  Recent observations of the environments of gamma-ray bursts (GRBs) favour
massive stars as their progenitors, which are likely to be surrounded by gas
and dust. The visibility of the optical and UV emission of a GRB are expected
to depend on the characteristics of both the dust and the GRB emission itself.
A reasonable distribution of surrounding dust is capable of absorbing all the
optical and UV emission of the optical flash and afterglow of a GRB, unless the
optical flash has a peak isotropic luminosity L_peak > 10^49 erg/s. This means
that dark bursts should exist and these bursts will have to be studied at
infrared rather than optical wavelengths. In this paper details will be given
about the infrared GRB dust emission. The reprocessed dust emission peaks at a
rest-frame wavelength of about 8 micron. Forthcoming space telescopes, in
particular the IRAC camera aboard the Space Infrared Telescope Facility could
detect this emission out to a redshift of about 2. However, an accurate
position of the GRB afterglow must be provided for this emission to be
identified, because the light curve of the reprocessed dust emission does not
vary on time-scales less than several years.
