During an annual meeting of the Legion held in Philadelphia, USA from 65438 to 0976, a kind of pneumonia broke out, which was called Legionella pneumonia, also known as Legionella disease. The pathogenic bacterium is Legionella pneumophila, which is a gram-negative bacterium, difficult to cultivate, and has strong resistance to the outside world, and can survive in tap water for one year. This kind of bacteria can exist widely in soil, lakes and rivers and spread through the air. Children from 2 years old to the elderly are susceptible to infection, which is distributed all year round and popular in summer. The disease has the following clinical features.

(1) The incubation period is 2 ~ 10 days, which is more common in immunocompromised patients.

(2) At the initial stage of the disease, there may be fever, general malaise, headache, muscle soreness, etc. 1 ~ 2 days, the body temperature can be as high as 40℃, accompanied by chills and dry cough. The stabbing pain in the chest is aggravated by breathing and coughing, and there may be a small amount of phlegm or blood in the sputum, often accompanied by abdominal pain, diarrhea and vomiting. In severe cases, mental retardation and delirium may occur, which may be accompanied by multiple system organ damage. There may be dry and wet sounds in auscultation of both lungs, but there is no sign of consolidation. The mortality rate is about 15%.

(3)X-ray chest film: There is patchy infiltration shadow on one or both sides, which can be interstitial or consolidation, or develop into nodular consolidation, and a few have pleural effusion.

(4) Blood routine: The white blood cell count increases, and the erythrocyte sedimentation rate increases.

(5) Urine routine: a small amount of protein and red blood cells can be seen.

(6) Serological examination: The titer of double serum increased within 1 week and reached the peak after 3 weeks. The diagnosis can be made if the titer is ≥ 1: 60 or has increased by more than 4 times, or if the titer of a single convalescent serum is ≥ 1: 128.

Treatment: At present, erythromycin is the first choice for Legionella pneumonia. Oral 20 ~ 40 mg/kg? D, 3 ~ 4 times a day. Intravenous medication: 20 ~ 30 mg/kg? D was added to 5% glucose at a concentration ratio of 1mg/ml. In addition, symptomatic treatment is also essential, such as paying attention to water and electrolyte balance, enhancing nutrition and improving immunity. Antibiotic treatment should last for 3 weeks.