  Flavor mixing of quantum fields was found to be responsible for the breakdown
of the thermal Unruh effect. Recently, this result was revisited in the context
of nonextensive Tsallis thermostatistics, showing that the emergent vacuum
condensate can still be featured as a thermal-like bath, provided that the
underlying statistics is assumed to obey Tsallis prescription. This was
analyzed explicitly for bosons. Here we extend this study to Dirac fermions and
in particular to neutrinos. Working in the relativistic approximation, we
provide an effective description of the modified Unruh spectrum in terms of the
q-generalized Tsallis statistics, the q-entropic index being dependent on the
mixing parameters sin {\theta} and \Delta m. As opposed to bosons, we find q >
1, which is indicative of the subadditivity regime of Tsallis entropy. An
intuitive understanding of this result is discussed in relation to the
nontrivial entangled structure exhibited by the quantum vacuum for mixed
fields, combined with the Pauli exclusion principle.
