Analysis: Fatalities grab headlines, but many cases unreported, say experts

This is because not everyone who has suffered from pneumonia will have been tested for the disease, particularly those with milder symptoms. This means these cases will not have been reported to health authorities.

Between 30 and 40 cases of the disease are reported each year in Scotland. The latest figures from Health Protection Scotland show there were 501 cases of the disease between 1995 and 2010, and 43 deaths. The most fatalities were in 1985, when six people died.

In 2009, there were 345 reported cases of Legionnaires’ disease in England and Wales.

Britain’s worst outbreak of the disease was at Stafford District General Hospital in 1985, which claimed 39 lives – the largest recorded total in a single outbreak. A further 175 cases were reported. The source was traced to an air-conditioning tower on the roof. Previously, the largest outbreak worldwide had been in 1976, in the US city of Philadelphia, when 34 people died.

In 1999, 32 people died from the disease at Bovenkarspel in the Netherlands. It is believed the death toll could be higher but that some victims were buried before the disease was identified. The bacteria was traced to a hot tub.

In 1984, one person died in Glasgow and there were 33 confirmed cases – 26 of those who became ill lived in the Dennistoun area of the city, downwind from a cooling tower. In 1994, one person died and nine people were infected in south-west Edinburgh. Cooling towers were suspected of being the cause.

In 2002, six women and one man died from the disease after a faulty air-conditioning system released the deadly legionnella bacteria into the air at an arts centre in Barrow-in-Furness, Cumbria. There were 172 confirmed cases. Barrow Borough Council became the first public body in the UK to be charged with corporate manslaughter, but was later cleared. However, it was fined for health and safety breaches.

Basildon University Hospital in Essex has seen two confirmed deaths from the disease since 2002. In 2002 it was fined £25,000 over the death of a man from the disease. In 2010 there was a second Legionnaires’ death at the hospital, while two other patients were treated with antibiotics. A further two patients died last year. In one case Legionnaires’ was a contributing factor. Cause of death on the fourth case is yet to be confirmed.

The hospital said that since the first case of Legionnaires’ disease in 2002, it had spent £2 million on remedial works to its plumbing infrastructure.

In 2010, two people in South Wales died and another 22 became ill. The source was believed to be cooling towers.

In May last year, three people died of the disease in the west of Scotland, in separate incidents.

There were also seven confirmed cases in the Greater Glasgow and Lanarkshire areas.