John V Lee

1
Microbiology of swimming pools and its control

• John V Lee
• BSc, PhD, FWMSoc, FRSPH
• Vice Chairman Pool Water Advisory Group
• Leegionella Ltd,
• 46 Howletts Lane, Ruislip,
• HA4 7RS
• Email johnvlee_at_leegionella.co.ok
• www.leegionella.co.uk
• Tel. [phone]
• Mob 44 (0) 7974741196

2
We will consider

• Swimming pools
• Spa pools
• synonyms commonly known as Jacuzzi (a trade
  name) hot tubs whirlpool spas
• Hydrotherapy pools
• Whirlpool baths
• A very wide range of infections can be
  water-borne we can only consider them very
  briefly

3
Origins of water borne infectious agents
(pathogens)

• Exogenous organisms that do not occur naturally
  in water
• Humans
• Directly via faecal contamination skin mucous
  membranes sweat
• Indirectly via sewage contamination
• Animals / Birds -
• Indigenous organisms that grow in water
  naturally and some may survive mains water
  treatment
• Sources ?
• surfaces (biofilm)
• sediment
• scums
• aquatic animals - reptiles, fish, molluscs
• protozoa

4
Water related infections modes of contraction

• Ingestion ( usually faecal oral pathogens)
• Contact
• Aerosol (inhalation)
• Aspiration (water going down the wrong way)

5
Examples of exogenous pool associated infectious
agents

• FAECAL-ORAL
• Bacteria - Eschericia coli O157 (EHEC),
  Shigella, Campylobacter,
• Viruses - Adenovirus Norovirus hepatitis A,
  Enterovirus, Echovirus
• Protozoan parasites - Cryptosporidium Giardia
• CONTACT
• Bacteria Staphylococcus, Pseudomonas aeruginosa
• Viruses Adenovirus, Molluscipoxvirus,
  Papillomavirus
• Fungi - Trichophyton, Epidermophyton

6
Outbreaks of disease associated with swimming
pools and spa pools England, Wales and N.
Ireland, 1990-2000
Cause Type of pool Type of pool
Swimming Spa Cases Hospitalised
Cryptosporidium 28 0 540 8
P. aeruginosa 2 4 107 0
Echovirus 1 0 46 0
Legionella 0 2 6 0
Unknown 1 0 10 0
TOTAL 32 6 709 8
Data from HPA CDSC
Update 1992 2010 80 outbreaks of infection
in pools in England and Wales including
Cryptosporidium, Legionella, Giardia, E. coli
O157, P. aeruginosa
7
Enterohaemorrhagic E. coli (EHEC, e.g. E coli
O157H7)

• Some swimming paddling pool and interactive
  water feature/splash pad outbreaks
• Severe bloody diarrhoea with cramping abdominal
  pains developing 1 10 days after exposure
• Self resolving in 5 10 days except
• Some cases, particularly under fives, develop
  haemolytic uremic syndrome
• Acute renal (kidney) failure
• 3-5 die
• Very low infectious dose
• Sensitive to chlorine

8
Cryptosporidium

• Protozoan parasite requiring host to reproduce
• Robust oocyst (4-6µm)
• resists chlorine disinfection
• survives but does not multiply
• Low infectious dose
• massive numbers shed in faeces
• increased infection risk
• Diarrhoea, abdominal cramps, loss of appetite,
  low-grade fever, nausea, and vomiting.
• Disease can be prolonged and life-threatening in
  the highly immunocompromised
• Potential for large-scale outbreaks
• Limited treatment options
• Most common cause of waterborne infection in UK

9
Disinfection Times for Faecal Contaminants in
Chlorinated Water (3 log 99.9 reduction)
E. coli O157H7bacteria lt lt 1 minute
Hepatitis A virus approximately 16 minutes
Giardiaparasite approximately 45 minutes
Cryptosporidium parasite approximately 15,300 minutes (10.6 days)
1 mg / L (1 ppm) chlorine at pH 7.5 and 25C
Data from Shields et al 2008n J Water Health.
2008 Dec6(4)513-20, and http//www.cdc.gov/heal
thywater/swimming/pools/chlorine-disinfection-time
table.html
10
Cryptosporidium outbreaks by vehicle in England
and Wales
(Data from the Health ProtectionAgency)
11
2012 18 outbreaks
Leisure centre 6 Holiday or caravan park
3 Hydrotherapy pool in medical setting 1
12
Examples of contributory factors in outbreaks of
cryptosporidiosis 1
Factor Example from outbreaks
Sewage cross-connection. Contamination in plant room.
Inadequate pool design and construction, including water features. Absence of as-built schematics filter by passing lack of flow meters or pressure gauges.
Faecal release or contamination from bathers. Documented releases people continuing to swim with diarrhoea or after diagnosis lack of adequate hygiene bather loads exceeded.
Inappropriate handling and disposal of stools. Disposed of in scum channel.
Inappropriate response to faecal accidents. Not documenting not following PWTAG procedure.
Secondary treatment absent or not working properly. UV lamps failed ozone decommissioned.
13
Examples of contributory factors in outbreaks of
cryptosporidiosis 2
Factor Example from outbreaks
Inadequate pool water circulation. Deadlegs inadequate pumps.
Inadequate coagulation. Coagulation absent or slug dosed.
Inadequate filtration. Inappropriate filter media laterals installed incorrectly filters poorly installed and maintained.
Inappropriate backwashing procedures. Timing frequency.
Gaps and weaknesses in policies and operational procedures and non-adherence to procedures. Contribute to spreading Cryptosporidium contamination widely in the pool.
Confusion in determining which national standards to apply Warm, large hydrotherapy-style pools.
14
Pool solutions some interventions for disease
reduction

• Good design and construction to prevent cross
  connections and spread of contamination.
• Circulation and treatment for learner pools that
  is separate from the main pool.
• Adequate pool water circulation, coagulation and
  filtration to remove contamination
• Filter rates lt25 m/h
• Continual coagulant dosing
• Good filter backwashing practice and procedures
  that do not increase the risk.
• A clear policy for recognizing, reporting and
  dealing with faecal accidents As Soon As Possible
  (PWTAG).
• Pool closure to prevent further risk where
  necessary.

15
UV disinfection secondary disinfection

• UV photons absorbed
• dimerisation of thymine (T) bases on
  complementary DNA strands
• Dimer prevents replication of the DNA
• Thus preventing ability to cause infection
• Effective wavelength between 200 to 300 nm
  (253.7 nm)
• Low dose UV up to 40 mJ/cm2 is most effective for
  Cryptosporidium control
• E.g. 22 mJ/cm2 offers 4.0 log inactivation
• US EPA has included UV as a key tool in meeting
  disinfection goals

16
Some key public health messages

• Shower, with soap, before using the swimming
  pool.
• Washing hands after changing nappies or using the
  toilet.
• Take children to the toilet before and offer
  frequently during swim.
• Children who are not potty or toilet trained must
  wear waterproof swim nappies.
• Do not swallow the swimming pool water.
• People with diarrhoea must not swim or for 48
  hours after symptoms have ceased.
• People with a cryptosporidiosis diagnosis must
  not swim for 2 weeks after symptoms have ceased.

17
Some contact transmitted pathogens indigenous to
water

• Bacteria
• Pseudomonas aeruginosa - otitis (ear
  infections), follicululitis
• Mycobacterium species - skin infections
• Protozoa
• Acanthamoeba species - conjunctivitis,
  keratitis, meningoencephalitis
• Naegleria fowleri - meningoencephalitis
• Helminths
• Trichobilharzia ocellata- swimmers itch

18
Pseudomonas aeruginosa folliculitis

• Spa pool / hot tub folliculitis is a superficial
  skin infection caused by Pseudomonas aeruginosa
• It occurs following exposure to inadequately
  maintained pools / spas
• The rash consists of red elevated papules, some
  of which may be pus-filled
• The rash can appear 12 hours to 2 days following
  exposure
• It itches, but usually resolves spontaneously.

19
A weekend with friends at the Sanctuary Health
Club

• gt50 cases
• Pseudomonas folliculitis contracted at spa pool
  leisure facility.
• Most cases misdiagnosed by GPs
• Pathogen detected in water and from cases.
• Evidence of pool operating system failure prior
  to onset of illness.
• Pool closed and treated.

20
Otitis externa (outer ear) infection from a
swimming pool.

• 4 of 24 people developed otitis externa as a
  result of swimming in a pool with a high level of
  Pseudomonas aeruginosa.
• Typing was used to establish that P. aeruginosa
  from the pool was the agent responsible for the
  outbreak of the infection. Seyfried PL, Fraser
  DJ. Health Lab Sci. 1978 Jan15(1)50-7.

21
Folliculitis associated with a swimming pool
inflatable.

• North East England 2002
• 35 cases, children boys with rash on chest and
  girls on back
• Infection associated with using inflatable (o.r.
  12 c.i. 1.05 136.8)
• Strains of Ps aeruginosa from inflatable were
  indistinguishable from those from patients
• 90 of 10 inflatables sampled in the area
  following the outbreak were colonised

Tate, Mawer Newton 2003 Epidemiol. Infect.
130 187-192
22
Mycobacteria spp.

• M. avium-intracellulare, M. kansasii,
  M.malmoense, M. xenopi etc.
• indigenous to water
• Grow in biofilms and are difficult to disinfect
• possible regrowth in water systems
• Mycobacteria colonise water treament membranes
  (RO, UF, MF)
• Can cause disseminating diseases in AIDS patients
• Mycobacterium marinum causes swimming pool
  granuloma
• Infection through abrasions
• Also a problem with fish tanks

23
Water aerosol and aspiration transmitted pathogens

• bacteria -
• Legionella spp. - legionaires disease,
  Pontiac fever
• various - aspiration pneumonia
• Non-tuberculous mycobacteria
• Protozoa
• Acanthamoeba spp. - encephalitis,
• Naegleria fowleri - meningoencephalitis

24
Spa pools Synonyms spa baths, whirlpools,
whirlpool spas , hot tubs, Jacuzzis

• Designed for a small number of people to sit in
  at a time not for swimming or total immersion.
• Not drained, cleaned or refilled between each use
  
• Water recirculated with filtration and
  (hopefully) chemical treatment
• Fitted with water and / or air jet systems
• Present in health clubs, health spas, hotels,
  sports centres, beauty shops/ centres, and
  private households
• 3rd most common cause of Legionnaires disease
  and other legionelloses
• A very common cause of P. aeruginosa folliculitis
• Can cause mycobacterial pneumonitis

Commercial overflow design
Domestic spa / hot tub
25
Spa pool associated Mycobacteria outbreaks - Hot
tub lung

• "Hot tub lung" is a rare (but increasingly
  reported) infection or allergic reaction of the
  lungs (allergic pneumonitis) due to inhaling
  Mycobacterium spp. from a hot tub
• Mycobacterium avium (Sugita et al 2000)
• 3/5 in family associated with home spa pool
• Non-tuberculous Mycobacteria (NTM) in 10
  immunocompomised patients (Khoor et al 2001)
• All associated with the use of a hot tub
• NTM in 5 patients (Mangione et al 2001)
• Isolated from a family of 5 and 2 tubs
• England
• Herts 2006 1 case associated with domestic spa
  pool
• Essex 2007 2 cases associated with domestic spa
  pool

26
Spa pools on display can also cause legionnaires'
disease

• Westfriese Flora, Flower show, Bovenskarpel, The
  Netherlands 1999
• Overall 226 cases with 28 deaths
• 77,061 visitors
• 281 water samples
• Risk of infection increased with time spent near
  spa
• 2 spa pools on display positive for patient type
• 1 misting machine positive for other type
• Trade fair in Kapellen, Belgium, 1999
• 80 persons who developed clinical symptoms, 13
  had positive urinary tests 4 deaths.
• Over 60.000 visitors attended the fair,

27
Legionnaires disease Cricket St Thomas Feb. 2003

• Largest hotel outbreak in UK since 1984
• 20 cases
• 2 deaths
• All had used spa pool

28
Mixed outbreak of legionnaires' disease and
Pontiac fever associated with spa pool ( CDR 14
September 2006)

• 2 confirmed cases of legionnaires disease, three
  confirmed cases of Pontiac fever and a further 73
  probable cases of Pontiac fever
• Flu-like symptoms including fever, myalgia,
  headaches and nausea over the previous week.
• Incubation period 24 and 48 hours, with symptoms
  lasting three to five days.
• Investigations revealed that all reported cases
  had been in the spa pool (or in very close
  proximity to it) over a period of at least seven
  days.
• There were no reports of illness in members who
  had used other facilities in the club.
• Water samples from the spa pool, the return flow
  from the massage jets and a short section of
  segmented pipe connected to mains water used to
  top-up the pool have all tested positive for
  Legionella pneumophila serogroup 1.

• Figure Onset date and time for confirmed and
  probable cases (n78) (one case onset unknown,
  one case 21/8/06, and one case 26/8/06)

29
Why are Spa Pools a problem?

• Elevated temperature 30 - 40C- encourages
  bacterial growth
• High organic load - dead skin,sweat etc., bath
  oils, body lotions soaps, cosmetics etc.
• High bather density and water reused
• Air and water circulation systems provide a large
  surface area for biofilm development
• Biofilm organisms are more resistant to treatment
• Pipes often inaccessible for biofilm removal
• Balance tanks often inaccessible
• Dust, leaves, grass, soil, bird droppings

30
Air and water circulation systems give a large
surface area for biofilm growth
A single modern spa pool may contain as much as
75 metres of flexible and fixed pipes with a
total surface area of 5.5m2
31
Whirlpool baths
32
Spa pool operation

• pH 7.2 7.8
• Chlorine
• Free 3 5mg/l
• Combined less than 1 mg/l
• Bromine 4 6 mg/l
• Daily
• Backwash sand filter and dump 50 of water in
  pool
• Weekly
• Drain and clean whole system including balance
  tank
• Clean strainers

33
Interactive water features / splashpads

• Very popular
• Easily contaminated
• Water recycled often with inadequate treatment
• Caused many outbreaks around the world, some very
  large
• Agents- Cryptosporidium, E. coli O157, Shigella,
  Norovirus

34
Guidance

• Joint HSE HPA Guidance
• Management of Spa Pools Controlling the Risk of
  Infection. London Health Protection Agency. 2006
  ISBN 0 901144 80 0
• 110 pages
• Can be purchased from the Public Health England

35
Guidance

• Swimming Pool Water Treatment and Quality
  Standards for Pools and Spas
• Pool Water Advisory Group 2nd Ed 2009
• ISBN 0951700766
• www.pwtag.org.uk

36
Conclusions

• The majority of pool associated infections result
  from bad maintenance and design
• Apart from crypotsporidiosis in swimming pools
  the greatest risk is presented by spa pools
• Well managed swimming pools are beneficial to
  health