Legionnaires Disease – Symptoms and Causes

What You Need to Know

Legionnaires’ disease is a severe type of pneumonia caused by legionella bacteria. People usually get infected by breathing in water or soil particles containing these bacteria.

The disease poses higher risks for older adults, people who smoke, and those with weak immune systems.

This same bacterium causes a less severe illness called Pontiac fever. While Pontiac fever usually gets better without treatment, Legionnaires’ disease can be deadly if not treated properly.

The good news is that antibiotics usually work well against Legionnaires’ disease when given early. However, some patients may still have health problems even after treatment.

Symptoms

Legionnaires’ disease typically develops 2-10 days after a person encounters legionella bacteria. Early symptoms often include:

• Headache
• Muscle pain
• High fever (possibly reaching 104°F/40°C)

As the illness progresses to the second or third day, additional symptoms may appear:

• Cough (sometimes producing mucus or blood)
• Difficulty breathing
• Pain in the chest
• Digestive problems (nausea, vomiting, diarrhea)
• Mental confusion or changes

While Legionnaires’ disease mainly affects the lungs, it can occasionally cause infections in other body parts, including wounds and the heart.

A milder version called Pontiac fever produces symptoms like fever, chills, headache and muscle aches without infecting the lungs. Pontiac fever typically resolves within 2-5 days without treatment.

It’s important to seek medical attention if these symptoms appear, especially after potential exposure to legionella bacteria in water systems or cooling towers.

When to See a Doctor

Early diagnosis and treatment of Legionnaires’ disease can:

• Reduce recovery time
• Prevent serious complications

Quick medical attention is especially important for high-risk individuals, including:

• Older adults
• Smokers
• People with weakened immune systems

Don’t delay seeking medical care if you develop symptoms after possible exposure.

What Causes Legionnaires’ Disease

Legionnaires’ disease primarily occurs when people breathe in tiny water droplets containing Legionella pneumophila bacteria. In nature, these bacteria live in soil and water without causing many problems. The danger comes when they multiply in human-made water systems.

Most infections happen in large buildings rather than homes. This is because complex water systems provide ideal conditions for bacterial growth and spread. Common sources of infection include:

• Cooling towers in building air conditioning systems
• Hot tubs and whirlpool spas
• Water heaters and storage tanks
• Decorative fountains
• Swimming and birthing pools
• Contaminated drinking water supplies

Other ways infection occurs:

1. Aspiration: You accidentally inhale water while drinking. If the water contains Legionella bacteria, it can cause infection in your lungs.

2. Soil Exposure: Some cases have been linked to gardening or using contaminated potting soil.

Home and car air conditioners rarely cause infections because they don’t use water for cooling. However, home plumbing can sometimes harbor the bacteria, though this is less common than building-related outbreaks.

The bacteria thrive in warm water systems where they can multiply rapidly. When water containing these bacteria is released as mist or spray, people nearby can breathe in the contaminated droplets and develop the disease.

Risk Factors

People who face higher chances of getting sick from legionella bacteria include:

• Smokers – smoking harms the lungs, making them more vulnerable to infections.
• People with weakened immune systems – this includes those with HIV/AIDS or those taking certain medications like corticosteroids or anti-rejection drugs.
• Adults over 50 years old.
• Individuals with chronic health conditions – such as emphysema, diabetes, kidney disease, or cancer.

Hospitals and nursing homes present special concerns for legionnaires’ disease. In these settings, the bacteria can spread more easily, and many patients already have health issues that make infection more likely.

Complications

Legionnaires’ disease can cause serious, potentially fatal complications without prompt treatment. These include:

• Respiratory failure: The lungs become unable to provide adequate oxygen to the body or remove carbon dioxide from the bloodstream properly. This is one of the most severe outcomes.
• Septic shock:
  • Characterized by a sudden, dangerous drop in blood pressure
  • Reduces blood flow to vital organs, especially the brain and kidneys
  • Forces the heart to work harder, eventually weakening it
  • Further decreases blood circulation throughout the body
• Acute kidney failure: This sudden loss of kidney function prevents proper filtering of waste from the blood. As a result, harmful levels of waste and fluid build up in the body.

Prevention

Water management systems in buildings play a key role in preventing Legionnaires’ disease outbreaks. Regular monitoring and cleaning of water systems help reduce risks.

On a personal level, avoiding smoking can lower your risk. Smoking damages the lungs and makes them more vulnerable to infection.

Proper building maintenance includes:

• Regular water testing
• Appropriate disinfection procedures
• Temperature control of water systems
• Cleaning of cooling towers

These measures can significantly reduce the chance of bacteria growth in water systems.