at SHLMPRL. At the time of this cluster, NHS Tayside did not use Legionella PCR tests. Instead in cases of severe community acquired pneumonia, where possible, samples are taken for a broad range of bacterial culture. In these cases, positive cultures were sent to SHLMPRL for characterisation. Culture positivity informed clinicians of treatment options.

Characterisation at SHLMPRLAll positive PCRs, cultures and sera pertaining to these cases were forwarded to SHLMPRL for further characterisation. Results are summarised in Table 3.

Table 3: Summary of clinical microbiology testing results for cases

CaseUrinary

antigen testL. pneumophila

PCRLegionella

species PCRCulture

Serology (L. longbeachae specific antibody response)

Organism

1 negative negative positive positive four-fold riseL. longbeachae serogroup 1



4 negative negative positive positive single high titreL. longbeachae serogroup 1

5 negative negative * positive *L. longbeachae serogroup 1

6 negative negative positive positive single moderate titreL. longbeachae serogroup 1

7 negative * * * four-fold fallL. longbeachae serogroup 1

(* = test not undertaken)


All cases were identified as having L. longbeachae Sg1 infections. All tested negative by urinary antigen testing and by L. pneumophila specific PCR (where tests were undertaken). Where tested, all Legionella species PCR was positive. Where tested all showed elevated titres to L. longbeachae specific antibody.

3.4 Environmental investigation

Environmental investigation was undertaken by EHOs within the relevant local authorities. In some instances, EHOs interviewed cases and completed the trawling questionnaire.

EHOs undertook a risk assessment of cases’ homes and garden with respect to water and soil / growing media / compost exposures. Where a risk was identified, if possible a sample was taken for microbiological analysis. Results of the investigation and sampling are summarised in Table 4.

Field investigation of cases’ homes and gardensVisits were made to the homes of cases, and for one case in addition their own holiday home where they had stayed during their incubation period. The water systems within homes were investigated and deemed low risk for all cases. No domestic hot and/or cold water samples were taken.

All cases had relevant exposures within their gardens. However, for one case this was deemed low risk as no water, soil, growing media or compost had been handled. Water sources within gardens were investigated and deemed low risk for a further two cases. For four cases, aerosol producing water sources had been used within the garden (garden hoses and garden fountain). However, as the water source was mains cold water, this was deemed low risk and no water samples were taken. For 6/7 cases, bagged shop-bought growing media had been handled directly in the two week incubation period, in some cases together with garden soil or bark mulch. Where bagged growing media remained, the bag was removed and samples provided for microbiological testing. In one case, all growing media that had been handled had been dug into the garden as soil improver around newly planted shrubs. In this instance samples of soil/growing media mix were taken from the ground at the site of planting.

All cases who had used bags of growing media in the two weeks prior to onset, had stored the bags in the period between purchase and use. 5/6 cases had stored the bags of growing media inside (the house) or undercover (garage, garden shed, greenhouse or polytunnel).

Tracing of products from retail outletsCases provided details of purchase of the bagged growing media, including rough dates and place of purchase. All products were bought at different times in the period end of July to mid-September and from different premises. EHOs used the packaging and barcode to identify manufacturer and sites of manufacture. Five different manufacturers were identified, in five different sites based in England, Scotland, Northern Ireland and Ireland. Manufacturers were contacted to identify dates of production and composition of the growing media.

The IMT agreed that as no single site was implicated, further investigation into sources of composted material (which was the most likely source of L. longbeachae contamination)12 was unnecessary, as it is understood that composting sites supply to local growing media manufacturers, due to high transport costs for this product.12


Table 4: Summary of results of environmental investigationC

ase

Wat

er s

amp

les

fro

m h

ou

se

Wat

er s

amp

les

fro

m g

ard

en

So

il/ g

row

ing

med

ia/ c

om

po

st

sam

ple

s ta

ken

Gro

win

g m

edia

bra

nd

(s)

Ret

ail o

utl

et

Man

ufa

ctu

red

wh

ere?

Co

mp

osi

tio

n

Gro

win

g m

edia

tes

t re

sult

s

Sto

rage

of

gro

win

g m

edia

at

ho

me

pri

or

to u

se

1 No No Yes

1. Topsoil

2. General purpose compost

Large chain garden centre

Northern Ireland

1. Topsoil: Mixture of soil and a small percentage (not specified) of composted tree bark from local Northern Ireland supplier. 2. Compost: Mixture of peat, woodfibre (produced by manufacturer), lime and fertiliser.

1. Topsoil: L. longbeachae serogroup 1 isolated.

2. Compost: negative.

yes, stored in house

2 No No Yes

Multi-purpose Compost

Independent garden centre

England Mixture of composted bark fines (45%), retail grade peat (20%), green compost (35%), Dolodust (0.05 %), base nutrients (0.24%), wetting agent (0.06%).

Manufactured on 6 November 2012. Suppliers of green compost are all local and in England or Scotland.

L. longbeachae serogroup 1 isolated

yes, stored in garden shed

3 No No Yes

Multi-purpose Compost


Scotland Composition unknown. Manufactured on 28 May 2013. Single local source of green compost.


yes, stored in garage

4 No No No - - - - - -

5 No No Yes

1. Fruit and vegetable compost

2. Bark mulch


1. Scotland

2. Bark mulch: manufacturer unknown

1. Fruit and veg compost: mixture of peat, wood fibre, green compost, Dolomitic lime, inorganic nitrogen and phosphorus.

1. Compost: L. longbeachae serogroup 1 isolated

2. Bark mulch: tested negative

yes, stored in greenhouse

6 No No Yes

Multipurpose compost - all media in bag dug into soil at site of new planting, samples taken from this site (soil/compost mixture)


Ireland Mixture of moss peat, green compost & coir, Dolomitic lime, wetting agent.Green compost produced by manufacturer.


yes, stored in polytunnel

7 No No Yes

Enriched compost


England Mixture of green compost, woodfibre, composted bark fines, coir, fertilisers and limestone.

Manufactured on October 2012. Green compost supplied by local producer.

Tested negative

yes, stored in garden shed


3.5 Environmental microbiology investigation

Samples of growing media and other garden samples taken from the homes of the cases were sent to Edinburgh Scientific Services (ESS) or Tayside Scientific Services (TSS) for microbiological testing. The main test employed by the laboratories is microbiological culture – a test which can take up to ten days to complete (given the number of bacteria present in a sample can be very small). In addition, ESS also employs PCR tests for detection of the presence of Legionella; specifically these are separate tests for L. pneumophila and Legionella species.

Where PCR results were positive or where colonies were obtained, these were forwarded to SHLMPRL for further characterisation. SHLMPRL employs a number of sensitive molecular techniques (including PCR techniques) which the scientific services do not and in some cases worked directly on the environmental samples in order to better characterise them.

The samples taken and summary of results is given in Table 4.

For testing of growing media and other garden samples, five out of eleven samples tested were positive for L. longbeachae Sg1. This equates to five samples linked to five confirmed cases. In each matched pair of clinical and environmental samples, the same strain of Legionella (L. longbeachae Sg1) was identified.

3.6 AFLP typing

All isolates were investigated using AFLP (amplified-fragment length polymorphism) typing at SHLMPRL. This technique uses PCR to amplify specific sections of the organism genome, which are then sequenced fully and the sequencing compared for homology. This technique is usually applied to L. pneumophila genome and there is very little information available for L. longbeachae genome comparison. This means that interpretation of these results for L. longbeachae is difficult.

This typing indicated that there were three types of L. longbeachae Sg1 (AFLP types 1, 2 and 3), as had been seen before in Scotland in samples from previous cases. Where clinical and linked environmental samples were available, in all cases the same AFLP type was identified for the case and the compost they had been exposed to during their incubation period.

3.7 Whole genome sequencing

The L. longbeachae isolates from the patients in this cluster and from the growing media linked to them were subjected to whole genome sequencing (WGS). This work was carried out at Edinburgh University by Professor Ross Fitzgerald in collaboration with SHLMPRL. Three or four separate isolates from individual patients were included where they were available; it was desirable to do this also for multiple isolates from the same bag of growing medium but they were not often available. A number of other Scottish isolates of L. longbeachae obtained by the SHLMPRL in the last ten years were also included. In the analysis of a cluster of cases WGS can be regarded primarily as a fine typing method, with great discriminatory power but it also has considerable ability to help elucidate the population structure of L. longbeachae.

Considerable diversity is seen among the isolates with a complex population structure showing many subgroups. Wherever multiple isolates from the same patient were sequenced they were shown to be almost completely identical. This is an important control observation as it validates the dataset and confirms that a single strain is responsible for causing disease in each patient.


The isolates from this cluster are no more closely related to each other than to other Scottish isolates in the last ten years and the information available suggests that the Scottish isolates are themselves a diverse collection. Additionally we have not found any close relationship between patients’ isolates and those from the samples of growing media that they had been working with. Whatever the cause of the cluster it does not appear to be due to the emergence of a new strain in commercially produced growing media.


4. Risk management

4.1 Prevention of further exposure to hazardous agent

Based on the epidemiological investigation (which identified 6/7 cases with exposure to recently purchased growing media) and the microbiological investigation (which identified the same species of Legionella in the patient and the growing media they were exposed to in 5/6 of these cases), the IMT agreed that this exposure was high risk for this infection for these cases. However, the environmental investigation did not identify a common retail outlet, a common manufacturer, a common manufacturing site or a common source or components used in the manufacturing process. Aside for providing general hygiene advice for user of growing media, the IMT took no further action in terms of preventing further exposure to sources of the hazardous agent as it appeared to be present in multiple sources.

Although this cluster was unprecedented in Scotland in terms of the number of concurrent cases, the overall risk of illness remains low. The incidence in 2013 was 1.64 cases of L. longbeachae infection per million population in Scotland (up from the annual incidence of less than 1 case per million population in Scotland for the years 2008-2012). Given the volume of growing media products and compost sold and the large number of gardeners in Scotland, the risk of being infected with this organism following exposure to contaminated growing media appears to be very low.12

4.2 Care of cases

The six confirmed cases were all severely unwell and required intensive care and ventilation. Periods of stay in hospital are detailed in Table 2.


5. Risk communication

5.1 Communication with clinicians

Following the identification of the first three cases, NHS Lothian circulated a letter to local clinicians, which detailed that three cases of unusual Legionnaires’ disease had been identified concurrently, caused by L. longbeachae. Symptoms were detailed and links with gardening and exposure to growing media were indicated.

Following the PAG on 12 September, HPS sent out a briefing note to all NHS board HPTs detailing the NHS boards affected, symptoms, microbiology testing results and types of test and samples to submit. This briefing note also provided general advice about garden hygiene and case definitions for the suspected outbreak. It was requested that HPTs consider cascading the briefing note to all clinicians and to local authority Environmental Health Teams. This briefing note was also forwarded to PHE, PHW, PHNI and CMO Office in Scottish Government. ECDC was also informed by email to the ELDSNet Team. No European Alert was issued due to the local nature of the cluster and suspected source(s). In addition, on 12 September, NHS Tayside sent a letter to local clinicians with details of the cluster, symptoms, illness identified as slow onset of respiratory illness and links with gardening and exposure to growing media were indicated.

A further briefing note was sent to all NHS boards HPTs following the first IMT meeting chaired by HPS on 18 September. In this note, a situation update was provided; updated general advice about garden hygiene; and actions for cascade to local authorities and microbiology departments; and points of contact within HPS for epidemiological and environmental investigation co-ordination.

No further communications were sent to clinicians.

5.2 Communication with the public

HPS did not receive any direct enquiries from members of the public. Following the PAG on 12 September, HPS, NHS Lothian and NHS Tayside prepared a press release which highlighted the cluster of cases in NHS Lothian. This was released by NHS Lothian. This press release also indicated that this type of infection was known but rare, and highlighted the importance of general good hygiene practice whilst gardening. No further specific risks could be highlighted as there was no common retail outlet, product or manufacturer.

At the IMT on 18 September, it was agreed that HPS would be the principal contact for information about the cluster and would handle national press enquiries. Any specific queries about cases were referred to the appropriate press departments in NHS Lothian or NHS Tayside.

Following the proactive press release on 13 September there was significant media interest in this cluster of cases. The IMT Chair, Dr Martin Donaghy, gave interviews with BBC and ITV news. Reporters from national and local papers rang HPS for further information.

Following every IMT, the press statement was revised and updated. However, following the initial proactive release by NHS Lothian on 13 September, all following revisions of the statement were reactive only. Following revision of the press statement after the IMT, it was circulated to all IMT members to ensure consistency of message across NHS Boards and local authorities.


5.3 Communication with retailers

Following the press release on 13 September, HPS was approached by a major garden centre chain, who wanted to provide their customers with reassurance for purchases of growing media. HPS prepared a short paragraph highlighting good garden hygiene with respect to growing media handling, see Figure 2 below. This statement was provided without HPS or NSS branding, so that retailers could amend wording and add their own branding.

The garden centre chain was content with this statement and displayed it at cash till points throughout their garden centres.

It was agreed by the IMT that this statement for proactive use only and would be shared with other retailers only if they approached HPS for advice. No other retailer did this.

5.4 Communication with manufacturers

Following development of text highlighting general garden hygiene for use by retailers (see Figure 2) this was shared with representatives of the Growing Media Association (GMA). The GMA had been in touch with NHS Lothian HPT and local authority EHOs during the course of the environmental investigation, to offer full support and collaboration in terms of tracing products and manufacturing sites with their member manufacturers. The text developed for retailers was shared with the GMA after it had been released to the major garden centre chain.

Figure 2: Text developed for retailers to display at point of sale of growing media

Gardening Good Hygiene

A few simple good hygiene tips can help you during gardening:

• Wear gloves.

• Wear a dust mask if you are working on anything dusty, particularly indoors.

• Wash your hands as soon as you finish.

• If you are going to smoke, wash your hands before doing so.

Storing and Handling Compost, Potting Mix, Mulches and Soil

As well as the general advice above, the following advice can help you avoid breathing in dust:

• Store compost, potting mixes, mulches and soil in a cool place, away from the sun.

• Open any bags carefully in a well ventilated area and if possible using a safety blade or sharp knife.

• Keep the door or a window open in greenhouses or sheds when potting-up plants or filling hanging baskets.

• Wear a dust mask if you are working on anything dusty, particularly indoors.


The GMA strongly disagreed with the lines in the HPS advice detailing use of a mask in certain circumstances. The GMA felt this was “strongly disproportionate to the risk, and possibly even alarmist”. The GMA followed this with release of a statement to the members of the Horticultural Trades Association (HTA), highlighting general garden hygiene and not including details about wearing a mask. The GMA statement is detailed in Figure 3.

Figure 3: Statement released by the GMA to members of the HTA

Legionella longbeachae in Growing Media

There have been reports of five more cases of Legionella with links to growing media in Scotland. The Growing Media Association takes this issue very seriously and has offered its full cooperation with NHS Lothian in its investigation into the source of the contamination.

In the meantime, the HTA and the GMA would like to reassure garden centres and their customers that the risk of infection is extremely low. This was confirmed by a recent report by Health Protection Scotland which recorded less than one case per million population per year between 2008-2012. Of the small number of infections diagnosed, those most at risk are those undertaking gardening activities indoors, and is greatest in those aged over 55 who smoke or have underlying chronic, medical conditions.

Compared with the number of gardeners in Scotland and the volume of growing media used, the HPS report concludes that the risks of severe disease are very low.

However, to reduce these risks further, we recommend that gardeners follow sensible hygiene precautions. These include:

• Wearing gloves

• Washing hands after all gardening activity, particularly before eating, drinking or smoking.

20 September 2013


6. Discussion and conclusion

6.1 Discussion

The cluster of Legionnaires’ disease cases described in this report is the first such cluster identified in Scotland caused by L. longbeachae Sg1 infection. Other cases of Legionnaires’ disease caused by L. longbeachae had been identified in Scotland before this cluster (eleven cases in the period 2008-2013), but cases had always been sporadic in nature.12 Clustering of seven cases with dates of onset over a period of one calendar month, in a small geographical area, prompted the investigation detailed here. Although no common source of infection was identified for these cases, this investigation was warranted due to the severity of the illness and the potentially large number of Scottish residents exposed to the contaminated source.

The sections below identify and discuss key findings of this investigation.

Case ascertainmentCases in this cluster were identified in two different NHS board regions, each with their own diagnostic microbiology service. The cases were detected using different microbiology techniques, which correspond to different clinical and microbiological protocols in place in each NHS board.

For NHS Lothian, clinical protocols for management of those admitted to respiratory, high dependency or ICU with community acquired pneumonia, alerts clinicians to take a lower respiratory tract sample (sputum or broncho-alveolar lavage) for a range of PCR tests including those for L. pneumophila and Legionella species. Cases 1-4 in NHS Lothian were detected as they were positive (unusually) for Legionella species. The sputum samples were then cultured and referred isolates were identified by SHLMPRL as L. longbeachae Sg1. A positive PCR result for Legionella species prompted alternative clinical treatment options more quickly than the culture and identification of the organisms, as this is more prolonged for Legionella species.

For NHS Tayside, clinical protocols for management of those admitted to high dependency or intensive care units with community acquired pneumonia, alert clinicians to take a saliva/sputum or broncho-alveolar lavage sample for a wide range of bacterial culture including on media specific for Legionella bacteria. This is not routine in all NHS boards to our knowledge. This local diagnostic service did not offer PCR for Legionella at the time of these cases. Subsequent colonies were identified by SHLMPRL as L. longbeachae Sg1, Case 5 was identified in this way and Case 6 was confirmed in this way. Although culture takes longer than PCR, the presence of Legionella colonies does prompt clinical treatment options, even though it took additional time to identify the responsible strain of Legionella.

Case 7 was identified by serology following treatment and recovery. It is unlikely that this case would have been identified if NHS Lothian had not circulated information about the cluster to clinicians (including primary care) and there had not been articles in the media. Serological detection of immune response to Legionella infection is only carried out at SHLMPRL and this service is available for samples from patients Scotland-wide. However, awareness that this service is available is perhaps less widely known and is certainly an unusual request from primary care clinicians. The use of serology was highlighted in the letter circulated to clinicians in NHS Lothian and NHS Tayside and this probably lead to the detection of this case.


Given that detection techniques for Legionella infections other than L. pneumophila Sg1 (detected using urinary antigen testing – all diagnostic laboratories hold kits for this) are variable across diagnostic laboratories, and use of serology is variable across different NHS board regions, it is likely that ascertainment of cases of community acquired pneumonia caused by Legionella species is also variable across Scotland. Indeed, it is likely that these cases are under-ascertained. Given that a confirmed diagnosis of Legionella infection may prompt alternative clinical treatment and is likely to improve clinical outcome, it is in the best interest of patients to optimise microbiological confirmation of infection. Accordingly, it is recommended that there is a discussion amongst diagnostic microbiologists in Scotland as to how best to provide equitable Scotland-wide provision of appropriate diagnostic tests in the light of emerging pathogenic strains.

Severity of illnessThe six confirmed cases in this cluster all had severe illness that required admission to ICU and ventilation. Severity of illness for Legionnaires’ disease cases is affected by immune status and other intrinsic risk factors including smoking. 5/6 of the severe cases had underlying medical conditions which may lead to immunosuppression; the remaining case was a smoker. So, all cases of severe illness had significant underlying intrinsic risk factors.

Given that gardening is traditionally a hobby for the older generation that is actively encouraged in “wellbeing” arenas and given the high proportion of the older population who experience immunosuppression due to underlying illness, it is likely that we will see further cases.

Epidemiological investigationThis cluster was of a small number of cases and as such had limited power to draw epidemiological conclusions. This cluster used a trawling questionnaire designed by HPS, containing specific questions about garden exposures and gardening activities. NHS board HPTs and EHOs found this questionnaire useful, although additional questions were added to it after first use. Results from the questionnaire were less effective at identifying any specific garden exposures or gardening activities which were high risk (other than exposure to growing media), due to the small sample number. To get a better idea of gardening activities which are higher risk, a larger sample is needed, perhaps in the context of an analytical study.

There is very little information published about the infectious risks of exposure to L. longbeachae. There is a single case-control study published by New South Wales, Australia14 which highlights use of potting compost, poor hand hygiene whilst gardening and proximity to dripping hanging baskets as increasing risk of illness. These findings have influenced the HPS advice regarding L. longbeachae, but further understanding of particular gardening activities which increase risk, would be beneficial.

Microbiological investigationMicrobiological investigation identified seven cases of L. longbeachae Sg1 infection, using three primary techniques – PCR, culture and serology. Where possible, more than one technique was used to corroborate results. Results from these techniques were consistent across the cases. Where undertaken: all tested positive for Legionella species by PCR; all were culture positive for L. longbeachae Sg1; all showed serological response to L. longbeachae Sg1. In addition, all were negative by urinary antigen testing. Whilst this is to be expected, it reinforces the concern that if


clinical management protocols do not suggest further investigation for Legionella infection following a negative urinary antigen test result, then cases may not be detected.

Five samples of growing media, linked with five confirmed cases, were L. longbeachae Sg1 positive by culture. This would suggest that growing media was the likely source of infection in these cases.

The AFLP results suggest that patient and associated environmental strains were indistinguishable. However whole genome sequencing identified differences between the patient and associated environmental strains. These results suggest that there is a large amount of heterogeneity in the strains found in compost and that multiple strains from the same compost would need to be sequenced to confirm a link. This follows a similar pattern to that encountered in environmental waters where the most pathogenic strains of Legionella are rarely detected in routine water sampling until there is a case or an outbreak and even then there are many cases/outbreaks where the source is never identified.

Environmental investigationThe environmental investigation was undertaken by EHOs in the relevant local authorities (four), co-ordinated by HPS. Sampling protocols and an understanding of risks were not in place before this cluster and co-ordination by HPS led to discussion and agreement around best practice. In order that this is shared more widely, it would be beneficial that this is incorporated into revised HPN national guidance for Legionella outbreaks and clusters.

In some cases EHOs had difficulty in tracing products as retailers delayed response to or ignored requests for information. Assistance from the GMA and HTA was welcome in resolving this. This should be borne in mind for future investigations.

HPS developed generic gardening hygiene advice for the public which was made available to retailers and was published on the HPS website. This was included in all media releases. This advice highlighted good garden hygiene in terms of wearing gloves, hand washing and refraining from smoking whilst handling garden products. In addition, advice included to open bags and use the contents in a well ventilated area, preferably outdoors and to wear a mask if the material is dusty.

Co-operation from retailers and manufacturers was generally good. The GMA had reservations and took a contrary view to HPS in terms of the information provided to retailers for the general public, specifically about the use of masks. In retrospect, it would have been useful for this to be discussed and agreed with the GMA before release, as this would have prevented the GMA releasing its own statement to members which whilst similar, was not the same as the message from HPS.

Risk managementThe investigation undertaken in 2012 into sporadic cases of L. longbeachae highlighted a possible risk management strategy of placing warning labels on bags of growing media.12 This was discussed at the Scottish Government at the time but no further action was taken due to existing UK labelling of bags with generic safety and hygiene advice and insufficient evidence that specific labelling in Australia and New Zealand had been effective. Another factor taken into account was the small proportion of cases of Legionnaires’ disease in Scotland caused by L. longbeachae (around 2% of cases) compared with around 50% of cases in Australia and New Zealand.


This conversation was revisited with Scottish Government and the UK Department of Health following this cluster. It was agreed that there was still insufficient evidence to take this strategy forward. However specific steps have been agreed and include that:

1. HPS should develop a hypothesis generating (“trawling”) questionnaire specifically for L. longbeachae cases and a protocol for the associated environmental investigation (including sampling). Based on indications from this trawling questionnaire a targeted investigation may be merited.

2. HPS should explore how best to raise awareness of risk of L. longbeachae infection from growing media, amongst those with highest risk – older and immunocompromised.

LimitationsEpidemiological investigation was limited due to the small number of cases in this investigation – this prevented statistical evaluation of risk. Clinical diagnostic practices were different in different NHS boards and this provided some degree of confounding in terms of case identification. The relative novelty of Legionnaires’ disease caused by this organism means that standardised epidemiological and environmental processes were still evolving and were not in place for the investigation of this cluster.

6.2 Conclusion

This was a cluster of cases in time for which no point source was identified. The reasons for increased incidence in Lothian and Tayside at this time are unclear.

The growing media linked to five cases in which L. longbeachae Sg1 was identified, came from different retailers, different manufacturers and was indeed made at sites in different countries. It is therefore likely that L. longbeachae contamination derives from multiple sources in multiple countries. This is supported by work which has identified L. longbeachae contamination in a variety of growing media, composted green waste and soil samples from a wide range of environments.10,11 It is possible that a significant proportion of growing media used in the UK is contaminated with L. longbeachae; but since very few cases are detected there must be a number of factors influencing likelihood of infection.

A number of combined factors which may explain this cluster are detailed below.

1. The composting process used to produce composted green waste is conducive for Legionella growth – elevated temperature and water release. At this time we do not know if the composting process continues after bagging or after sale.

2. Australia and New Zealand show seasonality in cases of Legionnaires’ disease caused by L. longbeachae, around times of increased use of growing media. Whilst this is traditionally in the spring, this cluster occurred at the time when gardeners start to prepare for the following year with planting of spring plants such as bulbs. Sporadic cases in Scotland outside this cluster, have not shown seasonality.

3. Immunosuppressed individuals, smokers and those who are older show increased susceptibility to Legionnaires’ disease. The majority of cases in this cluster meet these criteria.


4. The majority of cases of Legionnaires’ disease caused by L. longbeachae in Scotland have been in keen gardeners, who have had significant exposure to growing media. This includes multiple exposures, prolonged exposure and exposure in enclosed environments.

5. Climatic conditions may favour Legionella growth after bagging and/or point of sale. August and September were unusually warm in Scotland in 2013 and storage of bags post-sale in enclosed spaces (such as inside the home, garage, shed, greenhouse or polytunnel) may have led to the bags being very warm during the day and protected from cold nights by being covered. In such conditions, the organism may thrive.


7. Lessons learned and recommendations

7.1 Lessons learned

A lessons learned exercise was undertaken at the final IMT on November 27th, using a HPS standard debrief template. The overall view of the IMT was that this investigation had been well managed and was extensive and thorough. Specific points for further action are highlighted in the recommendations section.

7.2 Recommendations

A number of recommendations were made in the debrief exercise and a number of outstanding actions for the IMT were in place following the close of the investigation. These are detailed below.

Guidance1. Advice on L. longbeachae infection and investigation into cases should be included in the

HPN Guidance on Legionella cases, clusters and outbreaks in the community (due for revision in 2014).

2. Sampling protocols should be developed specifically for growing media sampling, which should also include information about use of masks during sampling. This should be included in the revised HPN guidance.

Meeting management3. Make every effort to include all relevant staff as early on in the investigative process as

possible and invite them to all IMT meetings. This will ensure that all agencies are fully informed at all times.

Investigation4. Review the Legionella longbeachae trawling questionnaire.

5. HPS should consider a proposal for an in-depth epidemiological study of L. longbeachae cases, to further investigate activities and high risk behaviours in such cases.

6. This cluster has highlighted differential use of PCR to detect Legionella in diagnostic laboratories in Scotland. Highlight this issue with the Scottish Microbiology and Virology Network and propose solutions that ensure provision of appropriate local and national diagnostic tests for timely screening of samples from all regions in Scotland.

7. SHLMPRL should highlight the use of serology for the detection of non-pneumophila Sg1 strains of Legionella and issue a reminder of the availability of this service at SHLMPRL to relevant diagnostic laboratory colleagues.

8. HPS should promote environmental research to further understand factors that affect growth of L. longbeachae organism in growing media to a level which can cause illness.


Risk management9. HPS should pursue the previous recommendations on improved surveillance and

exploration of novel approaches to awareness raising among at risk groups, and, maintain an active dialogue with Scottish Government and Department of Health regarding the issue of placing specific warning labels on bagged growing media.


8. References1. Management of Public Health Incidents: Guidance on the Roles and Responsibilities of

NHS led Incident Management Teams, published by Scottish Government and HPN, October 2011. Available at: http://www.scotland.gov.uk/Publications/2012/04/7816/downloads#res392131

2. Public Health (Scotland) Act 2008, available at: http://www.scotland.gov.uk/Resource/0039/00398162.pdf

3. European Centre for Disease Control, website available at: http://ecdc.europa.eu/en/Pages/home.aspx

4. European Legionnaires’ Disease Surveillance Network (ELDSNet), web pages available at: http://ecdc.europa.eu/en/activities/surveillance/ELDSNet/Pages/index.aspx

5. Guideline on the management of Legionella incidents, outbreaks and clusters in the community, published HPN, March 2009, available at: http://www.hps.scot.nhs.uk/resp/guidelinedetail.aspx?id=38930&subjectid=185,97

6. Details of Legionnaires’ disease in Scotland available from HPS website at: http://www.hps.scot.nhs.uk/resp/Legionella.aspx?subjectid=185,97

7. Legionellosis in Scotland in 2011 and 2012, published by HPS, August 2013, available at: http://www.hps.scot.nhs.uk/resp/wrdetail.aspx?id=55879

8. Legionnaires’ disease in Europe in 2011, published by ECDC, April 2013, available at: http://ecdc.europa.eu/en/publications/Publications/legionnaires-disease-in-europe-2011.pdf

9. Whiley H and Bentham R. Legionella longbeachae and legionellosis. Emerging Infectious Diseases, 2011, 17, 4, 579.

10. Steele TW, Moore CV and Sangster N. Distribution of Legionella longbeachae Serogroup 1 and other Legionellae in potting soils in Australia. Applied Environmental Microbiology, 1990, 56, 10, 2984-2988.

11. Currie SL, Beattie TL, Knapp CW and Lindsay DSJ. Legionella spp. in UK composts - a potential public health issue? Clinical Microbiology & Infection, 2013, first published online 24 Oct 2013

12. Increased incidence of Legionnaires’ disease caused by Legionella longbeachae in Scotland: Report from a National Incident Management Team, published by HPS, September 2013, available at: http://www.hps.scot.nhs.uk/resp/publicationsdetail.aspx?id=56005

13. DEFRA white paper setting out aims to reduce peat in growing media in the UK, available at: http://www.defra.gov.uk/environment/natural/whitepaper/

14. O’Connor BA, Carman J, Echert K, Tucker G, Givney R and Cameron S. Does potting mix make you sick? Results from a Legionella longbeachae case-control study in South Australia. Epidemiol. Infect., 2007, 135, 34-39.

15. PAS100 standard, details available from WRAP website: http://www.wrap.org.uk/content/bsi-pas-100-producing-quality-compost

16. Association for Organics Recycling (AfOR) L. longbeachae guidance, available at: http://www.organics-recycling.org.uk/uploads/article1894/39_AfOR_guidance_Legionella_longbeachae_I1R0.pdf

http://www.scotland.gov.uk/Publications/2012/04/7816/downloads#res392131

http://www.scotland.gov.uk/Publications/2012/04/7816/downloads#res392131

http://www.scotland.gov.uk/Resource/0039/00398162.pdf

http://www.scotland.gov.uk/Resource/0039/00398162.pdf

http://ecdc.europa.eu/en/Pages/home.aspx

http://ecdc.europa.eu/en/Pages/home.aspx

http://ecdc.europa.eu/en/activities/surveillance/ELDSNet/Pages/index.aspx

http://www.hps.scot.nhs.uk/resp/guidelinedetail.aspx?id=38930&subjectid=185,97

http://www.hps.scot.nhs.uk/resp/guidelinedetail.aspx?id=38930&subjectid=185,97

http://www.hps.scot.nhs.uk/resp/Legionella.aspx%3Fsubjectid%3D185%2C97

http://www.hps.scot.nhs.uk/resp/Legionella.aspx%3Fsubjectid%3D185%2C97

http://www.hps.scot.nhs.uk/resp/wrdetail.aspx?id=55879

http://ecdc.europa.eu/en/publications/Publications/legionnaires-disease-in-europe-2011.pdf

http://ecdc.europa.eu/en/publications/Publications/legionnaires-disease-in-europe-2011.pdf

http://www.hps.scot.nhs.uk/resp/publicationsdetail.aspx?id=56005

http://www.defra.gov.uk/environment/natural/whitepaper/

http://www.wrap.org.uk/content/bsi-pas-100-producing-quality-compost

http://www.wrap.org.uk/content/bsi-pas-100-producing-quality-compost

http://www.organics-recycling.org.uk/uploads/article1894/39_AfOR_guidance_Legionella_longbeachae_I1R0.pdf




9. Appendices

9.1 Members of the national IMT

Martin Donaghy Chair of IMT, Consultant in Public Health Medicine Health Protection Scotland

Alison Potts Epidemiologist Health Protection Scotland

Kevin Pollock Epidemiologist Health Protection Scotland

Michelle Marley Environmental Health Advisor Health Protection Scotland

Lynn Kidd Communications National Services Scotland

Joyce Dalgleish Communications National Services Scotland

Richard Othieno Consultant in Public Health Medicine NHS Lothian

Janet Stevenson Consultant in Public Health Medicine NHS Lothian

Lorna Willocks Consultant in Public Health Medicine NHS Lothian

Peter Harrison Health Protection Nurse NHS Lothian

David Ridd Communications NHS Lothian

Kirsty Licence Consultant in Public Health Medicine NHS Tayside

Jackie Hyland Consultant in Public Health Medicine NHS Tayside

Giles Edwards Consultant Microbiologist SHLMPRL

Diane Lindsay Senior Clinical Scientist SHLMPRL

Mary Hanson Consultant Microbiologist NHS Lothian

Kristjan Helgason Consultant Microbiologist NHS Lothian

Michael Lockhart Consultant Microbiologist NHS Tayside

Robbie Beattie Senior Manager/Public Analyst City of Edinburgh Council Scientific Services

Iain McCluskey EHO West Lothian Council

Calum Sharp EHO City of Edinburgh Council

Carly Smith EHO City of Edinburgh Council

Margaret Gregory Senior EHO Angus Council

Malcolm Elliot EHO East Lothian Council

Duncan McCormick Senior Medical Officer Scottish Government

Simon Cuthbert-Kerr Policy Advisor Scottish Government

Nick Phin Consultant Epidemiologist Public Health England

Linda Moan Minute taker, Project Support Officer Health Protection Scotland

Health Protection Scotland, NHS National Services Scotland, Meridian Court, 5 Cadogan Street,

Glasgow G2 6QE

Documents

NHS Legionella Report 2013