Legionnaires' disease

Tiny germs live in fresh water.

They like to stay in warm water. They can hide in hot tubs or big air machines.

These germs spread through wet mist. You might breathe them in from a fountain. This can make you feel very sick.

It can cause a bad cough. You might also get a high fever. Some people feel muscle pains too.

Most people do not get sick from these germs. It does not spread from person to person.

Doctors use medicine to help people get well. Keeping water clean helps keep everyone safe.

Legionnaires' disease is a type of pneumonia. It is caused by tiny germs called Legionella bacteria.

These germs live naturally in fresh water. They like to grow in warm water. You might find them in hot tubs or large air conditioning systems.

People get sick by breathing in a fine mist. This mist can come from fountains or cooling towers.

Most people who breathe the mist do not get sick. The disease does not spread from person to person.

If you do get sick, you may have a high fever. You might also have a cough or muscle pains. Some people feel very tired or have a headache. It can take two to ten days for symptoms to start.

Doctors can find the germs with special tests. They may test a person's urine or mucus.

Doctors use antibiotics to treat the illness. These are medicines that fight the bacteria. Keeping water systems clean and at the right temperature helps prevent the disease.

Legionnaires' disease is a serious type of pneumonia. It is caused by tiny living things called Legionella bacteria.

Most cases come from one specific type called Legionella pneumophila. This disease is part of a group called legionellosis. Another related illness is called Pontiac fever. Pontiac fever is much milder and does not cause pneumonia. Legionnaires' disease matters because it can make people very sick. It is estimated that the disease causes 2% to 9% of pneumonia cases found outside of hospitals.

The bacteria spread in a specific way. They live naturally in fresh water. They grow best in warm water between 77 and 113 degrees Fahrenheit.

People get sick by breathing in a fine mist of water. This mist might come from a cooling tower or a hot tub. The bacteria can also enter the body if someone swallows contaminated water. Once inside the lungs, the bacteria enter white blood cells called macrophages. The bacteria multiply inside these cells and then cause the cells to die. This process causes the lung infection.

We know about this disease because of a famous event. The name comes from an outbreak in 1976. This happened at an American Legion convention in Philadelphia. Investigators found the bacteria in the cooling system of a hotel. Since then, cases have been found all over the world. In the United States, between 8,000 and 18,000 people are hospitalized for this every year. Scientists have also developed tests to find the bacteria more quickly. One helpful test for urine was made by Richard Kohler in 1982.

There are many facts to know about the illness. Symptoms usually start 2 to 10 days after exposure. A person might have a high fever, chills, or a cough. Some people also have headaches or muscle pains. About half of the sick people also have stomach issues like vomiting. The disease is harder on certain people. It is more dangerous for older people or those who smoke. For healthy people, the fatality rate is about 10%. For people with other health problems, it can be as high as 25%.

Doctors use different tools to help people get better. They use a urine antigen test to look for the bacteria. They may also look at mucus or use chest X-rays.

To treat the infection, doctors use antibiotics. These are medicines that fight the bacteria. We can prevent the disease by keeping water systems clean. We must keep water either very hot or very cold. This keeps the bacteria from growing in pipes or tanks. Keeping water moving also helps stop the bacteria from settling.

Legionnaires' disease is a serious form of atypical pneumonia. This illness is caused by bacteria from the Legionella genus. While several species exist, the most common is Legionella pneumophila.

This bacterium causes over 90% of all Legionnaires' disease cases. The term legionellosis describes any disease caused by these bacteria. This group includes both Legionnaires' disease and a milder illness called Pontiac fever. Pontiac fever causes fever and muscle aches but does not lead to pneumonia. Legionnaires' disease is much more severe and requires careful medical attention.

The bacteria enter the human body through the respiratory system. Most people become infected by breathing in aerosolized water. An aerosol is a fine mist of water droplets suspended in the air. This mist can come from cooling towers, hot tubs, or even decorative fountains. In some rare cases, the bacteria enter the body if contaminated water is swallowed or enters a surgical wound. Once the bacteria reach the lungs, they target specific immune cells called macrophages. These white blood cells are meant to destroy invaders. However, Legionella bacteria are clever parasites. They enter the macrophage and prevent it from working correctly. Specifically, they block the fusion of phagosomes with lysosomes. Normally, a lysosome uses enzymes to break down bacteria inside a cell. By stopping this process, the bacteria multiply inside the macrophage until the cell dies. The bacteria are then released to infect more cells.

Legionella bacteria live naturally in fresh water environments like ponds and creeks. They thrive in specific conditions, particularly in man-made water systems. The bacteria grow best in warm water between 77 and 113 degrees Fahrenheit.

They can survive as intracellular parasites inside amoebae, which are tiny water-dwelling organisms. When bacteria and amoebae live together in a biofilm, they become very hard to destroy. A biofilm is a layer of microbes that sticks to the inside of pipes. Because of this, many different objects can harbor the bacteria. These include hot water tanks, humidifiers, nebulizers, and large air conditioning systems in hotels or hospitals. Even grocery-store misting systems used for produce can be a source.

The history of this disease began with a major outbreak in 1976. This event occurred during an American Legion convention in Philadelphia. Investigators traced the source of the illness to the cooling system of a hotel. This discovery led to the name we use today. Since then, cases have been found all over the world. In the United States alone, between 8,000 and 18,000 people are hospitalized for this disease every year. It is estimated that Legionnaires' disease causes between 2% and 9% of all pneumonia cases acquired outside of a hospital.

Symptoms of the disease usually appear 2 to 10 days after a person is exposed. In rare cases, symptoms may take up to 20 days to show. Common signs include high fever, chills, and a cough. The cough may be dry or produce sputum, which is thick mucus. About one-third of patients may cough up blood. Many people also experience muscle aches, headaches, and tiredness. About half of the patients suffer from gastrointestinal symptoms like vomiting or diarrhea. Neurological symptoms, such as confusion, can also occur in nearly half of those infected.

Diagnosis can be difficult because the symptoms look like other types of pneumonia. Doctors use several tools to confirm the disease. A urine antigen test is a common method. This test looks for specific proteins from the bacteria in urine. Richard Kohler developed a version of this test in 1982. While fast and reliable, it mostly only detects the most common subtype, Legionella pneumophila serogroup 1. Doctors may also use a sputum culture to grow the bacteria from mucus. Chest X-rays are also used to look for signs of pneumonia in the lungs.

Prevention focuses on managing water systems to stop bacteria from growing. One way to do this is by controlling water temperature. Keeping water either very hot or very cold can prevent Legionella from thriving. It is also important to prevent water stagnation. Stagnation happens when water sits still in pipes for a long time. Regular disinfection using chemicals like monochloramine can also help. This chemical is effective because it can penetrate biofilms. While there is no vaccine, good maintenance of building water systems is the best defense.