Francisella philomiragia is an aerobic, gram-negative cocobacillus. It is widespread in nature; in water, air, earth, dust, and mud and has been detected in most parts of the world. Problem can be contaminated rural waters because F. philomiragia can result in occasional infections in at-risk groups. In addition, F. philomiragia can cause serious consequences for aquaculture and fishing because it causes francisellosis in certain fish species. In this study, the growth kinetics of F. philomiragia and A. castellanii in the spring water "Vela Fontana" were monitored within a period of 40 days. The results showed that F. philomiragia survives longer in coculture with the amoeba A. castellanii. Furthermore, F. philomiragia does not replicate within the amoeba, but may oppose the amoeba-containing environment due to a possible endosymbiotic relationship. The interaction between F. philomiragia and A. castallanii indicates that amoebae are important environmental reservoirs for Francisella species, but they can also stimulate the survival of other human pathogens. As such, they can be reservoirs of tularemia and other infectious diseases through spring and surface waters. For the prevention of F. philomiragia, it is essential to understand how it survives, grows and replicates in aquatic ecosystems, and this knowledge can contribute to a better understanding of the epidemiology and microbiological ecology of the entire genus Francisella.