Legionnaires’ disease

The Legionnaires’ disease is a form of pneumonia. It is caused by Legionella bacteria. The major symptoms of the disease are shortness in breath, cough, fever, headaches and muscle pains. The bacterial infection of Legionella bacteria is called Legionellosis. The Legionellosis includes Legionnaires’ disease, Pittsburgh pneumonia and Pontiac fever.

About the Legionella bacteria

The bacteria are found in fresh water naturally. It is capable of contaminating hot tubs, water tanks, cooling towers. They enter human body when a person breathes in the mist that holds the bacteria. Also, they spread when their contaminated water is aspirated. In other words, they are air borne and water borne. They do not spread through people-to-people contact. No vaccine is available for the bacteria.

About Legionnaires’ disease

The disease is the major cause of 2% to 9% of pneumonia. The number of people affected by the bacteria globally is not known. No international organisation has taken steps to monitor Legionnaires’ disease and its outbreaks. This is because, the outbreak of the disease is rare. The first outbreak was recorded in 1976 in Philadelphia.

Mechanism

The Legionella bacteria enter the lungs through contaminated air or water. The bacteria are consumed by the macrophages in the lungs. Macrophages are white blood cells of the immune system. These macrophages consume anything on their surface that does not contain the individual’s identity. They recognize the identity of the cells by identifying the proteins and other molecules in the cells. In simple words, they consume the foreign bodies in the human system. The bacteria multiply within the macrophages and kills them. By this, the immune system in the lungs collapses. Slowly the lungs become vulnerable to infections and eventually becomes damaged.

Outbreaks

• In 1985, the disease killed 175 people in England.
• In 1999, a large outbreak of Legionnaires’ disease occurred in Netherlands. The outbreak killed 318 people.
• The world largest Legionnaires’ outbreak occurred in 2001 in Spain. More than 800 suspected cases were recorded.
• In 2005, around 127 nursing residents in Canada were infected by the disease. In the same year, 180 people were affected in Quebec of Canada due to contaminated water in cooling tower.
• In 2014, an outbreak occurred in New York affecting 12 people.
• In 2015: North California: 81 people were affected
• In 2017: Portugal
• 2019: Western North Carolina