Legionnaires' disease is a global public health issue. According to CDC's Morbidity and Mortality Weekly Report (August 2011), Legionnaires' disease increased 217% between 2000 and 2009. The disease-causing bacterium, Legionella pneumophila, is a waterborne pathogen found in natural and man-made water systems. Both potable and non-potable (utility) water supplies harbor Legionella pneumophila, and have been linked to outbreaks of both hospital- and community-acquired Legionnaires' disease.  

Ask The Experts

The following FAQs provide general and technical information about the disease. If you can't find the answer you're looking for, please click Ask the Experts tab and submit your question.




Legionella testing months after illness?

I was a guest at Polo Towers, Las Vegas in September during a Legionella outbreak there. I stayed a week and became very ill. I went to the doctor, the ER, and the pulmonary specialist. I was prescribed Leviquin twice a week. It did nothing. I then went to a clinic in Puerto Rico and got two Z packs that worked. I got home to find a letter from Polo Towers and Nevada CDC saying I was exposed and asking if I was tested for Legionella at the time. I was told it’s not a common thing to test for and I was not at the time. Is it true that you cannot test for it after recovery?

A blood test (Legionella antibody serology) or urinary antigen tests for Legionella are 2 tests for diagnosis. The antibody serology blood test still may be useful in diagnosing your illness.

Follow Up Question:

Thank you so much for the fast response. This will be accurate even seven months after recovery?

Follow Up Answer:

If the test is positive, it is circumstantial evidence that you contracted Legionnaire’s disease during the course of your illness. If the pulmonary specialist diagnosed pneumonia based on chest x-ray, the evidence is overwhelming. If the test is negative, the results have little meaning:

Two possibilities:

  1. You did not have Legionnaires’ disease
  2. You did have Legionnaires’ disease, but the antibody titer declined because the test was drawn late.

However, the antibody titer often reaches its peak 3 – 6 months later, and the rest remains positive for years in a few patients. So this test should be performed given the context of your letter from Nevada DOH. The Health Dept or your pulmonary specialist can arrange for the test. The pulmonary specialist should be given the info about the Nevada DOH letter. He might be able to assist you in confirming the diagnosis.

Diarrhea may be due to antibiotics?

I was discharged from hospital after suffering from a Legionella infection. I was prescribed with Levofloxacin which I took for four months. I have had all the expected after effects of the illness such as fatigue, lack of concentration, appetite loss, nausea, etc. Over the past few days I have found that my bowel has become looser. Is this is an after effect of the condition? Could it be due to the fact that I am now eating more than I was initially? The drastic gastro-intestinal effects which heralded the illness make me concerned that it is returning. 

For most patients, a 10 – 14 day course of levofloxacin is sufficient. Levofloxacin beyond that time may cause diarrhea, and if this is occurring, you should stop the levofloxacin and contact your physician for further instructions. He can be informed about my reply to you. The diagnosis to be ruled out is called C difficile colitis.


Persistent nausea after therapy?

My mom went into the hospital for nausea, diarrhea, and she had severely enflamed lungs. She was diagnosed with Legionnaire’s disease. She almost died and was on a ventilator for 11 days. She was extubated last night and was doing better, but now the nausea and diarrhea are back. She had a severe rash during her treatment. The doctors have discontinued her broad spectrum antibiotic. She still can’t get the nausea under control. Any thoughts?

There are some possibilities that should be considered. Antibiotics and other medications commonly cause diarrhea and nausea. If the Legionnaires’ disease is under control (e.g. fever has resolved); perhaps the antibiotics can be discontinued. 7 – 10 days of antibiotics is usually sufficient. Also, Clostridium difficile colitis (called “c diff”) could have occurred following Legionnaires’ disease and your doctors can test for this possibility using a test for stool. There could possibly be a gastrointestinal complication which can be investigated by CT scan. Good luck and congratulations to your doctors for making a difficult diagnosis.

Follow Up Question:

Thank you for such a quick response. The CT scan showed a hematoma outside the stomach. It has been contained and now we are hoping the body will absorb 100% oxygen at this point. Her levels are currently high 90’s. She is in severe pain, but stable.

Follow Up Answer:

Rifampin is an antibiotic that is occasionally given to patients with severe Legionella pneumonia. If this antibiotic was used (and it probably was not), it should be discontinued immediately – it interacts with anticoagulant drugs (blood thinners).


Empiric therapy for Legionella in Indonesia?

I suspect that I have Legionnaires’ and I’m in Indonesia. I have been to the hospital for tests. They have done a lung X-ray and they have been testing for TB without luck because I’m not spitting anything to get a clean result. I started with an ear infection a few days after being exposed to water. I got a fever and flu-like symptoms and then bronchitis. I am having night sweats, lethargy, and chest pains. It has been almost 35 days now. The first three days I took Zithromax (one tablet a day) as my ears were sealed up. There is no test here for Legionnaires’ and I’m told my blood must be sent to America from here and take a month for results. I think it is time to self-prescribe because the system is not so good here. Should I use the mix of erythromycin and rifampin? 

Legionnaires’ disease is a pneumonia that is diagnosable by chest x-ray. If the x-ray is negative, you do not have Legionnaires’ disease. Ear infection is not associated with Legionnaires’ disease. If you have symptoms for 35 days, it is unlikely that the infection is due to Legionella. TB must be excluded. Regardless, erythromycin and rifampin are no longer the drugs of choice for Legionnaires’ disease. Azithromycin or levofloxacin is effective.

Follow Up Question:

Thanks for your quick response. When you say TB must be excluded, what does that mean? In regards to the X-ray, how would they diagnose with out any experience? What do they look for? The X-ray had much web like texture in the lower area but said that the upper area did not show the normal signs of TB though they said it could be in the lower area already. From experience any diagnosis here is shoddy at best.

Follow Up Answer:

You need to consult a physician that you trust.

Legionella on autopsy?

My son in law died on 6/12/09 from what has been determined swine flu. His place of work did test positive for Legionella. He was taken to the hospital 6/1/09 then air lifted later that evening to U of M medical center. He died 10 days later. We did receive a call during this time saying he checked positive for Legionella, and then it was later called a weak positive. My question for you is after 10 days of treatment for something they were not sure of, (massive doses of antibiotics, etc) will an autopsy still show Legionnaires’?

Special stains for Legionella including PCR, fluorescent direct antibody, and various molecular techniques may yield the Legionella. Culture is most useful while the patient is alive. Following death, any microorganism may not survive, especially after a period of weeks. So, special stains and molecular methods are used for an autopsy.

I have symptoms of Legionnaires’, but the tests were negative?

My husband (57 yrs old) went to the ER with a 104oF temperature and shaking chills. He was diagnosed with pneumonia, but he had normal blood work, including WBC count. His condition deteriorated and he was intubated. He was critically ill and in ICU for 10 days and developed congestive heart failure. He recovered after heavy doses of antibiotics, including Rifampin, but tested negative for Legionella through urine and blood. They diagnosed him with suspected Legionnaires’ & sepsis based on clinical presentation.


Prior to the night he was hospitalized, I had an episode of shaking chills. While he was hospitalized, I had night sweats and a dry non-productive cough but no fever. After he was discharged, those symptoms persisted and I was extremely fatigued. I went for blood work and a chest X-ray. The X-ray and blood work were normal, except for mildly elevated liver enzymes. A week later,  my liver enzymes were normal, but Hep-B core AB, IgM was reactive. A follow up for Hep-B surface AB was nonreactive. The doctor suspected cross reactivity, and ordered repeat tests in 6 months. The Legionella pneumophila AB, IgG IF was 128.  Due to my husband’s condition, I was treated with a two week course of Levaquin, followed by more blood tests in 2-3 weeks. After 2 days on Levaquin, my cough and fatigue are gone, but night sweats continue. I have no weight loss or enlarged lymph nodes.


I was wondering if night sweats are associated with Legionnaires’? How likely is it that this could be due to Legionella? How long will it take for night sweats to go away once antibiotics were started? My husband and I both work together in a school.


Your husband’s symptoms are consistent with pneumonia including Legionnaire’s disease. The blood and urine test can be negative because the tests may not detect some Legionella subtypes (serogroups and species).

Your case is more difficult with respect to diagnosis. The chest X-ray is the test that confirms pneumonia, but your X-ray did not show pneumonia. Your IgG blood test suggests Legionnaires’ disease, but a second test 6-12 weeks after the first test is necessary for confirmation. I agree with your doctor to treat for Legionnaires’ disease. Symptoms of Legionnaires’ disease typically resolve after five days of antibiotics, if antibiotics are started early.

Follow-Up Questions:

I hope you don’t mind a few additional questions
1. Are night sweats a symptom of Legionnaires’?
2. You say symptoms typically resolve within five days if antibiotics are started early. I first had chills on Mar. 10th, cough/night sweats began March 14th, blood test done on March 26th and I received lab results & began antibiotics on April 6th. Is that early or should I expect it may take longer for night sweats to go away? My cough resolved in 48 hours.
3. My doctor is recommended repeat blood test in 2-3 weeks. Should the numbers quadruple in order for a positive diagnosis? Will that be long enough? I see you recommend 6-12 weeks.
4. Is this something we should inform the school about?

Follow-Up Reply:

Night sweats accompany the fever, so if fever resolves, so should the night sweats. Your doctor is well-informed. However, for Legionnaires’ disease the time of maximal seroconversion (technical lingo) is 6 to 12 weeks. No need to inform if your blood Legionella antibody titer is not elevated. Perhaps, your husband should have a repeat titer done also. Does he have a chronic underlying disease or does he smoke?

If none of your colleagues have contracted pneumonia recently, probably not a concern for your school. If your titer is elevated, feel free to email me again.

Persistent headache following Legionnaires’ disease?

My partner nearly died from this disease some 4 months ago. She had to be aspirated and was in intensive care for 3 days. She is suffering severe migraines on a daily basis. Her doctor seems to think it is residue of the Legionnaires’. I beg to differ. I’m interested in your thoughts. It is 4 months down the track and she is plagued by these pounding headaches. She has never been a sufferer of headaches before. Are headaches (chronic) on a daily basis a part of Legionnaires’?

Although headaches are common during the onset of Legionnaires’ disease, we have never encountered a patient with persistent headache months following recovery. Neurologic complications have occurred in patients who recovered, but this is rare. She should be seen by a neurologist to investigate other causes. We would be interested in follow up as to what the final diagnosis or solution was.


Does Legionnaires’ cause hallucinations?

My daughter was diagnosed during a recent hospital stay. Could aerosol spray tanning be a source of Legionella exposure? Is it common for patients with Legionnaires’ pneumonia to have visual and auditory hallucinations?

The hospital reported her case to County Public Health. Is she responsible for notifying her employer and property manager? Both her work and residence have large water delivery systems.

She is a cigarette smoker and the most likely source is drinking water, not aerosol tanning. Hallucinations are uncommon, but they could occur.

This is the duty of the health department. While the Pittsburgh, PA Health Dept would investigate possible drinking water sources, this is rarely done elsewhere. She may inform the property manager and ask if other residents have contracted pneumonia.


Are dysphagia, ulcers, and red eyes caused by Legionnaires’ disease?

My 17 year old son has a fever and is not responding to 3rd generation cephalosporins (400mg). He suffers from fatigue, headaches, extremely red eyes, cough, throat ulcers, dysphagia, weight loss, and anorexia. Despite giving him a full course of medication (cefspan and levofloxacin), he still has a productive cough and hand tremors. Are these symptoms a result of Legionnaires’ disease, and if so, why is he not responding to treatment?

Perhaps, he doesn’t have Legionnaires’ disease. Red eyes, throat ulcers, dysphagia, and weight loss are not symptoms of Legionnaires’ disease. Moreover, Legionnaires’ disease will respond to levofloxacin.


How long will Legionnaires’ cause fevers after being discharged from the hospital?

My friend (previously healthy 53 year old male) was diagnosed with Legionella via a positive urine culture. He was hospitalized and the first three doses of antibiotics were intravenous and he was then discharged on oral form (Levaquin-250 mg).


Today is his seventh day out of the hospital. He still has fevers and sweats, albeit not as intense. He is still quite fatigued. His appetite is better. He never had respiratory or GI symptoms. He has a doctor’s appointment in three days. How long can I expect his fevers and fatigue to last? I was very unimpressed by the hospital staff on their directions.

The information that you have provided is insufficient to answer your question with confidence. However, it appears that he may have been discharged prematurely. The criteria that we use for discharge are their fever response and ability to take food. So, many patients can be discharged on day five on oral antibiotics.

On the other hand, Levaquin is the right antibiotic, and he is improving. The dose should be 500 or 750 mg (not 250 mg). He also has no GI symptoms, which is a good sign. If he had nausea or diarrhea, intravenous antibiotics should have been continued. By the time he sees his physician, his temperature should be normal. If not, he should be re-evaluated. Fatigue will persist for a few weeks, but should gradually resolve given his previous good state of health.

Did he have recent travel history? If so, the water that he consumed may have been the source of Legionella. Good luck!

Sequelae after Legionnaires’ disease?

I had a very serious case of Legionella in May 2011, and returned to work about six months later, but I am now on sick leave due to concentration problems, lack of energy, and occasional breathing problems. I have seen reports that this is quite common, but do you have any statistics on how long it takes and if/how large a share of patients will have to live with this?


The patients with the longest sequelae (fatigue and difficulty concentrating are common problems) are those who were hospitalized for long periods in the ICU. In some of these patients, symptoms persisted for a year to 18 months. However, virtually all make a full recovery eventually.

I generally recommend to continue working despite the fatigue, since resting over a long period of time also contributes to lack of energy, prolonging the recovery. Stopping cigarette smioking is a major step forward.

Keep in mind that when I first encountered Legionnaires’ disease, the mortality was an incredible 40%. You have been cured with a few weeks of powerful antibiotics. The mortality is now <5% for those patients who receive the correct antibiotic early in the course. I would focus on activities including exercise, extra-curricular activities, and work to hasten your recovery.

Good Luck!


How long would it take for symptoms of Legionnaires’ disease to appear?

I have previously corresponded with you last year about a case against our hot tub company. If you do not mind, I have a few more questions for you.

Are there any symptoms of Legionella infection before 48 hours? All nine of the patients were ill between 8-24 hours of the alleged exposure and it is my understanding that there would be no symptoms that soon. None of the patients have tested positive for Legionella in blood or urine samples. One of the patients even had three antigen tests done in the following months.


There is no objective evidence of Legionnaires’ disease – pneumonia which can be life threatening – in the above question. Most patients will show evidence of Legionnaires’ disease by blood or urine tests.


The water sample from our hot tub showed the presence of the Legionella bacteria, but it had been in transport for 144 hours until it arrived at the testing center. Could this transport time affect the results?


Legionella grows readily in water at room temperature. The time of transport will have little effect on the presence of Legionella – either in increasing or decreasing the number.


Public health was called onsite, they saw the hot tub, and immediately declared that it was the source of the infection. They did not investigate any other possible sources. Are there food-borne bacteria that cause symptoms similar to what these patients experienced?

Public health stated that the hot tub was the source of Legionnaires’ to all the parties before any testing had been done. I believe that Legionella may be in a high percentage of hot tubs but the rate of incidence is very low because it is overstated as a source.


You did not list the symptoms that the patients had. Typical symptoms of Legionnaires’ are high fever, cough, and presence of pneumonia on a chest x-ray. Unless the drinking water was also tested, it is inappropriate and unscientific for Public Health to conclude that the Legionnaires’ disease was contracted from the hot tub.


Recommendations for fatigue problems?

I am currently working as a health coach (background as a dietitian) and I am seeing a young girl in her twenties who contracted Legionnaires’ a couple of years ago.


She has ongoing problems with fatigue. Are there any specific treatments, supplements, or dietary approaches you would recommend to help with her fatigue?


Chronic fatigue for more than one year after apparent recovery from Legionnaires’ disease is more common than realized. My advice is to return to work soon after Legionnaires’ disease treatment has ended and after consulting with your physician.

I would recommend to gradually increase activity and exercise to pre-illness levels regardless of fatigue (within reason); ideally, supervision by a trainer or a physical medicine rehabilitation professional would be ideal.


Coughing from Legionnaires’ 25 years ago?

I have had a chronic cough for 25 years. Sometimes it’s a lot of clear mucus. I had Legionnaires’ disease in 1990. I was sick for several months before someone figured it out what was wrong. When I get a cold it’s horrible. I can no longer remember NOT coughing. People really avoid me with the cough as it is frequently uncontrollable.


Is this cough most likely fallout from the Legionnaires’ 25 years ago?

The cause of your chronic cough is not from Legionnaires’ disease. If you have not already done so, you should consult a physician.

Mental illness from Legionnaires’ disease?

My mother had Legionnaires’ disease. During the illness, she had mental problems. She did not recognize family members, and she made up stories about what happened in her life. She felt continutally threatened. A few months later, the mental health issues disappeared.


Now, ten years later, the mental illness symptoms have suddenly reappeared. Why might this be? Can we cure it?

It is not unusual to experience neurological problems (the most common is confusion). These problems usually subside over a period of a few weeks if Legionnaires’ disease is treated early in the course with effective antibiotic therapy.

So, it is likely that the new symptoms of mental illness are due to a cause other than his Legionnaires’ disease from so many years ago (e.g. age-related disease). Your mother should consult a physician.

Recovery from Legionnaires’ disease without antibiotics?

While waiting for the results of the urine antigen test, I started to feel better so I declined the use of anitbiotics. It has been two weeks since I experienced the first symptons, but I have done the usual for a bad cold (lots of liquids, rest, vitamin C, zinc, etc).


Would NOT taking the antibiotics cause trouble for me down the road? Should I be retested to make sure I am Legionnaires’ free?

Legionnaires’ disease is a bacterial pneumonia that can be cured by antibiotics. The antibiotics used for Legionnaires’ disease are remarkably safe. Some patients with Legionnaires’ disease survive without receiving antibiotics.

One missing piece of info:

Was a chest x-ray ordered by your physician when the urine antigen test was done? If the chest x-ray was done, then you merely have to have a repeat chest x-ray now. If the chest x-ray shows pneumonia, then take your antibiotics as originally prescribed – usually azithromycin (Z-pak), levofloxacin (Levaquin), moxifloxacin (Avelox).

If the chext-ray shows that your pneumonia has resolved without antibiotics, and you feel fine, then you “dodged a bullet” and should go to church this Sunday and make a donation!

Should I go to Urgent Care after fever subsided?

I’m wondering if I still need to go to urgent care even if the 6 day fever stopped? Twelve days ago, I was exposed to an old window AC unit for 2 hours trying to sleep in a hot room (visiting a friend) in Portland, Oregon. Within about 20 minutes, I had a headache, and after 2 hours, felt bad, and turned the AC off. Four days later, the fever started. The next day, I had a cough and chills. I was totally out of it for 6 days with what felt like high fever. I was able to do infrared sauna each day for 30 minutes (because I have a health center and teach it), and then slept the rest of time. I also did a nettie pot, drank tons of water/coconut water, took a high dose of zinc, magnesium, and raw whole food powder shake. I ate little, mostly some fruit. I still had a serious cough, fever, chills, all over pain, nausea, and was totally out of it and could not think. Today is 7 days from the start of the fever. The fever is gone and my thinking is clearer, but I still have a serious cough, and if I get up, I need to lay down again soon, so I am wondering if I need to go to urgent care since I just read about what an AC unit can do to you and if I could have Legionnaires’ disease even though the fever stopped. Could I be healing on my own and avoid antibiotics?

It is unlikely that a window AC unit would be a source of Legionella. The urine antigen test for the diagnosis of Legionnaires’ disease will remain positive well into the infection. If you see a physician, you could request this test and the result would still be meaningful even after 2-4 weeks after the onset of pneumonia due to Legionella bacteria (Legionnaires’ disease). You should probably also have the physician evaluate you for pneumonia (chest x-ray) and then determine if antibiotic therapy is needed.

Valley fever or Legionnaires’ disease?

My doctor diagnosed me with pneumonia and treated me with azithromycin for five days. A week later, I showed up in his office with erythema nodosum on my lower legs. He decided to test me for Legionella (results were 1:256), Chlamydia pneumonia (IgG was 1:256) and coccidioidomycosis (+). Because the coccidioidomycosis result showed positive, he treated me with fluconazole (600 mg/day). A CT scan was taken which showed a small infiltrate in my upper right lob. Over the next five months, I slowly regained my health and the infiltrate calcified and decreased.  


My problem is that I’m not sure what I had because when my primary doc sent me to a pulmonologist, the pulmonologist said I never had cocci! He said I had Legionella pneumonia and that it is cured. My symptoms were night sweats, nausea, anxiety, pressure in my left lung area, sharp pain in my upper left shoulderblade, terrible fatigue and slight hematuria for 3 months. Is it possible that I had Legionella and not Valley Fever (coccidioidomycosis)?

  1. Does Legionella cause infiltrates that calcify?
  2. Does Legionella cause erythema nodosum?
  3. Does Legionella cause the other symptoms I experienced? 


  1. No, but Valley Fever commonly causes calcifications.
  2. It is rare in Legionnaires’ disease, and not uncommon for Valley Fever.
  3. Legionella causes acute pneumonia which generally requires hospitalization. What was the exact serologic test performed for coccidioidomycosis? The coccidioidomycosis serology performed before IgM antibody has a relatively high false positive rate, while the IgG antibody is more specific. I believe you more likely had Valley Fever (coccidioidomycosis).


Cooling tower outbreaks in the news. What is the explanation?

On your website I read that 79% of survivors in one study suffered neuromuscular symptoms. I am experiencing chronic pain in my elbows and knees that started fairly suddenly 3 years ago which have been treated with steroids and anti-inflammatories with little success. I haven’t been diagnosed or treated for legionnaires disease but have some concerns. I also work around a large 5 cell cooling tower and am inside the tower cleaning it once per year. Can a person get legionnaires and get well without specific treatment? If that is the case and, by chance, I were suffering effects from it, can it still be diagnosed? Would it eventually go away on its own? Is there any treatment? Thank you for any information on this.

As you know from our website, we do not believe that cooling towers play a notable role in Legionnaires’ disease. And, in our FAQ, we note that a CDC survey of cooling tower workers showed no evidence that these workers had any evidence of Legionnaires’ disease as measured by a blood test for legionella antibodies as compared to non-cooling tower workers. So, you would not be at risk for Legionnaires’ disease based on your profession.

Patients with Legionnaires’ disease can recover without antibiotics if the disease is mild and they are generally healthy. However, those that had neuromuscular symptoms in the study from the Netherlands had lung infection (pneumonia) with Legionella. However, joint pains are common and Legionnaires’ disease is not. So, the chances that Legionnaires’ disease precipitated your pains is highly unlikely. The treatment is the same for both: a period of rest followed by exercise and antinflammatory medicines. I assume that you have undergone a thorough medical examination since a number of infections and other illnesses can precipitate arthritis symptoms. Good luck.


My blood test is positive for Legionella – What does this mean?

I got ill like this last year from Feb. to Oct., I went to an Infectious Disease physician, and a Pulmonary specialist, had a spinal tap also, and no one could figure it out. The symptoms subsided, and I was able to function, but never really felt 100% well. I started feeling really crummy again, and my physician took 8 tubes of blood within a week, and it came back positive for Legionnaire’s disease. My physician told me it’s really only fatal in old people or if you immune system is compromised. I’ve been on Tequin for 10 days, and it didn’t work, I actually feel a little bit worse. I’m just finishing my second 5 day Z-pak. I still feel pretty awful, and I’m wondering if I’m ever going to get over this! My question is, is what kind of antibiotics should I be taking, what strength, and for how long? Last year I took Ketek, Biaxin, and it didn’t help.

The blood test means that you have been exposed to Legionella, but you probably do not have Legionnaires’ disease now. Legionnaires’ disease is pneumonia. Ketek, Biaxin, Tequin and Z-pak are highly effective against Legionella, so you need no further antibiotic therapy.

You may have a chronic fatigue-like syndrome associated with a past infection and it may be prolonged for about a year. Our recommendations are that you must try, no matter how difficult, to be active at home and work. You should get more exercise, not less. You should follow a healthy diet, and quit smoking. If you are overweight, lose weight. No more antibiotics are warranted. Our recommendations must be validated by your physician since we have insufficient information and have not examined you.

Can Legionella cause an enlarged liver?

Can infection alone result in kidney dysfunction?

Legionella can infect the kidney, but this is very rare. However, kidney dysfunction is a common complication of Legionnaires’ disease. So, if the antibiotics are effective (and they usually are), the kidney dysfunction can resolve.


Can arthritis occur after Legionnaires’ disease?

My 62-year old brother has just spent 3 weeks in hospital fighting a very severe case of Legionnaires’ disease (which was initially diagnosed as flu and then pneumonia). He has been a smoker for years but, of course, has had to give that up. He is extremely weak having only been on the path to recovery for one week. He is also suffering side effects of Legionella suddenly, i.e. inflamed joints. A joint suddenly swells up and becomes very stiff, hot and painful. His right knee and both elbows are really bad at the moment. What can he do to expedite recovery?


Symptoms of joint pain after recovery is common, but inflamed joints that swell up are not. If he does not improve in a few weeks, he should see an arthritis specialist.

Can Legionnaire’s disease lead to prolonged diarrhea?

My 82-year old father in law was diagnosed 4 weeks ago and has been in the hospital. He was discharged two weeks ago but still has diarrhea and sickness. He is losing weight and is now quite weak. He has also been diagnosed with Barret’s Oesophagus.



The acute symptoms of Legionnaires’ disease respond readily to antibiotic therapy including fever and diarrhea. However, weakness and fatigue can persist for months. The possibility of persistent diarrhea induced by antibiotic therapy should be considered (Clostridium difficile colitis). This illness can be checked by a laboratory test using the patient’s stool.

Epilogue: You were absolutely correct – my father in law was diagnosed with Clostridium difficile. However, he sadly died ten days ago. Many thanks for your reply.

I have taken antibiotics for four months and I still feel ill?

My pulmonary specialist says it is interstitial lung disease, with an underlying disease causing it. He and the Internal Medicine physician ruled out vasculitis and lupus. The infectious disease control doctor tested me for Legionnaires’ disease and the test was positive. Whatever it is, is causing intestinal problems. I still have fevers, headaches, joint pains, shortness of breath, diarrhea, and am tired all the time. I have received four months of antibiotics and am now taking Zithromax without getting better. Could test results could have been wrong about Legionnaires’ disease?

Please request that your Infectious Disease doctor fax us the test results. You have not responded to therapy that should have been curative for LD.


Can Legionnaires’ disease cause kidney dysfunction?

Can Legionnaires’ disease cause kidney dysfunction?


Legionella can infect the kidney, but this is very rare. However, kidney dysfunction is a common complication of Legionnaires’ disease. So, if the antibiotics are effective (and they usually are), the kidney dysfunction can resolve.


I had a positive Legionella test two weeks ago but have no received antibiotics.

I was quite ill about four weeks ago with fever chills fatigue and cough, now I am left with cough, sweats and fatigue but have not yet had antibiotics. I feel a lot better than I did. However, could Legionnaires flare up to make me ill again before my doctor starts me on antibiotics. I had the blood test two weeks ago which showed positive and I’m to have another blood test soon?



The information that you have provided is insufficient to answer your question. Legionnaires’ disease (LD) is pneumonia. To address the issue of antibiotics, your chest x-ray should show evidence of pneumonia. If the chest x-ray shows pneumonia, then antibiotic therapy including quinolones (levofloxacin) or macrolides (azithromycin) are highly effective. If the chest x-ray does not show pneumonia, then you may not have active Legionnaires’ disease at the current time and your physician must use his clinical judgment as to the interpretation of the blood test. Another test that is more specific (medical term) is the Binax urinary antigen which may assist your physician in deciding whether you should be treated for Legionnaires’ disease. Please refer your physician to our website,


I have had many medical problems after I contracted Legionnaires’ disease.

I contracted Legionnaire’s pneumonia and was in the hospital for 12 days, 4 of which I spent in ICU. The physicians had difficulty diagnosing my illness and I was treated with a variety of drugs. For the past 6 years I have suffered from a variety of health problems including asthma, hyperthyroidism, anxiety attacks, memory loss and difficulty concentrating as well as having a suppressed immune system. I was wondering if there is any connection between my illness and current health since I was healthy before contracting Legionnaires’ disease.

Most patients recover completely although it may take many months. See About the Disease on A few individuals have complained of subsequent asthma in queries to our website. As for your other symptoms, we are unable to ascertain if they are associated with your Legionnaires’ disease.


I developed asthma after I contracted Legionnaires’ disease.

I have auto-immune vitiligo and hypothyroidism. I would like to know why after contracting Legionnaires’ disease while on holiday in France and admitted to ICU on my return to England, where I was placed on life support, and three months later developed asthma/COPD though prior to infection suffered nothing. Asthma is prevalent in my family, my brother died from it after late onset at 31 – died at 41. Is this indicative of my future! My hair has fallen out in immense quantities, but I have slowly regained strength. I find my memory is a little troubling in that I forget, names etc.

Numerous patients with Legionnaires’ disease have asked why they developed asthma shortly thereafter. We have no clear-cut explanation, but we have never seen the development of asthma in our patients and it is not reported in the medical literature. Nevertheless, given the number of queries on this issue, we formulated a questionnaire to be completed by the physicians of these patients; this questionnaire included medical history and documentation of the asthma as well as confirmation of Legionnaires’ disease. Over the next 3 years, we continued to receive such queries from patients, and asked these patients to give the questionnaire to their physicians. We received a not a single documenting questionnaire from a physician.

Can a person have a blood test positive for Legionella without a history of illness?

Is it common for a person to have a blood test positive for Legionella without a history of illness? Is there any reason for concern for future illness?

The blood test (antibody serology) is most accurate when a person is ill with pneumonia. If the person has no pneumonia and does not have an abnormal chest x-ray, this person may have encountered Legionella many years ago and is ok now.

Based on our studies, we suspect that presence of antibody may be protective, since we never encountered patients who have contracted Legionnaires’ disease twice.


My husband with Legionnaires’ disease has no chronic illnesses.

My husband has been diagnosed with Legionnaires’ disease, but has no underlying risk factors that we know of. He was cured with erythromycin. He is 38 years old. Should we be concerned about his immune system and should his doctor be looking for reasons that he contracted this?

The answer may be yes, since it is unusual for nonsmokers to contract Legionnaires’ disease. Did he stay at a hotel or other large building in the 10 days before symptoms?

What is the mortality rate of Legionnaires’ disease?

What % of people die from contracting the disease?


The figures below are crude estimates.

Immunocompetent (healthy individuals) given appropriate antibiotics early, 0-9%; immunocompetent individuals not given appropriate antibiotics early, 20%-35%; immunosuppressed individuals (transplant patients, cancer patients, etc.) given antibiotics early, 5-20%; immunosuppressed individuals not given antibiotics early, 40-50%.


Legionnaires’ disease is pneumonia.

My aunt and grandma went on a cruise to Greece. They both returned sick and still suffer from shortness of breath, fatigue, and muscle weakness, including pulmonary edema. Their MD says there is nothing wrong and they have a mental problem causing these symptoms. I wonder if they could have Legionnaires’ disease. What are your suggestions? 

It is unclear if Legionnaires’ disease is the cause of their symptoms. I suggest that your relatives consult an infectious disease specialist. A chest x-ray taken at the time of their illness may be especially useful. Both a blood test for Legionella antibodies (serology) and possibly a urine antigen for Legionella may be useful diagnostic aids.

Your relatives may also notify their local health dept or the health dept where the cruise ship is located. Many outbreaks of Legionnaire’ disease have been linked to cruise ships.


Legionnaires’ can be complicated by ARDS-endocarditis?

Does Legionella lead to ARDS? My brother was hospitalized with the former and now has the later.

Legionnaires’ disease can be complicated by ARDS. I hope that with antibiotic therapy that he will recover, but the hospital course may be stormy. Good luck.

Follow Up Question: 

Thank you for your reply.  Unfortunately, the storm has arrived.  He is on many antibiotics with his fever unrelenting. We are now bringing in Infectious Diseases to look for other sources of infection. 60% c-Pap administered oxygen, all complicated by a poor performance of mitral heart valve repaired ten years ago. He is a 66-year-old practicing judge/attorney. Thanks again.

Follow Up Answer:

Please give the Infectious Disease consultant and the ICU Attending the message below:
Unrelenting fever in a patient with persistent pulmonary infiltrates in a patient with confirmed Legionnaires’ disease may be a result of 2 unsuspected diagnoses:

  • Legionella endocarditis (!) This is rarely diagnosed and there is virtually no literature on this except for our publications. I would ask the ID attending to look at these two articles describing a cluster of cases of prosthetic valve endocarditis at Stanford that occurred in the 80’s

Tompkins, L.S., B. Roessler, S.C. Redd, L. Markowitz and M.L. Cohen. 1988. Legionella prosthetic valve endocarditis. New Engl. J. Med. 318:530-35

Lowry, P.W., R.J. Blankenship, W. Gridley, N.J. Troup and L.S.Tompkins. 1991. A cluster of Legionella sternal-wound infections due to postoperative topical exposure to contaminated tap water. New Engl. J. Med. 324:109-112.

  • Nosocomial endocarditis due to Staph aureus. If TTE shows vegetations, empiric quinolone at super maximal doses (levofloxacin 750 q 12 or cipro 500 q 8 – adjusted for renal dysfunction)) should be strongly considered. Short-course rifampin in combination with a quinolone may break the fever. Although drug interactions and rising serum bilirubinemia will always be problematic. Note that quinolone plus rifampin is also active therapy against MRSA. Finally, if vegetations are present, surgical resection of the valve should be performed – although cardiothoracic surgery will have to be persuaded.