To combat animal diseases, we propose that Xenopsylla cunicularis Smit (Siphonaptera: Pulicidae), a specific flea of the European wild rabbit Oryctolagus cuniculus L. (Lagomorpha), can be used to carry a vaccine into wild rabbit populations to protect them against lethal diseases. Oryctolagus cuniculus is widespread throughout Europe, but X. cunicularis occurs naturally only in drier areas of Morocco, Spain, and southwestern France, raising questions about the flea's general use and the subsequent risk of uncontrolled proliferation outside its natural distribution. To evaluate this risk, fleas were released in five experimental enclosures containing rabbits (four in northern France and one in southwestern France as a control). Approximately one year later, adult and immature fleas were recovered from rabbits and warrens. The climate during the experiments was recorded and warren substrate granulometry was defined. Our results showed that northern France is not suitable for persistence of X. cunicularis because low temperatures reduce flea development and high rainfall all over the year keeps the soil damp, which is asphyxic for fleas, even on a sandy substrate. These implantation trials suggest that uncontrolled proliferation and permanent establishment of fleas are unlikely in northern France.