Legionnaire's Disease

Conventionally speaking, Legionnaire's disease is a type of pneumonia (lower respiratory tract infection) that is caused by a bacterial agent, legionella pneumophila. Although this bacterial agent has resulted in several cases of pneumonia for centuries, yet the biggest outbreak was reported in the year 1976 when a large group of people got infected in American legion convention. Since then, a large number of cases are routinely identified as physicians conduct specific testing and investigations to identify the pathogen. A specific season for getting legionnaire's disease is not yet identified and you can develop this infection around the year, but based on clinical data the incidence increases during early fall and summers.

Pontiac fever is another milder respiratory condition that is caused by the same causative agent i.e. legionella pneumophila and presents as flu-like illness.

What Are the Symptoms of Legionnaire's Disease

The initial symptoms of legionnaire's disease are mild in nature, but if no interventions or therapeutic measures are taken, the risk of developing more painful and complicated condition respiratory illness increases – also referred to as pneumonia.

The incubation period of legionella pneumophila is 6-8 days after the bacterial agent gains access within the human body. The symptoms begin to appear after 2 to 18 days of getting infection.

Initial symptoms of the disease include:

  • Flu like symptoms
  • Muscular pain
  • Headache (mild type)

Severe symptoms include:

  • High grade temperature
  • Severe muscular twitching pain
  • Muscle fatigue
  • Development of nervous disorders such as confusion etc.

Pneumonia symptoms include:

  • Dry cough at initial level leading to mucus and blood filled cough
  • Pain in the chest
  • Difficulty in breathing, causing shortness of breath


Complication of legionnaire's disease includes gastrointestinal symptoms such as loss of appetite, nausea, vomiting, stomach upset and diarrhea.

When to See a Doctor

Sever conditions such as chest pain and shortness of breath needs an emergency medical treatment. If you are noticing any of the symptoms (specifically high grade fever, difficulty breathing or impaired levels of consciousness) you may need urgent medical consultation to minimize the risk of life threatening complications. Additionally, you should seek early treatment for the pneumonia to restore optimal quality of life.

What Are the Causes & Risk Factors of Legionnaire's Disease?

Legionnaire's disease is caused by legionella pneumophila. It can enter from outdoor sources such as soil and mud. Indoor sources of water contamination include bath tubs, stagnant water places (pots), air conditioners etc.Other sources of water contamination include therapy equipment’s, pools, fountains, water retention and recycling system.

Risk Factors

Significant risk factors that may increase the risk of Legionnaire's disease are:

  • Persons who smoke frequently
  • Persons with compromised or weakened immune system
  • Persons who are suffering from any chronic type of lung disease
  • Persons who are older than 55years of age (especially men)

What Are the Treatments for Legionnaire's Disease?

As it is bacterial infection, the foremost treatment provided is antibiotics. The course of antibiotics should ideally be continued from 5 to 7 days. Complete recovery from this disease may take about 2-4 months. Generally symptomatic treatment is provided to maintain the normal day to day activities in sufferers. This includes:

  • In order to maintain optimal circulatory pressure and optimal levels of hydration, take plenty of fluids and maintain fluid balance in the body.
  • You can use over the counter painkillers such as acetaminophen to reduce the intensity of pain.
  • Non-steroidal anti-inflammatory (NSAIDS) drugs are also a good option for relieving pain, acute inflammation and discomfort.
  • Cough suppressants medications are also administered.

Note: Non-steroidal anti-inflammatory medicines such as aspirin must be given with care to patients who are under 20 years of age. If the symptoms are mild and infection is not complicated, then no significant treatment is required. This is mainly because most cases of Legionnaire's pneumonia resolves spontaneously in immune-competent individuals.

How to Prevent Legionnaire's Disease

The most common source of spreading legionnaire's disease and legionella pneumonia is water contamination, so major preventive care should be taken to clear all water sources from possible sources of infection. Air conditioning nowadays is considered as a necessary need, but it is imperative to keep in mind that most air circulation sources are a significant threat to the respiratory wellness. Contaminated air circulation also plays a vital role in spreading legionella pneumonia (hence also referred to as air conditioning illness).

  • In your house ensure that all pipelines that supply water are non-contaminated and does not contain any water with pathogen that may lead to legionella infection.
  • Maintain a regular flow of water in the pipelines as stagnant water leads to the inoculation and spread of this infection.
  • A high temperature should be maintained so that the heat does not permit the progression of growth of bacteria.
  • Before travelling abroad, always consult a medical practitioner to ensure your safety and vaccination status. Unfortunately, so far there is no vaccination that offers protection against this infection, yet early identification of symptoms may help in optimizing treatment options.

Watch the video below to have a quick view on Legionnaire's disease:

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