Have you ever had Legionella?

Feb 20, 2015 11:47:00 AM

Strange question you may think.  "Of course not" most of you would say, however, the chances are that you will have been exposed to Legionella bacteria at some time without knowing it and many of you will also have been infected, as the symptoms of some strains of the virus are very similar to acute influenza (flu).


It is now widely accepted by the scientific and medical community that the current reporting of Legionella-related illnesses is inaccurate and misleading.  Most people will not bother seeing a doctor for flu-like symptoms and simply rest and self-medicate until the symptoms pass.  If they do consult the doctor, in most cases, he/she will normally diagnose flu.


There are over 40 different known species of legionella bacteria - although legionella pneumophila causes around 90% of all infection. One type of legionella infection is known as Pontiac Fever, a respiratory disease with a short incubation period of 1-3 days and, usually, non-fatal but with symptoms similar to acute flu.  Full blown Legionnaires' disease, an acute form of pneumonia, is incubated between 2 and 10 days and can be fatal in 15 to 20% cases, with much greater risk for the elderly, smokers and people with a poor immune system.

Water mist can contain legionella

Legionella is transmitted by an air borne mist and can develop in still water between 25°C and 50°c.  Legionella can also lie dormant in otherwise 'safe' water systems for several years, as it protects itself in other matter available in the water system; such as biofilm, scale and corrosion deposits.


Many unsuspecting people have contracted legionella-related illness from such things as showers that have been unused for several days/weeks, from poorly treated recreational water such as whirlpool and Jacuzzis, spray from decorative fountains or water features.   Technicians have contracted Legionella when working on standby water pumps and water tanks that have not been in recent use or appropriately treated. There are documented fatal cases of shipyard fitters contracting Legionnaires' disease whilst stripping down pumps. Legionella risk assessment should be included in ship repair specifications and shipyards should be aware of the risks before the ship arrives at the yard.  Commissioning of water systems after dry-dock and new-builds should be carried out according to strict water safety procedures.


Ships and hotels should implement a water safety plan (WSP) as recommended by the WHO Water Safety Plan Guidelines.  This plan should cover all potential risks and should be reviewed and improved on a regular basis with regular risk assessments supported by independent auditors.

X Ray showing impact on Lungs

How often and where do people catch Legionella? It can happen in many places.  CTI Marine, a specialist in legionella prevention and water safety plans, had a client who stayed at a 5 star hotel in Shanghai at the beginning of January 2014.  The hotel had been quiet over the Christmas period, meaning a lot of rooms had been empty for at least one or two weeks. Immediately after arrival the client took a shower to freshen up.  Within 12 hours he thought he was getting flu as he began showing respiratory symptoms. As the client had travelled from Europe for a week long training course he decided to attend the course in spite of these symptoms.  Although he was in close contact with over 30 other people on the training course, none developed similar symptoms indicating that the infection was not of a contagious nature. By the end of the week his symptoms had greatly improved, although he did report that his breathing remained affected for over 2 months, particularly at night time when he suffered from bouts of wheezing.   On reflection, it is very likely that the client was suffering fromthe legionella related Pontiac fever which can only be detected by specific tests.


A recent fatality of a cruise ship captain from legionella may have been caused by something as simple as putting on the bridge windscreen washers, where the water had been sitting in the pipes for some days.  At a recent EU SHIPSAN ( meeting it was highlighted that significantly more water samples show positive for legionella on passenger ferries than on cruise ships; primarily because cabin showers are used infrequently meaning water can be sitting in the pipes for days.

Poorly treated recreational water can generate contaminated mist

Legionella can be designed and managed out of ships and hotels.  Prudent operators should consult with legionella prevention specialists who can review piping systems, procedures and advise on the most suitable water safety management plan.  These plans must be able to be effectively managed and internally audited by the Technical and Hotel team, who would update their risk assessments as required.  This operation can then be verified for compliance by a suitably accredited hotel and marine legionella prevention company.


There also needs to be more public, scientific and medical awareness related to the causes and symptoms of legionella infection before accurate reporting is possible and better statistics can be generated.  In addition, regulators need to make operators responsible for legionella control.  For example, UK legislation dictates that hotels require a legionella risk assessment and that other relevant documents are in place and reviewed regularly and/or when significant system changes are made.  Clearly, similar requirements should be in place internationally for hotels and ships.  The EU have established and funded the development of SHIPSAN with the objective of implementing common, European-wide, ship health and hygiene standards. The development and implementation of water safety plans is an integral part of the best practice guidance within the SHIPSAN Manual (European Manual for Hygiene Standards and Communicable Disease Surveillance on Passenger Ships).  It is very likely that other major port health authorities such as USA, Brazil, Australia and Canada will adopt similar requirements for water safety plans in the near future.  It is also understood that the Chinese authority responsible for port health is already considering the adaptation and implementation of the SHIPSAN guidance.

Grenville Cartledge

Managing Director

Four Gold

Grenville has been actively involved with the SHIPSAN project for more than four years through his work as Regulatory Consultant to the UK Passenger Shipping Association and the European Cruise Council Health & Hygiene sub-committee.  He was a trainer and facilitator at the recent, inaugural, SHIPSAN Advanced Water Safety training course in Athens.

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