  We make predictions for the diffuse far-infrared (FIR) emission from dust in
the intracluster medium (ICM) of the Virgo cluster using detailed information
on potential dust sources, grain heating and sputtering rates available for
this cluster from recent optical and X-ray studies. We show that the infrared
emission from dust injected by sources inside the core region of the Virgo
cluster is a factor of 10 below the detection limit of currently available
telescopes. The outer regions of dynamically young clusters like the Virgo
cluster have a further potential source of intracluster grains since they are
still accreting freshly infalling spiral galaxies which are presumably
contained in an accreting intergalactic medium (IGM). We show that cosmic ray
driven winds from the infalling spirals can inject grains into a subvirial IGM
that is external to the observed X-ray-emitting ICM. Sputtering during the
injection process and in the IGM is weak, so that the injected grains should
accumulate in the IGM until the infall brings them into contact with the hot
ICM. This effect dominates the dust injection rate from known sources embedded
in the hot Virgo ICM. Thus, any detection of diffuse IR emission would probe
the current dust accretion rate for the cluster, acting as an indicator of the
youth and the dynamical state of the cluster. The predictions for the Virgo
cluster are generalised to other clusters and the possibility of detection of
dynamically young clusters at cosmological distances is discussed.
