Legionnaires' disease is a severe type of pneumonia caused by the bacteria Legionella. The species Legionella pneumophila causes most cases, but other species of Legionella can also cause the disease. It is named Legionnaires' disease because it was first discovered after a pneumonia outbreak among people who attended an American Legion Convention in Philadelphia, Pennsylvania in 1976. Most people exposed to Legionella do not become sick with Legionnaires' disease. People who do become sick usually develop symptoms within 2 to 10 days after exposure, but it may take longer. The first symptoms may include headache, chills, muscle pains, and a fever that can be 104°F (40°C) or higher. Additional symptoms usually develop 1 to 2 days after the first symptoms and may include coughing, shortness of breath, chest pain, diarrhea, nausea and vomiting, and confusion. While Legionnaires' disease mainly affects the lungs, it sometimes causes infections in other parts of the body, such as the heart or within body wounds. A person can become infected from Legionella when they inhale mist or water droplets that contain the bacteria. Sources of exposure may include showers, faucets, whirlpools, grocery store misters, and water droplets passing through ventilation systems in large buildings (such as hotels, office buildings, and hospitals). People who are more susceptible to developing Legionnaires' disease after an exposure include adults over age 50, current or former smokers, and people who have a weakened immune system or a chronic disease. Generally, neither the bacteria nor Legionnaires' disease is spread directly from person to person. While large exposures can result in outbreaks, the disease usually occurs in single, isolated cases. Legionnaires' disease may be suspected by symptoms. Pneumonia can be confirmed by a chest X-ray. Legionnaires' disease is diagnosed when one of the species of Legionella is found to be the cause of the pneumonia by testing a urine sample (urine culture) or a sample of saliva and mucus that is coughed up (sputum culture).
Summary
Legionnaires' disease is a severe type of pneumonia caused by the bacteria Legionella. The species Legionella pneumophila causes most cases, but other species of Legionella can also cause the disease. It is named Legionnaires' disease because it was first discovered after a pneumonia outbreak among people who attended an American Legion Convention in Philadelphia, Pennsylvania in 1976. Most people exposed to Legionella do not become sick with Legionnaires' disease. People who do become sick usually develop symptoms within 2 to 10 days after exposure, but it may take longer. The first symptoms may include headache, chills, muscle pains, and a fever that can be 104°F (40°C) or higher. Additional symptoms usually develop 1 to 2 days after the first symptoms and may include coughing, shortness of breath, chest pain, diarrhea, nausea and vomiting, and confusion. While Legionnaires' disease mainly affects the lungs, it sometimes causes infections in other parts of the body, such as the heart or within body wounds. A person can become infected from Legionella when they inhale mist or water droplets that contain the bacteria. Sources of exposure may include showers, faucets, whirlpools, grocery store misters, and water droplets passing through ventilation systems in large buildings (such as hotels, office buildings, and hospitals). People who are more susceptible to developing Legionnaires' disease after an exposure include adults over age 50, current or former smokers, and people who have a weakened immune system or a chronic disease. Generally, neither the bacteria nor Legionnaires' disease is spread directly from person to person. While large exposures can result in outbreaks, the disease usually occurs in single, isolated cases. Legionnaires' disease may be suspected by symptoms. Pneumonia can be confirmed by a chest X-ray. Legionnaires' disease is diagnosed when one of the species of Legionella is found to be the cause of the pneumonia by testing a urine sample (urine culture) or a sample of saliva and mucus that is coughed up (sputum culture).Legionnaires' disease is a severe type of pneumonia caused by the bacteria Legionella. The species Legionella pneumophila causes most cases, but other species of Legionella can also cause the disease. It is named Legionnaires' disease because it was first discovered after a pneumonia outbreak among people who attended an American Legion Convention in Philadelphia, Pennsylvania in 1976. Most people exposed to Legionella do not become sick with Legionnaires' disease. People who do become sick usually develop symptoms within 2 to 10 days after exposure, but it may take longer. The first symptoms may include headache, chills, muscle pains, and a fever that can be 104°F (40°C) or higher. Additional symptoms usually develop 1 to 2 days after the first symptoms and may include coughing, shortness of breath, chest pain, diarrhea, nausea and vomiting, and confusion. While Legionnaires' disease mainly affects the lungs, it sometimes causes infections in other parts of the body, such as the heart or within body wounds. A person can become infected from Legionella when they inhale mist or water droplets that contain the bacteria. Sources of exposure may include showers, faucets, whirlpools, grocery store misters, and water droplets passing through ventilation systems in large buildings (such as hotels, office buildings, and hospitals). People who are more susceptible to developing Legionnaires' disease after an exposure include adults over age 50, current or former smokers, and people who have a weakened immune system or a chronic disease. Generally, neither the bacteria nor Legionnaires' disease is spread directly from person to person. While large exposures can result in outbreaks, the disease usually occurs in single, isolated cases. Legionnaires' disease may be suspected by symptoms. Pneumonia can be confirmed by a chest X-ray. Legionnaires' disease is diagnosed when one of the species of Legionella is found to be the cause of the pneumonia by testing a urine sample (urine culture) or a sample of saliva and mucus that is coughed up (sputum culture).
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Resource(s) for Medical Professionals and Scientists on This Disease:
Orphanetprovides GARD with information for this disease.
About Legionnaires disease
Many rare diseases have limited information. Currently, GARD aims to provide the following information for this disease:
Population Estimate:Fewer than 50,000 people in the U.S. have thisdisease.
Symptoms:May start to appear at any time in life.
Cause:This disease is caused by germs such as bacteria, viruses, fungi, or parasites.
Organizations:GARD is not currently aware of organizations specific to this disease.
Categories:Infectious Diseases
When Do Symptoms of Legionnaires disease Begin?
Symptoms of this disease may start to appear at any time in life.
The age symptoms may begin to appear differs between diseases. Symptoms may begin in a single age range, or during several age ranges. The symptoms of some diseases may begin at any age. Knowing when symptoms may have appeared can help medical providers find the correct diagnosis.
Prenatal Selected
Before Birth
Newborn Selected
Birth-4 weeks
Infant Selected
1-23 months
Child Selected
2-11 years
Adolescent Selected
12-18 years
Adult Selected
19-65 years
Older Adult Selected
65+ years
Symptoms may start to appear at any time in life.
Symptoms
The types of symptoms experienced, and their intensity, may vary among people with this disease. Your experience may be different from others. Consult your health care team for more information.
The following describes the symptom(s) associated with this disease along with the corresponding body system(s), description, synonyms, and frequency (Note: Not all possible symptoms may be listed):
Respiratory System Respiratory System
36 Symptoms
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Body Systems
Symptoms related to this disease may affect different systems of the body. Use the 'Filter and Sort' function to learn more about which body system(s) are affected by this disease and their associated symptom(s).
Medical Term
Abnormal lung morphology
Frequency
Uncommon
Very frequent
Very frequent
Always
Description
Any structural anomaly of the lung.
Any structural anomaly of the lung.
Synonym
Abnormality of lung structure; Abnormality of the lungs; Abnormally shaped lung; Unusal lung shape
Abnormality of lung structure; Abnormality of the lungs; Abnormally shaped lung; Unusal lung shape
36 Symptoms
Causes
What Causes This Disease?
Infection
Legionnaires disease is caused by an infection, or the process of harmful germs entering the body, multiplying, and spreading illness. Germs are bacteria, viruses, fungi, or parasites. Germs typically spread through other people or animals, or through contaminated food, water, or soil. Learn more about infectious diseases from the National Library of Medicine (NLM).
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How Can Patient Organizations Help?
Patient organizations can help patients and families connect. They build public awareness of the disease and are a driving force behind research to improve patients' lives. They may offer online and in-person resources to help people live well with their disease. Many collaborate with medical experts and researchers.
Services of patient organizations differ, but may include:
Ways to connect to others and share personal stories
Easy-to-read information
Up-to-date treatment and research information
Patient registries
Lists of specialists or specialty centers
Financial aid and travel resources
Please note: GARD provides organizations for informational purposes only and not as an endorsement of their services. Please contact an organization directly if you have questions about the information or resources it provides.
Clinical studies are part of clinical research and play an important role in medical advances, including for rare diseases. Through clinical studies, researchers may ultimately uncover better ways to treat, prevent, diagnose, and understand human diseases.
What Are Clinical Studies?
Clinical studies are medical research involving people as participants. There are two main types of clinical studies:
Clinical trials determine if a new test or treatment for a disease is effective and safe by comparing groups receiving different tests/treatments.
Observational studies involve recording changes over time among a specific group of people in their natural settings.
People participate in clinical trials for many reasons. People with a disease may participate to receive the newest possible treatment and additional care from clinical study staff as well as to help others living with the same or similar disease. Healthy volunteers may participate to help others and to contribute to moving science forward.
To find the right clinical study we recommend you consult your doctors, other trusted medical professionals, and patient organizations. Additionally, you can use ClinicalTrials.gov to search for clinical studies by disease, terms, or location.
What if There Are No Available Clinical Studies?
ResearchMatch helps connect people interested in research studies with researchers from top medical centers across the United States. Anyone from the U.S. can register with this free program funded by NIH. Researchers from participating institutions use the database to search for and invite patients or healthy volunteers who meet their study criteria to participate.
Join the All of Us Research Program!
The All of Us Research Program is inviting 1 million people from all backgrounds across the U.S. to help build one of the most diverse health databases in history. Researchers will use the data to learn how our biology, lifestyle, and environment affect health. This may one day help them find ways to treat and prevent diseases.
What Are Clinical Studies?
Clinical studies are medical research involving people as participants. There are two main types of clinical studies:
Clinical trials determine if a new test or treatment for a disease is effective and safe by comparing groups receiving different tests/treatments.
Observational studies involve recording changes over time among a specific group of people in their natural settings.
People participate in clinical trials for many reasons. People with a disease may participate to receive the newest possible treatment and additional care from clinical study staff as well as to help others living with the same or similar disease. Healthy volunteers may participate to help others and to contribute to moving science forward.
To find the right clinical study we recommend you consult your doctors, other trusted medical professionals, and patient organizations. Additionally, you can use ClinicalTrials.gov to search for clinical studies by disease, terms, or location.People participate in clinical trials for many reasons. People with a disease may participate to receive the newest possible treatment and additional care from clinical study staff as well as to help others living with the same or similar disease. Healthy volunteers may participate to help others and to contribute to moving science forward.
To find the right clinical study we recommend you consult your doctors, other trusted medical professionals, and patient organizations. Additionally, you can use ClinicalTrials.gov to search for clinical studies by disease, terms, or location.
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What if There Are No Available Clinical Studies?
ResearchMatch helps connect people interested in research studies with researchers from top medical centers across the United States. Anyone from the U.S. can register with this free program funded by NIH. Researchers from participating institutions use the database to search for and invite patients or healthy volunteers who meet their study criteria to participate.
Join the All of Us Research Program!
The All of Us Research Program is inviting 1 million people from all backgrounds across the U.S. to help build one of the most diverse health databases in history. Researchers will use the data to learn how our biology, lifestyle, and environment affect health. This may one day help them find ways to treat and prevent diseases.
ClinicalTrials.gov, an affiliate of NIH, provides current information on clinical research studies in the United States and abroad. Talk to a trusted doctor before choosing to participate in any clinical study. We recommend checking this site often and searching for studies with related terms/synonyms to improve results.
Contact a GARD Information Specialist if you need help finding more information on this rare disease or available clinical studies. Please note that GARD cannot enroll individuals in clinical studies.
Use the contact form to send your questions to a GARD Information Specialist.
Please allow 2 to 10 business days for us to respond.
ClinicalTrials.gov, an affiliate of NIH, provides current information on clinical research studies in the United States and abroad. Talk to a trusted doctor before choosing to participate in any clinical study. We recommend checking this site often and searching for studies with related terms/synonyms to improve results.
Contact a GARD Information Specialist if you need help finding more information on this rare disease or available clinical studies. Please note that GARD cannot enroll individuals in clinical studies.
Take steps toward getting a diagnosis by working with your doctor, finding the right specialists, and coordinating medical care.
Data collected from Orphanet and Online Mendelian Inheritance in Man (OMIM) are used to interpret and provide information on rare diseases. This includes names, synonyms, genes, symptom frequency, population estimates and more.
Human Phenotype Ontology (HPO) provides standard terminology that was used by Orphanet and OMIM to represent a disease's phenotypic features. HPO provides information on describing these clinical features.