Legionellen im hauseigenen Warmwasser - Auswirkungen auf die Gesundheit der Bewohner

Abstract

Only few epidemiological data on legionella diseases are available in Germany and studies on the prevalence of legionella antibody response in the population are scarce. We report on an epidemiological study on immune response in residents of homes with heavy and with minor legionella contamination in their hot-water system. 53 inhabitants of houseblocks with central hot-water system and high legionella contamination (6,049 +/- 17,995 cfu/l; 40% > 1,000 cfu/l) were studied. 92 persons living in 1-2 family houses with decentral hot water systems (244 +/- 1,434 cfu/l; 3% > 1,000 cfu/l) served as controls. All persons filled in a questionnaire on bronchial and fever diseases etc; blood specimen were tested for legionella antibodies (different methods: immunofluorescence, and ELISA), and urine specimens were analysed for legionella antigen. During this investigation in the population exposed to Legionella no cases of legionellosis were reported. The prevalence of legionella antibodies was twice as high in the exposed versus the control persons. Significant correlation between cfu/l and legionella antibody titer in the inhabitants were found. One person with high antibody titer and with legionella-free hot-water system in his home had reported about pulmonary problems after having stayed in a hotel. The positive antibodies of the other persons are most likely the result of asymptomatic infections caused by permanent exposure in their home hot-water supply. In conclusion, with regard to the increased prevalence of antibody titers against legionellae in the exposed inhabitants and the significant correlation between antibody titers and cfu/l in hot-water samples, the necessity to control and redevelop hot-water systems in homes is confirmed--even though no cases of legionelloses in the exposed population were reported.

LegionellaInfection Risk from Domestic Hot Water

“…Legionellae concentrations of 3–7,000 CFU/L could be sufficient to produce one case per year in a susceptible population ( 43 ), and these contamination levels correspond to those found in our study at the domestic level. In a recent epidemiologic survey on seropositivity in residents of homes with and without Legionella in the water systems, the prevalence of anti- Legionella antibodies was twice as high in persons in homes with legionellae as in those persons whose homes did not have legionellae ( 44 ). The antibodies were most likely the result of asymptomatic infections caused by exposure in their home water supply, as no cases of pneumonia in the exposed population were reported.…”

Microbial Growth in Drinking-Water Supplies: Problems, Causes, Control and Research Needs

“…1000 CFU/litre) systems and persons (n = 92) in family houses (3% . 1000 CFU/litre) (Heudorf et al 2001). However, persons living in residences with an elevated number of Legionella in water had significantly higher antibody titres than those in residences with a low number of Legionella.…”

Geographical variation of sporadic Legionnaires' disease analysed in a grid model

“…Some areas or cities report a higher incidence of LD than for the country in general, possibly with residential water systems as a source [4]. Domestic water systems are known to harbour Legionella and to be sources of LD, especially apartment blocks with complex hot-water systems [5].…”