  A new harassment model is presented that models the complex, and dynamical
tidal field of a Virgo like galaxy cluster. The model is applied to small,
late-type dwarf disc galaxies (of substantially lower mass than in previous
harassment simulations) as they infall into the cluster from the outskirts.
These dwarf galaxies are only mildly affected by high speed tidal encounters
with little or no observable consequences; typical stellar losses are $<10\%$,
producing very low surface brightness streams ($\mu_B > 31$ mag arcsec$^{-2}$),
and a factor of two drop in dynamical mass-to-light ratio. Final stellar discs
remain disc-like, and dominated by rotation although often with tidally induced
spiral structure. By means of Monte-Carlo simulations, the statistically likely
influences of harassment on infalling dwarf galaxies are determined. The
effects of harassment are found to be highly dependent on the orbit of the
galaxy within the cluster, such that newly accreted dwarf galaxies typically
suffer only mild harassment. Strong tidal encounters, that can morphologically
transform discs into spheroidals, are rare occurring in $<15 \%$ of dwarf
galaxy infalls for typical orbits of sub-structure within $\Lambda$CDM cluster
mass halos. For orbits with small apocentric distances ($<$250 kpc), harassment
is significantly stronger resulting in complete disruption or heavy mass loss
($>90 \%$ dark matter and $> 50 \%$ stellar), however, such orbits are expected
to be highly improbable for newly infalling galaxies due to the deep potential
well of the cluster.
