Legionellosis as an emergent disease (Adrià Claret, Albert Masmartí, Gerard Pompido, Oriol Iranzo)
Introduction:
Legionella is a recent discovered bacteria which was discovered in 1976. Even though is a recent bacteria, nowadays the treatment for this bacteria exists. So in this article we’ll talk about what is Legionella,what kind of diseases it can cause and it’s history.
What is?
Legionellosis is caused by the bacterium Legionella, which is an aerobic gram-negative bacillus that is spread through aerosolized water particles It’s severity ranges from a mild flu syndrome to severe pneumonia, sometimes fatal. It affects the respiratory tract. The symptoms are fever, headache, lethargy, muscle aches, diarrhea and, sometimes, bloody cough. The disease can be treated with antibiotics.
There are two types of infection caused by Legionella:
- Pontiac fever: it’s a milder infection with fever and muscle aches that last no longer than a week as the main symptoms.
- Legionnaires’ Disease: more severe infection, that results in pneumonia.
Who have the greatest danger?
Most people exposed to the causative bacteria don’t get sick, and the disease is not transmitted directly from person to person. The majority of patients are over 50 years old. The greatest risk corresponds to people with weakened immune systems or chronic diseases and to smokers and heavy drinkers. The outbreaks are usually related to air conditioning and water distribution systems, humidifiers and jacuzzis with poor maintenance.
Where it produce?
Legionellosis occurs throughout the world, but its frequency is unknown because many countries don’t have a good surveillance systems to detect and diagnose it.
In Australia, Europe and the United States of America, about 10 to 15 cases per million inhabitants are detected.
The bacterium colonizes cooling towers or other facilities that contain water at temperate temperatures, where it tends to multiply. If these bacteria move in aerosols (tiny drops) they can be inhaled, reach the lungs and start the disease. It is not spread from person to person.
How to prevent it?
The threat posed by legionellosis to public health can be reduced by regular cleaning, disinfection and maintenance of air conditioning and water distribution systems to minimize the growth of the causative bacteria. There are no vaccines against legionellosis.
Facilities that can transmit legionellosis:·
High risk facilities:
o Cooling towers and evaporative condensers.
o Industrial humidifying power stations that generate aerosols.
o Sanitary hot water systems with accumulator and return circuit.
or Thermal facilities.
o Jacuzzis, hot tubs and similar facilities.
o Cooling towers and evaporative condensers.
o Industrial humidifying power stations that generate aerosols.
o Sanitary hot water systems with accumulator and return circuit.
or Thermal facilities.
o Jacuzzis, hot tubs and similar facilities.
Low risk facilities:
o Humidifiers.
o Ornamental fountains
o Urban sprinkler irrigation systems.
o Fire water systems.
o Other devices that accumulate water and can produce aerosols.
o Humidifiers.
o Ornamental fountains
o Urban sprinkler irrigation systems.
o Fire water systems.
o Other devices that accumulate water and can produce aerosols.
¿Why is it called like that?
The name came from the first identification of the disease in 1976 when 182 people got sick and 29 died after attending the 3-day annual American Legion convention at the Bellevue-Stratford Hotel in Philadelphia, Pennsylvania. After 6 months of investigating, the CDC found the culprit: a previously unrecognized bacteria. This bacteria had been reproducing in the hotel's air conditioning system, in warm conditions. The bacteria subsequently spread to different rooms via water droplets in the air, going to the Legionnaires' lungs where the bacteria could cause a pneumonia. That explains the name of this bacteria: Legionella pneumophila.
Legionella pneumophila:
Legionella pneumophila is a Gram-negative bacterium with the form of a bacillus. It lives in stagnant waters at high temperatures and its growth is favored by the presence of organic matter. It requires oxygen to breathe and has a flagellum to move. 16 subgroups of L. pneumophila have been identified. Of the more than 30 species of Legionella that are known, Legionella pneumophila is responsible for the majority of infections in humans. It is the origin of 10% of cases of pneumonia, both in those acquired in the community and in hospitals.
In some countries it must to carry out controls for the prevention of legionellosis in facilities that use water in their operation, produce aerosols and are located inside and outside buildings for collective use, industrial facilities or means of transport.
The medium used for the isolation of the bacterium is the charcoal yeast extract agar.
History:
Since first legionellosis outbroke in Philadelphia in 1976, the disease has been transmitted from person to person colonizing different water installations where the L.pneumophilia bacteria can grow in biofilms, and there have been 3 important outbreaks of legionelosis so far.
The greatest outbreak was in July 2001 in Murcia, Spain , where it caused 6 deaths and more than 600 infected ones. The focus of the infection was in ventilation towers at El Corte Inglés, at the Health Service, at the Ministry of Agriculture and in the central office of Caja Murcia.
Another outbreak took place in 2014, in Catalonia, and there were about 10 deaths and more than 40 infected ones. However, in that case the focus was never found.
The last one was in Úbeda, Jaén, and it caused 4 infected people who were hospitalized. And again the focus was never found.
Conclusions:
We will wait till the revision.
Bibliography
· Legionella feeleii: pneumonia or Pontiac fever? Bacterial virulence traits and host immune response. Wang C, Chuai X, Liang M. https://www.ncbi.nlm.nih.gov/pubmed/30386929
· Legionnaires' Disease (Legionella Infection). Gossman WG, Sundaresha V. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2018-. 2018 Aug 22. https://www.ncbi.nlm.nih.gov/pubmed/28613558
· Legionnaires' Disease: Why Is This Potentially Deadly Disease Seemingly On The Rise? Bruce Y. Lee. Sep 3, 2018, 12:22pm. https://www.forbes.com/sites/brucelee/2018/09/03/legionnaires-disease-why-is-this-potentially-deadly-disease-seemingly-on-the-rise/
Legionella (enfermedad del legionario y fiebre de Pontiac). Centro Nacional de Inmunización y Enfermedades Respiratorias (NCIRD), División de Enfermedades Bacterianas. April 30, 2018.
Els treball és correcte en línies generals, però cal aprofundir en alguns aspectes i eliminar informació menys rellevant com el descobriment de la malaltia. No parleu de que el cicle d’infecció en els macròfags cel.lulars és essencial per la supervivència de Legionel.la a la natura, però a la natura no hi ha macròfags, aquests es troben als nostres pulmons. Com ho fa la Legionel.la per multiplicar-se i sobreviure en el medi natural?. Cal que expliqueu la importància dels biofilms i les relacions de parasitisme que estableix Legionella com a mecanismes de supervivència i dispersió. Seria interessant aprofundir en els sistemes de desinfecció, a quin tipus d’ambient s’apliquen cadascun d’ells: aigües, superfícies, sistemes de refrigeració, etc..... Caldria citar el BOE i especificar quins sistemes de desinfecció s’exigeixen en funció del tipus d’instal.lació. Per altra banda seria interessant que comentéssiu com es pot cultivar i identificar. Quines tècniques d’identificació es fan servir?.
ResponderEliminarHi ha algun tipus d’estacionalitat en la transmissió de la malaltia (primavera, tardor)?. Si hi ha un augment dels casos a la tardor o primavera, ho podeu mostrar amb resultats gràfics. Hi ha algun estudi que demostri la prevalència dels casos en funció de factors ambientals?. Pel que s’exposa al treball no sembla que en hotels o spass tingui importància la transmissió de la malaltia quan es coneix que hi ha hagut casos declarats en aquests tipus de serveis.