Legionella acquired its name after an-outbreak of a then-unknown “mystery disease” sickened 221 persons, causing 34 deaths. The outbreak was first noticed among people attending a convention of the American Legion—an association of U.S, Military Veterans. The convention occurred in Philadelphia during the U.S. Bicentenial year in July 21–24, 1976. This epidemic among U.S. war veterans, occurring in the same city as—and within days of the 200th anniversary of—the signing of the Declaration of Independence was widely publicized and caused great concern in the United States.
Landlords have a duty to ensure that their properties are free from health and safety hazards. This includes, inter alia, carrying out a risk assessment to assess for conditions that can encourage the spread of Legionella and subsequently mitigating or controlling such conditions. Provided an adequate knowledge of the property’s water system and what to look for in terms of the Legionella bacteria exist.
The genus Legionella is a pathogenic group of Gram Negative Bacteria that includes the species causing legionellosis (all illnesses caused by Legionella) including a pneumonia-type illness called Legionaires Disease and a mild flu-like illness callled Pontiac Fever
Once inside a host, incubation may take up to two weeks. Prodomal symptoms are flu-like, including fever, chills, and dry cough. Advanced stages of the disease cause problems with the gasinterestimol tract and the nervous system and lead to diarrhea and nausea. Other advanced symptoms of pneumonia may also present. However, the disease is generally not a threat to most healthy individuals, and tends to lead to harmful symptoms only in the immunocompromised host and the elderly. Consequently, it should be actively checked for in the water systems of all current hospitals and nursing homes.
According to the 2007 book Legionella and the prevention of legionellosis from the Wold Health Organisation temperature affects the survival of Legionella as follows:
- Above 70 °C (158 °F) – Legionella dies almost instantly
- At 60 °C (140 °F) – 90% die in 2 minutes
- At 50 °C (122 °F) – 90% die in 80–124 minutes, depending on strain
- 48 to 50 °C (118 to 122 °F) – can survive but do not multiply
- 32 to 42 °C (90 to 108 °F) – ideal growth range
- 25 to 45 °C (77 to 113 °F) – growth range
- Below 20 °C (68 °F) – can survive, even below freezing, but are dormant
Other sources claim alternate temperature ranges:
- 60 to 70 °C (140 to 158 °F) to 80 °C (176 °F) – Disinfection range
- 66 °C (151 °F) – Legionella dies within 2 minutes
- 60 °C (140 °F) – Legionella dies within 32 minutes
- 55 °C (131 °F) – Legionella dies within 5 to 6 hours
- 20 to 45 °C (68 to 113 °F) – Legionella multiplies
- 20 °C (68 °F) and below – Legionella is dormant
Our surveys involve the testing of all property water sources including all tanks and containers used for the supply of potable water and the issue of certificates proving the healthy supply of hot and cold water supplies.
During our inspections of all the prior loft spaces when carrying out Energy Performance Certificates it has been noticed that old galvanised cold water tanks have been found in awfull conditions containing dead birds, rusty conditions and even worse, considering that a lot of people clean their teeth using water supplied from these containers in their lofts it begs the question” How many people are falling ill from using this same water.
Therefore to be on the safe side all cold water tanks and installations where possible legionella may occur should be checked.