Between November 2011 and May 2012, an outbreak of Legionnaires' disease occurred in Calpe, Spain resulting in 25 incidences, including six fatalities. Of this number, 22 cases involved travellers from Spain, France, Belgium and the United Kingdom. The three remaining cases involved three hotel staff.

The travellers stayed at the same hotel between November 25, 2011 and May 2, 2012. The incidences where hotel staff members figured in were reported between December 2011 and January 2012.

A total number of 161 water samples were collected. All the samples collected from the hotel's tap water system yielded negative results. However, the water samples collected from the hotel's whirlpool tested on March 1, April 18 and May 8 yielded positive results. Subsequent testings conducted on the whirlpool water yielded negative results. After the initial positive test results, the appropriate control and disinfection procedures were conducted by the hotel management upon the request of local health authorities.

Apart from the importance of hotel Legionella testing, this outbreak of Legionnaires' disease in Spain offers hotels and similar establishments a few invaluable lessons.

For one, it is clear that the Legionnaires' disease cannot be transmitted between humans. Instead, those who succumbed to the disease share two things in common: they stayed at the same hotel, and it was during the same period of the outbreak.

According to the investigations conducted by local authorities, there are no other possible sources of contaminated water droplets other than the whirlpool.

What exactly can hotels and similar establishments do to prevent an outbreak?
First, it is crucial to be aware of high-risk areas. These include showers, taps, spas, whirlpools, cooling towers, ornamental fountains and humidified food displays.

It is also advisable to appoint one point person who will take charge of the Legionella control measures. This person should be given ample training in order to better inform other hotel staff about the threat of Legionnaires’ disease.

Water temperature should always remain constant and all taps and showers should be allowed to run for a few minutes once a week. These fixtures should be cleaned regularly to prevent the build-up of scales. Cooling towers should be cleaned and disinfected twice a year while water heaters should be cleaned once a year. Filters must be replaced regularly.

Legionella water testing should be conducted by accredited and duly-trained personnel. Take note that negative test results do not necessarily mean that there is no risk of an outbreak.

+Duncan Hollis