GC: n

S: WHO – http://www.who.int/water_sanitation_health/emerging/legionella.pdf (last access: 9 December 2015); WHOI.EDU – http://www.whoi.edu/oceanus/feature/legions-of-legionella-bacteria (last access: 9 December 2015).

N: 1. This term comes from Latin legio, -onis, a body of soldiers, legion; L. fem. dim. ending -ella; N.L. fem. n. Legionella, small legion or army.
2. Legionella is related to the genus Coxiella. Legionella is best known for causing Legionnaire’s disease. The bacteria are ubiquitous. Although largely aquatic, they can thrive in areas other than lakes and streams.
Legionella are Gram-negative. They can be rod- or coccoid-shaped. Most species are motile, and have one to three polar or lateral flagellae.
3. This pathogenic bacteria has its origen in 1976, discovered by a mysterious epidemic of fatal respiratory disease in Philadelphia. But there were other unsolved epidemics of acute respiratory disease, which were attributed to Legionella, dating to the 1950s.
4. Structural Oddities:

  1. Multiply where temperatures are between 20-45°C and nutrients are available. The bacteria are dormant below 20°C and do not survive above 60°C.
  2. It has a feature unique lipopolysaccharide structures on their outer cellular membranes.
  3. It is also unique in that the presence of antibodies and complement has little effect in squelching an infection.

5. How do people contract Legionella?

  1. The organism is aerosolized in water and people inhale the droplets containing Legionella.
  2. Aspiration

6. When people are exposed to the bacterium, it can cause the following illness:

  1. Legionnaires’ disease: Pneumonia (lung infection).
  2. Pontiac fever: Patients can have fever, headache, and body aches for a few days but improve without antibiotic treatment

7. The control of legionella bacteria in water systems: approved Code of Practice and guidance on regulations (L8, Fourth edition, Published 2013).

S: 1. DORLAND – https://goo.gl/4yt3L5 (last access: 11 December 2015); LPSN – http://goo.gl/ie2CpO (last access: 11 December 2015). 2. KENYON.EDU – https://goo.gl/AdzZ8x (last access: 11 December 2015); BIO.DAVIDSON.EDU – http://goo.gl/Garv7o (last access: 11 December 2015). 3. NCBI – http://goo.gl/2zfkB6 (last access: 11 December 2015); WHO – http://goo.gl/FAjHcs (last access: 11 December 2015); BBC – http://goo.gl/W06apf (last access: 11 December 2015). 4. BIO.DAVIDSON.EDU – http://goo.gl/Garv7o (last access: 11 December 2015); HSE.GOV – http://goo.gl/oOSzrn (last access: 11 December 2015). 5. LEGIONELLA.ORG – http://goo.gl/2WUpxD (last access: 11 December 2015); PHAC.ASPC – http://goo.gl/6LSXOE (last access: 11 December 2015). 6. CDC – http://goo.gl/APkks9 (last access: 11 December 2015). 7. HSE.GOV – http://goo.gl/IlpeXU (last access: 11 December 2015).


CR: bacterium, legionellosis, pneumonia.