Summary
Legionnaires’ disease or Legionellosis is a bacterial infection caused by the microbe Legionella pneumophila (L. pneumophila). The bacteria have the ability to affect multiple body systems but mainly affects the lungs. L. pneumophila causes a severe form of pneumonia that is often times fatal. It occurs worldwide but the United States has the highest incidence of reported cases. L. pneumophila is found in freshwater environments and human made building water systems.
| Formal binomial name of microbe: | Legionella pneumophila (L. pneumophila) |
| Gram stain (gram positive, gram negative or neither): | Gram negative |
| Is the microbe mobile or immobile? | Mobile |
| Primary habitat? (Where is the organism normally found or prefer to live?) | Freshwater environments and human made building water systems |
| Can the organism infect humans? | Yes |
| Can the organism infect other species? If so, which ones. | One case reported in 1998 in a calf in Italy. Other evidence of cases unknown. |
| Documented cases of antimicrobial resistance? | Yes |
| Number of infections per year in the US | 10,000-18,000 |
| Number of infections per year in the world | Unable to find as its not well reported or tracked in other countries. |
Causes
Legionnaires’ disease is contracted by inhaling the bacteria through contaminated water mist. L. pneumophila is naturally occurring in freshwater environments such as lakes and rivers. It is mostly a concern when it starts growing in places like hot tubs, air conditioners, and mist sprayers such as those in grocery store produce departments. Each year the US reports 10,000-18,000 cases of Legionella pneumophila. Other countries and animal cases have limited reports available as cases aren’t tracked as frequently.
Symptoms
Symptoms of Legionnaires’ disease include: cough, shortness of breath, fever, muscle aches, and headaches. It can also be associated with diarrhea, nausea, and confusion. People usually begin to exhibit symptoms within 2 to 10 days after exposure. People at increased risk of developing symptoms are those 50 years or older, current or former smokers, have chronic lung disease such as chronic obstructive pulmonary disease or emphysema, have decreased immune systems or are taking immunosuppressants, or have a chronic disease such as diabetes, kidney failure, or liver failure. Healthy people with exposure to the bacteria typically do not experience any of the above symptoms. Legionnaires’ is usually treated with antibiotics such as rifampicin, doxycycline and azithromycin. Resistance has been noted with the use of ciprofloxacin, erythromycin, clarithromycin, and moxifloxacin.
Severe case of Legionellosis seen on x-ray.
Prevention
Prevention includes thorough cleaning of standing water systems such as pools and spas as well as disinfection of these sources. Caution should be used at the grocery store for at risk patients to avoid the produce area while sprayers are activated. Meticulous hand hygiene and cleansing of fresh fruits and vegetables should also be used. If you believe you have been exposed to L. pneumophila, you should see your healthcare provider immediately and notify them of your possible exposure.
News on Legionnaires’ Disease
22 cases of Legionnaires’ Disease have been reported in a city in Union County New Jersey of which five people have died. The CDC is working with their local health department to further investigate the outbreak. Battle, P. (2019, May 24). 5 Dead in Legionnaires’ Disease Outbreak Tied to 1 NJ County. https://www.nbcnewyork.com/news/local/Legionnaires-Disease-Deaths-Cluster-New-Jersey-Union-County-Health-Department-510385801.html
McLaren Hospital in Flint, MI is being ordered by the state health department to correct its current problems leading to the outbreaks of Legionella at this facility. Out breaks have been reported at this facility since 2014 with two recent cases reported earlier this year. Carmody, S. (2019, June 12). Flint hospital threatens legal action after state order on Legionnaires’ disease. https://www.michiganradio.org/post/flint-hospital-threatens-legal-action-after-state-order-legionnaires-disease
The Vale of Glamorgan in Wales has had a high number of Legionnaires’ disease cases over the last ten months. There have been 10 cases so far this year in the Vale of Glamorgan whereas 2018 there were only 7. All of Wales typically sees a total of 30 Legionnaires’ disease cases each year. Stephens, L. (2019, June 21). Hunt for source of deadly Legionnaires? disease after nine cases. https://www.walesonline.co.uk/news/health/mystery-over-source-potentially-deadly-16468074
References
Battle, P. (2019, May 24). “5 Dead in Legionnaires’ Disease Outbreak Tied to 1 NJ County.” nbcnewyork.com, https://www.nbcnewyork.com/news/local/Legionnaires-Disease-Deaths-Cluster-New-Jersey-Union-County-Health-Department-510385801.html
Carmody, S. (2019, June 12). “Flint hospital threatens legal action after state order on Legionnaires’ disease.” michiganradio.org, https://www.michiganradio.org/post/flint-hospital-threatens-legal-action-after-state-order-legionnaires-disease
Fabbi, M., Castellani Pastoris, M., Scanziani, E., Magnino, S., & Matteo, L. (1998, July). “Epidemiological and Environmental Investigations of Legionella pneumophila Infection in Cattle and Case Report of Fatal Pneumonia in a Calf.” ncbi.nlm.nih.gov, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC104957/
“Legionnaires’ disease – Symptoms and causes.” (2018, January 11). mayoclinic.org, https://www.mayoclinic.org/diseases-conditions/legionnaires-disease/symptoms-causes/syc-20351747
“Legionnaires Disease Cause and Spread | Legionella | CDC.” (2019, February 25). cdc.gov, https://www.cdc.gov/legionella/about/causes-transmission.html
“Legionnaires’ Disease | Legionella Pneumonia.” (2018, August 2). medlineplus.gov, https://medlineplus.gov/legionnairesdisease.html
Rahimi, B., & Vesal, A. (2019). “Antimicrobial Resistance Properties of Legionella Pneumophila Isolated from the Cases of Lower Respiratory tract Infections.” biomedpharmajournal.org, http://biomedpharmajournal.org/vol10no1/antimicrobial-resistance-properties-of-legionella-pneumophila-isolated-from-the-cases-of-lower-respiratory-tract-infections/
Stephens, L. (2019, June 21). “Hunt for source of deadly Legionnaires? disease after nine cases.” walesonline.co.uk, https://www.walesonline.co.uk/news/health/mystery-over-source-potentially-deadly-16468074
“Symptoms” – Legionella.org. (2019) http://legionella.org/about-the-disease/what-is-legionnaires-disease/symptoms/
“What is Legionnaires’ disease?” (2016, June 16). mnn.com, https://www.mnn.com/health/fitness-well-being/stories/what-you-need-to-know-about-legionnaires-disease