Legionnaires’ Disease: Symptoms, Causes, Treatment

Legionnaire’s disease is a lung infection caused by a bacteria called Legionella pneumophila. It is a microparasite that survives in an oxygenated environment like water reservoirs.

doctor holding a lung x-ray

In 1976, a lung infection outbreak got 200 hospitalized and 35 died in Philadelphia, Pennsylvania. The incident happened in the American Legion Convention where a new bacterium discovered. The infection got spread through the hotel’s air conditioning system where people inhaled the virus and got sick. After this incident, it became known as Legionnaire’s Disease.

What is Legionnaires’ Disease?

Legionnaire’s disease is a lung infection caused by a bacteria called Legionella pneumophila. It is a microparasite that survives in an oxygenated environment like water reservoirs. They are capable of growing and reproducing inside the cells of their host. Inside the host’s cell, it creates a process generating excess amino acids for its proliferation.

How do you get infected by Legionnaires’ disease?

Usually, the disease is acquired through breathing in the mist. A mist is a cloud environment that allows water particles to suspend in the air, like a fog. This mist may come from a spa, hot tubs, showers, air conditioning of facilities like in buildings, hotels, hospitals and many more.

There is a big chance that one will have the legionnaire’s disease if a person is smoking, has a weak immune system, and usually old people who are above 50.  

There are two ways how one gets infected:

  • Soil: Legionella pneumophila lives in the oxygenated environment. People who are exposed to working with soil; like gardening and farming, have a big risk of acquiring Legionnaires’ disease.
  • Aspiration: This is when liquids enter the lungs through choke while drinking or a cough. If in case the water is contaminated and has accidentally done the aspiration there may be a big chance of getting a legionnaires’ disease.

Symptoms of Legionnaires’ Disease

This disease develops after the exposure with the bacteria for a couple of days, ten days most. And a mild fever experience may take place. This fever called Pontiac fever is an acute and mild upper respiratory infection that has flu-like symptoms. Nausea, fever, headache, and cough may be experienced but without pneumonia. Here are some of the symptoms of Legionnaires’ disease:

  • Headache Symptom: This symptom occurs in any part of the head, a sharp pain that can happen in a certain location or spread across from one point to another.
  • Muscle Pain: this symptom happens when the body feels low and experiences an unusual cause of pain.
  • Fever: the symptom that is linked with the body temperature. One may feel very hot and shivery as this condition happens. The thermometer is used as the tool to read body temperature and identify in what condition the body is.
  • Cough Symptom: this symptom is an instantaneous response of the body from irritants in the airways. It may bring up mucus as the bacteria have penetrated inside and sometimes may involve blood as it worsens.
  • Shortness of Breath: This symptom is a sign of respiratory infection as it is a combination of heart and lung condition that affects the breathing process of a person. Combined with chest pain it is dangerous and needs immediate action.
  • Gastrointestinal problems: symptoms of vomiting that discharges food from the stomach is a bad sign of the infection. Diarrhea too, having a watery stool on a regular basis is an alarming situation that needs medical attention.

Causes of Legionnaires’ Disease

The Legionella pneumophila survives in an oxygenated environment like in soil and water. It can reproduce greatly in all kinds of water systems such as hot tubs, mist sprayers, and so on. Let’s look at the areas where the bacteria is present:

  • Water bodies: Lakes, rivers, and streams even oceans have bacteria as it is a mix of harmless and harmful disease-causing bacteria like Legionella, Giardia Lamblia, and many more.
  • Water systems of establishments: this is a well-designed water system and flow of water supply in an establishment. The use of pipes, valves, and space keep the water in the area and divide it for some time. This water may be infected with various bacteria from different sources like an amoeba.
  • Hot tubs: this is a large pool full of water that is commonly used for relaxation and pleasure. If the water is contaminated by the bacteria there is a big tendency that it may cause legionnaire’s disease.
  • Air conditioning: this could be one of the main causes of the spread of bacteria as humidity affects the whole room through water vaporization and cools the whole room. This leads to people breathing the bacteria in that specific contaminated place.
  • Fountains: this is an infrastructure that pours water into a basin and supply water for drinking or amusement. Bacteria can live in fountains and develop rapidly there over time which may cause infections while drinking water or if accidentally inhaled droplets.

Treatment of the Legionnaires’ Disease

As of the moment, there are no vaccines that can prevent Legionnaire’s disease. One important solution to prevent this is to consistently maintain water systems through water management programs. In this way organisms that can’t be seen don’t stay long and multiply in the waster area. If people get infected and has already experienced the disease these are some of the treatments that need to be executed:

  • Antibiotics: these are specialized medicines that kill bacteria inside the body. This usually takes a week and more depending on the status of the patient. Antibiotics are directly injected into the vein so that it will circulate immediately in the body.
  • Oxygen Therapy: This is a machine that supplies oxygen to a patient that needs a required amount as per prescription. In cases that the Legionnaire’s disease is very grave, this is being used as a treatment for recovery.


Legionnaire’s disease is may cause lung failure and death if there’s no immediate and proper action taken. It is important to consult doctor ones there are things that are unusual with your health and situation. Keeping the water systems clean is very important, may it be in establishments or at home, to avoid complications about health. These are preventable diseases but in preventing this there must be consistency. Consistency in cleaning to disinfect the waterways of your home or establishment.

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