Legionella

Legionnaires' disease or legionellosis is a pneumonia caused by any type of legionella bacteria. The Pontiac fever is a form of leginellosis without pneumonia.
Symptoms are fever, chills, and a cough (often with sputum and blood). Muscle aches, headache, tiredness, loss of appetite, loss of coordination, chest pain, or diarrhoea and vomiting are also common symptoms.
If untreated, Legionnaires’ disease usually worsens during the first week and can be fatal. The most frequent complications are respiratory failure, shock and acute renal and multi‐organ failure.
If treated immediately the fatality is less than 5%.  In hospital it can reach 40–80% because of often already weak health condition of the patients.

Transmission

Legionellosis is transmitted by inhalation of aerosolized water and/or soil contaminated with the Legionella bacteria.
It is not an airborne disease but only Legionella contaminated mist or dust can reach the lungs.

Reservoirs

Aquatic systems with a temperature between 25 and 45°C  with an optimum temperature of 35°C where Legionella established within amoebae in a symbiotic relationship. Legionella has been found in water systems at temperatures up to 66°C.
Central air conditioning systems in office buildings, hotels, and hospitals are sources of contaminated water.
Other places it can dwell include cooling towers used in industrial cooling systems, evaporative coolers, nebulizers, humidifiers, whirlpool spas, water heating systems, showers, windshield washers, fountains, room-air humidifiers, ice-making machines, and misting systems.

Mechanism

Once in the lung Legionella bacteria invading macrophages, a kind of white blood cells, multiply and causing the death of the macrophage. Once the macrophage dies, the bacteria are released from the dead cell an infecting other macrophages. First symtoms of legionallosis aprearing after 2 to 10 days. Pontiac fever patients showing symptoms after an icubation time between 5 hours and 3 days.

Diagnosis

Legionellosis is relatively rare form of pneumonia many clinicians have not encountered before and thus may misdiagnose. A further issue is that people with legionellosis can present with a wide range of symptoms, some of which (such as diarrhea) may distract clinicians from making a correct diagnosis.

Treatment

Effective antibiotics include most macrolides, tetracyclines, ketolides, and quinolones.

Prevention

Legionella growth can only be sustained in water if nutrients are available, either from the source water or from other microorganisms. Thus, poor quality water or water that has not been effectively treated may allow legionellae to proliferate within the system.
Bacteria in water systems tend to adhere to surfaces and develop an organic protective matrix, creating microenvironments known as biofilms.
Legionellae can thrive in biofilms, either directly or as parasites of certain protozoa that graze on the films. Low flow rates supporting the establishment of biofilms.
Clean, disinfected water, sufficient flow rates, temperatures over 66°C and biofilm removal eluding Legionella its livelihood.

TwinOxide

Chlorine dioxide is not only removing sporae, bacteria and viruses it also kills protozoa like amoeba hosting legionella.
Additional chlorine dioxide is removing already established biofilms.

Mazingira Technologies

We are not only providing TwinOxide as a easy to use chlorine dioxide delivery system we also provide dosing systems to ensure a constant and efficient water disinfection.
We are providing the Water Quality Services Division of the Ministry of Water with labratory reagents and equipment to test water for legionella.
Beside sample taking and laboratory services our consulting services include how to establish a monitoring system for your water system to prevent legionella contamination.

Sources

http://www.who.int/mediacentre/factsheets/fs285/en/
http://www.who.int/entity/water_sanitation_health/emerging/legionella.pdf
https://en.wikipedia.org/wiki/Legionnaires'_disease

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