dissemination, and excretion of HPAI-H5N1 viruses have been
proposed in different bird species we further tested the hypotheses
that (i) the respiratory tract is the source of HPAI-H5N1 virus
detected in pharyngeal swabs in tufted ducks, as was suggested by
Keawcharoen et al., (2008); (ii) HPAI-H5N1 virus can replicate in
the olfactory mucosa, like in ferrets (Bodewes et al., 2011;
Schrauwen et al., 2012), and (iii) HPAI-H5N1 virus does not
replicate in the intestinal epithelium even though viral antigen can
be detected in cloacal swabs