  The radio counterparts to the 15-micron sources in the European Large Area
ISO Survey southern fields are identified in 1.4-GHz maps down to about 80
microJy. The radio-MIR correlation is investigated and derived for the first
time at these flux densities for a sample of this size. Our results show that
radio and MIR luminosities correlate almost as well as radio and FIR, at least
up to z ~ 0.6. Using the derived relation and its spread together with the
observed 15-micron counts, we have estimated the expected contribution of the
15-micron extragalactic populations to the radio source counts and the role of
MIR starburst galaxies in the well known 1.4-GHz source excess observed at
sub-mJy levels. Our analysis demonstrates that IR emitting starburst galaxies
do not contribute significantly to the 1.4-GHz counts for strong sources, but
start to become a significant fraction of the radio source population at flux
densities < 0.5 - 0.8 mJy. They are expected to be responsible for more than
60% of the observed radio counts at < 0.05 mJy. These results are in agreement
with the existing results on optical identifications of faint radio sources.
