Collins [1; 2] examined human and various animal populations for the prevalence of
Legionella- specific antibodies. They found that in the 286 human sera that they
examined, 99.6% tested negative; suggesting that humans are rarely infected by
Legionella, or that protection wanes and so most of the population are likely to have
little or no pre-existing acquired-immunity against Legionnaires' disease. However Wedege el
al [3] have found raised antibody levels in a population up to one year after an outbreak.
It is very unlikely, therefore, that pre-existing acquired-immunity will affect the observed
probability of infection, the duration of the incubation period, or indeed the dose-dependency
of these two variables. There are, however, other less well quantitatively characterised
factors related to, for example, innate immunity, aging and smoking, that probably are risk
factors for the development of Legionnaires' disease.
Reference List
- COLLINS M. T., CHO S. N. & REIF J. S. (1982) Prevalence of antibodies to Legionella
pneumophila in animal populations Journal of Clinical Microbiology 15, pp. 130 - 136
http
- COLLINS M.T. (1986) Legionella Infections in animals Israel Journal of Medical
Sciences 22, pp.662 - 673 http
- WEDEGE E., BERGDAL T., BOLSTAD K., CAUGANT D. A., EFSKIND C. J., HEIER H. E., KANESTROM A.,
STRAND B. H. & AABERAGE I. S. (2009) Seroepidemiological study after a long-distance
industrial outbreak of Legionnaires' disease Clinical and Vaccine Immunology 16, pp.528
- 534 http
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