旅行时感染的风险增加,这可能与接触有段时间未被使用的新水源有关。积水中嗜肺军团菌的浓度较高。[13]Den Boer JW, Nijhof J, Friesema I. Risk factors for sporadic community-acquired Legionnaires' disease. A 3-year national case-control study. Public Health. 2006;120:566-571.http://www.ncbi.nlm.nih.gov/pubmed/16707144?tool=bestpractice.com[14]England AC III, Fraser DW, Plikaytis BD, et al. Sporadic legionellosis in the United States: the first thousand cases. Ann Intern Med. 1981;94:164-170.http://www.ncbi.nlm.nih.gov/pubmed/7469207?tool=bestpractice.com[29]Sopena N, Force L, Pedro-Botet ML, et al. Sporadic and epidemic community legionellosis: two faces of the same illness. Eur Respir J. 2007;29:138-142.http://www.ncbi.nlm.nih.gov/pubmed/17005576?tool=bestpractice.com流感和严重急性呼吸综合征的危险因素。