Francisella tularensis is a Gram-negative, intracellular bacterium causing the zoonosis tularemia. This highly infectious microorganism is considered a potential biological threat agent. Humans are usually infected through direct contact with the animal reservoir and tick bites. However, tularemia cases also occur after contact with a contaminated hydro-telluric environment. Water-borne tularemia outbreaks and sporadic cases have occurred worldwide in the last decades, with specific clinical and epidemiological traits. These infections represent a major public health and military challenge. Human contaminations have occurred through consumption or use of F. tularensis-contaminated water, and various aquatic activities such as swimming, canyoning and fishing. In addition, in Sweden and Finland, mosquitoes are primary vectors of tularemia due to infection of mosquito larvae in contaminated aquatic environments. The mechanisms of F. tularensis survival in water may include the formation of biofilms, interactions with free-living amoebae, and the transition to a 'viable but nonculturable' state, but the relative contribution of these possible mechanisms remains unknown. Many new aquatic species of Francisella have been characterized in recent years. F. tularensis likely shares with these species an ability of long-term survival in the aquatic environment, which has to be considered in terms of tularemia surveillance and control.

中文翻译：

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兔热病作为一种水传播疾病：综述。

土拉弗朗西斯菌是一种革兰氏阴性细胞内细菌，引起人畜共患土拉热病。这种高度传染性的微生物被认为是潜在的生物威胁因子。人类通常通过直接接触动物宿主和蜱虫叮咬而被感染。然而，兔热病病例也发生在接触受污染的大地水环境后。过去几十年来，水源性兔热病暴发和散发病例在世界范围内发生，具有特定的临床和流行病学特征。这些感染是重大的公共卫生和军事挑战。人类污染是通过饮用或使用受土拉菌污染的水以及游泳、溪降和钓鱼等各种水生活动而发生的。此外，在瑞典和芬兰，由于受污染的水生环境中蚊子幼虫的感染，蚊子是兔热病的主要媒介。F. tularensis 在水中的生存机制可能包括生物膜的形成、与自由生活的变形虫的相互作用以及向“可生存但不可培养”状态的转变，但这些可能机制的相对贡献仍然未知。近年来，许多新的弗朗西斯氏菌水生物种已被鉴定。土拉菌可能与这些物种一样具有在水生环境中长期生存的能力，在土拉菌病监测和控制方面必须考虑这一点。