Testings for Legionellosis in the Taiwan Area － A Preliminary Report －
1996 Vol.12 NO.8
In the summer of 1976 at the 200th Anniversary gathering of US veterans in Philadelphia, 221 participants were infected with acute pneumonia, and 34 of them died as a consequence (1). This incident shocked not only citizens of the entire country, but was also of great concern to the medical world. In 1977 Dr. McDade, of the US Centers for Disease Control and Prevention (CDC), identified the pathogen from pulmonary specimens, naming it Legionella pneumophila. But there had been at least four outbreaks even before 1976. As early as 1947, a rickettsia-lilce medium was isolated from infected guinea pigs. In 1965, the first outbreak had occurred in Washington, DC, with 81 patients and 15 deaths reported. Then, in 1974, another outbreak occurred in a hotel (2). Around 1,000 to 1,300 cases are reported to the CDC each year. In fact, many cases are not diagnosed and, therefore, the incidence of Legionellosis may well be much higher than the number of cases actually reported (3). Anyone is susceptible to the infection, although there have been very few patients under 20 years of age. Several outbreaks have occurred among hospitalized patients. In Taiwan, there have been cases of medical care personnel (including dentists and pathology technicians) infected with Legionellosis who have then required long-term hemodialysis as a result of renal failure(4). Even deaths had been reported in Taiwan as late as 1995 (IFA titer as high as 1:2048), when the matter attracted the attention of health and medical circles. Though many infections are not diagnosed, studies show that at least half of the Legionella infections are related to pneumonia. The older the patient (and many are older than 50 years), the more serious the condition. Smokers, diabetes patients, patients with chronic pulmonary diseases, kidney diseases or malignant neoplasms, patients with impaired immune functions and particularly patients on corticosteroid treatment or with organ transplants are more prone to Legionella infections. The male-female sex ratio is about 2.5:1, and the mortality rate is about 5-30%.