Legionnaire’s Disease Awareness: How It Spreads and How to Stay Safe
Summary: Legionnaire’s Disease is a severe form of pneumonia caused by Legionella bacteria found in water systems. This article explains its origins, symptoms, risks, treatment, and key preventive measures to stay safe.
Origin
The 58th annual convention of the American Legion was held in Philadelphia in the year 1976. As many as 200 people were affected by a type of severe pneumonia, of which 29 succumbed to the disease, thereby giving it the name Legionnaire’s Disease. It was associated with the inhalation of the aerosolised water of the improperly maintained air conditioning system of the hotel.
Legionella bacteria are known to cause Legionnaire’s Disease (severe pneumonia) and Pontiac fever (mild fever with muscle pains and headaches).
Home of the Legionella bacteria
Legionella bacteria are naturally found in freshwater environments, i.e. lakes, hot springs, creeks, and streams. However, these minimal levels are not potentially harmful.
The bacteria can also be found in man-made building water systems, drinking water systems, cooling towers of large air conditioning systems, the water present in the fluid tank (of the windshield wipers) of a vehicle, hot tubs and spas, showers and faucets, humidifiers and decorative fountains, swimming pools, and birthing pools.
The bacteria thrive in water and are capable of rapid growth in the following conditions:
- Biofilm – the slime facilitates the rapid growth of germs
- Temperatures ranging between 20oC to 50oC
- Improper disinfecting of the water body
- Slow-moving or stagnant water
How does Legionnaires’ Disease spread?
- When a person breathes in aerosolised water (mist in air conditioners) or soil that is contaminated with Legionella bacteria, it leads to atypical pneumonia called Legionnaire’s Disease.
- Aspiration – coughing or choking while drinking water, causing water to enter the lungs mistakenly
- By contaminated water entering a wound, open or cut skin
- By entering your nostrils during a nasal rinse/using a neti pot
- By storing contact lenses in water
- By water splashed on the eyes (when you are wearing contact lenses)
- By contact with contaminated soil while gardening or using potting soil
Symptoms to watch out for
The following are the symptoms of Legionnaire’s Disease:
- Fever, headache, and muscle ache on the initial days
- Followed by cough (with mucus), shortness of breath, nausea, vomiting, diarrhoea, chest pain. These symptoms are generally noticed after a period of 2 to 14 days, or even longer, after exposure to the bacteria.
Diagnosis of Legionnaire’s Disease
A chest x-ray can show the presence of pneumonia, and to check if it is Legionnaire’s Disease, the following tests are recommended:
- Urine test
- Laboratory testing, which involves taking samples of (I) sputum (phlegm) and (II) washing from the lung
Treatment of Legionnaire’s Disease
- Antibiotic medication
- In some cases, hospitalisation and observation with treatment
In extreme cases, there are chances of lung failure, septic shock, kidney failure, and death from complications arising from the disease.
Who is susceptible to Legionnaire’s Disease
- Infants aged 6 months or younger
- Adults aged 50 years and above
- Patients with health conditions like chronic lung disease [including chronic obstructive pulmonary disease (COPD)and emphysema], diabetes, weakened immune system, liver failure, kidney failure, and cancer.
- People who wear contact lenses
Preventive measures
The following preventive measures may curb the bacteria:
- Let the water flow out of the faucet for two minutes, for hot and cold, respectively, before use
- Use of proper biocides or chemical treating of large cooling towers
- Removal of stagnant water from the HVAC system
- Follow proper cleansing process for devices like portable humidifiers, CPAP machines, neti pots, showerheads and faucets, water filters, air conditioning systems,
- Use professional cleaning services for gyms, large organisations with industrial air-cooling systems
- Get your vehicle cleaned and sanitised frequently
The following preventive measures may curb the bacteria:
- Let the water flow out of the faucet for two minutes, for hot and cold, respectively, before use
- Use of proper biocides or chemical treating of large cooling towers
- Removal of stagnant water from the HVAC system
- Follow proper cleansing process for devices like portable humidifiers, CPAP machines, neti pots, showerheads and faucets, water filters, air conditioning systems,
- Use professional cleaning services for gyms, large organisations with industrial air-cooling systems
- Get your vehicle cleaned and sanitised frequently
- The disease does not spread through personal contact.
Studies And Research
- A study shows that affected patients displayed signs of fatigue (75%), neurological symptoms (66%), and neuromuscular symptoms (63%) after recovery.
- A study conducted by the research team from New York showed the following results:
Taking into consideration the temperature, precipitation, and UV light, it was seen that the “air concentration of sulphur dioxide – a component of air pollution- decreased in New York” simultaneously with the rise of LD cases. “With the falling of sulphuric acid levels with decreasing pollution, the bacteria that survived were airborne for longer periods, thereby increasing the risk of infection”. The results stated that this possible connection “may help understand transmission, predicting risks and designing interventions.”
- [5] A surveillance summary published in the Morbidity and Mortality Weekly Report, following research carried out by the US Centres for Disease Control and Prevention (CDC), showed the findings “from tracking waterborne disease outbreaks involving drinking water from 2015 to 2020. Public health departments, regulators, and drinking water partners can use these findings to identify emerging waterborne disease threats, guide outbreak response and prevention programs, and support drinking water regulatory efforts.”
Raising awareness about the proper and effective maintenance of the water systems is the key solution to combat this infection. All Institutions should take proactive measures to keep the bacteria at bay. After all, prevention is better than a cure.
- Medicine and Diseases
- 16 September 2025
- 11:00
